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Help: Rings for a +.030" Specialloid Piston wanted

miked

Active Forum Website User
VOC Member
Hello,
I wondered does anyone know a source of replacement piston rings for a + .030" Specialloid piston?

My Comet barrel is on size and only .002" out of round, but I may have to have a rebore if I can't find any replacement rings (1 broke while removing it).

Many thanks in advance,

Mike
 

Bill Thomas

Well Known and Active Forum Website User
VOC Member
Hello Mike, I think you might have to have the ring grooves made deeper and wider, And fit car rings, I hope I am wrong !! We will see if anybody comes up with something, I used rings from an old Leyland van, Brian Chapman told me of the trick, John From USA said he used old chevy Rings ? Good Luck, Bill.
 

Howard

Well Known and Active Forum Website User
VOC Member
Not sure what the problem is. If finding Specialoid piston rings is the problem, I can't help. If it's the +30 which seems a strange size (to me at least) can you get +40 rings and gap them to the bore?

H
 

miked

Active Forum Website User
VOC Member
Thanks for the replies chaps!
As Bill mentions, the spares company rings are deeper than the originals, which are only available in STD, +.020" & +.040" sizes.
It did cross my mind to machine the piston to accept the +.040" rings (as I had already purchased a set) and then gap them to suit. I was unsure that machining the groove wouldn't weaken the piston & if there was a risk of the modified ring being under too much (sprung) tension.
It would also be on the limit of my modest skills, so I would be "putting a job out", which always invloves its fair share of hassle / disappointment.

I'm no expert Howard, but I think +.030" was a standard oversize from the factory, but yes I suppose today it is not a common one - hence my predicament...

Cheers,

Mike
 

miked

Active Forum Website User
VOC Member
Thanks David,

They have a UK agent not too far away from me, so I will call them when I have some exact measurements to hand and see if they can help.

Thanks again,

Mike
 

vibrac

Well Known and Active Forum Website User
VOC Member
Just cant get the right sized cast iorn drain pipes anymore -damm plastic :)
 

Nomadnigs

Forum Website User
VOC Member
Reactivating an old thread as it seems I am facing the same problem as Mike. I have a '49 Rapide which is having the engine serviced and rebuilt by Ben Kingham at BSK. He says the bore is fine with minimal wear but would benefit from a set of new piston rings. The engine currently has Specialoid pistons at +30thou bore (yes this was a standard oversize apparently). The older type of Specialoid pistons had narrower rings than those available through VOCS today. We have sent a message to Hastings piston rings (link above) but no joy. I would definitely like to avoid an unnecessary rebore out to +0.40 all because we can't find a set of replacement rings. If anyone knows of a secret source or has a spare set sat in their shed, I would be very grateful to hear from you.

All the best

Nigel
 
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