IthinkItWasBlue Posted September 14, 2019 Share Posted September 14, 2019 Hello All! Hoping you can help me finish this BANE of a project and get it on the track where it belongs dam it! Ok the car is a 2002 WRX AWD, I have rebuilt the engine replacing the Crank and ConRod Bearings with King Racing spec. Lapped the valves, new seals and gaskets. Other mods include lightweight flywheel, ACL Clutch, Catalytic converter removal, straight headers and A/C removal. I have also switch my rear diff to a STi 6 speed spec.....which leads to my major problem... The car will not rev past 5k rpm. What am I missing? Could it be the diff? My other problem sounds like a crankshaft rattle, but surely the bearings haven't worn as the car only has 100 miles since the build. Could it be the Flywheel bearing that rattles? I feel a vibration through the car under heavy load and its it's pretty much the only part that hasn't been removed or replaced 🙈 Looking forward to some advice. Quote Link to comment Share on other sites More sharing options...
Tidgy Posted September 14, 2019 Share Posted September 14, 2019 are you sure its not piston slap your hearing? Quote Link to comment Share on other sites More sharing options...
IthinkItWasBlue Posted September 15, 2019 Author Share Posted September 15, 2019 I'm not sure what piston slap is, I assume it's the same as valves touching the piston? it's like a rattling sound but sounds higher up the block and resonates under the inter cooler. It's not constant only when you rev up over 3k rpm you start to notice. I replaced the Cylinder head on D/S from another engine, stripped and rebuilt the head replacing everything as I removed. Could it be the tappet discs need adjusting for clearance? Cheers Quote Link to comment Share on other sites More sharing options...
Jay762 Posted September 15, 2019 Share Posted September 15, 2019 Piston slap is the noise you get before the forged pistons warm up and expand to fill the bores with a closer tolerance - it should go when the engine is up to temperature 1 Quote Link to comment Share on other sites More sharing options...
IthinkItWasBlue Posted September 16, 2019 Author Share Posted September 16, 2019 Thank you mate, I'm learning every day. It does sound better after warm up, is it curable? I assume it will go after the engine runs in? My other problem is why I cant get past 5k rpm? Anyone had this malarkey after a rebuild? Quote Link to comment Share on other sites More sharing options...
Tidgy Posted September 16, 2019 Share Posted September 16, 2019 piston slap isnt needed to be cured, it's just a natural result of putting forged pistons in it, If your worried about it get it checked out by a specialist. Quote Link to comment Share on other sites More sharing options...
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