Bad day on the dyno!

[eric1h]

Originally Posted by Cobra4B

It all depends on how hot they are... oil pressure varys drastically w/ temp. You sure it's a high volume pump? LPE generally sells a ported LS6 pump which still has the stock gerotor. The LS4 pump has a different gerotor which flows more oil with each revolution.

70 psi at idle hot is too high... trust me. Hot being abotu 210 oil temp.

This is the oil pump I bought

http://www.lingenfelter.com/mm5/merc...egory_Code=C54

I dont see how too much oil flow or pressure(unless its REALLY high) is a bad thing.


What else would could cause the hight pressure if it is indeed too high?

Oil senders are iin the same location s before, in the oil filter block. Possible obstruction in the oil cooler?

[Cobra4B]

Originally Posted by eric1h

This is the oil pump I bought

http://www.lingenfelter.com/mm5/merc...egory_Code=C54

I dont see how too much oil flow or pressure(unless its REALLY high) is a bad thing.


What else would could cause the hight pressure if it is indeed too high?

Oil senders are iin the same location s before, in the oil filter block. Possible obstruction in the oil cooler?

You bought a Melling high volume pump throgh LPE... good pump. Very similar to the LS4 GM pump I have in my car. So.... your pressures are still way high.

The relief valve in the pump could be stuck creating excess oil pressure.

[eric1h]

Originally Posted by Cobra4B

You bought a Melling high volume pump throgh LPE... good pump. Very similar to the LS4 GM pump I have in my car. So.... your pressures are still way high.

The relief valve in the pump could be stuck creating excess oil pressure.

This a thread from Ls1 tech, mine sounds about the same

http://www.ls1tech.com/forums/genera...-pressure.html

[Cobra4B]

I'm pretty sure the melling uses a 42lb relief spring vs. the stock 32. The LS4 pump I have (the original version) has a 48lb relief spring. Seeing over 60psi at hot idle is higher than normal.

Even running a high volume pump and 20w50 oil it should be in the 50s, 60 max. Not 70 like you're seeing.

Did you notice a pressure drop when the noise started? What oil pan are you using? Some of these high volume pumps rand the oil pan dry on standard f-body pans. Too much oil got caught up in the heads and couldn't drain back fast enough. Shouldn't be an issue w/ the C5 pan and an oil cooler installed (extra capacity).

[NZGTRA17]

Originally Posted by eric1h

This is the oil pump I bought

http://www.lingenfelter.com/mm5/merc...egory_Code=C54

I dont see how too much oil flow or pressure(unless its REALLY high) is a bad thing.


What else would could cause the hight pressure if it is indeed too high?

Oil senders are iin the same location s before, in the oil filter block. Possible obstruction in the oil cooler?

Eric have you had a chance to start pulling the engine down and if so what have you found so far?

Regards oil pressure and what is "right", there are many many opinions on this. Oil pressure in race engines will vary widely due to differing bearing clearances (normally looser to promote flow and reduce bearing temps), oiling system differences and dry Vs wet sump configs (dry sump pressure is normally low at idle compared to wet sump but changes in a more linear fashion with rpm). I have generally adopted the old racers rule of thumb of seeking to have 10lbs of pressure for every 1000rpm at racing speeds. Anything above the 10lb rule (i.e. having 90lbs of pressure at 6000rpm Vs 60lbs) is wasting hp, putting additional temperature into the oil and aerating the oil. I do not get to worried about idle oil pressure unless it is glaringly low or high.

Trust that the major components in the engine come out OK and that no major rework is required.

Kel.

[eric1h]

no, no drop in pressure, and keep in mind the car probably ran for 10 minutes total, off the trailer, on to the dyno, warmed up for a few minutes and did one pull.

the oil pan i have is the moroso, 7 qts plus the cooler and about 5ft of lines. I honestly think i had a rod bolt stretch when the car "free wheeled" for 20-30 seconds at high rpm(@ 5000rpms) this was when the throttle stuck open(not enough return spring apparently)

Eitheer that or a lifter collapsed. who knows. I will hopefully start pulling it apart later this week when i finally get some free time.

[Cobra4B]

A failed lifter would be an easy fix assuming it didn't destroy too much else. If that's the case put a good cam in it.

As for oil pressures... I'm just going off my experience w/ these cars for 10 years and 10 years as an active member on the Corvetteforum. Kel is 100% right about how pressures vary. But, with a stock shortblock, high volume oil pump, and wet sump system your pressure is a bit high from the norm accross the LSX family.

The LS7 does run lower pressures at idle, but of course that's because it's a semi-dry sump.

Your motor came out of a 2004 right? Anything 2001 and up has very good rod bolts. Stretching one is pretty much unheard of. I run my car to 7k often w/o issues.

Let us know what you find when you get into it... www.ls1howto.com is a great site for doing heads/cam stuff on LSXs.

[eric1h]

So, I finally dropped the oil pan, don't really know what to think!

The oil was BLACK BLACK BLACK, except for the streaks of new oil i put in.

Good news and bad......

Bad news is it looks like i trashed a bearing in #5


Good news is the damage appears to be mainly isolated to the #5 cylinder bearing, so SLIGHT scuffing on the crank, and a little heat mark on the rod cap...

WARNING large HI-RES photo below



there was a decent amount of metal and crud in the oil. I am still scratching my head as to what happened, going to measure the rod bolts to see if they streteched


So, what now? Should I do a FULL rebuild, or just replace the bearings? How the heck to i get all the metal shavings out of the engine, and most importantly, WTF caused this in the first place?

[eric1h]

Some more pics....

here is the slight scuffing of the crank.... it looks like it can be pretty easily polished off, i could almost rub it off with my finger and there are no grooves where my finger could dig in...




The other bearings all looks great...

[Cobra4B]

No clue how #5 could have been the only issue... you post on LS1tech.com yet? I'd slap some new bearings in there and see if it runs. If it doesn't... well then re-build it all.

[NZGTRA17]

Eric, possible causes for the bearing to 'pick up' and get damaged like this are;

- Engine has been run for a short period with no oil in it or has had a momentary period of oil starvation (may have happened prior to you getting the engine or could possibly even have happened when the oil hose burst during install),
- Pick up in new sump is to close to the bottom of the sump (min of 3/8" standoff clearance required) and has caused pump to cavitate and draw in air at higher rpm,
- There is a gasket leak in oiling system allowing air into the system.

These are just some possible causes.

Regards what to do Eric, from similar previous experiences I would recommend the following (based on race engine practice) but note that I am not aware of LS repair costs in the States so you need to factor in economics of rebuild Vs sourcing another shortblock etc;

- Strip engine,
- Have damaged crank throws polished and measured to determine if you can get away with not regrinding the crank,
- Regrind crank if required,
- Replace rod bolts and resize rods,
- Fit new main and rod bearings,
- Strip and check oil pump, replace if damaged,
- Pull oil gallery plugs from block and have it thoroughly washed out,
- Flush entire oil system (reverse flush) carefully especially the oil cooler.

You may get away with doing less Eric but then again by cutting a corner you could have a similar issue re-occur.

Kel.

[Gatorac]

This was a used engine, right? How confident are you in The history of it?

[Jim woodruff]

I am sorry to hear your problems with the engine. Kel is correct strip it down and do it correct the first time every time I have tried the easy fix it has bit me in the butt and cost more dollars down the line. Be sure and send the cooler out to be cleaned I did not the last time and It bit me too. Best

[panozracing]

rebuild!!! dont risk and explosion...

[eric1h]

Any thoughts on the best way to reverse flush the oil cooler?

btw, THIS SUCKS