Al2011

Hi everyone, I have a question that I can't find the answer too. Without you guys here I probably would of sold the car a long time ago and got a Chebby. I have a 455 motor that I believe is rebuilt but not 100% for sure. I was going to rebuild it again to put non stock parts, pistons, cam etc when I feel I have all the knowledge I need. Now I know there should be connecting rod side clearance but the motor I have apart only has a .002 clearance on two rods and the rest of the rods have no clearance. Not even .001 on the feeler gauge. What kind of problem would this make and how can it be corrected? Would this cause the motor to overheat? That would be my guess. Or will break in loosen them up after a while? Also what would this do too oil pressure? The motor came out of a running car but the guy that sold it too me said motor runs hot always. And yes I can turn the crank by hand but they are touching except for one.

Thanks you all for all your help!!!

Oldsmaniac

Are you prying the rods apart when measuring....the specs are in the shop manual...I dont have mine here to look up...

Al2011

No I didn't pry them. I was looking at the link below, didn't look like he was prying. I have the correct specs for street or strip but what would happen if they are all touching each other w/o any clearance specs? Can the rods be bent? I'm just looking for any mistakes the first builder made so i won't make the same

http://www.popularhotrodding.com/tec.../photo_13.html

don71

Tv shows and magizines rarely tell you everything you need to know.

If you carefully rap on the crank snout backward with a wooden block and hammer, then rap it forward from the fly wheel side, You can then take your measurements. If the engine is on a stand, you'll have to pry on the flange at the rear,because you wont be able to swing the hammer back there.

In other words, knock the crank back and forth a coulple of times along its length. You don't have to beat on it, just give it a good thump. In some assembly manuals like GM, they call this "tonking".

don71

The service manual says pry with a screw driver.

Clearances are .002"-.011"

Al2011

Thanks for the replies, I'll give that a try as soon as I get home today. So do you mean to pry where the sides of the rods meet?

J-(Chicago)

I set mine up bigger than the .011 tolerance, and I haven't had a problem yet in 3 years of beating the snot out of it. Mine are more like .018"-.024" I'm also using a 8 quart pan and a high volume pump though.

Rick Finsta over on ROP is running high 11s with .030" Rod side clearance.

I'm not saying to open them up, just letting you know that you can probably get away with "close enough" on that spec.

don71

Yes

cutlassefi

You should be able to just pull the rods apart with your fingers.
Tapping the crank back and forth is usually reserved for check crank thrust clearance not rod side clearance. The rods may not necessarily spread apart when you do that anyway.

If you have around .015 or better you'll usually be fine with most any application. If you don't have enough you'll need to pull one rod/piston off each journal and surface the side of the rod big end.