Engine Noise

[nissannut]

I have an R33 GTR and just rebuilt the motor with replacement polished crankshaft, new bearings, forged rods and pistons, new water and oil pumps, crankshaft balancer, ported head and HKS GTSS turbos, APEXI Power FC and 90mm exhaust, Apexi boost controller etc etc.

420 BHP at all 4 wheels at 14 psi but the engine makes a tapping sound which gets louder when it warms up. It sounds similar to a spun bearing and is loudest near the bellhousing.

Its driving me and my (excellent) GTR-experienced mechanic nuts. All valve clearances are on spec. and it runs beautifully.

I would be very grateful for any suggestions!!!!!!!!!!!!!

[wrxhoon]

The way you described it sounds like a big end but not spun yet , just picked up and if you leave it she will spin . This could be due to several factors, only the engine assembler would know.

Possible factors, not enough clearance, to much clearance, not assembled with lube and by the time you built up oil pressure the bearing picked up, cranc not measured to make sure it was to spec , wrong bearings used even faulty bearings.. Put all these to your engine assembler and see what he says.

How many k's have done since the rebuild ?Is it getting worse?

[nissannut]

The way you described it sounds like a big end but not spun yet , just picked up and if you leave it she will spin . This could be due to several factors, only the engine assembler would know.

Possible factors, not enough clearance, to much clearance, not assembled with lube and by the time you built up oil pressure the bearing picked up, cranc not measured to make sure it was to spec , wrong bearings used even faulty bearings.. Put all these to your engine assembler and see what he says.

How many k's have done since the rebuild ?Is it getting worse?

I've done 4000 k's since the rebuild, and it may be a bit louder, but alternatively my paranoia may be incresing.

[Zas)-(]

I've done 4000 k's since the rebuild, and it may be a bit louder, but alternatively my paranoia may be incresing.

lol well im no bloody mechanic but from what ur saying most probably you shaved the head and thus its hittin on the head.. replace it to stock head and see what happens mite fixed your problems , maybe put a gasket to increase the height as the pistons would be clamming the head..

thats my idea... whoever shaved the head did too much...

remember mechanics do onething without giving thought on what the effects or strain would be on the other side of the engine..