Special piston rings

[Nickodell]

Sadly, Matilda's compression has fallen over the 27 years I've been driving her to the point (140 highest cylinder, 120 lowest) where there is serious blowby. Reboring is probably not possible because she is already 60 thou overbored. Many years ago in England there were special piston rings made for just this kind of problem, with a kind of spring to press them out and accommodate ovality. The two brands I remember were Wellworthy and Cords. The top ring was stepped to avoid contacting the wear ridge at the top of the cylinder.

Does anyone know if these are still available, here or in the UK?

 

[jumpinjan]

The ridge can be removed with a rented (if anyone still has them) ridge reamer.
Anymore, I'm just happy to be able to just buy a set of rings.

 

[Nickodell]

Doesn't help the ovality, though.

 

[V6 JOSE]

Nick,

If you want to keep on driving Matilda for another 27 years, I would suggest boring the block and putting in a new set of pistons and rings. The worn cylinders will never give you full compression and the rings won't last long. I'm sure that there are .080 over pistons that can be found. These old engines had pretty thick castings, so you wouldn't need to worry about the cylinders being weak.

If you cut corners, you will never be happy with it. You will have wasted your time and money, unless you don't expect to be around in another 27 years. The cost will be more, but the results will be worth it.

Jose

 

[lemansvk]

I had the problem of oval bores 10 years ago when I rebuilt mine and 60 thou were the biggest OS pistons that were listed for the 1600 block - this in a country where there was a Rootes factory and companies like REPCO made replacements parts for them. I suspect that 80 thou OS is just not going to be available without sourcing to some special piston.

My solution was a block from another Rootes car (Super Minx) - easy in Australia, but a degree of originalty lost.

Vic

 

[mikephillips]

It's not a cheap solution but look into what some of the other guys have done, see about custom pistons with rings. It's not an off the shelf solution necessarily but it ought to work.

 

[Nickodell]

Thanks for the responses, guys. Rick: if I'm around in 27 years I'll be 97 and I rather doubt I'd be driving Matilda. More like an electric wheelchair.

 

[Series3Scott]

What's wrong with sleeving the cylinders to accommodate an off-the-shelf piston and ring size?

 

[Jim E]

You can sleeve but the cost is right at $100 a hole to do it, then you still have to buy new pistons. Thing would be to have the folks Steve S. used make a set of 80 or 90 over pistons. Actually I would clean the block check it for cracks and see what bore it will clean up at, poke it close to that then order pistons and bore/hone it to the in hand pistons. Of course the thing to really do is have the pistons made to run Chevy rods but that is a whole different story.

Nick do not know about magic rings but there is or was a machine used to knurl pistons folks did that when they could not afford to do it right. Seems Alpine owners used the knurler gizmo I have opend up two 1725s that had knurled pistons.

 

[Nickodell]

Lots of suggestions. Thanks, fellas.

 

[sunbeam74]

Jim,

I think I paid $585.00 for my Venolia pistons, rings, wristpins, and shipping. They offer a wrist pin in a standard size that is just slightly larger than the Alpine stock size and you simply have to have the shop hone the little end bushings to the correct tolerance.

Simply tell them you need a piston to fit a bore "X" in size (of course this is the cleaned up bore) and they will make the piston to the correct dimension.

They are relatively fast and shipped within 3-4 weeks. No discounts until you order 50+

Steve

 

[skywords]

Why not get another block? I have collected several.