# Auto Engines Aren't Designed to Take Full Power for More Than a Few Minutes...

Discussion in 'Ford' started by rv6ejguy, Jun 28, 2014.

1. Oct 9, 2017

### pictsidhe

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Swapping the overly heavy stock front pulley for a sexy aluminium billet one is a very popular speed mod. Not one that I've ever done, though...
The speed industry is littered with examples of expensive 'upgraded' components breaking way before the stock ones.

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2. Oct 9, 2017

### Toobuilder

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Replacing a pulley is one thing - but in Ross' example he's talking about the dampener (I think). Big difference!

3. Oct 10, 2017

### Mreinh3233

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Don't boats use auto engines, don't they run wide open most of the time, don't they make 2000hrs plus between overhauling, and are they not mounted to a propeller through a gear box of some kind? So why can't they be used in aircraft with some modifications?

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4. Oct 11, 2017

### pictsidhe

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The front pulley usually is the damper on most modern engines. I've not seen one that wasn't since maybe 70's engines, but they might be out there...

5. Oct 11, 2017

### mcrae0104

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Tonawanda... Wait, didn't they make an auto engine in your town that's been successfully used in a lot of airplanes?

6. Oct 11, 2017

### Winginit

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Think about that for a minute. The reason "some" of these parts break is because they are pushed to absolutely extreme levels of HP by various means that "No stock component could reach, muchless survive". Its to be expected that many of these parts will fail. I remember many years ago a racing team building a dragster engine that would only be used if they reached the championship round...it was built to endure one race...hopefully. Its unfair to suggest that "ALL" high performance parts can't compare to OEM components. Compare the materials used in many aftermarket crankshafts and the aftermarket wins handsdown. Look at connecting rods and compare the endurance levels of powdered metal or Titanium rods to the strength of forged rods. How bout comparing pistons. Compare valves, lifters,springs,rocker arms....and the aftermarket industry wins again. While there are some aftermarket components which have poor records, there is virtually always a plethora of choices which allow for quality components. I think you will find that 99% of quality aftermarket hi-po parts are way stronger than OEM parts and DO NOT fail before a stock OEM would have failed.
That being said, if a builder doesn't know how to correctly assemble the components, even the best components in the world will fail. Its unfair to blame the components when you know they are better than OEM quality and composition. Its like when an V8 powered airplane goes down because the pilot ran out of fuel and the headlines read, " V8 powered Wingding crashes". How long would a Nascar engine survive with OEM parts ?

If I'm reading the facts correctly, a harmonic balancer was replaced with a simple pulley. If thats correct, you can't blame the aftermarket pulley because it wasn't designed to dampen, and you can't blame the crankshaft because someone removed the dampener. If the crank was a replacement made of a different material, the OEM dampener wasn't designed to work with it, so a properly tuned aftermarket balancer like a Rattler or Fluidamper may have worked.

Moving to aviation needs, there are plenty of OEM engines which need virtually nothing changed to survive the demands put on them as long as coupling them to a propeller is done properly. Aero engines have certain rpm ranges which should be avoided because of resonance. Put one of those aero engines in a different airplane and use a different propeller and you are taking pretty much the same chance that a one off auto engine faces with those changes. Any engine can self destruct with resonance, whether its aero, auto, modified or stock. Many auto engines are only run at loafing rpms in airplanes, some are run at more elevated rpms. Usually niether situation places the engine under unrealistic stress and failure by self destruction because of component quality is seldom the reason. So OEM quality is probably fine for most conversions, and aftermarket parts can be even better if properly assembled. While a hyperutectic piston may produce acceptable results in a turbocharged engine, especially with computer control, no one should tell you that hyperutectic is a better piston than a forged aftermarket piston.

Last edited: Oct 11, 2017
7. Oct 12, 2017

### pictsidhe

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Look at aftermarket Rover K series parts for example. The factory parts were much more reliable in TUNED engines than the aftermarket 'upgrades'. After a few years of broken cranks, the aftermarket had to get its **** together...
Changing the material of a crank doesn't affect the vibrations much, it's changing dimensions and weights that does. Changing the flywheel or rods will affect it. If you are hoping for a major power increase from an engine and expecting to keep reliability by throwing oney at it, you are likely to be disappointed. Want power? An OEM turbo engine is the way to go.
How many aftermarket parts get a fraction of the testing of OEM ones? The majority are designed with TLAR engineering and a material upgrade. Even the OEMs, who will test parts for thousands of hours, get caught out too often.
A butterfly flaps its wing in Peking, and there is a storm in Moscow. A part can cause a failure in a seemingly unconnected part. Changing to unbreakable titanium rods has caused valve spring failure. Are you going to wear a few engines out each time you upgrade something to check that the whole engine is still reliable? I'm planning to upgrade an engine for my project, then I'm going to run it for a month or two before building a fresh one. The parts are cheap enough for me to do that... I've already been running one mod for a few years now, though the engine is still in a scooter, safe place to try it!
While many older engines had issues, few modern engines do and are much harder to improve on.
Many racers seem to think that dampers and balance shafts are a luxury for comfort, not engine prolonging devices, so take them off in the name of performance. Bang goes their expensive engine after a few races and they wonder why. Meanwhile, Joey Cheapskate, who's only messed with the top end but is nipping at the big spenders heels, has an engine that lasts two seasons before the bottom end finally lets go. He replaces it with one from a junkyard and is rolling again. That happens, a lot. You don't hear about it much as the magazines and tuning press are funded by people selling tuning stuff...

To get reliability, you are going to have to do a LOT of work to beat the OEM stuff. I'd much rather trust OEM than aftermarket. I've seen too much broken aftermarket stuff, much of which I made the mistake of buying...

Aren't most NASCAR engines built by the OEMs?

8. Oct 12, 2017

### TFF

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Up through the mid 70's NASCAR engines had to use OEM parts that came in a car; through the 90s you had to buy "production speed parts". They were special parts but that is why a Ford 427s ,Chevy L88s and Chrysler 426s are worth tons of money. Even now NASCAR have to use approved "factory" parts. Now days when a NASCAR engine really blows, because it is rare, they call it an old school blow up grenade. Parts are either good enough or not, and until you run them, you dont know really.

9. Oct 12, 2017

### Daleandee

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This is where an engineer makes his living. How many tines have we seen someone want to "beef up" a part to keep it from failing not realizing that it was designed to fail and by making that part stronger moved the failure to a more critical or hard to access/inspect/service area of an engine or air frame?

I learned this as a young boy the first time I hit something solid with a 3 HP Briggs lawn mower engine. It quit running and wouldn't even try to start after replacing the blade. Once I learned about & replaced the aluminum shear pin between the crank & the cast iron flywheel I was back in business. With out that shear pin I would have been buying another crankshaft.

Dale Williams
N319WF @ 6J2
Myunn - "daughter of Cleanex"
120 HP - 3.0 Corvair
Tail Wheel - Center Stick
Signature Finish 2200 Paint Job
157.8 hours / Status - Flying

10. Oct 12, 2017

### Daleandee

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:ban:

Dale Williams
N319WF @ 6J2
Myunn - "daughter of Cleanex"
120 HP - 3.0 Corvair
Tail Wheel - Center Stick
Signature Finish 2200 Paint Job
157.8 hours / Status - Flying

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11. Oct 12, 2017

### pictsidhe

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A farmer friend of mine was cursing some shear bolts that kept going on him. They were hard to get at and $15 each. He asked my advice. I looked at one, noticed it was a standard 8.8 metric bolt with a ripoff price and told him to buy those instead, but on no account to put beefier ones in unless he fancied changing$1000 gearboxes...

12. Oct 12, 2017

### Winginit

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Ok, lets look at the rover V8. It started as an OEM GM engine designed for Olds,Buick,and Pontiac use. It had production problems because they couldn't control the casting process and they were having to scrap so many they sold the rights to the engine to Rover. Rover used a different process and were fairly successful, but it was a small capacity engine. Rover began upgrading the engine with larger bores and strokes and changed the metalurgical composition of the crankshaft. They modified the heads and added 4 bolt mains to the deep skirt block. This OEM engine suffers from two known problems ...oiling and coolant leaks. Check some Craigslist ads and you will find a multitude of Rover in perfect condition for sale. Perfect condition except for that pesky overheating coolant problem. They are for sale because the owner "thinks" they have a blown head gasket, or so he says in the ad. A little research will turn up the fact that these OEM engines are prone to developing a water leak between the cylinder liner and the block. This is a major problem in Rover engines.

https://westernmass.craigslist.org/cto/d/2005-land-rover-lr3/6340521862.html

https://westernmass.craigslist.org/cto/d/2001-land-rover-discovery-ll/6340067789.html

https://buffalo.craigslist.org/cto/d/2003-rang-rover/6330989044.html

How do people wishing to use one of these engines resolve the issue? They look to the aftermarket industry where a company named Darton produces a special liner with a lip on it, and it can only be purchased thru one specialized source to the best of my knowledge. The old liner is completely bored out, and if needed, an aftermarket source will weld the aluminum bore (if needed) so it can be remachined to accept the new liner. As far as I know there are no more problems with overheating at that point. These engines are a favorite of many British MG enthusiasts and they have installed lots of them in their sporty little "race" cars.

Note in the video that poor manufacturing by the OEM caused the problem.

Those enthusiasts looking for even more displacement adapt OEM Buick crankshafts (simply because they are cheap and fit the block). They must use an aftermarket seal adapter to make it work along with aftermarket pistons.

Lets look at another very popular engine thats often converteted for airplane use....the Corvair. It has been used for many years and as more of them were used, some OEM crankshafts began to break. Now, the aftermarket seems to have solved the problem. First their research discovered that the radius at the edge of the crank throw in many engines wasn't machined properly and had a step in it. This was a perfect point to set up a stress riser and cause breakage. Remember this was OEM machining on an OEM crank. So the aftermarket stepped up and designed a 5th bearing for support and even a new stronger forged crank for more displacement.

What about Toyotas. Anybody out there been part of the factory extended repair program because their Toyota engine was using a quart of oil every 1000 miles. Guy stopped by my house to look at something at had on Craigslist last week. Told me he was retired from Toyota. Forgot what he told me was wrong with the first one, but the second one had a lemon transmission. Now he retired from Toyota, and he said he would never buy another one. He was driving a nice Ford pickup.

Lets not forget the much ballyhooed Cadillac Northstar engine. Or, something newer. How bout an LS7 Chevy. GM makes a big production out of how they designed special toolingfor assembling these engines. Their video shows a machine that torques all the main bearings at the same time and how only one technician assembles this precision engine. They talked about how they precisely balance the engines components and use Titanium connecting rods for strength and lightness. Well I bought all the individual components to assemble my own LS7 when you could still get some good prices because most LS7 components would not fit the available LS1 engines.
I bought a complete set of new titanium rods. One of them came without any wristpin bushing in it. I found out that the titanium rods were lighter but not as strong as forged rods, and they had galling problems...so I sold them. I bought a brand new set of OEM pistons complete with rings that had been removed from a never run crate engine. I bought two sets of them. I placed them on a scale and weighed them ...expecting to find them very close in weight. Big surprise, they were all over the place in weight.

(Note one piston was broken in shipment)

Like I said, I'm not knocking OEM stuff overall, but you can't blindly state that that all OEM is good and anyone who uses aftermarket parts will have problems. You have to be reasonably competent whichever way a builder chooses to go. What I always find to be oxymoronic is the profession that its okay to use various materials to build a non-factory built airplane, but someone is foolish if they use non-OEM parts in their engine.....which they will absolutely have to use some type of non-OEM adapter to make it all work.

Last edited: Oct 12, 2017
13. Oct 12, 2017

### TXFlyGuy

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We wanted power, but reliable power. That is why when choosing a performance cam, we went OEM. The GM Hot Cam option for the LS3.

Note: Some of the aftermarket companies actually produce parts for the OEM types. Mahle is one company that comes to mind.

14. Oct 12, 2017

### Mreinh3233

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I believe so.

15. Oct 12, 2017

### Grelly

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On that subject, this caught my eye: http://newatlas.com/yanmar-dtorque-111-turbo-diesel-50hp-outboard/51675/

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16. Oct 12, 2017

### tspear

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17. Oct 12, 2017

### Winginit

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There are lots of companies that make parts for OEMs and also sell on the aftermarket. For the most part, I'm a proponent of using OEM stuff. It is good quality and often the best that can be bought. Other times, there are stronger,better,lighter parts available on the aftermarket for reasonable prices. I have an LS3 in my shop that was purchased with the "factory Hotcam" already installed. This is a great bang for the buck and they are pretty reliable and popular. Does it have the best components possible....No. BUT, it is still plenty rugged for use in an airplane. I am not aware of any faults that would cause this engine not to be a good choice for use in an airplane just as it comes from the factory. The only place I can think that might benefit from an OEM upgrade is the rocker arms and maybe the pushrods. I know there have been problems with the rocker arm bearings in some LS engines, and I don't know if the 3 version of the LS was upgraded or not.

There are several companies that make high quality head gaskets that can solve some OEM problems, but also allow different combinations of bore and stroke to be employed. Sometimes its just a matter of gettin a proper bore size or the proper thickness to get a certain compression ratio. Other times they are preferrable because they are more durable and better to contain compression than the available OEM gasket.

For the most part I have found that quality aftermarket companies make durable products that last as long as OEM and often out perform OEM. Can I say that ALL aftermarket products offer superior reliability over OEMs...NO. What I am saying is that an improperly adapted engine can/will fail whether it is only OEM or only aftermarket. Neither engine can survive out of control harmonics.In the homebuilt world its easy for mischaracterizations to create an impression that grows into an "internet accepted fact". Think about how long we heard that "Auto Engines Aren't Designed to Take Full Power for More than a Few Minutes". At least on this site that myth has been pretty well put to rest. I don't want to see another myth that gives all aftermarket parts the same undeserved reputation. Are there some junk parts on the market...most certainly, but there are some very high quality stuff that exceeds OEM standards too. I just think we should refrain from trying to generalize criticism as being all encompassing for any product type. It creates misconceptions and makes experimentation progress more slowly.

Depends on what you want to consider an OEM employee. The racing teams assemble their own engines but the racing team has a contract with the OEM...so are they OEM employees? They often perform development work for the OEM and interact with OEM engineers exchanging data and parts. I would say that most of the parts used in the NASCAR engines bear little resemblence to what comes off the assembly line. Not sure just how the Toyota situation operates. Might be more of an OEM factory tech involvement there.

http://nascar.nbcsports.com/2016/11...nue-to-supply-engines-to-chip-ganassi-racing/

Last edited: Oct 12, 2017
18. Oct 12, 2017

### poormansairforce

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19. Oct 12, 2017

### tspear

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Here is the key point that you guys have been talking past each other. There is a fairly common held belief among hot rodders I know that aftermarket is always better than OEM. This is patently false, there are no absolutes. Further, depending of what you are discussing the OEM part may actually be pretty good, or it may be a piece of crap. Same holds true for the aftermarket.

Tim

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20. Oct 13, 2017

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