Well my lt1 must be wanting to eat all my money. After my rebuild and some diagnosis we thought it just needed a good seat. Well the smoke got better then worse. Ran a compression check. 175-180 cold on all cylinders. Not great but not bad. Had a valve job done at the machine shop. So I guess its tear down time. Dam the lt1. Pretty much think its rings. Gap was a little wide. That or the pistons that came out of the junkyard engine are junk. Already tried to sell it but nobody wants lt1 cars anymore. Plenty for 1500-2000 running around here and ls1 cars are in the 5k range. So guess its rebuild number 4.



On a side note where did everyone go. Been awhile since I have been on here. Mainly since my car has seen 1200 miles in the last 43ish months while eating 10k in parts and blowing up because of bad new parts. Car is cursed.

 

How did you seat the new rings?

 

Is it common to use junkyard pistons on an engine rebuild?

 

Might be as simple as an intake manifold gasket not sealing up completely. Might be leaking oil from the lifter valley underneath the gasket and into your intake runners. Just a thought. Either way, hope you get it figured out

 

if you cheap out on parts youll run into trouble... just go through it again and see what ya find!

 

Rebuild #4 lol.... Pretty sure the hard parts are NOT the problem.

 

Try this break-in procedure from Hasting Piston Rings.
http://www.hastingsmfg.com/ServiceTi..._procedure.htm
Don't baby it when breaking it in, Spare the rod, Spoil the child.

 

i guess i dont have any advice LOL ive rebuilt alot of LT1 cars, i even have 2 pretty stout LT1s in my personal collection... and ive never had this problem... maybe valve seals? piston ring gaps are lined up and not staggered?

 

Before tearing anything down get a leakdown done to find out if your consumption is coming from the top end or bottom or both.

 

Junkyard STD bore pistons? New rings? Honed block?

 

PHR mag did this with a stroker crank (377ci) and made 507 fwhp so it's not so far fetched.
http://www.popularhotrodding.com/tec...s/viewall.html

 

Wasn't busting on him brother. It's a good idea as long as the cylinder taper is good and rings gap correctly. I would ensure the compression rings are spaced out and gap good from TDC to BDC.

 

I got 449TQ @ 4700 437HP @ 5400 with stock heads on a 385ci, carb manifold.

 

Hey guys here is the back ground on the rebuild. Had the first engine in my car blow up. As a temp thing we got a junkyard engine. It lasted 600 miles then had low oil pressure. So took it apart and found it had been rebuilt poorly. It had .030 over pistons. So with the two engine I built one out of parts. Used my factory stock block bored .030 over. Used the .030 pistons and had the 374 heads cleaned up with a new valve job and valve seals. When building used all the right ring gaps as per factory specs. Rings were set 90-100 degrees apart. Pretty much one at each end of the piston skirt on the outside of the block. Engine runs like a champ except for the oil pouring out the back once again. Break in was done as follows.

Warmed up the engine. Drove the car with some lower speed 80% throttle pulls with engine breaking afterwords. Did this for about 12-14 miles. Let it idle for a few mins back at the house. No smoke at that time. Started it up the next day to move it. Decided to drive it to the store and back before the oil change. Started smoking when you pulled 70% or more. So parked it and called a buddy. Took it to his shop. Ended up pulling the plugs and doing a compression check and checking all the sensor,tune,etc. Plus were fouled out so cleaned them and no change. All sensors are reading right. Stock tune had no change. So drove it for 130 more miles smoke pretty much went away. So picked the car back up and drove it back down and the more I drove it trying to seat it the more the smoke came out. Now its smells strongly of oil and is smoking at idle along with take offs and engine breaking.

 

Did you change all the valve stem seals? I used Hastings rings for my rebuild and the have a small dot that news to face the piston skirt, anything minuscule you might have over looked like that ?

 

All the valve stems were changed. All dots were up and followed by the instructions.

 

im having the same prob with it has a new crate motor put in it... have u foung anything out yet ???

 

Yep. Decided to tear down the engine. Found that the pistons that came from another lt1 I had bought were not lt1 pistons but sbc pistons. You can use these but you need to use a sbc oil ring. Which is smaller? than the lt1 oil ring. So pretty much oil was getting past the rings at a huge rate. I think I still have a picture where I was turning the motor by hand and you could see the oil deposit on the cylinder wall.

 

The LT1 rings were what you used? They would be quite a bit different than say a 5/64ths or 1/16 inch ring. that a SBC normally uses.

 

Yeah it was my fist time rebuilding a motor. I did not know the difference. I used lt1 rings.