Ok so after a week after putting back the engine together with the new heads and everything, the car was running great. But on Friday after taking it to the tuner in the morning we went back to the shop in the evening to check up on how the car was doing. So then the tuner tells us that there was a knocking sound in the engine. So after inspecting it and trying to figure out where the noise was coming from, we thought it was coming from the head. We did a compression test and all cylinders got 160 psi except for the cylinder close to the firewall drivers side, that one had only 130 psi of compression. Its the same side where the knocking noise seems to come from. So after we took out the left head, all the valves seem to be good. But we notice some chips in the cylinder head right by the valves the same chips were on the piston, only on one side of the piston. All of the pistons seem to be chipped and so is the head. Is looks like if someone took a screwdriver and started hammering on the pistons and the head. I'm pretty sure its not the valves that were hitting against the piston since the chips to the side of the valves.And the engine had been running great for a week with no problems at all.

So what can these chips be from?

The crankshaft seal almost blew out too causing it to leak oil.

Mods:

Stage 2 plus Crower cams
PI head swap, Ported and polished.

 

You had bad detonation. Number 8 cylinder is usually the one to show the worse signs which it seems to be on your car. Was it doing anything wrong before you took it to the tuner? Was he tuning for your nitrous?

Basicly your engine is toast and needs a rebuild.

 

Yeah i was thinking it was maybe detonation. But where would the knocking sound come from? Detonation itself?

Yeah the stang was running great for one week, with no problems. I only WOT it like 3 times. And on friday when i went back, he just told me it had a knocking sound. At this point I really think its his fault. He is a Diablo Tuner dealer and he supposadely does custom tunes (street tune).

 

Okay so he fould what the problem was. The used PI intake manifold he had bought (from a member on here) had metal pieces inside, thats probabably the reason why it was parted out, the previous intake manifold owner probably messed up his engine too. So all these metal pieces got in between the piston and the head and thats why there's chips in the piston and on the head. And it also seems that on only one head, the valves seems to be slightly hitting the piston. He is 100% sure there hitting with the piston.

But why would it all of the sudden would the valves hit the piston? Can this be caused by over rev's? I find it hard to believe that the tuner adjusted timing so much that it would start doing this.

 

If you were detonating then the knocking sound is more then likely spun bearings. You will find out when you disassemble it. Did you see the metal picese in the intake? This all sounds kinda fishy.

 

Yeah, at this point im thinking the tuner threw some metal pieces inside the intake mani. Cause as soon as we got there he said he could take it apart for $250 dlls just to see what was wrong with it.


Okay guys, so here is a question. My friend is 100% sure the valves were hitting with the piston just barely. So lets say the tuner moved timing so much that it made the valves kiss the piston. So now, what can I do to undo all the timing settings he did? Cuz if I put it back together the valves will probably start hitting the piston again. So how can I move timing or how Can I adjust it again to stock?

I have the Diablo Sport tuner, and he was tunning it with the diablo sport. He is a dealer.

 

There is nothing the tuner could have done to make the valves start hitting the pistons. He would have to pull the front of the engine apart to do that. More then likely what he did was add too much spark timing and detonated the hell out of your engine. If your valves were hitting then its your fault.

 

There are metal pieces in the intake, and the piston only has chips. The metal pieces that I found are much bigger and they are also in between the piston and the head, i have no idea where they came from. And how can the valves hitting the piston be my fault? If it were my fault the valves would of started hitting since day 1, when the engine was put together. It had been a week and the engine was running great.


So how can I go back to stock timing settings?

I thought this forum was more active..............