930: Flame Ring?

930LDR · 08-27-2011, 05:53 PM

I'm rebuilding my 930. Going with new Mahle 3.3L P&Cs and had the heads resurfaced and rebuilt. Was about to put the heads on today and started to do some research on flame rings. Will be running a max of 1.0b of boost with Supertec head studs. This is principally a track car. I need to keep an eye on the budget but also want to make sure that I don't end up being a penny wise and pound foolish.

Wanted to tap the brain trust for some opinions.

Ken911 · 08-27-2011, 08:46 PM

some shops just lap the cylinder heads to the top of the cylinders other swear by flame rings. I lapped mine and they have never leaked. but next time it comes apart for efi I'm thinking it might flame ring it.

nocarrier · 08-28-2011, 11:20 AM

I've been thinking about flame rings as well and have been doing quite a bit of research on them and here are some of the things I have come across or learned along the way.

1. Flame rings aren't for holding more cylinder pressure. They are more designed to keep the cylinder head and cylinder aligned properly. Kind of like a huge shuffle pin. Apparently when the heads shift around on the cylinders, it compromises the two surfaces and that's when the leaks start.

2. Once you flame ring the heads, the cost of any further machining goes up a lot! For instance, when you have to re-surface the heads, you also have to re-cut the grove for the flame rings as well. Of course, same goes for the cylinders. I am not sure but I think you have to replace them as well every time the heads come off.

3. With a good set of head studs @ 1.0 bar you shouldn't need them

I was leaning toward them at first but the more I learn about them coupled of what I am expecting to get out of my motor in terms of longevity and power output, I am thinking I can save the money.

This of course if just my opinion and I am still learning a lot about these engines. I'd love to hear what others think about these.

afterburn 549 · 08-28-2011, 11:59 AM

1.B should be fine..there are even 2.7 eng running 1 bar..could not think of who......

CaptainCalf · 03:08 PM

After test fitting the heads and cylinders I decided to flame ring cuz they have a lot of room to roam w/o flame rings and that's the problem...after a few track events you could develop leaks:
The Beautiful Puzzle: 1987 3.3L 930 EFI Build

Henry Schmidt · Henry Schmidt's Garage

At 1.0 bar of boost, the Supertec heads studs will offer sufficient stability for long life and consistent performance.
Flame rings are becoming more and more obsolete as cylinder and stud technology improves.