WTB Shim Under Bucket

GR124 · Postby **GR124** » Mon Jul 27, 2020 9:25 am

I'm setting up cams in a head with SUBs.
They measure 8mm OD, 6.1mm ID, 2.8mm deep. I will need all 16 at various thickness of course
I know I can purchase the shims in the US.

Is there a reasonably priced supplier in OZ?

greenMachine · Postby **greenMachine** » Mon Jul 27, 2020 9:59 am

There was, I got mine from Melbourne.

Precision Shims

:mrgreen:

The American · Postby **The American** » Mon Jul 27, 2020 3:54 pm

I ordered some from the company linked above this morning. I’m buying 8 @1mm for the initial measure, and then I will purchase 16 in the actual sizes once measured up.

greenMachine · Postby **greenMachine** » Mon Jul 27, 2020 5:18 pm

Hmmm. I have always had SUBs when I have had to re-measure, so this hasn't arisen.

I'd forget about the 1mm ones, assemble with no shims, and measure like that. If the feeler gauge can't handle the gap, use a piece of bar stock of known uniform thickness as packing. Or use several leaves of the feeler gauge to make up the desired thickness.

Regardless, you will end up going back a second time for the one(s) you got wrong ... ask me how I know this. Actually, don't. :roll:

Or you could ask me if I have any leftovers that might come in handy ... :wink:

GR124 · Postby **GR124** » Mon Jul 27, 2020 11:33 pm

greenMachine wrote:Hmmm. I have always had SUBs when I have had to re-measure, so this hasn't arisen.

I'd forget about the 1mm ones, assemble with no shims, and measure like that. If the feeler gauge can't handle the gap, use a piece of bar stock of known uniform thickness as packing. Or use several leaves of the feeler gauge to make up the desired thickness.

Regardless, you will end up going back a second time for the one(s) you got wrong ... ask me how I know this. Actually, don't.

Or you could ask me if I have any leftovers that might come in handy ...

This is exactly what I will be doing GreenMachine. I'll be pulling out the existing (SUB) Shims and remeasuring with the bucket sitting on the valve tip. I will mic measure some 1mm sheet metal as a start packer and feeler from there. Thanks for the heads up on Precision Shims, I'll email them tomorrow.

some Maruha Cams will be up for sale soon

greenMachine · Postby **greenMachine** » Tue Jul 28, 2020 1:04 am

I didn't realise you already had SUBs.

I'd measure the gap with the shim(s) in place, then measure each shim, add, then subtract target clearance. Assumes you will not have binding with the new cams, is the base circle smaller or larger than the current cams? Providing you have a micrometer, that's how I'd do it, and how I did it with mine, three times IIRC (twice for new cams).

It avoids the big gap when the shims are removed, but requires care in recording each measurement and doing the math to get the gap and the shim size, but you will need to be careful with any method.

You can do it without shims, providing you can accurately measure the big gap, while in theory that is very doable (as above) I'd want to be confident I had that sorted before I committed to it.

When I did my last, a small valve grind/lap, I found that by shuffling the shims around I had a few shims of the correct size, and a couple that could be ground down to size - reducing the shims needed to be bought. Every little bit helps!

:mrgreen:

GR124 · Postby **GR124** » Tue Jul 28, 2020 9:27 am

greenMachine wrote:I didn't realise you already had SUBs.

I'd measure the gap with the shim(s) in place, then measure each shim, add, then subtract target clearance. Assumes you will not have binding with the new cams, is the base circle smaller or larger than the current cams? Providing you have a micrometer, that's how I'd do it, and how I did it with mine, three times IIRC (twice for new cams).

It avoids the big gap when the shims are removed, but requires care in recording each measurement and doing the math to get the gap and the shim size, but you will need to be careful with any method.

You can do it without shims, providing you can accurately measure the big gap, while in theory that is very doable (as above) I'd want to be confident I had that sorted before I committed to it.

When I did my last, a small valve grind/lap, I found that by shuffling the shims around I had a few shims of the correct size, and a couple that could be ground down to size - reducing the shims needed to be bought. Every little bit helps!

I'm removing a cam with a ~33mm base circle and installing a cam with the standard 36mm BC. So in theory the gap will tighten up by 1.5mm. I did measure every SUB and started the process of calculation. I'm not real smart, I could see me stuffing up a calc. I have decided to KISS and remove existing SUBs install new cams measure gap. Oh and then subtract the standard clearances. Sadly no existing shims will be the correct size for the new set up.

manga_blue · Postby **manga_blue** » Wed Jul 29, 2020 8:12 pm

I picked up a cheap set of 8 shims, all the same size and a little thinner than I needed. I installed these under each cam in turn and used the resulting gaps for SUB to cam to calculate the actual thickness needed. Then had them cut to order by Precision Shims. No errors. If you didn't want to buy throwaway shims you may be able to do the same thing with tablets of fixed thickness magnetised metal on the valve tops.

The American · Postby **The American** » Wed Jul 29, 2020 9:26 pm

Ordered Sunday night, arrived Wednesday morning.

It sounds like we need a few sets of these 'initial measure' shims to pass around for those doing an initial conversion?

plohl · Postby **plohl** » Wed Jul 29, 2020 10:22 pm

There's a good to fair chance that you'll need to grind down the hats so they don't sit on the collets. Just make sure to check

The American · Postby **The American** » Wed Jul 29, 2020 11:35 pm

plohl wrote:There's a good to fair chance that you'll need to grind down the hats so they don't sit on the collets. Just make sure to check

Thanks Shane!

GR124 · Postby **GR124** » Thu Jul 30, 2020 1:06 pm

plohl wrote:There's a good to fair chance that you'll need to grind down the hats so they don't sit on the collets. Just make sure to check

that's a really good point. It is difficult to measure the from tip of valve stem to collets. My existing SUB has a skirt of 2.8mm deep. Spoke to Chris at precision shims, off the shelf is 2 and 3mm skirts. There are plenty of way to skin this cat. He could have ground them to 2.8mm. I'm going to use 3mm skirt shims and invert them and position them on the stem of the bucket.

The American · Postby **The American** » Thu Jul 30, 2020 1:53 pm

plohl wrote:There's a good to fair chance that you'll need to grind down the hats so they don't sit on the collets. Just make sure to check

Is the distance from collet to valve tip a known distance - my searching has not turned up a particular measurement. The shims I have for test fit and measure have 3mm skirts and so the distance from collect to tip will need to be more than that for these to work...

GR124 · Postby **GR124** » Thu Jul 30, 2020 2:02 pm

I don't believe that there would be a known dimension as some of the head guys when setting up grind the top of the valve tips to achieve valve lash clearances. If you are just using the shims to set up you could DIY grind the skirts. It's the shim thickness you require for your dummy shims.

plohl · Postby **plohl** » Thu Jul 30, 2020 8:00 pm

I have to take heaps off them when I have done my clearances using these style (it's the same gary uses), but none of my valvetrain is standard. At a guess easy <1mm of the skirt remains. It'll really just depend on how long the valve is.
I generally use flat discs, ~12mm OD, but again, different spring retainers.

Did you find a builder?