80trans_am

Ok hello everyone I'm new here but need some major help. I just did an engine transplant in my 80 TA to a SBC 388 stroker. Everything is brand new and it feels really strong but I am burning some major oil.

I drove it about 300 miles this weekend and I noticed my oil pressure kept going down a little bit every 30 min or so. So when it got to about 40psi I checked it and it had leaked about a quart in only 120 miles. Now it leaks a little from the rear main but that fine and I can account for about a 1/4 quart from that but I have burned about 3 quarts in 3-400 miles. The guy who built the engine said its the Molly rings setting in but I have a hard time believing that the rings setting in could reduce the oil consumption that much. Please help she's my baby :-(

jam01

did you break the engine in properly, your engine builder should have given you specifics on this.

LS6427

iTrader: (2)

The rings not being seated properly in the first 2-3 miles the engine is running......is everything. Meaning wide-open-throttle runs right off the bat when the engine is brand new.

Also, the tune......if its too rich right off the bat the rings will never seat and you'll burn oil like that for the life of the engine.


1)So....how exactly did you break it in?
...a)Brand new engines need full throttle runs right off the bat to break them in properly?
...b)They must not be too rich either

2)Did you get an immediate dyno tune after the engine went in? Or, did you drive it around WITHOUT a dyno tune for the first few hundred miles real easy and not run it HARD? THIS IS BAD IF YOU DID

This is how you break an engine in properly:
http://www.mototuneusa.com/break_in_secrets.htm

****Then there's the oil changes for the first 500 miles. Changes at 50, 100, 150,200, 300 and 500 are a must. New engines shed metal their entire lives, but they shed a TON for the first 500 miles. You don't want all that crap pounding your bearings in that first 500 miles.

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80trans_am

The dude who built the bottom end said he ran it for about 30 min to break In the rings. Now for the remainder of he break in I've done everything that came in the comp cams break in manual. Including the oil changes break in lube all that. Now an interesting tid bit of info that I learned today whil driving it was that she doesn't seem to burn any oil except on takeoff then theres nothing until 2100 rpm. Then there's like a damn fog behind me. But other then that I think I did everything on my part to hbreak her in properly.

LS6427

iTrader: (2)

If he just started it up and let it run (idle) for 30 minutes....he ruined a brand new engine. Rings will not seat properly like that. It must be run HARD right off the bat. Every LSx engines that comes off the assembly line gets dynoed HARD, right off the line. Then they install it and its broken in as much as it will ever be. When we buy them at the dealership, they are race track ready instantly.....but those oil changes up to 500 miles are still highly recommended.
I've learned over the years, lots of builders have no clue how to break in an engine.

The car needed to be put on a dyno or road tuned...IMMEDIATELY on the engines first start up.......to break it in properly. Its not just running it hard for the first 2-3 miles, it can't be pig rich when doing it, or the cylinders will get "gas washed" during break in, and the rings won't seat by the time the cross hatches are gone from the cylinder walls.

I had this happen to a fully built LS6 434ci.....I had to pull the engine and re-hone it and put it back together. It burned like a quart every 250 miles. Mine was pig rich and I drive it home from the shop who installed and it and tuned it.

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80trans_am

All right so I tried that break in method as a last ditch effort to save my engine and it actually helped a little. Imean she still is burning a little but but I think it's getting better. I drove another 100 miles and she was only about 1/4 a quart low but I also have a rear main leak so that can account for a little bit. But I talked to a couple mechanics and I've gotten mixed opinions. Some say I need go re hone and ring and a couple think that because I have such hard rings I need to wait another 1000 miles before I go freaking out. Hopefully I don't need to spend another 2500 bucks but we'll see. If any of you have any other ideas or tricks l would love to hear them!! Thanks ls6427 and jam01

LS6427

iTrader: (2)

There is absolutely no way any ring can take 1,000+ miles to break in, thats crazy. From our LSx engines to mini vans to semi's to Formula F1 engines to NASCAR engines to Top Fuel dragsters........all these rings seat immediately after the engines are built, run hard, tuned.......then they put that brand new engine on the track and race them....

Some people who had rings that did not seat right put some very thin oil in it and ran the **** out of their engines and it seated them, or at least seated them a lot better.

Or maybe ask the builder about using some kind of break-in oil (mineral spirits or something) Do a a few ***** Out runs.....it might seat them.

You should NOT be burning any oil at all....none....with that many miles on the engine.


I'm actually building a new motor starting next week.....not sure what yet. Its getting installed in my car, then I'm trailering it to my tuner where he's going start it for the first time to tune it on the dyno and run it as HARD as possible for its first 4-5 dyno pulls. After that, its ready for the track, if I wanted to race at a track of course.

I actually might start it for 30 seconds just to make sure it runs of course......but thats it.

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DisasterFormula

iTrader: (1)

If you have a rear main leak and are burning oil at this juncture, I'd go back and tell him to fix it. Then when it's all together, you go and make sure it's tuned up right and then broken in properly. Either that, or money back for fcking it up.

80trans_am

Ok so after weeks in the shop they figured it out!! The hit who built the top end trimmed the valve guide plates causing them to dump oil into the combustion chamber. $50 fix, thank god!! I was not looking forward to 1500+ dollars of work to re hone and ring!!! Thanks for the input!!

Jr.Samples

So did he fix the rear main seal too?

Moly rings do take 500 to 1,000 miles to fully seat and can use a little oil until they do.

DisasterFormula

iTrader: (1)

Seriously. I'd be chewing them out until they fixed the rear main, for free! If they had the engine pulled apart enough to hone the cylinders and put in new pistons and rings, they had it pulled apart enough to put the rear main in their right and make sure it was working.

LS6427

iTrader: (2)

BUT.....the cross hatches on the cylinder walls are GONE in a matter of 10-15 miles...........if the engine is not run ***** out wide open throttle in the first 2-3 miles....you lose that window for the rings to seat properly.

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The Alchemist

iTrader: (19)

Good info in here. I too am finishing up a build and will be running break in oil for the first 500 miles which will encompass at least 3 oil changes along the way. My intention is to fire it up, let it come up to temp for 1-2 minutes checking all the connections, fuel and oil pressure etc and make sure I don't have any leaks then to take it out for a 5-10 mile romp at least, maybe more, then drop the oil and filter. Then take it back out for a 30-40 mile romp. Oh, did I mention that I plan to push 10-15 lbs of boost at it as well?

I figure after a solid 100 miles of this and I should be good to go.

LS6427

iTrader: (2)

I suggest 5-6 oil changes in 500 miles.

Also, make sure that first 5-10 mile trip sees WOT runs.........preferably in the first 2-3 miles. Just make sure its up to operating temp before smacking it.

My suggestion: Do not drive it easy for 10-15 miles.

Do this method, 5 runs and you're done with break-in: http://mototuneusa.com/break_in_secrets.htm

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The Alchemist

iTrader: (19)

That's the plan. Let it get up to temp while checking everything, then romp on it and let it see boost pressures right from the get go.