Finally I have copper available. Yay!

For those wondering what a shim is for please read THIS, it explains a little of the technical background. Here is the general gist of their purpose anyway:

These are intended to space the head away from the block hereby reducing the compression ratio, lower compression ratios are beneficial to turbo applications. These can also be used to run heavily milled high-compression heads on standard pump petroleum.


I will calculate costs once numbers have been submitted but don’t worry, it’s looking quite reasonable;

Material thickness availability;

0.7 mm
1.2 mm
1.6 mm
2.0 mm
3.0 mm

Basically the prices will be good if there is a MINIMUM order of 5 per material thickness/gauge. So if you want a 1.2 and no-one else wants one the prices will be high. If there are 4 people at 1.6mm and you can settle for a 1.6mm instead of your 1.2mm then that’ll ensure better prices.

I have tried and tested the metal shims which are cheaper but some people fear they will corrode (read back on previous link). The new shim design is much better as I had the benefit of improving them after testing on my rip-snorter A12.

So who is interested in some copper head shims to run more boost or to save that over milled speedway head? Even if you're keen but want to find out costs just say so, it will all help to make the prices cheaper, thus more appealing, thus cheaper etc etc.

I'm keen on one to suit A14 turbo. Not sure what thickness on recoed motor i would need but I'm sure the more experienced will answer that. Cheers Andrew

depending on price i could be kneen on a 0.7 and a 1.2

With some good numbers (i.e 5 per material thickness) I reckon we can expect these prices approximately;

0.7 mm- $40
1.2 mm- $55
1.6 mm- $65
2.0 mm- $75
3.0 mm- $100

+ GST

Here is the quotation I was given a few months ago from the Thailand company 'GasketsToGo' someone recommended them to me and they charge AUD$150 + for just the 1 off 2mm shim excluding postage, group order of 20+ isn't much better. (note their prices are in UK Pound, or GPB or UKP).

So there you have it, Australian sourced shims with 50% savings to be had (assuming we get good numbers )

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  06-1614 Chris Lyons Solid Copper.jpg (119.22 KB)

Andy, it was suggested by bige that each 2cc accounts for half a compression unit. So when I placed a 2mm shim on my motor I introduced an extra 9.5cc (approx) to each cylinder, essentially dropping the ratio by 4.75 units.

3mm shim (78mm bore) is around 14.3cc per pot (someone correct me if I'm wrong?) equating to a huge 7.15 unit drop.

My combustion chambers were tiny though, measuring in at 20cc. Stock H89 heads are 29cc and stock H75 heads are 31cc.

Don;t take it for gospel but just a round about idea on what size shim you'll need to drop your CR.

Here is how the thicknesses will influence the comp ratios (78mm bore on shim) running head shim on it's own. Please double check your own numbers. Let me know if I've made a mistake in my numbers.

0.7 mm Shim = 3.34 cc or 1.5 cr unit drop

1.2 mm Shim = 5.74 cc or 2.87 cr unit drop

1.6 mm Shim = 7.65 cc or 3.83 cr unit drop

2.0 mm Shim = 9.56 cc or 4.78 cr unit drop

3.0 mm shim = 14.34 cc or 7.2 cr unit drop

If you know all your numbers I can help work out what thickness you'll need.

I guess I'll start a list. I'll be in contact with the previous people who were interested and see if they're prefer copper to mild steel.

0.7 mm Shim
clyons8
taiparacer

1.2 mm Shim
clyon8
taiparacer

1.6 mm Shim
clyons8
Gylezy

2.0 mm Shim
clyons8

3.0 mm shim

Is this a shim or a head gasket?

Edit: good price though less than halve from ridgecrest

Hey Chris i might be interested in a shim, is it too late? Once i get the engine specs (maybe tomoz) ill know what current shim it's got, so i can change it for a larger one and run it on PULP rather than methanol. Make it a bit more user friendly haha

Edit: if you have head gaskets as well I'll be interested ;)

Head gasket or shim? Depends how you want to use it. If you want an approximate 2.5 thickness run a 2.0 shim with a gasket.

I intend to run these bare on the engine, no gasket either way. Hylomar aerosol is the reputed preference to sealing these but I'd expect them to seal well on their own if the surfaces are clean and flush.

0.7 mm Shim
clyons8
taiparacer

1.2 mm Shim
clyon8
taiparacer
D
Armiee*

1.6 mm Shim
clyons8
Gylezy

2.0 mm Shim
clyons8

3.0 mm shim

Bump