Thread: Rod Clearance too tight

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Tight is usually a good thing however I have measured the rod bearing clearance on the first 2 cylinders and I get .0015". The normal range for Hipo street is .002-.003. The bearings are King brand and crank and rods are std scat with capscrew ARP.
Unfortunately, beacause I have checked this clearance twice and have over- stretched the bolts. Out of the box, the bolts measured 1.944 now they are 1.956. When I checked the clearances, I torqued at 55 psi. I've never experienced these issues before. Anybody have any suggestions. Thanks

i buy bearings and fit the crank buy a 1X bearing and split it that will get you 002 if your at 1.5 or use the hole 1X you will come in at 002.5 every engine i build i check and fit the bearings you can get small and big bearing in a set . i start out checking housing bores and making them where i want them if i have to .so i know were i am at i buy more then one set of rods and mains to hand fit the crank .how are you checking them . as for your bolts they will streched there coming to the strech spec on the bolt your ok .over a build i will run the bolts up and down many times check housing bore size check bearing size and build engine we have re used bolts were they been up and down 20 times i never lost one from this .after 2 rebuild i pitch the bolts less in spec about the 3 time around the rods get a rebuild this is not that big of a deal .i keep alot of bearings on hand i do not have a crank grinder and if a good crank i like not to grind on new cranks or a good used one so i will fit them.. hey jerry he is in FL want to take a ride

How did you check the clearance???

Many times I have have peolpe come back to me saying clearances were too tight--they had used plasticguage---took rods (or mains) torqued up, set the crank size on my Sunnen guage, and the rod or main had the clearance needed---It has always been a plastic guage and too tight deal that didn't prove out to be tight--- but keep checking

Originally Posted by jerry clayton

How did you check the clearance???

Many times I have have peolpe come back to me saying clearances were too tight--they had used plasticguage---took rods (or mains) torqued up, set the crank size on my Sunnen guage, and the rod or main had the clearance needed---It has always been a plastic guage and too tight deal that didn't prove out to be tight--- but keep checking

yep it is not that close on rods we tested some time ago seams on rods it reads small .hard to beat the sunnen

Thanks for the replies guys. Yes, I did use plastigauge. I adhere strictly to the procedure for using plastigauge. I have not checked with micrometers. I pretty much gave up after checking number1 and 2 cylinders when I read .0015''. I used the green plasticgauge with nothing to keep it in place and torqued to 55#.
Because I have stretched the first 2 cylinder bolts (4bolts) do you think that when i install the first 2 cylinders again, i should simply torque them and use a stretch gauge on the remaining cylinders? Thanks again.

Originally Posted by flanker1970

Thanks for the replies guys. Yes, I did use plastigauge. I adhere strictly to the procedure for using plastigauge. I have not checked with micrometers. I pretty much gave up after checking number1 and 2 cylinders when I read .0015''. I used the green plasticgauge with nothing to keep it in place and torqued to 55#.
Because I have stretched the first 2 cylinder bolts (4bolts) do you think that when i install the first 2 cylinders again, i should simply torque them and use a stretch gauge on the remaining cylinders? Thanks again.

take one of your rods you check and use a bore gauge .find some one that has one or buy one there not to much if you buy a cheap one on E bay sunnen is the best but $$ you can find them used on e bay if your building engines alot it good to have .that s the only way to check them. mic your crank . then with your mic set. O off a bore gauge to mic.check your rod with bearing in it all tq from 12:00 and 6:00 see what you have now if its 1.5 or 002 or ?