Well I think i'm ready for machining. What sort of clearances for bottom end and mains using TA1541HP rod bearings and TA1551 main bearings? What sort of questions should I ask an engine rebuilder about BBB's to try and find one that knows what he is talking about?
One of the first things that I'd ask is about bearing clearances and make CERTAIN that he understands that Chevy clearances WON'T work. Also, it would help if he'll be boring your block with deck (torque) plates.
.0015 to .0020 max on rods and mains. Two thousands is okay for more of a strip car. One and a half is better for the street/strip car. I think a good # to shoot for is .0017" in a perfect world.
Hey Guys, Let me start of by saying that I do not build to many street engines. The engines that I am involved with are usually full race or street strip. But the more I get involved with Buick engines (or any engine) I am finding that the professional engine builders are going to larger clearances everywhere. There thoughts are... "I have seen many engines fail because the clearances are too tight but rarely see an engine fail because the clearances are too loose.". I have heard this several times. These are more like questions than statements..... Lets say you have .0015 of main bearing clearance. That would equal .00075 on each side of the bearing. If the main bore is off even a bit then you will no clearance somewhere. Or if you detonate the engine once it is likely to bend the crankshaft a bit and take out any clearance you may have on one side of the main journal. I guess what I am saying here is... to me... these clearances would seem like they are too tight. If you have an engine apart focus on getting the VOLUME of oil where it needs to be. Then run your bearing clearances up to .0025 minimum mains and .002 on the rods. Engine builders out there... does this make sense or am I crazy. OK... I am crazy.. we don't need to debate this but does it make sense. Thanks
Thanks for your input guys. John, I see your point. It will be interesting to see what others have to say on this topic. Royden
