Special Piston Rings - 1mm

[skibum]

Hi,

My Dad is having his race engine rebuilt and his mechanic has noticed that he has some rather special race pistons from the 80's (He races in classic touring cars)- I think they are Marley Pistons? Anyway, he's having real trouble sourcing replacement Piston Rings. In particular he needs some that are 1mm thickness.

Does anyone know of a good supplier that might be able to help or alternatively a manufacturer that could run a small batch?

Season starts in April so the clock is ticking...

Thanks

Rich

[wildoliver]

Could they be mahle? Not a piston expert but not heard of marley. And cant be arsed to check google.

[skibum]

could well be - only talked about it over the phone so didnt catch a spelling.

[limegreennutter]

That'll be Mahle.

Marley make roof tiles, not good in an engine

[limegreennutter]

www.mahle.com/

[boosted ls1]

They'll probably be moly? Maybe the mechanic's from the west country! Rings don't usually have any id on them. The pistons could be Mahle but anybody could have supplied the ring pack.

Look closely at the ring face that rubs the cylinder bore. Has it got a grey band, if so that's the moly. Also, what engine is this and what's the bore size.

Boosted.

[Matthew-TMM]

Manley?

[martind]

Matthew-TMM said:

Manley?

That would be my guess as well, Manley is a very big race part manufacturer in the USA.
1mm ? sure its not 0.043 in. = 1.09mm ?
What engine is it for ? that might give us more of a clue.
If the mechanic can't source or identify parts properly for a race engine hes meant to be rebuilding , how can he rebuild it properly ?

[skibum]

Cheers for the responses. They are Mahle pistons in a 323 BMW engine. Apparently the pistons are 80.56mm bore.

From all the conversations he has had with manufacturers and suppliers I think they will just have the piston re-engineered to take 1.5mm rings that they can get hold of.

Thanks for the ideas though - much appreciated

Rich

[boosted ls1]

skibum said:

Cheers for the responses. They are Mahle pistons in a 323 BMW engine. Apparently the pistons are 80.56mm bore.

From all the conversations he has had with manufacturers and suppliers I think they will just have the piston re-engineered to take 1.5mm rings that they can get hold of.

Rich

Do you know what's special about the rings or why replacements can't be found? I'd be a tad concerned about enlarging the piston grooves. Have you the ring specifications? The PH massive could do a search, lol.

Boosted.

[wildoliver]

I think if I was your dad I would probably just bite the bullet and buy a full new set of pistons and rings, at least then he knows he has ring availablilty and isn't going to have the crown seperate from the piston at peak rpm due to a fault in the machining to take bigger rings.

[skibum]

I think that because the Pistons are these special Mahle ones and were race pistons from back in the 80's they don't have a set of rings available in the right size anymore. Its a pretty highly tuned engine and changing to new Pistons/Rings is going to be expensive and possibly lose him some power.

Apparently the rings for each piston are 3mm, 1.5mm and 1mm. He can get hold of the 3mm and 1.5mm ones its just the 1mm ones that are proving elusive.

Will enlarging the grove by 0.5mm affect the integrity of the piston?

[boosted ls1]

skibum said:

Will enlarging the grove by 0.5mm affect the integrity of the piston?

I wouldn't do it. Mainly because it will be difficult holding the piston accurately. You could end up with the groove being all over the shop and it could have the wrong ring depth or side clearances.

Boosted.

[wildoliver]

skibum said:

I think that because the Pistons are these special Mahle ones and were race pistons from back in the 80's they don't have a set of rings available in the right size anymore. Its a pretty highly tuned engine and changing to new Pistons/Rings is going to be expensive and possibly lose him some power.

Apparently the rings for each piston are 3mm, 1.5mm and 1mm. He can get hold of the 3mm and 1.5mm ones its just the 1mm ones that are proving elusive.

Will enlarging the grove by 0.5mm affect the integrity of the piston?

1) Yes it is but no it shouldn't. I'm quite sure piston design has advanced not gone backwards.

2) I don't know. without seing the piston i would say it is hard to guess, but a new set of pistons is a lot cheaper than a full new engine because one has disintegrated.

[HarryW]

Try these www.totalseal.com/SearchByBore.aspx