Main and Rod Bearing Clearance on a Street/Race Engine

[blackgn1]

What's the ideal bearing clearances on a more race directed engine? I have used the search function for about an hour and a half. Everyone has thier opinion. I see .0015-.002 more than any clearance. I don't want to beat a dead horse. Let's say we are using an aftermarket crank most likely a stroker crank. RPM's questionable. Over 6000.

 

[750H.P.V6]

.0015" is a bit tight for a high H.P. engine. I'd go with .002"-.0025"myself. If it was just a street motor with less than 500H.P. .002" would be fine. Why not ask Russ what he likes?

Neal

 

[TurboBuRick]

IMO Little looser is better.

 

[blackgn1]

I have'nt talked to Russ in quite a while. Wonder if he's going to get back in this madness? I have noticed that in the 80's and early 90's Stage Engine guys were running .0023-.0027 I'm not sure what clearances they would be using today. You guys numbers are about what I was thinking. Thanks everyone!!!!

 

[Chris Hogeland]

.002/.0025 and you will be fine.

 

[turbodave231]

If you have a very good crank (very little journal runnout, taper or out of round) you can run tighter clearances. If the crank is questionable or has out or round, more clearance is needed to avoid grabbing a bearing. I prefer to set them up tight. in the .0017-.0022 range for a street application. A little looser for a race only application .0019-.0025. Just my opinion of course.

 

[blackgn1]

I will be using a new crank. Most likely a TA or Webber Stroker Crank. I'm having problems trying to figure out these bearing clearances. Rather which clearance is best. I fell sure I want to run over 6000rpm. I want to turn it up if I'm going to spend this kind of money. I've been deburring the inside of my block when I'm not turning wrenches on the car. Pan rails have been decked. I have hours of work to go before it goes to the machine shop for line bore/hone, cylinders bored, decked, girdle installed, ect. I've got to get the bearing clearances decided soon. Thanks for all the replys.