BC valve springs

[suprarich]

Ok, here is the deal on the comp springs. They are .953 OD and rated at 55lbs seat pressure at an installed height of 1.5 inch. At 1.325 installed height the seat pressure jumps to 80.5 lbs. The coil bind is .950 so this leaves you a threshold of .375 lift or approx 9.5mm. The max lift should only be a certain percentage of the coil bind, which I would put at .350 or approx 8.86mm.

The open pressure of the spring at 1 inch (or .325 lift) would be 127 lbs

so these spring would be safe (lift wise)for any regrind or BC cam. For a cam in the 9mm and up range, I would use the ferrera dual set up.

 

[QWIKSTRIKE]

Ok, here is the deal on the comp springs. They are .953 OD and rated at 55lbs seat pressure at an installed height of 1.5 inch. At 1.325 installed height the seat pressure jumps to 80.5 lbs. The coil bind is .950 so this leaves you a threshold of .375 lift or approx 9.5mm. The max lift should only be a certain percentage of the coil bind, which I would put at .350 or approx 8.86mm.

The open pressure of the spring at 1 inch (or .325 lift) would be 127 lbs

so these spring would be safe (lift wise)for any regrind or BC cam. For a cam in the 9mm and up range, I would use the ferrera dual set up.

Thanks Rich.....awesome information to know. I knew that this was proven to be a decent spring from this data that you offered in that thread. You guys now have the low down on a very good competitively priced upgrade path.

 

[QWIKSTRIKE]

I have been running 7200 rpms on stock springs and retainers for over a year now with no drama. So the Comp Cams or BC springs should have no issues with 7200 to 7400 rpm.

Sean

An extra 700-900 rpm isn't taht much of a deal if the parts are not 200k old.lol Great info sean
If the parts are new 7m valve springs I may try this. The stock seated pressure is about 36-40psi seated. For 70.00 2nd day shipping the competition cam springs are a steal if you arent going over 7500 rpms IMHO

 

[Zazzn]

Stock 1jz i've taken up to 7500 RPM.

8400 on crower 2jz set on my 1jz.

 

[Jimmysmk3]

agreed all good info!

 

[JimR]

Does anyone have any long term reports of valvetrain wear or lack thereof using the Comp Cams 975's with stock or aftermarket cams?

 

[QWIKSTRIKE]

I have used them for years just take the plunge