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

miked

Active Forum 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 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 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 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 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
 

Nomadnigs

Forum 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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