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rwratschko

shims problem

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i fittet new exhaust valves. non lotus ones. the seat is also regroundet. put the head on the block and the cAm carriers on and now.....

the thinnest shim i need is a 0,75 mm one the thickest 1,15mm

the problem is that the shims start at about 1,5mm

so i have 8 ex valves with to small clearanve to fit standard shims.

has anybody suggestions what to do easiest now?

1. buy thinnest lotus shims and ground them to 0,75mm and so on.

2. find shims from an other car make . vw golf for example.

3.take head off and take valves out again and cut them off 1mm

4. ground tappets inside 1mm

5. 1mm paper gasket on exhaust side cam carrier.

6. new valve guides in the head

7 new valves ( original lotus ones)

did anybody have this problem already?

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Cheapest solution would be to try to find another car's shims of that thickness but 0.75 mm is pretty thin.

Best solution is to get new valve seats fitted to your cylinder head as yours must be pretty badly recessed by now.

Taking so much off your shims or the inside of the tappets would go through the hardening meaning that the clearances would soon be out of spec again. Same for shortening the valves. New valve guides won't help. Raising up the cam carriers on gaskets is a bodge rather than a fix and may lead to oil leaking onto your exhaust and catching fire.

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.75 is very thin, as Trevor said the grinding would be too deep, so you'd have to have them re-treated.

The tops of the valves can be ground, but that's a job for an engine repair shop.

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thanks for fast replies,

i think i will take off the head again and ground/cut the valves 1mm off.

this will make the local engien shop as they told me it is the cheapest version. it only about 40 eur for all 8 valves.

the valves at their end are not hardened they told me.

the more expensive possibility is to renew the valve seats (as andretti wrote) but is is very expensive : about 540 eur for the work plus material.

thanks for help

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