Author Topic: Stuck Valve Shim  (Read 445 times)

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Offline thehackmechanic

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Stuck Valve Shim
« on: Monday,March 02, 2020, 09:56:32 AM »
I'm doing my first valve adjustment on my twin-cam after its rebuild 700 miles ago. I got the cams and tappets out without incident, but the shim for #1 exhaust valve is stuck in the spring retaining cup. I've tried a pretty powerful rare earth magnet, and it won't budge. I can't find any posts on this on any of the Lotus sites, but I see posts in the motorcycle world about putting a right-sized socket on the spring retainer and pressing down on it or rapping it gently with a rubber mallet. Can I do that here?

--Rob Siegel
'74 TCS, 24k miles, up and running after 40 years
'72 BMW 2002tii
'72 BMW Bavaria
'73 BMW 3.0CSi
'79 BMW Euro 635CSi
'99 BMW Z3M Coupe
'99 BMW Z3
'96 Winnebago Rialta

Five books available on Amazon (www.amazon.com/s/ref=nb_sb_noss_1?url=search-alias%3Daps&field-keywords=rob+siegel)

Offline jbcollier

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Re: Stuck Valve Shim
« Reply #1 on: Monday,March 02, 2020, 11:17:19 AM »
If the engine is at TDC, and both cams are out, then you can do that with cylinders 2 & 3.  Not with cylinders 1 & 4 though as the valve may hit the piston.

No chance of using a small screwdriver or pick and working it out at the side of the shim?

Offline thehackmechanic

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Re: Stuck Valve Shim
« Reply #2 on: Monday,March 02, 2020, 11:43:20 AM »
Boy, there's not much there to pry.

I've ordered a stronger magnet. Think I'll try that before anything more extreme.
'74 TCS, 24k miles, up and running after 40 years
'72 BMW 2002tii
'72 BMW Bavaria
'73 BMW 3.0CSi
'79 BMW Euro 635CSi
'99 BMW Z3M Coupe
'99 BMW Z3
'96 Winnebago Rialta

Five books available on Amazon (www.amazon.com/s/ref=nb_sb_noss_1?url=search-alias%3Daps&field-keywords=rob+siegel)

Offline thehackmechanic

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Re: Stuck Valve Shim
« Reply #3 on: Monday,March 02, 2020, 12:29:59 PM »
SOLVED by Rohan over on the Elan forum:

"Never seen it happen before, normally they lift out with the follower stuck to it by a film of oil. The shim should only be supported at the centre on the valve stem I would try tapping the shim down gently with a punch on one side and the other side should come up so you can then pry it out"

Worked perfectly.
'74 TCS, 24k miles, up and running after 40 years
'72 BMW 2002tii
'72 BMW Bavaria
'73 BMW 3.0CSi
'79 BMW Euro 635CSi
'99 BMW Z3M Coupe
'99 BMW Z3
'96 Winnebago Rialta

Five books available on Amazon (www.amazon.com/s/ref=nb_sb_noss_1?url=search-alias%3Daps&field-keywords=rob+siegel)

Offline BDA

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Re: Stuck Valve Shim
« Reply #4 on: Monday,March 02, 2020, 12:49:08 PM »
Yippee! Glad you got it out!  :beerchug:

Offline jbcollier

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Re: Stuck Valve Shim
« Reply #5 on: Monday,March 02, 2020, 02:08:55 PM »
Congrats on getting the shim out.

Ok, a little on the paranoid side I'll admit, but, it's not a good idea to use magnets to remove engine parts unless you absolutely have to.  Using a magnet, magnetizes the part.  Not a lot, true, but some.  This then leads to the part attracting metal filings that would normal drain away.  Again, mildly paranoid, but still good practice.