Metal In Combustion Chamber

[Al Despo]

Hi guys, a friend was driving his r32 gtr when a sudden rattling started. We assumed it was bottom end and proceeded to replace the bearings which didn't look too bad which posed a few questions when we put it back together. Upon first crank over the noise was still there so we split the head and block

Inside cylinders 5&6 were bits of metal and stuck on top of the combustion chamber. So checking the turbos there was no visible sign of pieces missing thus far

So where could the shards come from in terms of the intake as two cylinders had the metal inside?

Car is 90 model Nismo edition and is stock apart from ball bearing turbos

I will post pics tomorrow

Thanks!

[MrStabby]

How do the valves and valve seats look?

[Al Despo]

Valves and seats look fine, the damage is only on the sides where the piston gets the closest to crunch the metel into the head. We also pulled the pistons out to check possibility of a ring letting go and somehow being sucked through the intake to the other cylinder but they were fine as well. Spent today also looking for any gizmos on the way through intake from the intercooler on and checking for bits of broken metal within etc. The bits that came out do look some sort of ring or washer.

So tomorrow will entail stripping the head apart, sending it away to get it checked for any possibility of something wrong and checking the turbos in more detail along with the intercooler in case anything could be still lodged assuming its come through the intake. Otherwise has to be put down to debris, but surely something must of let go.

Really blind to what the problem is.....

[mad082]

have you checked the tips of the sparkplugs?

[Al Despo]

have you checked the tips of the sparkplugs?

Yes we did before spliting the engine, the plan was to send a camera through the spark plug hole to see what was going on. In any case it was one of the first things that we had a look at but they are all in tact. If not anything like that, it might have to be said something has fallen or was placed somewhere along the intake during a previous service or something and has finally made its way into the cylinder. The car was breaking down at boost when warm before this but I cant this being a cause of that.

[Adriano]

Does it look like valve guide?

[Al Despo]

Not really but who knows the head is being checked anyway and so far i have been told its fine. At least the engine will get new bearings, rings and gaskets and an n1 oil pump lol

[luke gtr]

Tips if the injectors?

Highly doubful, but possible.

Post results if/when you find anything.

[Al Despo]

They're all good as well, probably find out tomorrow if it's anything in the head