LS1 Engine for aircraft?

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Brian Clayton

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Dec 7, 2012
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Ivey, Ga and Centerville,Tn
I have yet to see someone say what exactly is the reliability problem with auto engines. PRSU aside.... Who has the pile of broken cranks, rods, blocks? I am sure Ross would agree, the hard parts in aircraft engines and auto engines are made the same, and the stock internals on either are nowhere as nice as aftermarket race parts. People keep bringing up the reliability issue.... what is it? What breaks that doesn't break in a "aircraft" engine?
 

rv6ejguy

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Jun 26, 2012
Messages
3,749
Location
Calgary, Alberta, Canada
I have yet to see someone say what exactly is the reliability problem with auto engines. PRSU aside.... Who has the pile of broken cranks, rods, blocks? I am sure Ross would agree, the hard parts in aircraft engines and auto engines are made the same, and the stock internals on either are nowhere as nice as aftermarket race parts. People keep bringing up the reliability issue.... what is it? What breaks that doesn't break in a "aircraft" engine?
Couldn't have said it better. People against auto conversions usually have a "feeling" that auto engines won't run at WOT 3000-4500 rpm for a long time but in 10 years on forums, nobody has ever shown me a lot a broken parts to back up their feelings. In fact, as I've said so often, the OEMs test every new design far in excess of what the FAA requires for certified engines. Typical modern day endurance testing involves between 200 and 1200 hours at WOT, torque peak to power peak rpm on a single example and they would run dozens of examples similarly to validate the design prior to production release.

Does anyone here really think running an LSX at 2500-2800 rpm WOT is going to break it or wear it out prematurely? GM did a test way back on the LS1- 420 hours I believe at FULL rated power. Everything within limits upon disassembly.
 

Brian Clayton

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Joined
Dec 7, 2012
Messages
1,042
Location
Ivey, Ga and Centerville,Tn
Look at generators and big water pumps driven with automotive engines and small engines (briggs type). Hours and hours and hours at full load. Some are even made to change the oil without shutting the engine down. Want a direct drive? Fine, turn it upside down and put a dry sump pump on it. Thrust bearing issues? Pick a bearing and some basic machine work and there you go. Looks to me like dedicated aircraft engines in aircraft enviroments fail more often than automotive engines in automotive enviroments (mechanical failure from stress not abuse). When is the last time you saw a cylinder and head come flying off of a v style or inline automotive engine? Or saw a cracked flywheel flange? If LS engines has the same failure rate as a Rotax, people would walk instead of drive. Yes, I understand the stresses of a WOT engine are different than the subdued driving habits of people, but I don't believe it is that much different. I would hazard a guess to say that the constant up and down revs of a engine coupled to a transmission are far greater stresses than WOT stresses of a prop at a fairly constant rpm. Ross has been flying his "car engine" for how long? How many hours? And no offense intended, but it probably was not worth a crap as a car engine.
 
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ekimneirbo

Guest
Look at generators and big water pumps driven with automotive engines and small engines (briggs type). Hours and hours and hours at full load. Some are even made to change the oil without shutting the engine down. Want a direct drive? Fine, turn it upside down and put a dry sump pump on it. Thrust bearing issues? Pick a bearing and some basic machine work and there you go. Looks to me like dedicated aircraft engines in aircraft enviroments fail more often than automotive engines in automotive enviroments (mechanical failure from stress not abuse). When is the last time you saw a cylinder and head come flying off of a v style or inline automotive engine? Or saw a cracked flywheel flange? If LS engines has the same failure rate as a Rotax, people would walk instead of drive. Yes, I understand the stresses of a WOT engine are different than the subdued driving habits of people, but I don't believe it is that much different. I would hazard a guess to say that the constant up and down revs of a engine coupled to a transmission are far greater stresses than WOT stresses of a prop at a fairly constant rpm. Ross has been flying his "car engine" for how long? How many hours? And no offense intended, but it probably was not worth a crap as a car engine.



RV6 Guy Quote "Couldn't have said it better. People against auto conversions usually have a "feeling" that auto engines won't run at WOT 3000-4500 rpm for a long time but in 10 years on forums, nobody has ever shown me a lot a broken parts to back up their feelings. In fact, as I've said so often, the OEMs test every new design far in excess of what the FAA requires for certified engines. Typical modern day endurance testing involves between 200 and 1200 hours at WOT, torque peak to power peak rpm on a single example and they would run dozens of examples similarly to validate the design prior to production release.

Does anyone here really think running an LSX at 2500-2800 rpm WOT is going to break it or wear it out prematurely? GM did a test way back on the LS1- 420 hours I believe at FULL rated power. Everything within limits upon disassembly.

I added the quote from RV6Guy into this reply because I agree with both him and Brian. The thing about WOT is that its a subjective term. On certified Lyc/Cons 2700 rpm is often referred to as WOT.........but it really isn't. These engines are capable of spinning at higher rpms, its just that the propellors they are turning limit the rpm because of tip speed. I'm sure I'm not telling Brian/RV6 anything they don't already know, but others seem to refer to the reccommended rpm of the propellor as being the maximum WOT of the engine. Its incorrect to say that these engines won't turn higher rpms and do so for an extended period of time. There are several different certified engines that do turn higher rpms and utilize a reduction gear.
Any engine can have its maximum WOT established by the engine manufacturer and then modified by an individual. GM makes some big block engines to work in pumping situations that have cams designed for low rpm only useage. Take this engine apart and put a different cam in it and the required valves and valve springs and you can change its operating rpm range. So any engine can be purpose built to operate in a given range. The sweet thing about most automotive engines is that they have been engineered to thrive in spite of poor treatment and maintainance and still run at higher rpms than a certified engine can even dream of. The massive pistons and power pulses won't allow the GA airplane engines to run that fast, but they will run faster than 2700 rpms.
On another thread in the general automotive section, the venerable Ron Watanaja mentioned that basic engine to basic engine, the reliability of automotive engines exceeds aircraft engines. (I don't want to put words in his mouth, so you should read the thread and see if you agree with my understanding of what he said) The problem usually arises in the method of adapting the auto engine to the propellor.
 

Toobuilder

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Agree with the general gist of the above thread, but to make a small correction: WOT means "wide open throttle" - a reference to the angle of throttle blade opening or manifold pressure. This is unrelated to "redline" which is most often a reference to RPM. Many aircraft engines are at "WOT" from the beginning of the takeoff roll, through the flight and until the descent phase- often with substantially less than redline RPM for most of that time.

One can just as easily be at "WOT" at redline or some substantially less RPM. Additionally, you can also be at WOT and still well under 100% power.
 

Brian Clayton

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My idea of WOT and probably Russ too, is 100 percent open throttle with the engine loaded as hard as it will pull at a given rpm. 100% power would be subjective to the peak power of the engine. I am sure that if you re-cam a 0-200 and spin it up to wherever the heads quit, it would make quite a bit more than 100 hp, thus moving 100% power to a different rpm versus whatever they are stock. If you change a LS1 to run at say 2500, and load it 100 percent there, then the stresses would be less than higher rpms. Then you could start hacking down the parts to lose weight (like aircraft engines) because the stresses are less. I can say one thing from my experience with race engines, high rpm kills much, much faster than high horsepower or high loadings. I don't see why a LS1 engine could not be lightened up a good bit, because of lower stress. Heck, race cranks can be made down 30 lbs or so lighter than stock cranks....made for engines that make 2-3 times stock power at 2000-3000 more rpm than stock redline.
 

rv6ejguy

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I use the term WOT a lot because so many lay people think that since auto engines spend most of their lives at part throttle cruise that they will wear out or blow up if you run long periods of full throttle. If at WOT, then hp developed just depends on rpm and altitude/ MAP. In geared auto conversions we normally only rev to about 2/3rds to 3/4 of peak power or redline rpm as the case may be so in stock form we have derated them to about 65-75% power and the mechanical stress levels are far below any critical levels. Many good auto engine designs can produce 4-5 times the stock hp output when turbocharged using the stock crank, rods, block, head etc. (I've done it) That is how big some of the design margins are. You can't say that about any certified engine designs to my knowledge.

We do need to manage piston and valve temperatures for longevity. You can either run rich as the OEMs do at high power levels or replace the stock parts with forged and stainless parts respectively. Many modern designs already have under piston oil jets to cool them and excellent valve and seat materials. These engines don't need any changes for aviation use in most cases.

I agree with Brian about rpm, it is the main killer of longevity. This is why I had such great success with small turbocharged road racing engines vs. larger displacement atmo competitors. We only had to rev to 6500-7000 rpm to beat them with 1/2 to 2/3rds of the displacement while they had to flog their engines at 8500 to try to keep up. They often broke valvetrain stuff and rods/ cranks. My stuff never broke.
 
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ekimneirbo

Guest
Agree with the general gist of the above thread, but to make a small correction: WOT means "wide open throttle" - a reference to the angle of throttle blade opening or manifold pressure. This is unrelated to "redline" which is most often a reference to RPM. Many aircraft engines are at "WOT" from the beginning of the takeoff roll, through the flight and until the descent phase- often with substantially less than redline RPM for most of that time.

One can just as easily be at "WOT" at redline or some substantially less RPM. Additionally, you can also be at WOT and still well under 100% power.
I overlooked that point in my comments and you are correct that WOT is when the throttle blade is parallel to the intake tract opening. I don't think most certified engines are exactly at WOT when they hit the redline on the tach. I think there is still some room for movement which will take the engines above the 2700 rpm point, but I may be wrong about that. I would think that it would be hard to get all engines of a same type to run at exactly 2700 rpms when the throttle plate is WOT. To me it would seem that there has to be some leeway in the combination of parts used to attain a given rpm setting. Not all jets or intake tracts or carbs are going to function exactly the same.......so 2700 rpms may occur at less than WOT due to jetting, intake variations, filters, and even the density of the atmosphere.
 

rv6ejguy

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I overlooked that point in my comments and you are correct that WOT is when the throttle blade is parallel to the intake tract opening. I don't think most certified engines are exactly at WOT when they hit the redline on the tach. I think there is still some room for movement which will take the engines above the 2700 rpm point, but I may be wrong about that. I would think that it would be hard to get all engines of a same type to run at exactly 2700 rpms when the throttle plate is WOT. To me it would seem that there has to be some leeway in the combination of parts used to attain a given rpm setting. Not all jets or intake tracts or carbs are going to function exactly the same.......so 2700 rpms may occur at less than WOT due to jetting, intake variations, filters, and even the density of the atmosphere.
We often fly at WOT for lower pumping losses at high altitudes. 8000 to 8500 feet gives about 75% power. Depends on prop rpm. With a CS prop, you have more choices in power settings via set rpm.
 

ekimneirbo

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Some reference info for LS engines

Gen III & Gen IV Small Blocks
Part NumberDescriptionLitersCIDHPTQBoreStroke
19165628LS327/3275.33273273473.780"3.622"
17801267LS15.73463503653.898"3.622"
17801268LS65.73464053953.898"3.622"
19156262LQ96.03643453804.000"3.622"
*19165484LS26.03644004004.000"3.622"
*17802134LS364/4406.03644404044.000"3.622"
12611022L996.23764304244.0653.622"
19171224LS376/4856.23764854754.065"3.622"
19171225LS376/5156.23765154694.065"3.622"
19201992LS36.23764304244.065"3.622"
19211978LSA6.23765565514.065"3.622"
19201990LS96.23766386044.065"3.622"
19171821CT5256.23765254714.065"3.622"
19165058LS77.04275054704.125"4.000"
* Discontinued
LS Compatibility - Heads vs. Intakes
IntakesHeads
EnginePart #ManifoldPort Type12559855 LS112564824 LS6/LS212562319 LQ988958665 CNC LS688958622 CNC LS612582713 L76/L9212615879 LS388958698 CNC L92
LS1/LS688894339EFICathedralYesYesYesYesYesNoNoNo
LS2/LQ4889586754-bblCathedralYesYesYesYesYesNoNoNo
LQ4/LQ9N/AEFICathedralYesYesYesYesYesNoNoNo
L7612590123EFIL92NoNoNoNoNoYesYesYes
LS312610434EFIL92NoNoNoNoNoYesYesYes
L76/L92/LS3255344164-bbl w/injL92NoNoNoNoNoYesYesYes
L76/L92/LS3255344014-bblL92NoNoNoNoNoYesYesYes
L92/LS319166952LSX 4bblL92NoNoNoNoNoYesYesYes
L92/LS319172322LSX 4bblL92NoNoNoNoNoYesYesYes
LS7 '05-'0812568976EFILS7NoNoNoNoNoNoNoNo
LS7 '0912610435EFILS7NoNoNoNoNoNoNoNo
LS7255344134-bbl w/injLS7NoNoNoNoNoNoNoNo
LS7255343944-bblLS7NoNoNoNoNoNoNoNo
LSX 45419166948LSX 4bblLS7NoNoNoNoNoNoNoNo
19166950LSX 4bblLSX-CTNoNoNoNoNoNoNoNo
19166954LSX 4bblLSX-DRNoNoNoNoNoNoNoNo
No=not compatableYes=direct compatability
IntakesHeads
EnginePart #ManifoldPort Type19201807 LSX-L9219201805 LSX-LS319213963 LSX-LS912578450 CNC LS719201806 LSX-LS719166981 LSX-CT19166979 LSX-DR12480090 C5R
LS1/LS688894339EFICathedralNoNoNoNoNoNoNoNo
LS2/LQ4889586754-bblCathedralNoNoNoNoNoNoNoNo
LQ4/LQ9N/AEFICathedralYesYesYesNoNoNoNoNo
L7612590123EFIL92YesYesYesNoNoNoNoNo
LS312610434EFIL92YesYesYesNoNoNoNoNo
L76/L92/LS3255344164-bbl w/injL92YesYesYesNoNoNoNoNo
L76/L92/LS3255344014-bblL92YesYesYesNoNoNoNoNo
L92/LS319166952LSX 4bblL92YesYesYesNoNoNoNoNo
L92/LS319172322LSX 4bblL92YesYesYesNoNoNoNoNo
LS7 '05-'0812568976EFILS7NoNoNoYesYesNoNoNo
LS7 '0912610435EFILS7NoNoNoYesYesNoNoNo
LS7255344134-bbl w/injLS7NoNoNoYesYesNoNoNo
LS7255343944-bblLS7NoNoNoYesYesNoNoNo
LSX 45419166948LSX 4bblLS7NoNoNoYesYesNoNoNo
19166950LSX 4bblLSX-CTNoNoNoNoNoYesYesNo
19166954LSX 4bblLSX-DRNoNoNoNoNoYesYesNo
No=not compatableYes=direct compatability
LS Compatability - Heads vs. Blocks
BlocksHeads
EnginePart #Bore Size12559855 LS112564824 LS6/LS212562319 LQ988958665 CNC LS688958622 CNC LS612582713 L76/L9212598594 LS388958698 CNC L92
LS1/LS6125611663.89"YesYesYesYesYesNoNoNo
LQ4/LQ9125728084.00"YesYesYesYesYesYesYesYes
LS2/L76125689504.00"YesYesYesYesYesYesYesYes
L92/LS3125847274.06"YesYesYesYesYesYesYesYes
LSA/LS9 4.06"YesYesYesYesYesYesYesYes
LS7178028544.125"YesYesYesYesYesYesYesYes
LS7*255344274.125"YesYesYesYesYesYesYesYes
C5R124800304.12"-4.16"YesYesYesYesYesYesYesYes
LSX S/B192139643.89"YesYesYesYesYes***
LSX191664543.99"-4.25"********
LSX TD191660973.99"-4.25"********
No=not compatableYes=direct compatability*=4.00 min Bore**=4.125" min Bore***=4.100" min Bore
BlocksHeads
EnginePart #Bore Size19201807 LSX-L9219201805 LSX-LS319213963 LSX-LS912578450 CNC LS719201806 LSX-LS719166981 LSX-CT19166979 LSX-DR12480090 C5R
LS1/LS6125611663.89"YesNoNoNoNoNoNoNo
LQ4/LQ9125728084.00"YesYesYesNoNoNoNoNo
LS2/L76125689504.00"YesYesYesNoNoNoNoNo
L92/LS3125847274.06"YesYesYesNoNoNoNoNo
LSA/LS9 4.06"YesYesYesNoNoNoNoNo
LS7178028544.125"YesYesYesYesYesYesYesYes
LS7*255344274.125"YesYesYesYesYesYesYesYes
C5R124800304.12"-4.16"YesYesYesYesYesYesYesYes
LSX S/B192139643.89"*****************
LSX191664543.99"-4.25"*****************
LSX TD191660973.99"-4.25"*****************
No=not compatableYes=direct compatability*=4.00 min Bore**=4.125" min Bore***=4.100" min Bore
LS Series Blocks
OriginPart #MaterialDeck HeightBoreMain BoltCap MaterialCrank Jrnl DiaOilingRr Main SealMax StrokeMax HPUsage
LS1/LS612561166Alum9.2403.89"6IronStd LS 2.56Wet1 Pc4.00"450Street
LS212568950Alum9.2404.00"6IronStd LS 2.56Wet1 Pc4.00"450Street
L92/LS312584727Alum9.2404.065"6IronStd LS 2.56Wet1 Pc4.00"525Street
LS717802854Alum9.2404.125"6PMStd LS 2.56Dry1 Pc4.10"550Street
LS725534427Alum9.2404.125"6PMStd LS 2.56Dry1 Pc4.10"550Street
C5R12480030Alum9.2404.117"-4.160"68620 SteelStd LS 2.56Wet1 Pc4.10"900Pro
LQ912572808Iron9.2404.00"6IronStd LS 2.56Wet1 Pc4.00"500Street
LSX19166454Iron9.2603.99"-4.250"61045 SteelStd LS 2.56Wet1 Pc4.25"1500+Street/Pro
LSX19166097Iron9.7003.99"-4.250"61045 SteelStd LS 2.56Wet1 Pc4.50"1500+Street/Pro
LS Series Heads
Part #OriginMaterialPort SizeValve AngleChamber CC'sInt ValvesExh ValvesPort TypeRocker StudNotes
12564825Bare LS2 & LS6Alum21015 degree64.52.001.55CathedralBoltBare LS2/LS6
12564824Stock LS6Alum21015 degree64.52.001.55CathedralBoltHollow/Sodium filled Valves
12576063Stock LS2Alum21015 degree64.52.001.55CathedralBoltSolid stem valves
88958622CNC LS6Alum25015 degree61.92.001.55CathedralBolt11.2 compression
88958665CNC LS6Alum25015 degree652.001.55CathedralBolt10.5 compression
88958765CNC LS2Alum25015 degree64.52.001.55CathedralBoltSolid stem valves
12582714Bare L76/L92Alum26015 degree702.161.59L92BoltSolid stem valves
12582713Stock L76/L92Alum26015 degree702.161.59L92BoltSolid stem valves
88958698CNC L76/L92Alum27915 degree682.161.59L92BoltSolid stem valves
12598594Stock LS3Alum26015 degree702.161.59L92BoltHollow/Sodium filled Valves
12578450Bare LS7Alum27012 degree702.201.61LS7BoltBare LS7
12578449Stock LS7Alum27012 degree702.201.61LS7BoltTitanium/sodium filled valves
25534428As-cast LS7Alum-12 degree662.201.61LS7BoltTitanium/sodium filled valves
12480005 *C5R 1st designAlum21011 degree382.181.63C5RShaftAs cast-no seats, guides *
12480090C5R 2nd designAlum21011 degree302.181.63C5RShaftAs cast-no seats, guides
19201807LSX-L92 Small BoreAlum26015 degree702.001.55L92BoltHollow/Sodium filled Valves
19201805LSX-LS3Alum26015 degree702.161.59L92BoltHollow/Sodium filled Valves
19201806`LSX-LS7Alum27012 degree702.201.61LS7BoltHollow/Sodium filled Valves
19166981LSX-CTAlum30211 degree452.201.61LSX-CT/DRShaftCNC machined bare head
19166979LSX-DRAlum31311 degree502.25-2.281.6-1.65LSX-CT/DRShaftCNC machined bare head
*Discontinued

LS Series Head Gaskets & Bolts
Part #EngineThicknessMax BoreDescription
12498544LS1 2002-2004.047"3.92Standard LS Bolt Pattern
12589226LS1 & LS6.051"3.92"Standard LS Bolt Pattern
12589227LS2.051"4.02"Standard LS Bolt Pattern
12610046LS3 & L92.051"4.080"Standard LS Bolt Pattern
12582179LS7.051"4.140"Standard LS Bolt Pattern
19170418LSX.051"4.100"Standard LS & 6-Bolt Pattern Blocks & Heads
19170419LSX.051"4.200"Standard LS & 6-Bolt Pattern Blocks & Heads
19170420LSX.051"4.250"Standard LS & 6-Bolt Pattern Blocks & Heads
178005681/2004 & up LS EnginesIncludes 15 bolts5mm shorter than 1st Design
1249854597-1/04 LS EnginesIncludes 15 bolts

LS Series Camshafts
Part #DescriptionDuration @ .050" liftMax Lift (In) (1.7 rocker)Lobe SeperationTechnical Notes
125653082002-2004 LS6 CamI:204 E:218I:550 E:550117.5Cam requires valve spring P/N 12586484
125609502001 LS6 CamI:207 E:217I:525 E:525116Cam requires valve spring P/N 12586484
12480110ASA CamI:226 E:236I:525 E:525110Cam requires valve spring P/N 12586484 "ASA" cam for off-highway use
12480033Hot Cam KitI:219 E:228I:525 E:525112Kit includes 16 LS6 Valve Springs P/N 12565117 and retainers
88958733LS Hot CamI:219 E:228I:525 E:525112Cam only for Hot Cam Kit 12480033
19166972LSX-454 CamI:236 E:246I:600 E:600110Max lift with 1.8 rockers .635/.635
88958606Showroom Stock camI:239 E:251I:570 E:570106.5Showroom Stock racing design, requires hollow intake valves #12565311, hollow exhaust valves #12565312, valve springs #12586484, and aftermarket notched pistons or machined stock pistons
12571251LS7I:211 E:230(1.8 Rocker) I:591 E:591121Stock LS7 camshaft
12561721LS1 2001-2004 LQ9 2002-2006I:196 E:201I:467 E:479116Stock cam for 2002-2006 LQ9 and 2001-2004 LS1
88958722LS Stage 2 CamI:227 E:239(1.7 Rocker) I:551 E:551108Max lift with 1.8 rockers .583/.583
88958723LS Stage 3 CamI:233 E:276(1.7 Rocker) I:595 E:595107Max lift with 1.8 rockers .630/.630

LS Series Pistons
Part #Engine SizeBore SizeOversizeRod LengthPin TypeComp RatioWith ChamberDescription
889842455.7L3.898"-6.098"Pressed-65.00Hypereutectic LS1 & LS6 replacement
889842465.7L3.898"+.010"6.098"Pressed-65.00Hypereutectic LS1 & LS6 replacement
890174786.0L4.000"-6.098"Floated10.9065.00Hypereutectic LS2 & LQ9 replacement
890174796.0L4.000"+.020"6.098"Floated10.9065.00Hypereutectic LS2 & LQ9 replacement
126026247.0L4.125'-6.067"Floated11.0070.00Hypereutectic LS7 replacement includes Titanium Rod
890181717.0L4.125"+.020"6.067"Floated11.0070.00Hypereutectic LS7 replacement
19166957LSX3764.065" 6.098" Flat-4032 Forged Aluminum -Piston comes w/ rings
19166958LSX4544.185" LSX rod0.866Dished-4032 Forged Aluminum -

LS Rings
Part #Bore SizeOversizeRing ThicknessDescription
124992343.898"-1.5, 1.5, 2.5mmSet of 8 ring packs, standard size for LS1 & LS6
124992364.000"-1.5, 1.5, 2.5mmSet of 8 ring packs, standard size for 1999-2005 LQ4 & LQ9
124992353.780"-1.5, 1.5, 2.5mmSet of 8 ring packs, standard size for 1999-2005 5.3L
890174844.000"-1.5, 1.5, 2.5mmProduction ring pack for 2005-2006 LS2 & 2006 L76
888942434.000"-1.5, 1.5, 2.5mmProduction ring pack for 2005-2006 LQ9
890177764.125"-1.2, 1.2, 2.0mmProduction ring pack for 2006 LS7
890177774.125"+.020"1.2, 1.2, 2.0mmOversize LS7 ring pack

LS Series Push Rods
Part #EngineMaterialDiameterLengthDescription
12593344LS1, LS2, LS3, LS6 & L921010 Steel5/16"7.325"Production pushrod
12593344LS71010 Steel3/8"7.750"Production pushrod

LS Series Valves
Part #EnginePositionValve SizeStem Dia
12565311LS6Intake2.00"8mmHollow Stem
12563063LS2Intake2.00"8mmSolid Stem
12590773L76 & L92Intake2.165"8mmSolid Stem
12605223LSAIntake2.165"8mmSolid Stem
12569427LS3Intake2.165"8mmHollow Stem
12605524LS9Intake2.165"8mmTitanium
12591644LS7Intake2.20"8mmTitanium
12565312LS6Exhaust1.50"8mmSodium Filled
12563064LS2Exhaust1.50"8mmSolid Stem
12582719L76, L92 & LS3Exhaust1.59"8mmSolid Stem
12605525LS9Exhaust1.59"8mmSodium Filled
12578455LS7Exhaust1.61"8mmSodium Filled
17801930LS2 & LS6(4)Intake & (4)ExhaustI -2.00" E-1.50"8mmLS6 Hollow & Sodium Valves

LS Series Valve Springs
Part #EngineStyleInstalled HeightOpen PressureMax LiftDescription
12586484Standard LS2, LS6 & LS6Beehive Style1.800" Installed @ 90# pressure1.250" @ 295 # pressure.570"Individual
12499224Standard LS2, LS6 & LS6Beehive Style1.800" Installed @ 90# pressure1.250" @ 295 # pressure.570"Set of 16 P/N 12586484
12589774Standard L76/L92 SpringsBeehive Style1.800" Installed @ 90# pressure1.300" @ 264# pressure.530"
12578457LS7Beehive Style1.960" Installed @ 101# pressure1.368" @ 310# pressure.600"

LS Timing Components
Part #EnginePartOil Pump SystemDescription
12588670LS2Timing Chain DampnerStandardWill not Fil LS1 & LS6 fitted with P/N 88958607
12581276LS7Timing Chain DampnerLS7 2-stage1.1mm thinner than 12588670
12576407LS1, LS2 & LS61X Camshaft Gear-3-bolt design; uses (3) bolts P/N 12556127
12586481LS1, LS2 & LS64X Camshaft Gear-3-bolt design; uses (3) bolts P/N 12556127
12585994L92 - Combination Cam gear and VVT activator4X Camshaft Gear-1-bolt design; use P/N 12588151
12556582All Non LS7Crankshaft GearStandardWorks with 12576407 and 12586481 cam sprockets
12581278LS7Crankshaft GearLS7 2-stageWorks with 12576407 and 12586481 cam sprockets
12586482All LSTiming Chain -Fits all LS 1997-2008
12585997L92 & LS3Timing Chain Tensioner-Includes retainer and bolts
12556127LS1,LS2,LS6 & LS7Camshaft Gear bolts-For use with 3-bolt (non V.V.T.) cams
12588151L92Camshaft Gear bolts-Combination bolt and valve for variable valve timing - use with 12585994 Camshaft Gear

LS Crankshafts
Part #ApplicationMaterialReluctor WheelStrokeDescription
8901752297-04 LS1/LS6 & 2005 LS2Nodular Cast24X3.622"Balanced for 3.898" bore engines
125886122006 and up LS2Nodular Cast58X3.622"Balanced for 4.00" bore engines
12568820LS7Forged Steel58X4.00"Rebalancing required if LS7 rods and pistons are not used. 2-stage Oil pump
19171619LSForged Steel58X4.00"Rebalancing required if LS7 rods and pistons are not used. Standard wet sump Oil pump
125593531997-2005-24X-1997-2005 Reluctor Wheel
125867682006 and up -58X-2006 and newer Reluctor Wheel
89060436All LSRear Main Seal--Rear Main Seal for all LS engines
LSX Crankshafts
Part #NoteMaterialReluctor WheelStrokeDescription
191703888-bolt flywheel or flexplate required4340 premium steel58X3.622"Reguires Balancing
191703898-bolt flywheel or flexplate required4340 premium steel58X3.750"Reguires Balancing
191703908-bolt flywheel or flexplate required4340 premium steel58X4.00"Reguires Balancing
191703918-bolt flywheel or flexplate required4340 premium steel58X4.125"Reguires Balancing

LS Connecting Rods
Part #ApplicationMaterialPiston FitLengthDescription
125687341997-2004 LS1 & LS6PMPress6.098"Sold Individually
126175702005-2008 LS2 & LS3PMFloat - Bronze Bushing6.098"Sold Individually
12586258LS7TitaniumFloat - Bronze Bushing6.067"Sold Individually
19166964LSX I-beam4340 Forged SteelFloat - Bronze Bushing6.000"Set of 8, weight matched - NOT compatible with production pistons-for use with LSX Pistons INCLUDES 7/16" 12-point SAE 8740 rod bolts
19166965LSX I-beam4340 Forged SteelFloat - Bronze Bushing6.100"Set of 8, weight matched - NOT compatible with production pistons-for use with LSX Pistons INCLUDES 7/16" 12-point SAE 8740 rod bolts
19166966LSX I-beam4340 Forged SteelFloat - Bronze Bushing6.125"Set of 8, weight matched - NOT compatible with production pistons-for use with LSX Pistons INCLUDES 7/16" 12-point SAE 8740 rod bolts
19166967LSX I-beam4340 Forged SteelFloat - Bronze Bushing6.150"Set of 8, weight matched - NOT compatible with production pistons-for use with LSX Pistons INCLUDES 7/16" 12-point SAE 8740 rod bolts
19166968LSX I-beam4340 Forged SteelFloat - Bronze Bushing6.200"Set of 8, weight matched - NOT compatible with production pistons-for use with LSX Pistons INCLUDES 7/16" 12-point SAE 8740 rod bolts
11600158 Rod BoltLS6---Recommended in Gen III performance engines-Bolts have greater strength than pre-2000 rod bolts- 1 per package
11609825 Rod boltLS7---Required for LS7 builds-bolts are stretch to yield and can not be reused - 1 bolt per package
89017573 Rod BearingAll except LS7/LS9---Connecting Rod Bearing - (1) per rod required
89017811 Rod BearingLS7/LS9---Connecting Rod Bearing - (1) per rod required

 

HoneyMoneyToo

Member
Joined
Jan 19, 2016
Messages
5
Location
Georgia, USA
Fist post and joined just to comment on this. I know this is an older thread but ... When my dad died in 01 I got his brand new off the lot 5.3 vortec 327ish cubic inch (LS based) reg cab silverado 2wd. I was 14 at the time and my mother drove me everywhere in it until I was 15 -16. I am from a small town with LOTS of dirt roads so I Pounded and Pounded on that engine. I raced people, I did donuts, all kinda stuff a teenager would do :). I even ended up putting a 125hp shot of NOS on it for when I went to the drag strip. That motor NEVER let me down. My water pump went out once and a fuel pump but other than that no problems from engine. I busted 2 transmissions with it and had 160,000 ish miles on it before I took it out to put another LS based motor 6.0 vortec (LS based, LQ9) around 2011. If that motor can take all that I put it through all those years and WOT pulls and still run, its got my vote. With that said If you took an almunium 427 or 408 (6.0 bored .30 over with 4" stroke) used top quality parts (forged, with ARP fastners, ect) set up for low end TQ and HP "derated" it and only ran at 2500-3000 RPM for the redline like other plane engines. Whats the difference besides air cooled, dual spark plugs ect? Just a LOT cheaper you can set up redundant sensors and such (to an extent) ... No matter what they are all man made and are all prone to break from defects or what not, invest in a BRS parachute :)
 

ekimneirbo

Banned
Joined
Oct 31, 2014
Messages
1,009
Location
Deep South
Fist post and joined just to comment on this. I know this is an older thread but ... When my dad died in 01 I got his brand new off the lot 5.3 vortec 327ish cubic inch (LS based) reg cab silverado 2wd. I was 14 at the time and my mother drove me everywhere in it until I was 15 -16. I am from a small town with LOTS of dirt roads so I Pounded and Pounded on that engine. I raced people, I did donuts, all kinda stuff a teenager would do :). I even ended up putting a 125hp shot of NOS on it for when I went to the drag strip. That motor NEVER let me down. My water pump went out once and a fuel pump but other than that no problems from engine. I busted 2 transmissions with it and had 160,000 ish miles on it before I took it out to put another LS based motor 6.0 vortec (LS based, LQ9) around 2011. If that motor can take all that I put it through all those years and WOT pulls and still run, its got my vote. With that said If you took an almunium 427 or 408 (6.0 bored .30 over with 4" stroke) used top quality parts (forged, with ARP fastners, ect) set up for low end TQ and HP "derated" it and only ran at 2500-3000 RPM for the redline like other plane engines. Whats the difference besides air cooled, dual spark plugs ect? Just a LOT cheaper you can set up redundant sensors and such (to an extent) ... No matter what they are all man made and are all prone to break from defects or what not, invest in a BRS parachute :)
Good first post...I like the way you think.
 

pistoncan

Well-Known Member
Joined
Aug 9, 2008
Messages
90
Location
Vienna, Missouri
There are several companies manufacturing items to use an LS series engine. Most of them use a reduction drive. This seems to be one of those situations where everyone follows the same lead and assumes it must be the only/best way. I'm not saying its wrong, but to my way of thinking, it may not be the best way...at least in my set of circumstances.

If you use a reduction drive, what do you gain?

1. You gain the ability to run the engine at a higher RPM and create more HP
for takeoff. You will also need more HP to carry the weight.
2. You can run the engine at a somewhat higher RPM level and increase cruising speed. This along with the added weight will reduce the distance you can travel before landing, and may be greater than the airplanes maximum speed. You'll get to the gas pump quicker....
3. You increase the cost and complexity of building the airplane and reduce the TBO. You place added strain on the engine components at higher rpms.
4. You may have to compensate to get your weight and balance to offset the added weight. You lose cargo capacity, and gliding distance, increase stall speed.

My opinion (and its just that...an opinion) is that trying to mimic an airplane engine is the best way to go. If 160/200 hp is sufficient to fly the airplane, then what good is having 300 hp? When cruising, you will probably only require a 100HP or so, and if you want to fly at top speed, figure how many HP you need and shoot for ...say 20 more than that and direct drive.

How do you get there? My opinion again...cubic inches. Everyone wants to purchase a readymade factory engine and plug and play. A 427 cu in LS7 doesn't weigh anymore than a 346 cu in LS1...but it sure costs a lot more.
(About $13K) Its 505 hp right out of the crate and GM sells a computer and harness that you can plug and play for under $1K. But...the 505 HP is at an RPM well above where you need to run. The LS1 5.7 Liter may meet your needs, but why not look at getting more cubic inches in an engine that weighs the same. To increase your power down low (2000-2800 rpm) the best way is to add cubic inches. Look at buying a 427 LS7 block and putting a stroker in it. You can actually build them even bigger than 427and for a whole lot less than a factory titanium rod version.

Now, back to the direct drive scenario. Everyone is throwing up their hands and saying the engine is not designed to deal with the thrust, the harmonics, or the prop twisting and flexing.

OK, how many of you have ever looked at or measured a crankshaft in a Lycoming? The crank has a 2.375 diameter crankshaft main journal and they use it on O320/O360/O540......even a 540.

An LS1/LS7 has a 2.650 diameter main bearing. Thats over a 1/4 inch larger than a Lycoming. (Also, a conventional smallblock Chevy has a 2.65 diameter on the 400 cu in block, and 2.45 on a 350 cu in block)

Thrust face...the Chevy won't handle the thrust. Well there is where the "rub" comes in. The LS1/LS7 engine has the thrust face in the middle of the crank instead of at the rear. My opinion, thats not good, because a propellor will be pulling on the back half of the crankshaft with no thrust face supporting it. (My solution later) On a conventional smallblock Chevy the thrust bearing is at the rear of the engine. The thrust of a Lycoming is applied directly against the face of the aluminum engine case. Look at one and you will see that its not an extremely large contact area....and its directly against the aluminum....hmmmm. So while I don't know if the Chevy will handle the thrust with no problem, I've never seen any factual information showing it can't.
(Hopefully someone will jump in here and provide that info if I am wrong)

The Lycoming does have an elongated snout which contains the equivalent of two rod bearing surfaces with a space in between.This purportedly provides the strength to resist the prop side loading. It does a good job. It would seem that if a small housing were made that could support a set of those bearings and an oil supply and return routed to it, then one would have a virtual equivalent of the Lycoming . A short shaft would have to be made to bolt to the Chevy and protrude thru the housing for mounting the prop.

The LS1/LS7 also has a crankcase which extends down past the crankshaft and uses 6 bolts to retain the main bearing caps...as opposed to 2 or 4 on a conventional smallblock or 2 thru studs on a Lycoming.

Another important factor here is cylinder filling. Its hard to get enough air into an engine at the lower rpms so you need air velocity. My opinion again...some generic LS1 heads will probably accomplish that task better with small intake passages than some more expensive high flowing (upper rpm) heads. That means you can buy em cheap. Am I right in this assumption...I dunno, but it sounds good. Also, Chevy is experimenting with some 3 valve heads because they can flow much more air than two valve heads...even at lower rpms. If it ever happens, it would be a nice upgrade.

Oh, I almost forgot...the crank will break. Well maybe it will and maybe it won't. They break off airplane engines so some will probably break off some auto engine conversions...if they aren't done properly. Both types of crankshafts can be bought made from the same materials, so I don't see a problem there. As for harmonics...some airplane engines are not supposed to be run in certain rpm ranges...or they may break. Auto engines may suffer the same problem, but there is equipment available to test them. Also you can put a harmonic damper on an auto engine. Everyone calls them "balancers" but the truth is that they are dampers that are designed to absorb harmonics. They are designed to work in a certain range and the rubber absorbs the harmonic vibration. Aftermarket units can be purchased which work over a broad range of rpms. The rubber absorbs the vibration and prevents it from increasing. Ever see one for an airplane engine? I haven't, but there probably is one somewhere.

As for information on conversions, Contact Magazine is a great nuts and bolts source of information, and Mick Mayall has some books out that has combined all the articles from the magazine. If you are serious about conversions, thats where I would reccommend starting.

I've rationalized a lot of things here because its what I want to make happen. If you disagree or have other ideas, feel free to state them. I'm always willing to learn...like I said, this is just my opinion.


Last comment...Weight

I purchased a 98 LS1 Firebird and removed the engine. On a scale I own it weighed 399.5 lbs without the starter and alternator, but with the power steering pump still attached and some water in its block. The starter and altenator showed 21 lbs. It had the factory welded tube exhaust manifolds attached also. No flywheel. I had the scale calibrated a few years ago and assume its accurate as I have only used it a few times....again I could be wrong but at least it something other than speculation.
Even a Merlin engine used a gear reduction unit.
 

HoneyMoneyToo

Member
Joined
Jan 19, 2016
Messages
5
Location
Georgia, USA
Yes, the prev post was right about the weight, they all differ but are very close to that number. If you were using a LS motor I would most certainly put a thrust bearing for forces applied from the prop. They are not designed to take those types of forces and would have premature failure some where in the bottom end.

My truck was dynoed for 408 HP and 476 TQ at the rear wheels. That means I am making "about" 450 and 500 at the crank. That is on 100 shot with a 228R Texas Speed (228/228 .588/.588 114LSA) cam other than that and a tune and bigger fuel injectors the motor is all stock. From what I have found on the online forums (performancetrucks.net mostly) the stock bottom ends will hold up to about 600 HP and I believe that is a 4 bolt main in the LQ9? I am not sure so don't quote me on that.

Also you can send your stock heads to Texas Speed and for $750 they will port/polish them, they are aluminium from factory flow good and cheap so why not? You can get a New aluminum 6.0 block for $1,200 or a bigger bore LS3 for $1,600... I bought my LQ9 at a swap meet from a junk yard, $1,500 for wiring harness, gas pedal, computer, and complete engine with alternator/PS pump ect with a 3 month warranty. It is an iron block but im sure you could find an aluminium one and bore it out and get all new bearings (thats a new motor) or buy new. You would still have less than $10,000 in it and another $5,000? for the reduction drive or direct drive, just need something to carry the thrust to the block through the transmission mounts (mine has 6-7 bolts with 2 thick dowels to line it up) but I am saving $20-25,000 over the "Certified" motors. BUY a BRS parachute with left over $ and you will be golden. Don't put all your eggs in one basket, if they both fail, it was time for you to go "home".

Maybe in 20-30ish years when I am 50-60 I can afford a new $50,000 engine for my $200,000 velocity (with my BRS parachute built in):)

Also, I have 2 engines (5.3 Iron blocks with aluminum heads) wiring harnesses, computers, HP Tunners tuning software, ect. if anyone reading this wants to build a test engine (LS based) from the parts or try to develop some parts/engine that are for "experiential aviation" purposes.
 

Midniteoyl

Well-Known Member
Joined
Sep 3, 2003
Messages
2,406
Location
Indiana
A quick Google search shows a couple of article were they got 100+ HP on both the 4.8L and 5.3L by simple head and cam swaps..
 

ekimneirbo

Banned
Joined
Oct 31, 2014
Messages
1,009
Location
Deep South
Yes, the prev post was right about the weight, they all differ but are very close to that number. If you were using a LS motor I would most certainly put a thrust bearing for forces applied from the prop. They are not designed to take those types of forces and would have premature failure some where in the bottom end.

My truck was dynoed for 408 HP and 476 TQ at the rear wheels. That means I am making "about" 450 and 500 at the crank. That is on 100 shot with a 228R Texas Speed (228/228 .588/.588 114LSA) cam other than that and a tune and bigger fuel injectors the motor is all stock. From what I have found on the online forums (performancetrucks.net mostly) the stock bottom ends will hold up to about 600 HP and I believe that is a 4 bolt main in the LQ9? I am not sure so don't quote me on that.

Also you can send your stock heads to Texas Speed and for $750 they will port/polish them, they are aluminium from factory flow good and cheap so why not? You can get a New aluminum 6.0 block for $1,200 or a bigger bore LS3 for $1,600... I bought my LQ9 at a swap meet from a junk yard, $1,500 for wiring harness, gas pedal, computer, and complete engine with alternator/PS pump ect with a 3 month warranty. It is an iron block but im sure you could find an aluminium one and bore it out and get all new bearings (thats a new motor) or buy new. You would still have less than $10,000 in it and another $5,000? for the reduction drive or direct drive, just need something to carry the thrust to the block through the transmission mounts (mine has 6-7 bolts with 2 thick dowels to line it up) but I am saving $20-25,000 over the "Certified" motors. BUY a BRS parachute with left over $ and you will be golden. Don't put all your eggs in one basket, if they both fail, it was time for you to go "home".

Maybe in 20-30ish years when I am 50-60 I can afford a new $50,000 engine for my $200,000 velocity (with my BRS parachute built in):)

Also, I have 2 engines (5.3 Iron blocks with aluminum heads) wiring harnesses, computers, HP Tunners tuning software, ect. if anyone reading this wants to build a test engine (LS based) from the parts or try to develop some parts/engine that are for "experiential aviation" purposes.
I have a couple of LS1 blocks. They can only be overbored slightly and the early ones can only
be honed ....so there is not much you can do unless you have Darton sleeves installed. By the time you do that I think its better to buy an LS3 ($1700) or LS7 ($2700) Block. The LS 7 has some additional features besides just a larger bore. Realize that if you operate either of these two engines (LS3 with 4" stroke) (LS7 ) at an rpm range of 3000 (3500) or so , the ports in the heads will
not need to be large, and in fact, something like stock LS1 heads should work well. Just clean them up and blend them near the valve seats. Haven't checked lately, but last time I bought some LS1 heads, they could be had for as little as $100 a pair. There is also a couple of aluminum SUV or Truck heads that flow like the LS6 but have bigger combustion chambers...which works out well for keeping compression low. The thing is that if you plan to do something like this, I'd sell the engines you have and get the block and heads you plan to use....rather than put money into experimenting with something you can't use later. Once you have the block and heads, most other components will have similar prices because you don't need the high performance parts. A truck intake gives more low end torque and you can get them as new take offs with the fuel rails and injectors for maybe $150. What ever you buy, remember that you are only turning 3000 rpms so
air flow will be just fine with low performance parts. Don't waste money on a high performance cam if a stock truck cam will give the low rpm power. I have some info on reccommendations for cam selection. The crux is that its all about cylinder filling. You only need to get half as much air into the engine in one minute at 3000 rpms. Don't need bigger injectors or throttle body.

How do you like your HP tuners software?
 
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