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Talk about engine building here. New products, tricky questions or showcase your work - If it's engine building related it's welcome here.
= Resolved threads
Hi
Im in the process of rebuilding my engine and I was just wanting to check what the main and big end bearing clearances should be or what clearances people use on there 4G63 builds?
Thanks Dan
As discussed in the Engine Building Fundamentals course, the clearances are going to depend on what the engine will be used for. If you're looking at a stock or mildly modified engine then there's little reason to stray from the factory specifications. For our drag engine program we moved slightly looser than factory spec and ran 0.002" on the big ends and 0.0025 on the mains coupled with a Motul 300v 15W 50 oil.
Thanks for your reply Andre. The car will be running about 550bhp and will be revving to about 8500-9000rpm on the oem crank. The car will mainly be a track car. The clearance i have on my engine is 0.0023 mains and 0.0027 big end using a bore gauge with standard size race bearings. Will this be ok and what oil would you recommend?
Thanks Dan
You're a little looser than what I'd usually run but not out of the ball park. I'd still recommend an oil in the 15W-50 range.
For 500whp-600whp we do 0.00025 for the rod bearings and .00030 for the mains, This is very common in DSM's which share the same engine with your evo 2. so your clearances are about right using 15/40w
