My LS1 Motor tanked on me....Time to build a Forged 408 :)

[S2H]

I went to a car show/cruise in/get together on tuesday night...
I was hammering in the car a lot on the way home cause it was nice out and I was having fun...
wednesday... I didnt do squat..car sat parked..
thursday morning... went to change the plugs out and the new ones fouled immediately, lots of white smoke and some fluid coming out of the exhaust.

not sure exactly when it went south.. but it was all good when I drove to the gathering in tuesday...so I'm guessing it happened on the way home
and I really didnt check it when I got home because it was late and dark and I was too tired to care or look at teh back of the car..I sat in the car for a few minutes before I got out because I was finishing up a phone call


I've always had a little bit of a puff of white smoke when hot, and its always used 1/2 qt of oil every 3000 miles... I didnt think much of it because LS1's are notorious for using oil...

did a compression test.. and got 85ish psi on all cylinders... low for a stock ls1, but I have a huge cam with a lot of overlap..

the car made 408/398 on a dynocom dyno that seems to match right up with a mustang dyno...

anyways...
tearing into the motor tomorrow evening. I'm gonna guess on the rings.
fluid that was coming out seems to be oil...and quite a bit of it.. has a slight smell of gasoline, so fuel is probably getting past the rings somewhere and into the oil...

really no idea what exact thing caused it..figure its been on its way out for a while and it just finally went over the edge on the drive home


gives me an excuse to buy the new motor..
I had plans to buy a TCI 6x Racing transmission first.. then a forged 408, followed by a maggie...
guess the order is reversed now...first comes the forged 408, then transmission, then the maggie

[69lt1bird]

Sorry to hear about the engine. White smoke would have been you burning coolant.
I broke ring lands o two pistons last fall after playing at the drag strip. Factory ring gaps are too tight and they took out the lands between the compression rings and the bottom ring and oil rings on two pistons.

[ctd]

I feel the pain!

Mine was on the dyno recently, I've always had a slight vapor/mist escape from the filter breather cap.

That turned to smoke then oil while on the dyno, did not run real nice on the way home. I wasn't sure I was going to get home.

I've been asked if I have done a compression test or leak down, don't need to has been my response.

Here is a good one, I did a cylinder balance test via the scanner............all is good!

When I contacted Tony Mamo from AFR, he hand finished the cylinder heads & Fast 90/90, he said I could just go directly #7 cylinder. There I would find the problem.

I have some done searching into this as to why, back cylinders are the problem most every time. The agreed failure is heat, it is just if it is caused by cooling or fuel.

You may find this of some value depending on what you find.

http://www.ls1tech.com/forums/6180624-post24.html

[69lt1bird]

Mine broke 5 and 7. That is one reason for buying flow tested injectors, always put the fattest ones in the back, helps with potential lean fueling issues.
Mine ran fine going home, like Scott, it sat and then when I fired it up it developed an oil leak, pushing the dipstick tube out of the block, too oil filler cap off it looked like Old Faithful belching out smoke. Had 200 psi on 6 holes and 85 on 5 and 7. OOPs

[ctd]

Did you go with forged pistons on the rebuild?

[69lt1bird]

No, I never plan on spaying or going FI so there is no need for forged in my case.
Coated Speed Pro replacements and Hastings rings. So far so good.

[S2H]

Sorry to hear about the engine. White smoke would have been you burning coolant.
I broke ring lands o two pistons last fall after playing at the drag strip. Factory ring gaps are too tight and they took out the lands between the compression rings and the bottom ring and oil rings on two pistons.

except there's no missing coolant...and the combustion leak test was negative....
its definitely oil... trust me...its fairly obvious by the feel of the liquid coming out of the pipes.. LOL

I just gotta figure out who I want my shortblock from...
theres a hand full of places I trust.... none of them open till tuesday..

stupid labor day weekend....
guess I wont be going to the holley ls fest either now...LOL
was only gonna be able to make it on the 3rd day... but now I'm not going at all

[S2H]

one of the tests I did was unplugging one bank of injectors...
passenger side... no smoke... drivers side, only one that didnt cause smoke was #3
1/3/5 all smoked as I added them to the mix...

gotta say though... my car idles pretty dam good on 4 cylinders...LOL

[ctd]

Way to many horror stories & short blocks, I think the list is very small with whom to trust.

I'm keeping mine simple, LS3 & a stroke crank. Slight hone to insure the bores are true. Forged pistons as a safety measure.

A bit more cam as well, going from 346 to 416.

More tuning practice.

[S2H]

I'm positive mine has been on its way out for a while now...
have had a little oil pressure tick for as long as I've owned it...probably started with the previous owner...
oil pressure sits at 40ish... but once in a while it drops a little and then comes back up
pretty sure its not the sender..LOL

and I beat the tar out of it all the time.. I bought it as a daily driver / toy
and I have a backup vehicle.


whole reason I want to go 408 is to keep it simple..make good power.. and be able to move over all my existing stuff that I have on the LS1 and only have o buy a few small things to complete the engine.

[ctd]

Mine is a C5 so the complete drive-line hits the lower deck.

I will need to upgrade the clutch for the second time, have rear diff upgraded so I don't twist the output shafts off, trans brace, on & on it goes. The motor will almost be minor compared to the rest.

I could have purchased a C6 Z06 by the time I'm done this round.

The journey has been & still is good fun, I would have missed all the steps if I had gone that way though.

I've never considered financial independence to be that important!

[TXZ0603]

Sorry to hear bro. I know the pain of it though. My 7K forged boosted motor is puffing some oil. Although for mine, all the compression is good and only 10-15% leak down on 2 cylinders. This damn hobby sucks some times

[S2H]

at least I'm not going thru motors as bad as when I raced a pro stock alcohol car...LOL
under 7 seconds in a 1/4 mile = lots of parts to replace all the time..LOL