Valve shim 3.10mm wanted

petex19

petex19

True Classic
Anyone have a 3.10mm shim that would exchange for a 3.35mm shim?
To Ontario, Canada or New York state, USA

Thanks in advance
 
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a 3.10 shim is too thin, the edge of the tappet bucket will be proud of the shim and wipe out the cam lobe in short order... In general, a 3.25 or 3.30 is as thin as you can go... sounds like you need a thicker cambox base gasket to get the shims correct.

SteveC
 
fiatfactory said:
a 3.10 shim is too thin, the edge of the tappet bucket will be proud of the shim and wipe out the cam lobe in short order... In general, a 3.25 or 3.30 is as thin as you can go... sounds like you need a thicker cambox base gasket to get the shims correct.

SteveC
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or you have a burnt/burning/stretched valve. Is it an exhaust valve that needs the thin shim?
 
SuperTopo said:
or you have a burnt/burning/stretched valve. Is it an exhaust valve that needs the thin shim?
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The head was just taken apart by machine shop, cleaned, inspected, skimmed and new valve guides. Machine shop said valves and head checked out perfectly.
 
petex19 said:
The head was just taken apart by machine shop, cleaned, inspected, skimmed and new valve guides. Machine shop said valves and head checked out perfectly.
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If the engine has run, then this is a stretched valve. If it's not yet run, the machine shop screwed up.
Ask them if they know what "setting the stem heights" means.
 
petex19 said:
The head was just taken apart by machine shop, cleaned, inspected, skimmed and new valve guides. Machine shop said valves and head checked out perfectly.
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Two possibles solution:
1) shave the tip of the valve (About 0.5mm)
2) Put a thicker cambox gasket.
 
Yves said:
Two possibles solution:
1) shave the tip of the valve (About 0.5mm)
2) Put a thicker cambox gasket.
Click to expand...
I was able to buy a Volvo 3.20mm shim which is exactly the same diameter as fiat shims and got me close enough to the cam gap spec.
 
Measurements for the greater good. Not being contrary or arguing. Operational clearances and such. This discussion intrigued me to make some measurements.

I measured 30 cam followers / buckets. Every one of them had a 3.0mm depth in the shim area. I measured new and used.

I verified this by installing a 3.0 shim no oil, and checked it with a straight edge. could not get .0015 to pass, then i used a 3.25mm shim and did the same test. i was able to pass a .010 feeler gauge which is .254mm but a .011 would not pass.

So mathematically a 3.05 shim could be used. I would be weary of a 3.0mm shim due to the fact if it is even the bucket could be contacted. That doesnt take into account the possibility of the cam hitting the side of the bucket first before it rides on the shim. I will check that next time i am adjusting valves i will verify.

On some race engines I have built, I have used shims as thin as a 2.45, but i did have the cam followers milled down to 2.50.

Please understand I am not arguing, just did some measurements because i wanted to know. I knew it in the past but had forgotten it i guess.
 
When I was putting my 1500 engine together, I ran into a situation where the required shims were needing to be somewhat thicker than they were on the 1300 with the same camshaft. After some measurement, I found that the 1300 tappets were about 0.5 mm thicker than the ones that came with the 1500. That allowed me to go with thinner shims by using the 1300 tappets. If you have a collection of tappets lying around, you might want to measure them and see if you can find a thinner one that will allow a thicker shim.

In the 1300 vs 1500 tappets, I found that the 1300s had a dimple on the top side but the 1500s did not:

Fiat SOHC 1300 and 1500 Tappets - Top View.jpg
 
dllubin said:
When I was putting my 1500 engine together, I ran into a situation where the required shims were needing to be somewhat thicker than they were on the 1300 with the same camshaft. After some measurement, I found that the 1300 tappets were about 0.5 mm thicker than the ones that came with the 1500. That allowed me to go with thinner shims by using the 1300 tappets. If you have a collection of tappets lying around, you might want to measure them and see if you can find a thinner one that will allow a thicker shim.

In the 1300 vs 1500 tappets, I found that the 1300s had a dimple on the top side but the 1500s did not:

View attachment 83561
Click to expand...
I have found differences between the point where the valve stem meets the bucket and the shim pad on the bucket. The buckets do wear on the top of the valves. and i can say that I have noted as much as .030 in thickness difference between new units. But the shim retainer to the shim seat seems to be a constant at 3mm
 
I don't think that the difference in thickness for my tappets was due to wear as the thinner 1500 tappets had 50K on them while the thicker 1300 tappets had 81K on them. The measurements on both sets had a tight distribution.
 
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