thanks Frew. does anybody know the lift on these cams? i need to let ZZP know so they can tell me if I also need to buy their retainers w/ their 78# valve springs so i dont get "coil bind"

 

i dont know the lift, but im pretty sure the gmr cams will work with supertechs 78# valve springs and retainers

 

bill. they were used for a few races.

 

yep. thats what Area ran IIRC

 

and solid lifters.

 

if you dont have solid lifters... dont buy this.

 

actually im buying ZZP's valve springs and need to find out if I need their retainers. Also, I looked at cimotorsports.com b/c they have solid lifters but its for the 2.2. I e-mailed them to see if they fit my '07 cobalt SS and im waiting for a reply.

 

yes. all cobalt ecotecs use the same valvetrain (excluding valves and cams)

 

wait a minute, our cars have overhead cams...so that means we dont have lifters right? the cam hits the valves directly.

 

You have a piece that acts like a lifter. It is called and adjuster, hydraulic valve lash.

 

so i would be buying the part that the spring sits around?

 

http://www.gmpartsdirect.com/catalog/frameset.cfm

heres an explosion of the head, this might give you a better idea of what you will need

the link doesnt work correctly, type in our car into the bar, then from the left side of the page click engine, then cylinder head, then choose cylinder from the center of the screen, then click view illustration

 

hydraulic lash adjuster. sits under the rocker arm . we don't have bmw's, or lash caps like in toyota's. you can run these cams on stock lifters. for a very short time before they over extend due to the smaller base circle on the cam itself.

 

before what over extends? smaller base circle on the cam...you mean smaller lobes? im sorry, i dont quite understand

 

before the stock lifters overextend, since the gmr are regrinds they have a smaller base circle on the cam

 

gotcha. if these are regrinds, which means that they regrind the stock cam, then how do they make anymore performance since you cant make the lobes any larger?

 

These were made from "blanks" That were purchased from the plant in Germany partial ground. Cam bearing lobes and ends were machined but the lobes were left un-machined to allow for the proper grind with out having to make the bas circle smaller.

 

alright. thanks a lot guys

 

Here are the cam profile curves. The provide assuming a 1.69 rocker ration a max lift of .441 in for the intake and .437 in for the Exhaust cam.

 

If anyone here is looking to get their hands on another set of the gmr cams, I have a set as well. Like mentioned before, there are other parts needed to get these to work right.

 

The head profiles are the same for all three models. The 2.0 head and 2.2 head are compatible as far as parts go.

 

kool

 

Yep, only difference is you can shim the solid lifters on a 2.2, but not on a 2.0 head
As long as you are following the build book method to adjust them (with a lathe) of choose the BLE ones, no difference

 

They have higher lift than production so you will need sprins as a minimum. When I ran them in the Land speed record engines we used solid lifters. I never ran them without solid lifters so i can not comment on how they would work with the hydraulic.

 

Can someone knowlegable please state some fact about the GMR cams? (Mine are still in the box waiting on the winterbuild but and I read now several conflicting things about these.)

- Regrinds or not? (Base circle diameter GMR vs. stock)

- Exact problem with standard lash adjusters. (Overextending or just collapsing because of agressive profile?)

- Solutions for the above.

- Best CR to go with these? Will these effectively lower dynamic compression? (Build book was raised to 10.0:1 and Area said something similar about not working that good with the LSJ's 9.5:1...)

Thxs,

Frank