Shim over or under the bucket? - That is the question.
Give me all your thoughts and experiences.

Our parts cost enough the way it is, and when you multiply it by two for DOHC then its really costly. The last thing I wanna do is spend money for aftermarket shim-under-buckets to go with my new cams and springs if I don't realy have to, but if its a significant gain on reliability then I'm all for it.

The only real gain I'm seeing is that the bucket will retain the shim from flying around inside the head and doing further damage, in the event of a spring shattering. Is spring shattering an issue? I know Marky had it happen, anybody else? Is there any other plus that I'm not recognizing? If so then I want to know.
I would like to hear both sides of the story though, so please - chime away.

 

Shim under bucket is usually a lighter, therefore higher revving design, and it shouldn't "fly off", so it is "safer". Shim on bucket means you can adjust the valves without removing the cams. Heavier design, as the shim has to be large enough to accept the cam lobe, it also takes the wear and is cheaper to replace than the bucket itself. [img]i/expressions/face-icon-small-cool.gif[/img] I've adjusted the valves on a couple of Ferraris, shim on bucket, pretty cool.

 

I'm curious - how do you change shims without removing cams with a shim-on-bucket? I've only adjusted valves on my DS, and i removed the cams to change the shims. It poved tricky to get the shims off the buckets - I had to use a needle forced between them at the little groove that the stock buckets have on each side.

 

Hightower
A trick to get the shims out of the bucket is when they are stuck ,take a blow gun and at the edge of the shim blow it out.The air breaks the vacum on the bucket. Becareful it will blow it out of you hand and into the motor.Then you will be fishing for it.
J Ross

 

I think piece of mind with a high rev engine is worth it to me- after Marky's incident there was no doubt what I wanted. Web Cams has the kit that includes the shim underbucket, titanium retainers and double valve springs that are the stiffest springs I've ever seen. Price wasn't too bad either.
I guess it really depends on the other mods you have in mind and what power level you're trying to reach.

 

You need some trick tools. I haven't adjusted the DS valves, but for Ferrari I have a couple of trick screwdrivers with big bends in the ends. I force one between the cam and bucket, depressing the bucket and opening the valve. Then I put the other bent screwdriver between the cam and the lip of the bucket. Then I have a pair of funny pliers that reach around the cam and grab the shim through those two slots. You have to make sure those slots are to the outside before you start. I also have a dial gauge set up so I can measure the shims as they come out and go back in. [img]i/expressions/face-icon-small-cool.gif[/img]

 

Thanks a lot guys.
The needle works just as easy as compressed air - its a trick I picked up as a kid getting stuck legos apart.
I just didn't know how a guy would get the cam off the shim to remove it, and Fourlix has explained that. Sounds risky, but if a person is skilled enuogh to be extra careful of marring anything then I can see it being a timesiver on multiple cylinder engines. No harder than the DS is though, I suppose I'll stick with cam removal.

I believe I've made my choice - shim under bucket. Its great to know that Web offers it, because I'm fairly sure that's who I'll be getting the cams from.

 

What`s WEB CAMS? do they have a web site or phone# that i can see the kits there selling?