I've got my block completely stripped down and it is currently at the machine shop to be boiled out and to have the bores checked. I did a home measure and they appear to be in spec and are in excellent condition. The pistons (9:1 compression) also are in great condition and cleaned up very nicely. Assuming that the machine shop says that the bores are ok, I would like to just replace the rings.
Easier said than done, apparently. My car is a very late 66 and has Brico pistons that include the "maxiflex 50" oil control rings. The suppliers I have visited all reference AE pistons. Except for early 3.4 pistons, there is no mention of rings for the Brico pistons. Are the Brico pistons the same design as the AE pistons, at least in terms of the three ring groove dimensions?
Does anyone know of a good reference for ring-piston interchangeability? I did a quick search on this forum but nothing seemed obvious.
Thanks in advance for any guidance!

 

Have you contacted SNG Barratt, one of the forum sponsors? They may be able to suggest a solution for the piston rings.

 

Here is a link to their page for the Mk2 crankshaft and pistons:

https://www.sngbarratt.com/English/#...Ids=%5B2693%5D

 

Thanks NBCat. I did reach out to SNG but they did not seem sure.

 

I have used Hastings rings for a 3.8 and the engine does not use oil. They make a ring set for a 3.4, part number is 5782.
https://apaengineering.net/HastingsC...artdetail/1978

 

Thanks Jagboi64. Thank you for the lead. I will have to contact Hastings directly. It looks like they have two different sets for the 3.8 but it is not clear if they work with the Brico pistons.
I did hear back from SNG Barrett but they gave me the PN for a 3.4L. As with the Hastings site, it is not clear if their rings work with just the AE Pistons or if the Brico pistons are actually the same.
To make this all the more frustrating, the service manual says that Brico pistons were used and makes no mention of the AE. It provides measurements for the rings and the rings that were in my engine are not quite the same. The ring thickness on my my old rings is actually 10 thou more than the book, so that makes me wonder, too. Its also a little frustrating that fractional inch, decimal inch and mm are used by the different suppliers.
I'm ranting.... I may end up getting all new pistons just to be sure. The last thing I want to do is put it all together and find that I have little compression or the pistons seize in the bore because I used the wrong rings.

 

I would wait until you get a report back from your engineering shop on bore wear, taper & ovality. If fine you might be better off buying a new set of Mahle or whatever pistons & rings. If a rebore is required you will have to do that anyway. You can't mess around with ring/groove clearance issues.

 

I got the report back from the machine shop yesterday and the bores are slightly out of round so we decided to bore them 0.020 over. That essentially took care of the ring question. All new pistons and rings are on the way.
Thanks to everyone for the input!!

 

That's good news. Now you can move forward with confidence. The 3.8 could be an oil user above Jaguar norms. They did much work in this regard with the 3.8 (mainly pistons & rings) with its cylinder liners made from Brivadium. One of it's best features.

Accurate bores & modern pistons & rings & you should have a fine engine.

Under your old situation if ring to groove clearance closed up at operating temperature with all clearances normalised & you suffered an over tight ring in a groove it would have meant engine out again & stripped.