Mick Hemings big valve head

Joined
Feb 11, 2021
Messages
2
Country flag
Hello,
I have a 750 Norton Atlas head with a Mick Hemings big valve conversion - done many years ago.
I now need to replace the valve guides but of course Mick isn’t with us anymore.
Does anyone know where I can find out what valve guides Mick used on his big valve conversions.
From the shape and my crude measurements of the guide OD they look like STD 850 commando guides.
Thanks
 
Hello,
I have a 750 Norton Atlas head with a Mick Hemings big valve conversion - done many years ago.
I now need to replace the valve guides but of course Mick isn’t with us anymore.
Does anyone know where I can find out what valve guides Mick used on his big valve conversions.
From the shape and my crude measurements of the guide OD they look like STD 850 commando guides.
Thanks
I was told by George Mezzalini of Mez porting that he had done the big valve heads for Mick
Sadly George is no longer with us either and I've no Idea if that was the case?
I'm not sure about an atlas head but the large diameter guides used on the 850 can be very troublesome
Cracked heads ,loose guides etc especially on an rh4 head that has 32mm ports
Are your guides bad or are you changing them as a matter of course?
Some people choose to go for K liners to avoid the chance of the guide coming loose or being misaligned
I've no experience of them myself,but they may well be your solution
 
If only the ID is worn then get them lined with K liners, no risk of the head being scrapped and you may even drop the seat recut and only have to the grind in new valves..
 
Last edited:
Many thanks for the initial responses.
These guides have been in the head for a long time and I used it in a race engine for a season. They’re not loose and the head doesn’t show any sign of cracking. It’s only
ID that’s worn. Valve stems are fine.
I’ll look into the K liners this seems like a good solution all round.
 
I had Mick do repairs on a big valve short stroke head in the mid/late '70s, twice, once relatively minor, the second to recover 'catastrophic' damage.

He fitted valve guides with a flange that the spring seat sat on! Very different to standard. But so was that head.

Did Mez actually do the work? I think he did, though I pieced this together much later and didn't know Mez existed at the time the work was done.

However, Mick was still doing big valve heads after Mez had died. So I think Mick learnt the required skills and purchased the required equipment and tooling to do it himself.

I would be interested if anybody knows more detail, but it changes nothing.

Without Mick and his services that head would have been scrap.
 
Back
Top