after 232K of operation, and running boost as high as 20psi with no means to measure EGT or detonation here is the pics of the engine tear down.
fully assembled engine/trans on the subframe
intake removed
timing belt was oil soaked to i just cut it to save time.
You can’t see it in the pictures but the right (front bank) cam seal poped out of place as was blowing a huge amount of oil from it.
rear bank cams removed. buckets and shims still in place.
Rear bank head removed. Note that there is one clean piston (cylinder 3)
closeup of the cylinder walls on the rear bank. This is typical of a high mile SHO engine. The ridge at the top is minimal and is pretty much limited to carbon buildup.
head off the front bank. Not seen well in the pictures. Cylinder 6 (far right) was full of oil. cylinder 1,2,4,5 look normal but the 2 far right cylinders are not normal. One is really clean and one is taking a bath in oil.
cylinder 6 bathing in oil
This is cylinder 2. I am no expert but this looks pretty normal for a high mile engine I think.
Head off the rear bank. Note how clean cylinder 3 is.
I have a low mile SHO engine on a stand waiting to go in the turbo car. The only problem is i’m waiting on a special order go fast part that needs to be installed before the engine goes in.
The block in the pictures will be cleaned and will recieve some 9:1 pistons and I will try and max my turbo out when its done later this summer.
The signs of detonation are the cracked ring lands and the wear pattern on the rod bearings. Ignoring the fact that it has 232k.
Detonation, while not severe enough to melt the dome of the piston, was present.
Please for the love of God. Since you have this engine out and I assume you are planning on rebuilding it. Do it right the first time. Take some time and money and actually use quality parts and do the job correctly. Get an EGT gauge. Tune the car properly this time. If you are not sure what you are doing, hire someone. It will save you lots in the long run.
I thought that cracked ring lands typically occur because the cylinder pressure is too high. What on the rod bearings gives signs of detonation? I’m not doubting you I just want to learn. In the past I have tried beating the shit out of the car in 90+ deg weather and pulled plugs but I never saw anything unusual on the plugs. We could never get the tuning software to show us that we were getting detonation. I think we went as high as 25deg of advance at 14psi. Actually I think that is where it was pretty much where we left the timing. That said I don’t know if the computer was pulling timing and not displaying it on the tweecer or if it was just letting it knock away.
The rod bearings have 33K on them. the car had sever rod knock at 199K and everyone said the engine was toast because it was audible but the crank was not scored and all the new bearings were on the tight side of the spec so I rolled with it.
For now I am dropping the boost to 10psi but I am installing a 3" exhaust instead of 2.5 and I will be installing a custom set of boost cams that are due to arrive today. The engine going in is another stock one except for cams this time. I am going to the dyno next week before carlsile and I am definately hoping for the 400WHP numbers… What is the break in period for new bearings?
More updates this weekend.
edit: forgot to add we used a AEM wideband for tuning. I never installed my EGT monitor but i did buy one.
If you notice most of the wear on teh bearings aren’t on the 12 and 6 O’clock positions but rather closer to 1 and 7. That usually gives signs of pre-ignition (detonation).
got the engine mostly put back together last night. todays project is to complete engine assembly and get that hore back in. If its not running today it should be for sure by tomorrow.
