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MG MGB Technical - Piston Rings

Just curious. Can piston rings be replaced on the original pistons? If so would it require honing the cylinders? Would this help the engine? Thanks
Bob Ekstrand

Sure!
Providing the bore is within specs(diameter and ovality). This used to be a common process. If the bore is OK (You will need to mic it) it can be honed. I have always preferred ball hones. You may also need a ridge reamer to remove any ridge formed at the top of the bores where the rings end their travel. If you are lucky there will be little or no ridge. This is also a good time to renew your rod bearings and possible rebuild your oil pump.
Don't order your parts until you have the engine apart and measured. You don't know if someone has bored the engine or turned the crank sometime during the car's life.

Cheers,
Rich
Rich McKIe

Hello,

It was recommended for TR6 to replace rings and bearinng in 60,000 miles range.
In fact a good set of rings are the one made by Total seal.

Cheers,

Jean
Jean Guy Catford

Just to complete my idea. It is normal to replace in B engine as it is from a similar design to have to replace those parts.

Cheers,

Jean G.
Jean Guy Catford

The best rings for a rering are Hastings! (IMO)
Len Fanelli

Bob-
In a nutshell, yes, it can be done in some cases if the bore and the piston diameters are both still within factory specifications, and the grooves in the pistons are both clean and unworn. Doing the measurements will require both inside and outside diameter micrometers. However, you may not need to consider new rings as of yet. Before you start to pull the engine out and tear it down so that the measurements can be taken, run a wet compression check. This is done by pouring a tablespoon of oil through each of the spark plug holes, screwing in a pressure gauge, and then bringing the cylinder up to Top Dead Center. Post the results and we can work from there.
Steve S.

Bob,

You are asking if new rings will help your engine.

If your engine just needs new rings, it will help. If your engine does not need new rings, then it will not help. If your engine needs a lot more than new rings, then new rings will not help much.

Steve S. is trying to get you to check to see if you need new rings.

If it does just need new rings, then the cylinders should probably at least have a glaze breaker run through them to make the new rings seat properly.

Speaking correctly, honing is a machining process used to perfect the bores to the correct tolerances, while glaze breaking is just done to give the cylinders the right surface finish. You can run a glaze breaker with a variable speed electric drill, but honing requires more sophisticated equipment. I suspect that when you asked if honing was needed, you meant glaze breaking. I used to make the same mistake myself until I saw the puzzled look on my machinist’s face when I mentioned that I had honed my own cylinders.

Charley
C R Huff

This thread was discussed between 26/06/2009 and 29/06/2009

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