NC30 - Skimmed head shims

[lukemillar]

Hi all,

I while ago someone posted a really nice template for the shims needed to restore the height of the cam towers if you are skimming the heads. However, looking at my project and then some old threads on here it seems you actually need a couple more (gear tower and valve cover bolts). I have modified the diagram here:

http://img41.imageshack.us/img41/9742/shimstemplate.jpg

Bt was wondering if anyone who has had them made before, could confirm my measurements on parts 4 + 5 before I send it for them to be made.

Cheers
Luke

EDIT: Updated link with revised template

[hunter]

I'v got a tony scott engine,and he never put (gear tower and valve cover bolts)shims in.

[scooble]

what did he do instead?

[skinnydog0_0]

what did he do instead?

I would guess at (might be wrong) that the cams were ground and re-profiled during the tuning work and the amount taken off the heads was accounted for in the cam work. As for the cam gears, on mine there seemed like enough play to allow for a few thou or more off the heads, so you would probably get away with those.

[lukemillar]

The only shim I don't fully understand is the cover bolts. Is that because the bolts protrude through the cam towers unless they are shimmed up or doesn't it matter?

[hunter]

Sorry That is what i ment, There were shims under cam carrier,but not the cover.

[Lane]

I literally just sent off an email with the attachment of the template to my mate who is going to fabricate some up for me.

My measurements were quite different and you've now put doubt in my mind so i'm gonna head to the garage tomorrow after work and recheck.

[Lane]

I wouldn't have been able to get to sleep tonight had i not gone and checked it.

Part 5 ID i have at 10.5mm, instead of 9mm, it needs the extra width to clear the locating dowels on one side of each gear tower (are yours still in situ?)

And hardly a big deal but i measured the cam cover bolts (part 4) ID at 13mm just to keep it snug.

What do you think???

[lukemillar]

I'm pretty sure I measured the ID of the hole in the gear tower i.e the bit that fits over the dowels as getting a decent read with a micrometer in the head was proving tricking due to space.

With the valve cover bolts I'm think I did the same (measure the grommet rather than the hole)

I'll double check mine as well.

End of the day, I'd rather have a hole that is too small as I can widen it, but I can't make a bigger hole smaller!

[Lane]

True, or we can to and fro a little and both get it right the first time :)

I measured the seat of the cylinder head with a set of digital verniers.

Let me know what you find.