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90 Bore Pistons

A_HRD

Well Known and Active Website User
VOC Member
A pal of mine (Fred) in the Mid Glos Section has a Comet engine with Bob Dunn for conversion to a Big Bore job. By all accounts, work has stopped on it because Bob can't source any more of the 90mm pistons he was using. (I don't know which make they were - does anyone else?).

Fred would be interested to know if there are any other suitable sources out there - so he can inform Bob when he gets back from his holidays....

I said the Forum would know - so I hope you can prove me right....

Peter Barker
Bristol, UK.
 

Comet Rider

Well Known and Active Website User
VOC Member
Piston sources

Hi Peter,

Firstly try Russell and Debbie (I've got one of the Vinparts 90mm bore kits on my Comet)

If that fails go on the web for CP pistons as used by the TPV 600 kits (bare in mind that the listed piston is a 92mm bore for the 600 kit) and ask if they can help you.

Failing that try Wiseco, JE pistons etc on the web to see if they have anything suitable. Also I will be in the US the week after next, so could bring something back in hand luggage

Neil
 

A_HRD

Well Known and Active Website User
VOC Member

Neil,

Thanks for the helpful reply. I've had a look around the internet and given Fred the phone numbers of the ones you mentioned and a couple of other manufacturers too. Of course, most want a minimum batch size...

In the meantime, Russell has been in his usual helpful mode and, although having none in stock at the moment, he has offered Fred the one he was holding-back for his own Comet project. This one is of Omega parentage - but I'm not sure if the rings are suitable for a Nikasil bore...

Peter Barker
Bristol, UK.
 

roy the mechanic

Well Known and Active Website User
VOC Member
If you are capable to work-out what is required, contact Venolia pistons in California, u,s,a. they can make anything you can dream of. Been doing this for me for 30+years.
 

Upstreeter

Well Known and Active Website User
VOC Member
When the late Ian Hamilton built my big bore Comet engine ('Give your Comet the performance of a Rapide' - remember?), he used a JE piston. Actually I've foolishly used three, finally discovering that a valve was ever-so-slightly kissing the piston rim and every time I took it to Montlhery and it got thrashed to within an inch of its life, it melted one. At £110 each it was getting a little silly and as the very much alive and to the point John Renwick said "you boys will keep repeating the same mistakes". My dad eventually sussed it and re-adjusted things and the last piston (so far) gives no trouble. As you can probably tell I am mechanically 'challenged' and as my dad has recently passed on to the great grasstrack in the sky...oh well, I'll just have to pay up and look big in future.
 

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