TheSamba.com :: View topic

Sat May 16, 2015 7:54 am

hey,

I have searched the forum quite a bit and I know this topic has probably been flogged also!;-) but I do have a question , I have the CB performance 1490 HD single springs . Is it necessary to have them shimmed ? I have read that this also protects the springs from chaffing the heads. Any truth to this or can I run them as they are without shims and not worry at all!

Any clearance on this topic would be welcome !

Sat May 16, 2015 8:15 am

Going to be like asking about pulleys. Everyone will say something different. Stock didn't have them and if you buy heads they won't have them. If your going to tune your valve train to your application, use them.

Sun May 17, 2015 12:13 pm

I install a .030 under each exhaust spring and a .060 under each intake spring with single springs. I shim race springs to .120 of coil bind. Everyone has their preferences. I at least like a single shim under each spring to prevent chafing of the spring perch.

Sun May 17, 2015 12:40 pm

I would shim them. but check first to see what they need or just to be sure there is no bind. race springs need to be about .050 from coil bind,some closer.street & daily driver if your not buzzing it and stay away from valve float then a .015 hard shim will do to protect the spring seat in most cases.never shim with out checking first..
I dont know why 56ovlk does 30 on ex&.060 on intake,probably dosent realy understand whats going on in there.and thats ok.

Sun May 17, 2015 1:02 pm

Thanks guys. Seems overall consensus is that shimming is necessary to prevent chaffing into the heads!!already have the 0.015 shims just need to widen the diameter a bit so that they fit under the springs!!:-)

Sun May 17, 2015 1:52 pm

Do not open the spring perch for a larger shim. Get a shim that fits. opening this area for a larger shim will allow the spring to move around. You want to keep the perch tight to the spring.

Sun May 17, 2015 2:01 pm

Yeah, just buy a pack of shims from Aircooled.net or another VW Shop. The reasoning behind thicker shims under the intake valve is that the intake valve is bigger and heavier than the exhaust valve so in theory would need more spring pressure.

Sun May 17, 2015 8:20 pm

correct on dont enlarge the spring pocket, but incorect on the thicker on the intake valve. what happens if you float the intake valve???usualy not a lot unless you go brain dead,but the exhaust is going toward the piston as the piston is going toward the ex valve :shock: crash!!! the intake valve is chasing the piston. same reason when you fly cut the piston for valves.the ex knotch is deeper for just that reason.

Sun May 17, 2015 11:28 pm

Will not the enlarge the spring pocket ,but my shims diameter is a bit smaller than expected and will not fit the spring pocket thus the need to enlarge the shim diameter itself and not the pocket.

Mon May 18, 2015 12:34 am

Most engines the springs are setup at a particular "installed height".
Most go by 1.550, So doing the bare minimum and following general advice you'd set them all at 1.550" give or take .020

now, to go a step further you check the springs for pressure and what height they coil bind, and can decide to set them at a different height depending on what valve lift you are running, or pressure you want.

Mon May 18, 2015 8:18 am

I receved a new set of heads that were less than 1.5 installed hight,1.48 as I recall.and no shims on the duel springs......somebody was asleep at the wheel or just didnt give a shit...or was just told to assemble& didnt know what else to do.shim it 4 times and it's still too tight :shock:

Mon May 18, 2015 8:55 am

I got some springs from web cam and they bind before they even get to .500 throw the shim and the spring away , lol

Mon May 18, 2015 9:29 am

raul arrese wrote: I got some springs from web cam and they bind before they even get to .500 throw the shim and the spring away , lol

Wow, what was the installed height?

Dan

Mon May 18, 2015 12:40 pm

Dan Ruddock wrote: raul arrese wrote: I got some springs from web cam and they bind before they even get to .500 throw the shim and the spring away , lol

Wow, what was the installed height?

Dan
I don't remember dan , maybe have it written down , but they were Brand new DRD heads