Too large shim

Technical advice Q&A

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Durango2k
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#1 Too large shim

Post by Durango2k » Fri Mar 11, 2016 10:05 pm

...I received about 10 shims on thursday from SNG, and found that one of them, K, is too large, diameter is about 1 mm more then any other shim I own, being new or old.

It means it sits on the inner perimeter of the upper valve cup, and thus is faaaar too thick so I instantly noticed that.

But if it would "just" fit while not sitting on the valve but on the cup, this might have disastrous consequences when the valve mooves and mooves and slowly works its way out of the two small halfcircle cotters....

I'll send SNG a note on monday with a pic, just two things

- how can that happen - are V12 shims for example larger ?

- check your shims carefully before mounting, if there's a mishappen, its a darn costly one.

I may well use my dremel to make it smaller, but if SNG acts fast enough and sends another one, I'd prefer that. Lets see.

Carsten
Jag E '66 S1 2+2, 74’Citroen DS 23 Pallas iE, 73’ Citroen SM 3.0, 54’ Citroen 11 BL, 71‘ Velosolex, 88‘ Unimog U1650

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PeterCrespin
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#2

Post by PeterCrespin » Sat Mar 12, 2016 1:37 am

What is your shim diameter? I have about a hundred shims and they do vary in OD. If it did not fit inside the spring retainer the bucket would sit far higher than any other.

Didn't you have problems with valve fitted height? Did you grind your valve tips? It may not be a shim issue unless all the other shims are fine with that valve?
1E75339 UberLynx D-Type; 1R27190 70 FHC; 1E78478; 2001 Vanden Plas

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Durango2k
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#3

Post by Durango2k » Sat Mar 12, 2016 9:08 am

Hi Pete,

It simply sits on the retainer bucket. Any other shim does not.

All other shims leave a small outer gap between themselves and the bucket.

Oh and of course the cam follower bucket sits very proud- I doubt the cam would turn.

I mean in this case it is easily found but if if if it is not that obvious it is simply dangerous.

Nothing has been done to alter valves. I am between B and K on the inlet side and K and P on the exhaust side.

Carsten
Jag E '66 S1 2+2, 74’Citroen DS 23 Pallas iE, 73’ Citroen SM 3.0, 54’ Citroen 11 BL, 71‘ Velosolex, 88‘ Unimog U1650

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#4

Post by PeterCrespin » Sat Mar 12, 2016 9:59 am

What is the diameter of the shim?
1E75339 UberLynx D-Type; 1R27190 70 FHC; 1E78478; 2001 Vanden Plas

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#5

Post by Durango2k » Sat Mar 12, 2016 10:49 am

I can only use a wooden ruler from Felix' school bag right now, but I believe

17 mm for the correct one and

18 mm for his bigger brother.

Mail sent, scientific proof* included.

Kind regards,

Carsten

*1685's science is meant here.
Jag E '66 S1 2+2, 74’Citroen DS 23 Pallas iE, 73’ Citroen SM 3.0, 54’ Citroen 11 BL, 71‘ Velosolex, 88‘ Unimog U1650

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