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TXFlyGuy

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Oh Happy Day. Wish you all the best.
Fell in love with P-51's when every Sunday after WW-2 the AG would practice making runs on a hill about 2 miles north of my Grandfathers farm . After Sunday dinner, I would go to the front porch and wait for the string of P-51's and my private airshow.
Dan
Wow! How cool was that!
 

Pops

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Job out of high school I worked for a men that was a Flying Tiger with the P-40's and then flew 51/s in WW-2. We ate lunch together every day and had long talks. Would love to set and spend time with him again.
 

Rockiedog2

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I had a new high dollar motor years ago. First flight there was a problem similar to TFG’s. Did everything possible to determine if there was damage and all seemed ok. Flew it a while and couldn’t get it outa my mind. Built up another one and mounted it up.
Whole new world...and that was on a cheap, forgiving airframe.
 

TXFlyGuy

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I had a new high dollar motor years ago. First flight there was a problem similar to TFG’s. Did everything possible to determine if there was damage and all seemed ok. Flew it a while and couldn’t get it outa my mind. Built up another one and mounted it up.
Whole new world...and that was on a cheap, forgiving airframe.
Thought about doing just that.
 

TXFlyGuy

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Peace of mind is money well spent. Then if things go bad we know we did all we could.
Yes, it certainly is. I have exhausted all avenues of diagnostics on the engine. Everything has come back positive in my favor. We will do one more compression check on a hot engine, vs. a cold check.

Hutter Performance is satisfied with what they saw during the borescoping of the cylinders.

A final decision will be made after we get everything put back together...new fuel system and coolant lines, plus do some full power runs.
 

Pops

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Sometimes your guarding Angels whispers in your ears.
All of my life, if I have a lingering doubt in my mind about anything in the airplane, I fix it.
The reason to never buy all the airplane you can afford. Buy less than you can afford and do a no expense spared maintenance on the airplane.
Airplanes are expendable , people are not.
 
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Rockiedog2

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Yes, it certainly is. I have exhausted all avenues of diagnostics on the engine. Everything has come back positive in my favor. We will do one more compression check on a hot engine, vs. a cold check.

Hutter Performance is satisfied with what they saw during the borescoping of the cylinders.

A final decision will be made after we get everything put back together...new fuel system and coolant lines, plus do some full power runs.
You’ll probably be fine with all the pros you got on it. I only had one redneck to depend on.
Couldn’t get past it. Ruined the plane for me.
Good luck
 

delta

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I hope your cooling issues get resolved with this engine. I'm personally more worried about keeping chips out of the prop governor. A few hours of touch and go's should let you know if anything else is going on.
 

TXFlyGuy

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I hope your cooling issues get resolved with this engine. I'm personally more worried about keeping chips out of the prop governor. A few hours of touch and go's should let you know if anything else is going on.
We share your concerns, and the oil will be changed at 4 hour intervals to start.
 

Mike0101

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The main coolant lines from the bulkhead to the radiator are 1 1/8" I.D.
We are going to add larger lines from the pump to the firewall. These are the 3/4" lines.
Plus a larger overflow bottle will be added, 2 qt size.View attachment 103073

View attachment 103074View attachment 103075
In my previous post, I keyed in on performance shop's suspicion of "trapped air". As others have pointed out, your line size is your biggest issue... 3/4" lines are far too small, you are exceeding 200 ft/sec flow, which for a liquid is far too high (assuming 45GPM at about 4000-5000 RPM).
Also at idle or low RPM LSx (or LTx) pump jut doesn't have much head (pressure) and flow.

I've attached a pic of Evans high flow pump for illustration.
LS3 pump.jpg
When you have a severely restrictive path to and from heat exchanger (radiator), then path of least resistance is to simply recirculate coolant in block - which is, what is very likely happening.

When looking at pump, the bottom ports (2) are coolant return, and top 2 ports are coolant supply to block. Where thermostat is (bottom right), would be coolant return from radiator... Also notice cabin heater ports (2), the smaller is supply and larger one return.

Upsize your lines throughout, and preferably follow GM in which, return line size is larger than supply - this helps to compensate for pressure drop.
Also for testing, maybe go back to water, as viscosity will be cut in half or more depending on what coolant you are using... As mentioned by others, 10 PSI pressure drop is not out of the question (could be more, AN fittings don't have the best hose to fittings transition). Modern water/coolant pumps just don't have much extra pump head (pressure) built in, in order to keep parasitic losses low...
 

Doran Jaffas

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Jun 25, 2019
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Sometimes your guarding Angels whispers in your ears.
All of my life, if I have a lingering doubt in my mind about anything in the airplane, I fix it.
The reason to never buy all the airplane you can afford. Buy less than you can afford and do a no expense spared maintenance on the airplane.
Airplanes are expendable , people are not.
Excellent words of wisdom.
 

proppastie

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NJ
Sometimes your guarding Angels whispers in your ears.
I like to say "the engine is talking to you" or "someone was looking out for me" ......had it happen to me many times and twice in the last 4 months......I hope I keep listening and/or my luck does not run out.
 

delta

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I don't remember if you have magnetic drain plugs and temp sensors in the reduction but at 4 hrs if it smells ok, I'd explore ways to filter the stuff and re use it. Clearly just a global warming thing and in no way tied to my personal cheapskate way of doing things...
 

TXFlyGuy

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Yes, I have a magnetic drain plug in the oil pan, plus a temp sensor is installed in the gearbox (PSRU).

Not really interested in using my oil again, but it does get taken to the local auto shop for recycling.
 

wsimpso1

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Saline Michigan
Glad to hear the insides all come up clean. Vent the fight spots on that engine and get it flying.
 

skydawg

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Jul 26, 2016
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56
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Denver, Colorado
We had to work through many coolant issues developing our V8 conversion for Cessna 172. without knowing what you are working with, I would concentrate on being sure system is completely free of air. Start by adding coolant using a vacuum pump which sucks all the air out, and sucks the coolant in so no air is reintroduced. depending how you Plummed your LS water pump bypass lines, this could be an issue as the LS pump thermostat has a bypass function, that’s why it has the extended arm on seal flange, so it could be just not opening and simply continuing to circulate flow through engine.
if you are not using a thermo stat, that’s a problem because the bypass port must be blocked....you can get a bypass plate for the LS online at racing shops. The LS thermostat is different than normal t-stats, visually compare the two And you will likely see what might be going on.

if this doesn’t help, it’s likely some small air pockets expanding in the pump or thermostat. On the LS stock thermostat there is a beefed-up area on top designed to drill and tap a small port for purging air. This is easiest way. But you can also wedge thermostat open with an aspirin pill to circulate coolant long enough to purge air back to expansion tank (vapor in the thermostat won’t get it hot enough to open on its own, causing coolant to stay in block and not flow thru radiators). if your radiators are not hot when engine reaches over 190 (when stock thermostat is supposed to open), cool and is not exiting engine.

it’s important to have a surge tank fill at highest point to collect air and push it to the expansion tank, as with the engine rear side at lower elevation and opposite of the LS steam port, it’s difficult to remove all air. you can see how we installed the surge tank and expansion tank high up on the C172 firewall on website.
Www.corsairpower.com

as far as temperature sensor being bad, which type are you using? Most ECMs will use a 5v reference signal so it’s easy to check with decent multimeter. I suspects is not in contact with coolant fluid due to air pocket as port is positioned at highest part of engine with a taildragger.p install. As far as over heating, the Corsair POH and service manual says to change oil if over 275F was reached as engine temps climb substantially after shutdown, and pressure test system to 25 psi for 5 minutes. One more thing if using a OEM ECM and sender....car manufacturers think drivers perceive a quality engine condition When the engine temp gauge stays pinned at the 12 o’clock position, so the system is programed to keep it there if within about 15F before it starts to move, so it’s not an accurate reading. The ODB port will give you actual temp.

one more thing if engine overheated at altitude.....the pressure cap is rated in PSI, the higher the PSI rating, the higher coolant temp can get before boil over. Typically, a 16 psi cap is used. However, the rating is a PSId rating, meaning it’s differential pressure so the psi rating actually decreases with altitude quite a bit compared to normal car use altitudes . It’s important to figure out max aircraft altitude and then decrease in ambient pressure, and calc what cap pressure you need to prevent boil over. Likely something like 3-4 more psi will do the trick, but be sure your system is rated for the greater pressure plus at least 5-10 psi safety margin. if not, a 16psi cap will boil over at lower temperature.

the Corsair POH has normal engine temps 180-220F, and most cars with LS engines use 210F as normal....this is hotter than needed but improves emissions. I would not go much below 190F in your design as you want to burn off moisture efficiently. I wouldn’t sweat it if you see 250-260F for a short time either, say during climb IF your coolant system is designed properly (the engine can take it but lots of stress on coolant system). Remember, after you shut down temps rise, so if you shut down at 275F, I’d expect temps continued to climb well above 285F. this could maybe possibly warp a head or damage gasket, but pressure testing system will tell. Corsair system ECM activates radiator fan after shutdown when needed to reduce post shut down temps....similar to most cars, and recommend you program the same feature.

there’s a lot of other things to look at but I’ll bet looking at these items will solve your issue. If not, PM me.
 
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