3.1 head spacer

[fastback4]

My 3.1 heads where checked today and found to have no cracks and where .015 and .017 warped perspectivly (left and right). My machinist says that head spacers can be used after he resurfaces the heads. This would eliminate the need for longer pushrods to make up the head milled difference. Question is how many of you have used a head spacer and is it a risky solution to warped heads?.....Thanks.....Tom

[SappySE107]

Longer pushrods for milling heads? Maybe shorter, but not likely. They do not make head spacers but they do make rocker arm shims to lift them up .010 or .020".

[zoideraserb]

Longer pushrods for milling heads? Maybe shorter, but not likely. They do not make head spacers but they do make rocker arm shims to lift them up .010 or .020".

Autozone has .020" Shim Gaskets listed for my 2.8 so they should have them for a 3.1 as well... 19.99ea

[Superdave]

Not worth the trouble..


Which 3.1 is this?

[pocket-rocket]

97 3100.

http://60degreev6.com/forum/f97/1997-3-1-cyl-compression-results-t45929

[geoffinbc]

Thats a lot of milling for stock aluminum heads. Some shops have machines to twist aluminum heads back into shape or at least get them within .005" and then you can mill them. I would just get some used heads that are not warped and rebuild them.

[Superdave]

so you are looking at a max of .017" milled then?

People have been running .020 thinner gaskets on gen2 3.1's forever without issues. I doubt you'll have any. Your compression will be higher of course so you may gain a little power.

[fastback4]

Shorter is right..not longer

Longer pushrods for milling heads? Maybe shorter, but not likely. They do not make head spacers but they do make rocker arm shims to lift them up .010 or .020".

Shorter is right..not longer

[fastback4]

3.1 head shim

Check this out. The owner of this machine shop (40 years experience) also told me my head had been worked on before because i have bronze valve guides. Says he's never seen bronze used before in the 90's 3.1/3.4 GM. Problem is i told him this car was bought new by me in 1997 and had 3 miles when purchased and never out of my sight. So he say's, "Well then it's a test car!!! HuH!

[SappySE107]

Can you get some pics?

[fastback4]

If you mean pics of the heads valve guides, sure....as soon as i go get the heads back from the shop.....

[asylummotorsports]

GM would at times install bronze guides to "save" a head rather than scrap it.

It's also why there were .005 overbored engines with pistons you can't buy.

Chrysler was famous for that on 340's and Hemi's.

Usually late in a production run to get stuff out the door.

[SappySE107]

guides or guide liners?

[pocket-rocket]

GM would at times install bronze guides to "save" a head rather than scrap it.

It's also why there were .005 overbored engines with pistons you can't buy.

Chrysler was famous for that on 340's and Hemi's.

Usually late in a production run to get stuff out the door.

The engine out of my wifes Daewoo has oversized rod journals from the factory. DOHC 2.2l built by GM.

[fastback4]

guides or guide liners?

He said guides. I'll ask again today when i pick the heads up. I'll take some pics of what he shows me to be bronze.....Tom
P/S going to the scrape yard to look at 2 3.4 engines out of the car. Does not know what they came out of. Where are the numbers to check for engine size accuracy and year of engines.