Valve Shim Problem

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BT124

Valve Shim Problem

Post by BT124 »

After installing new valve shims on my 1979 Spider I was rechecking the gaps by turning over the engine a little at a time. The #1 exhaust shim slipped out and is jammed under the cam lobe. It must not have properly seated. I'm hoping that I haven't damaged the exhaust valves because as I turned it over a little the exhaust cam didn't move and the timing belt slipped over the gear teeth. I didn't turn it over very much, so who knows. Anyway, Not a good day.

My plan is to try to pry it out without damaging the camhousing. If that doesn't work I guess I'll be taking off the exhaust cam housing and removing the cam. Of course this means resetting timing and new timing belt since the intake cam moved but the exhaust cam didn't. Any suggestions, other than to start drinking more! Oh well, may have needed a timing belt.
Thanks
narfire
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Re: Valve Shim Problem

Post by narfire »

I don't believe the 2L is an interference engine. Yes you will be getting another belt. I've had that happen but the head usually is not on the engine. I can then move the cam backwards a bit and then between a magnet and some poking about, I can get it out. My thoughts...take the belt off, back the cam up a bit if you can and remove. Having a new belt is a good thing.
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BT124

Re: Valve Shim Problem

Post by BT124 »

Thanks Narfire. Good advice. I've heard the term "interference" engine but not sure what it means. Does it mean that valves don't hit Pistons or what? I'm kind of guessing, obviously.
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RRoller123
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Re: Valve Shim Problem

Post by RRoller123 »

Yes, in a non-interference engine, the valves don't extend to the point that they would hit the pistons if the cams stopped turning and they were stuck open, as happens in a timing belt break. Interference engine, valves, etc. can get smooshed.
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focodave
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Re: Valve Shim Problem

Post by focodave »

I'm pretty sure the 2L is, in fact, an interference engine in that the auxiliary shaft lobe can contact the crank if it is not timed properly, or if there is a failure of the timing belt.
I believe the top end, if stock, is non-interfering.
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131
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Your car is a: 1982 131 Superbrava warmed 2.0 litre.
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Re: Valve Shim Problem

Post by 131 »

You should be able to lever the valve bucket down so the spring pressure is not on the shim and it can be removed.
Mick.

'82 2litre 131, rally cams, IDFs & headers.
vandor
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Re: Valve Shim Problem

Post by vandor »

The valves may not hit the pistons, but in this instance there would be a slight possibility that the two valves hit each other.
It depends on where the intake cam lobe was when the exhaust cam stopped. It's unlikely with stock cams, but possible. With performance cams with high lifts this can very easily happen if one is not careful during assembly.
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