[RT]

I'm reassembling my .030 over 454 and have been checking the torque at each piston. At the second, I had 7#. Then when I put in the third, it jumped up to 24#. Uh oh, something wrong here, so I pulled out the piston, checked everything over and found a slight discolored line on the cylinder wall at about the location of one of the oil rails. Not a scratch in the wall, b/c I couldn't feel anything, but something I could see. I removed the rings, checked everything over, reinstalled them and then reinstalled the piston checking the torque reading as I tightened the bearing cap. This time, I got 12# (+ or _). I installed the 4th piston and am at about 15#'s.
Anyone have experience with this? I can't understand what would have made the third piston so tight.
Thanks,
Rich

 

[GRUMPYVETTE]

obviously youll want to check the piston to bore clearance at several locations along the circumference of the bore to piston clearance, and check the blocks cylinder bore for consistent diam. and the bore being truly round in shape and but don,t forget to check the piston ring groove back clearance in the ring grooves and the ring end gaps plus look for piston pin bind in the piston pin bore, look for rod journals that are tapered or out of round and connecting rods with a big end thats not round or bearing that are not consistent in diameter across the bearing bore, but Ive also occasionally seen guys try to install rods without checking side clearance or who failed to get the correct side of the connecting rods facing each other or guys using rod bearings that didn,t have the correct edge bevel to clear the journal s radias edge, usually the narrower clevite (H) series have extra clearance

 

[jackie schmidt]

It' real easy to "curl" an oil ring. But you checked that obviously.

 

[RT]

It' real easy to "curl" an oil ring. But you checked that obviously.

Thanks for both of your responses, but the oil ring "curling" seems very likely to me.
Rich

 

[BillK]

Rich,
I don't know how accurate the torque deal is but it sounds like you may have had the oil rings on wrong the first time. Some brands of rings can be a pain to get them on right. I guess if you do enough of them you almost get to where you can feel it when you push the piston in the hole. You should pretty much be able to push it in by hand pretty easily. Sounds like you got it straightened out ok though

 

[RT]

Thanks Bill, Everything looked fine when I pulled it back out, so I wiped everything down, double checked the compression ring gaps, re-oiled and reinstalled. That seemed to do it. I guess an oil rail got out of place as it went into the bore, can't explain it any other way.
BTW, I found a video of a guy installing pistons by wiggling them into the bore instead of the more common "tap them with the back of a hammer" method and I tried it, but it wouldn't work for me.

Thanks,
Rich