3 angle valve job effects on valve clearance

[92ShoOff]

Hey guys, the machinist that has my 3.2 has just finished my block and will be doing a 3 angle valve job on my cylinder heads next week. He mentioned to me that when doing that work the clearance on valves (between the shims and the cam lobes) would decrease. I was already planning on getting my hands on some different shims because mine were out of spec and had 150k on them before being touched.

I explained to the machinist that my shims had too much clearance and he said I might be able to still use my old shims and if there's not enough clearance he thinks he could grind the shims down to spec. with this special machine he has. What do you all think about that? Does that sound like a bad idea?

If he can grind down shims to spec. then maybe I can just get a bunch of shims thicker than what I need and have him grind them down to the sizes I need. The one thing that concerns me about possibly doing this grinding of the shims is that the surface will not be as smooth. As you all that have handled these shims know, these things are very smooth and shiny... which is obviously to prevent wear of the cam lobes. If the shims were ground down would they not be as smooth. Input on this would really be appreciated. Thanks in advance!

-Andrew

 

[sho'd]

i imagine if you select shims that have one really good side, you could always grind down the back of the shim, and leave the good side up that makes contact with the lobes, simplest solution i can think of for you, good luck hope it works out for you.

 

[Rockledge]

I'm also curious if anyone else has ever "modded" their SHO's shims like that. Certainly sounds possible.

A good machinest should be able to obtain a proper surface on both sides of the shims, no?

 

[Off Road SHO]

I'm also curious if anyone else has ever "modded" their SHO's shims like that. Certainly sounds possible.

A good machinest should be able to obtain a proper surface on both sides of the shims, no?

I guess a really good machinist with the proper machine could do it but it's going to be time consuming for him. The thing that makes it difficult is that the two sides of the shim have to be absolutely parrelell ( I've always had trouble spelling that word; feel free to trade out any consonants or vowels as you see fit). Not just really close, but absolutely, positively dead on. Now if he can do this, and be cheaper than a 3 dollar shim of the correct thickness, my hat's off to him, and you should try and keep him as a friend.

Tom

 

[sho'd]

)not just really close, but absolutely, positively dead on. Now if he can do this, and be cheaper than a 3 dollar shim of the correct thickness, my hat's off to him, and you should try and keep him as a friend.

Tom

yeah i would like to have a friend like that, that would be benificial by all means. well put Tom

 

[RStalveyARFF]

FYI, the SHO comes with a 5 angle valve job from the factory...

 

[Off Road SHO]

FYI, the SHO comes with a 5 angle valve job from the factory...

Really? It doesn't look like a 5 angle. I'll have to take a closer look next time.

Tom

 

[AREA 91]

Forget all the hastle of grinding down shims. Just rent a kit form someone, or post in the WTB section, when you find out the sizes you need.

 

[RStalveyARFF]

that's the info that was passed down to me Tom...

 

[LOUDSHO92]

Just use different shims. I am sure you can get what you need. I have a lot of different sizes.

You only really need a clean up job as a valve job wont do much, it will hurt low end flow with only a little on the top gains. I would just clean it up and be done.