Accuracy of Valve Clearences

[SwissSteve]

I have a question how accurate the value clearences need to be when setting up the valve clearences. It seems that everytime I take the camshaft out and refit, the reading can vary by a couple of thou. The allowed tolerances are gives in the manual as +- 1 thou.

It takes me 1 week to reorder the shims from the UKand at this rate I will miss the summer before getting the head back on . Also the ordered shims arewithin a 3 thou tolerence of what I ordered when I check them with a micrometer.

So how tight must I be with these measurements andare there any consequnces if a couple of though out?

[Andrew S]

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6 - 8 thou for inlet and 16 -18 thou for exhaust. Stags can run slightly quieter with the wider tolerance. As long as you don't get less than the 6 or 16 thou, then don't worry and if it wasn't noisy before you started, then you should be OK

Good luck

Andrew

[SwissSteve]

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Thanks for the response.

The Haynes manuel states 8 to 10 for inlet valves and you mention 6 to 8, which is correct?

Am I correct in assuming the inlet valvesare smaller than the exhaust valves?

TIA

[Kevin Garrod]

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SwissSteve wrote:

Am I correct in assuming the inlet valvesare smaller than the exhaust valves?

TIA

The inlets are the larger valve.

[SwissSteve]

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Back to Square one on my measurements but thanks for that important clarification.

[stustag]

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This might help you Steve there are 2 pages.

[SwissSteve]

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Thanks for the diagram, that does help.

[Coppo]

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Hi Steve.

I made the sheet up when I rebuilt my engine. Found it so helpfull to get the correct size shims to order.

PM me if you would like to see it.

Tried to paste it here for you to see, did not come out to good.

Paul.

[alan_thomas]

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SwissSteve wrote:

It takes me 1 week to reorder the shims from the UKand at this rate I will miss the summer before getting the head back on .

Steve, if you have a 'friendly' local engineering works witha surface grindernear you the following may save you some time sourcing the shims from England.

Work out the sizes you need, mic up the existing shims. Some will be the correct size, some will be oversize and some too thin. You cannot do anything about the ones that are too thin you need to get a few spares but the oversize ones can be stuck in the grinders magnetic chuck and a couple of passes will grind the shim to the value you want.

I did this and the only problem I had was explaining to the grinder that one thousand of an inch was close enough. He was used to grinding to a much greater tolerance.

I never throw the old shims away and I have a collection from my days with TR7 and sprint engines to fall back on.

- Alan

[SwissSteve]

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Thats an idea. I have a full set of oversized shims.

[GDPR]

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Steve

I have a large box of Stag, Dolomite, O series, S series and Rover SD1 6 cyl shims (all the same diameter, just some chamfered and some not - makes no difference for our purposes) that I collected over many years working on Rover Triumph.

If you have a request for an odd size shim, I might be able to help but will need a couple of days to sort through to see if I have the size you want....... unfortunately my imperial micrometer has been damaged so requests in metric please.....

Russ

[NickA]

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kryten wrote:

Steve

I have a large box of Stag, Dolomite, O series, S series and Rover SD1 6 cyl shims (all the same diameter, just some chamfered and some not - makes no difference for our purposes) that I collected over many years working on Rover Triumph.

If you have a request for an odd size shim, I might be able to help but will need a couple of days to sort through to see if I have the size you want....... unfortunately my imperial micrometer has been damaged so requests in metric please.....

Russ

I thought chamfered shim'swere a no no. Can't remember where I read that though.

Metric,Pah, Mr Triumph would turn in his grave.

[GDPR]

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NickA wrote:

kryten wrote:

Steve

I have a large box of Stag, Dolomite, O series, S series and Rover SD1 6 cyl shims (all the same diameter, just some chamfered and some not - makes no difference for our purposes) that I collected over many years working on Rover Triumph.

If you have a request for an odd size shim, I might be able to help but will need a couple of days to sort through to see if I have the size you want....... unfortunately my imperial micrometer has been damaged so requests in metric please.....

Russ

I thought chamfered shim'swere a no no. Can't remember where I read that though.

Metric,Pah, Mr Triumph would turn in his grave.

It never stopped me - rebuilt many a Sprint head with chamfered shims in it...... well they were free!

Never had a problem, so maybe just a purist's view.....

[Kevin Garrod]

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SwissSteve wrote:

The Haynes manuel states 8 to 10 for inlet valves and you mention 6 to 8, which is correct?

When I did mine I went by the Haynes figure as I don't have a ROM (must get one)and it runs fine and sounds OK. I wonder if the figures are different on MK1s and MK2s? the heads aren't identical so maybe that explains the discrepency, just guessing though. BTW I have a MK2.

[Bob Heritage]

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Kevin Garrod wrote:

SwissSteve wrote:

The Haynes manuel states 8 to 10 for inlet valves and you mention 6 to 8, which is correct?

When I did mine I went by the Haynes figure as I don't have a ROM (must get one)and it runs fine and sounds OK. I wonder if the figures are different on MK1s and MK2s? the heads aren't identical so maybe that explains the discrepency, just guessing though. BTW I have a MK2.

The correct inlet gap is 8-10 for both.