I'm pulling apart a head with the early valve retainers fitted, these use a large collet groove and wire clips to hold the collets together.

Should I replace these with later valve and valve collets or are they just fine?
I believe at the least I will need to replace the four inlet valves as they are pretty worn out..

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

Hi there,

What are the engines spec?

Standard or there abouts i would reuse what was there.
Depending on condition of course.
Performance i would start thinking about upgrading to the later single or triple groove valves.
High performance definitly upgrade.

Cheers

Its a 998 and this is an early 295 head I am pulling apart.
Use will be spirited, but not excessive as its a daily driver.

Are these early valves regarded as reliable still?

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

I've never had any problems with them up to 7500rpm or so, back in the day.
But I'd leave those wire clips off, at 6500rpm + they fly off anyway.

Fit the little O-rings in the bottom of the grooves like they are designed to be.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

The design of that style of collet is just fine, they are no more renown for giving troble than any of the others, fling the wire clip though.

Having said that, the little I could see of your valves they should be place in the same place as head bolts (bin).

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Mick, I have a 20lt bucket full of good valves out of 202 heads and a assortment of good valves out of other heads and colletts etc.
I fit the valves ,double springs, and "K" liner guides out of a honda BA18 head [one does two mini heads] so plenty of left over std mini stuff.
Let me know what you want in size etc and I will sort a full set out for you

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Research is the difference between speculation and investment. Anyone who copys some one else will always be second
www.minisprintgt.com

Thanks David, I appreciate that very much.

The valves I have here measure 31mm(inlet) and 25.7mm(Exhaust) and are 87mm long.

Its odd, but I did a search through Minispares and see that the only 31mm valves they have are exhaust, which prompted another thought. I can't think of a reason why an exhaust valve cannot be used in an inlet. Is this correct? I figure there might be problem the other way around with heat however..

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

Mick,
31mm (1.219") is the std size for a 295 inlet.
p/no at karcraft is 12G296.

You can't use inlet valves in exhausts, usually they are only silchrome steel and will burn out.
You could use exhausts as inlets though...

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Oh, and with a change in valve to single groove, does the collet change as well as the spring cap?

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

The only word of 'caution' or 'beware' I would add is that exhaust valves have an ever so slightly thinner stem to deal with the extra heat they see, from my own experience, this does lead to increased oil consumption.

Use bigger valves, machined down.

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I agree I was going to say that, but only thought of it last night after I logged off...
Diameter difference is about .001".
In days of yore I used to buy semi-finished K steel valves from Dufor/TRW, and machine the heads and collet grooves.
These days you can buy nice oversize valves for smallbore heads from Lindsay Seibler. No machining needed.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Thanks everyone, as always I appreciate the advice.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.