Currently I have a CompCam XR282HR Roller Retrofit Cam combined with a pair of 190cc AirFlowResearch Heads (#8015) which already came with valve springs that are similar to the springs recommended for this grind. The only difference being that the CompCam Springs are dual springs while the AFR springs are Single.

My question is... Will the single springs part# 8020 on the AFR heads work well with the XR282HR cam or should I just ditch them and use the Dual Spring from CompCam?

The reason I ask is when I ordered the AFR heads, I told the guy what I intended to install and I assumed I would get the all matched parts on my head when ordered. But after more than a year using this combo, I was looking through my old invoice from AFR and found that the springs are Intended for Hydraulic Cam not a Roller Cam. Now I am wondering if I am being cheated out of some horsepower at high RPM because of my Springs.


The specs are as follows:

** edited 7/14/2004 **
INCORRECT specs. AFR part # 8020 are DUAL springs.
** see updated specs 12 posts below **

Specification for AirFlowResearch Springs (AFR part#8020):
*Outside diameter 1.437 in.
*Inside diameter .720 in.
*Seat Load 120 lbs at 1.800 in.
*Open Load 300 lbs at 1.250 in.
*Coil Bind 1.090 in.
*Rate 325 lbs.
*Max recommended Lift .550

Specifications for CompCams Dual Springs (part# 986-16):
* Outside diameter: 1.430 in.
* Inside diameter: .697 in.
* Seat Load: 120 lbs. at 1.750 in.
* Open Load: 280 lbs. at 1.250 in.
* Coil Bind: 1.150 in.
* Rate: 296 lbs.

Spec for CompCam Grind XR282HR (12-432-8):
Roller Cam Retrofit
Dur @ .050 230 in, 236 ex
Valve lift .510 in, .520 ex @ 1.5 ratio

Thanks

 

As cheap as springs are, I'd suggest getting what the cam mfr recommends. Substituting valve springs is all about risk / reward: in this case, moderate to large risk, very little reward.

 

replace them, springs are cheap. look for springs from comp, lunati, or crane they all make good stuff. stay away from gmpp and k motion among others.

 

Do you know the installed height of the springs?
120 of seat pressure seems reasonable, but what seat pressure do you want?
The AFR springs look ok for lift.

 

The difference between single springs and double springs, is the number of springs. (duh)

What that means, is that in a single spring, one individual spring is doing all the work; in a double spring, it's split between 2.

A spring is a coil of wire. As it goes through life being used, it bends. When it bends, it heats up. Take a piece of coat hanger wire, bend it a few times as fast as you can until it breaks, and feel the ends immediately. When you get through cursing me, you'll understand better what happens to springs.

Since dual springs spread work load between 2 springs, they also spread the heating effect out, making each incremental length of the wire run at a lower temp. The cooler they run, the longer they'll last. Springs that reach the end of their service life of bending back and forth do a most disturbing thing (just like that coat hanger wire): they break. When that happens, the valve drops into the cylinder; and the results are never pretty. Without going into details, let's just say that valve fragments are incompressible.

Plus, with dual springs, if one breaks, the other (hopefully) will still be there; and the valve won't fall in.

As cheap as it is to do the right thing, it would be unwise to leave the stock AFR stuff (which is known to cause trouble) on there. Do the right thing, you'll be glad you did. Do the wrong thing, you'll more than likely wish real hard you had done the right thing when you had the chance.

 

I am not sure what the installed height is but after thinking about it, I think I will just go with the springs that CompCams recommend.

RB83L69 finally knocked some sense into me. Thanks RB..

Now I wonder if the CompCams Dual Springs (part# 986-16) will fit in the AFR 190cc heads.

But now I am faced with new questions...

Would I need new retainers?

Do the Dual Springs fit in the heads without machining or other mods? Do I need shims?

Does anyone have any insight into this new delema?

Thanks

 

Just call Comp and they will tell you what springs to go with for that cam. I'm about 99% sure the 986-16 springs will fit your heads. I run those on my AFR's. If worried about how the springs will fit, just take your heads to a reputable machine/head shop. Another good idea would be to have your springs pressure tested to make sure you got the right springs. My car didn't even have the right springs on it when I bought it, because they weren't checked. It had a set of solid roller springs on the heads, which were way too strong and damaging to the hyd. roller lifters. I'd definitlely suggest a set of Comp or Trickflow titaniam retainers. Anything that will lighten up the valvetrain will help power and wear on the engine.

 

If the retainers you have are the right diameter (1.45" outer, more or less) and have the right step on the underside for the inner spring, then you can re-use them.

The springs should fit in the pocket. IIRC AFR uses .530" OD guides, which are a good bit smaller than the inner diameter of the 986 inner. You can even use Teflon valve guide seals if you want to, there should be enough clearance for that.

As far as shims, you'd just need to measure the "installed height" of the spring; i.e. the distance from the bottom of the retainer, to the surface of the spring pocket. Use shims to bring it to the spec height. Being aluminum heads, you definitely want to use some amount of shims; the springs will dig into the casting if you don't.

If your retainers are shaped like this, and have the right diameters in the right places (see http://www.compcams.com/Technical/Cu...ML/340-349.asp for the 986 dimensions) they'll work.

 

Ummmm, like this....

 

Thanks guys for your input.

One thing puzzles me is that after reviewing the Valve chart. My XR282HR cam has a lift of .510 intake .520 exhuast. The spring that CompCams recommends for this cam is 986-16 which, according to the list, can only take a MAX lift of .500.

Still I am going to give the guys at CompCams and get thed right springs that should go with my Cam.

Thanks again for everyones input.

 

RBL8369... Thanks for the visual on retainer.

 

Just a hunch but Comp will probably recommend the 987 springs for that cam. I run the 987s in my AFRs and didn't have to machine the spring pockets.

 

I AM A MAJOR BONEHEAD!!!

At the Begining of this post, I stated the AFR Springs # 8020 were single spring... WELL I WAS WRONG!!!. THEY ARE DUAL SPRING!!! The CORRECT specs are as follows:

Specification for AirFlowResearch Springs (AFR part#8020):
* DUAL SPRING.
*Outside diameter 1.437 in.
*Inside diameter .720 in.
*Seat Load 120 lbs at 1.800 in.
*Open Load 300 lbs at 1.250 in.
*Coil Bind 1.090 in.
*Rate 325 lbs.
*Max recommended Lift .550

Since I hear that the AFR springs are not very good, I may still go with the Comp 987 springs. But the AFR Studs are out for sure though. I'm going with ARP studs for roller rockers (little longer).

Just wanted to update this thread for anyone who may use this info for future reference.