Thread: Rod and main bearings

Tweet

1978 2bolt 454 30 over, crank turned 10 on the rods 10 on the mains, what kind of clearance will I need when I check with plasti gage? also crank end play clearance, at what cap do check end play, front/rear? Its been a long summer glad to be back.

i do not use plasic gage but can be from .001.5 to 003.5 rods about the same with the mains. crank end play can be .006 to .010 and that 5 cap last one with the thrust .i not telling were i set my bearing at it a on hear its a engine builder deal . not a smart A$$ thing . this has abit to do with how its going to be used bigger clearance size will let more oil past the bearing and you can have a lower oil psi . but i will tell you 002.5 on rods and mains and your good to go. make sure you set the upper cap so your running on the upper and lower part of #5 thrust bearing make sure you use some sealer on the end rail of #5 cap from rear main seal to the cap register

Yeah my engine builder doesn't tell me the clearances either. From what I read .002 to .003 on the high side for race/performance engine.

-Chris

Generally speaking, the motor will be faster with more clearance, but will be down on oil pressure. It's a balancing act.

the motorcycles i think was the suzuki GSXR i was checking for oil clearance .the guy ask me how much ? crank pin size was abit under 1.500 .very hi rpm i was thinking all of .002 one .001 per 1inch of journal size and abit more for hi rpm so 002 it was i thinking by the suzuki book was 003+ and at the time i did check the bearing shell it was not a delta wall bearing .so loose is fast .long as you can keep it running on the oil

Thank you for the input guys! looking through my hope cest of new parts , I think summit sold me the wrong rings,sealed power E-233K 30 I looked them up an info reads as, non file fit, the rings on the KB 203 pistons have to have x-amount of gap...u guys know, anyway, I dont want to file on a ring that is non file fit? give me a part number for good set rings 78 454 30 over 4speed
street mostly. thanks for the help.

you can end gap any ring set with a gap... i check end gap all the time and file fit to use if they need more gap your better with a 030 std ring set then a lets say a .035 thats less you have to file with the KBs