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Wed Aug 20, 2025 5:32 pm

Hey all,

TLDR: I suspect that my dual carb big bore engine from my "stock" 1972 super beetle is not actually stock, and am trying to better understand what I've got/where to get parts and all that jazz.

I primarily work on Japanese cars/engines, so I am not super familiar with these beetles. Recently I bought a 1972 super beetle with a seized engine to fix up, but am running into some issues regarding finding the right parts. PO claims "Everything is stock, all parts are there".

The only thing seizing the engine was that dirt had been packed into 2 of the cylinders. so I opened and cleaned everything up, and am trying to get it all back together. For now, I am replacing all the gaskets and piston rings so I can at least check the engine's compression.

I believe these beetles come stock with a 1.6L engine, so I ordered a set of Grant's 85.5mm piston rings and found that they are too small. upon checking, turns out my engine's pistons are 88.9mm, so I am led to believe that this is not a 1.6 and also not stock. Also, only now did it occur to me that the engine is also dual carb. which as far as I can tell is definitely not standard.

Is this a common modification to beetles? if so, does anyone know where on earth I can find piston rings for this thing? the old ones no longer exist so reusing them is not an option unfortunately.

Again I'll admit that these cars are quite foreign to me, and so any help is greatly appreciated!

Much thanks!
-C

Wed Aug 20, 2025 5:39 pm

Your stock engine is likely a 1679cc upgrade. No big deal.
Pistons and cylinders are cheap. Buy a replacement set from AA pistons.

Before ordering make sure to measure your engine case cylinder openings so you buy the correct size cylinders. Oh, and the head openings too.

I have a 1679 here in Oregon and it is a good runner for street driving.

Welcome to the samba.

Wed Aug 20, 2025 7:49 pm

Did you measure the pistons or is that what they had on the piston face? You may have an old set of 90mm NPR piston and cylinder set up. If so the type 4 90 mm rings will not fit. Grant does make a set for these but you got to call them to get the part number.

Thu Aug 21, 2025 12:56 am

pondoras box wrote: Did you measure the pistons or is that what they had on the piston face? You may have an old set of 90mm NPR piston and cylinder set up. If so the type 4 90 mm rings will not fit. Grant does make a set for these but you got to call them to get the part number.

I measured for myself and got 88.9mm. My thought process is that I'd get 90mm rings and just file them to size if they were too big, but they're kind of a pain to find so I wanted to make sure I'm not missing something blatant before I ordered the wrong parts again. Ill look into ones that you mentioned and double check my measurements.

Thu Aug 21, 2025 4:59 am

I’ll check my set of 90’s and see what they’re marked with but I’m guessing you got some vintage 90’s. Like I said call grant they got them.