I'm curious what you guys know about the maximum and minimum side clearances for connecting rods. My manual says for stock steel .008 - .012 and for High-RPM Steel .008 - .015. I have a Scat 4340 crank that has extra radious journals and Lunati 4340 Streetrace rods. I am concirned because I have .022 clearance between the rods. Do I have a problem here or can I expect a little extra clearance because of the extra radiousing. I have the matching Clevite 77 bearings to go with the crank. I have shot off a email to Lunati but I am curious what you guys have to say. Thankyou for your input - Barry (Just for extra info the bearing clearances are bang on .002)

My Smokey Yunick book says .013" to .015". Says rod side clearance is not critical but if you get up to .025" then you are getting too loose.
Says extra side clearance allows excess oil to be thrown around on the cyl walls, etc.
David

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Check my web page for First Gen Camaro suspension info:
David's Motorsports page (http://ourworld.compuserve.com/homepages/David_Pozzi/)
First Gen Suspension Page (http://ourworld.compuserve.com/homepages/David_Pozzi/first_gen_suspension.htm)
67 RS 327 original owner. 69 Camaro Vintage Racer, 65 Lola T-70 Chev SB Can-Am Vintage Racer

Thanks David, I also got a response form Lunati and they said not to worry, They said anything up to .020 is fine. They said mine are a bit loose but I shouldn't worry. I'm still a little concirned but feel a little better about it. I also sent off a e-mail to Scat just to get their opinion as well. Thanks again for your post. - Barry

Pete,
It is easy enough to find out what is casuing it. There are specifications for the thickness of the rods, and the distance between the faces of the crank. The size of the radius has absolutely nothing to do with it. You need to measure the rods, if they are too thin, send them back. Same deal with the crank. If it's too wide, send it back. I personally am getting sick and tired of seeing some of the junk that the manufacturers are sending out now days. Even worse is the amount of time I have to spend checking it and then trying to explain to customers why they should send it back. One customer has brought me 3 (!) new 454 Chevy cranks and every one of them was junk in my opinion. Way too much taper in the rod journals etc. He has sent them all back. All in the name of trying to save a buck by purchasing a "inexpensive" crankshaft.
I know that the manufacturers are telling you it is ok, but are they going to come out and fix it when your motor is using oil due to the amount being thrown up on the cylinders by the extra clearance ? I doubt it. I think .022 is too much. Find out what the problem is, rods or crank, and get it fixed now, not after you put the motor in the car and have problems.
Jsut my 2 cents worth,

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Bill Koustenis
Owner
Advanced Automotive Machine
Waldorf Md
1971 Chevelle "Heavy Chevy" original owner
1973 Z-28 ..one family car...Brother bought it new in 73

Thanks for the advice Bill I will do the measuring and talk to my supplier and see what can be done. Thanks again - Barry

dont worry run it my buddy passed on a 377 just for that reason threw a fit at the builder who took it back an threw it in his own race car, the car has been raced every weekend and somenights and is very competitive and strong there is a article this month forget which rag about building motors with tight compression and loose bearings to eliminate friction an heat. this guy only runs 2-3 quarts oil and has 0 oil pressure at half track!!! go figure