Pitted tappets

Technical advice Q&A
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rblumsom
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#21 Re: Pitted tappets

Post by rblumsom » Mon Sep 21, 2020 4:30 pm

Thanks Christopher,
It looks like it's going to be an iterative process. Thus far I've managed to get the exhaust bank correct (all 5.5-7 thou) at the third go round. Interestingly, and I should have noticed this initially, some of the shims that I removed were obviously (to the naked eye) wedge-shaped so I'm guessing that this might not have helped matters!

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mgcjag
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#22 Re: Pitted tappets

Post by mgcjag » Mon Sep 21, 2020 5:12 pm

Double measure everything even the new shims that have the size on them.....wedge shape shims...thats a new one....Steve
Steve
1969 S2 2+2 & Building a C type replica

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#23 Re: Pitted tappets

Post by steve3.8 » Mon Sep 21, 2020 9:45 pm

mgcjag wrote:
Mon Sep 21, 2020 5:12 pm
wedge shape shims...thats a new one....Steve
Its an old one!. Apparently just after the ice age, cavemen mechanics used to grind shims on the side of rotating stones called bench grinders and could not guarantee the shims being parallel :thumbdown:

Richard , i would recommend an engine oil with a zinc content, its a good choice for tappet health .
Steve3.8

64 3.8 fhc, 67 4.2 fhc

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#24 Re: Pitted tappets

Post by rblumsom » Tue Sep 22, 2020 5:26 pm

I thought that I'd share some pictures of the worst offender:
IMG_4057.jpg
IMG_4057.jpg (65.47 KiB) Viewed 102 times
IMG_4058.jpg
IMG_4058.jpg (90.39 KiB) Viewed 102 times
It certainly looks as though it has been attacked with some sort of grinder.
It measured 74 thou in the middle, 77 thou at the thick edge and 63 thou at the thin edge!

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#25 Re: Pitted tappets

Post by rblumsom » Tue Sep 22, 2020 5:34 pm

Steve, thanks for the advice on oil.
I had already bought 10 litres of Valvoline VR1 20W-50 (I had seen this recommended elsewhere on the forum).
Apart from a slight re-bore and head skim, and with the exception of ancillaries (e.g.1-2-3 Ignition) my engine is standard.
Do you think that this oil will be suitable ?
Many thanks,
Richard.

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#26 Re: Pitted tappets

Post by MSM » Tue Sep 22, 2020 7:42 pm

rblumsom wrote:
Tue Sep 22, 2020 5:26 pm
I thought that I'd share some pictures of the worst offender
It certainly looks as though it has been attacked with some sort of grinder.
It measured 74 thou in the middle, 77 thou at the thick edge and 63 thou at the thin edge!
That is absolutely appalling. No wonder you were having trouble getting repeatable results.
Mike

S2 FHC

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#27 Re: Pitted tappets

Post by mgcjag » Tue Sep 22, 2020 7:57 pm

Wow thats impressive grinding.....i do hope the same guy didnt do your head scim :hammerdrill:
Steve
1969 S2 2+2 & Building a C type replica

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#28 Re: Pitted tappets

Post by steve3.8 » Tue Sep 22, 2020 9:26 pm

Hmm nice, it may or may not be the case but that shim being tapered excessively could have been repeatedly tipping the tappet bucket in such a way it has caused the galling /damage, that's if it came from the same bucket.It would have worn the bucket sleeve badly at the very least.
Im no expert on oils Richard or anything else for that matter really :bigrin: , Vr1 oil is fine and has a zinc additive .
Regards Steve
Steve3.8

64 3.8 fhc, 67 4.2 fhc

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