how much CCP for compression releases

[george248]

Someone told me the Andrews 55 would be a little soft on the bottom at 10.3:1 and 190 ccp.   Wiseco pop-ups would give me 10.6:1 and 197.7 with the 55 cam.  Is this too much ccp?  What would be ideal for this cam?  Andrews says 9.8 to 10.2 so what gives?  They must be very conservative with the compression figures.

[Midnight Toker]

O.K., I’ll take crack at it. I think what Andrews recommends is for the average user; rather safe than sorry.
Do you have a carb or EFI? I think 10.3:1 or so would be just fine for the 55’s. when you increase your compression, tuning your motor becomes the issue. As for as compression releases, the old rule of thumb is 185ccp, that’s where you have to start considering the releases. 190 and on, compression releases will save your starting system from certain death.
I hope this hacks response is up to par.

MT

[larluvssandra]

I'm running the 55g cams at 10.4 cr, and a good 198 ccp.  I recommend the releases for sure, think you would be sorry if you don't.  I don't think you would be disappointed with those cams and 10.3 cr.  I wouldn't recommend any more comp.
Larry

[taz95dog]

george , i'm using the 55-g too(also my brother does too).we both have c/r of me-10.25 him 10.5,i have 175ccp, he is around 200ccp. both bikes run strong.by the way i'm at 2300 ft .he is at sea level.we both use c/r,comes in handy on hot restarts. it won't hurt to have them;and it should help...good luck...taz...

[Herko]

IMHO, if you send a set of heads to a porter, have him go ahead and drill/tap for the CR's while the heads are there. Pretty cost effective.
Then later on, if you want to install the Domes of the Himalaya's pistons, just screw in the CR's.

[Scramjet]

George,

I set up the wife's 95"/SE211 cam in a 2006 softale at 185 ccp.  It starts like butter.  We do not need compressoin releases on that build.  I run a 2007 with 200 ccp that has had numerous starter problems.  The 2007 and later bikes have a different starter arrangement that seems to struggle at higher compression.  With that being said, a buddy has 197 CCP on a 2007 that seems to start just fine.  He has compression releases but he rarely, if ever, uses them and has no problems starting.

B

[maineultraclassic]

I have 195 CCP and I use my compression releases all the time.

I really don't need to use them all the time, but it sure makes it easier for the starter...........and they sound cool too.

Steve