[bonnebird]

I am about to start assembly of a 455 bored .030" so 4.180 bore will an ARP part # ARP-900-1850 tapered ring compressor work in this instance it is advertised at 4.185

Thanks

[25stevem]

What pistons are you running ?
Since your posting in the street section I will assume that even if your running a forged piston that you do not have anything more then .004” piston to wall clearance.
This would make for your bore being a max of 4.184” which would then allow the tapered compressor your questioning to work as intended.

If your bore is dead nuts at 4.180” then you need one that’s no more then that size or maybe .001” smaller.

Find out from your machinist the exact size of your bore .

[racegto65]

Originally Posted by 25stevem

What pistons are you running ?
Since your posting in the street section I will assume that even if your running a forged piston that you do not have anything more then .004” piston to wall clearance.
This would make for your bore being a max of 4.184” which would then allow the tapered compressor your questioning to work as intended.

If your bore is dead nuts at 4.180” then you need one that’s no more then that size or maybe .001” smaller.

Find out from your machinist the exact size of your bore .

Actually most oversize pistons are made under by the amount to hone to the next oversize. 4.03 pistons are 4.028 etc. for cast and 4.026 for forged etc. as forged run a little more clearance for expansion.

As to the original question that is the compressor I use for .060 over 400 Pontiacs and Chevy's and .030 over 455 Pontiac's

[Dragncar]

I started to use a tapered ring compressor on my build. Did not feel tight enough for me. Was worried about breaking a ring.
Went back to my Summit adjustable tapered ring compressor as I could snug it up on the piston.
It went well.

[bonnebird]

Thanks for the reply's,
I am running older TRW L2359 pistons and the clearance is around .003" to .004" so I'm thinking the tapered compressor will be good to go.

[67Fbird]

so long as the machine shop did a PROFESSIONAL job ( chamfered the bore) you will be fine. Seems the idea of actually FINISHING machine work seems to be a LOST ART...my recent build required -.020 deck cut and what I got was razor sharp bores.....yeah $220 to cut .020" off and they can't even FINISH the job...

[Formulas]

actually if there is a generous chamfer 180° around the bore the skinny oil rail can expand on the way in and catch i would just knock it down enough not to be a knuckle hazzard

i just experienced this

[Formulas]

should of said 360° in previous post but i was unable to bring that forth

[track73]

I have a few tapered ring compressors that are adjustable. Just put in the piston sans rings and adjust until it slides without much effort.