View Full Version : Modern pistons for a 3-main B-series engine

03-18-2006, 01:23 PM
I'm rebuilding my 3-main MGB engine to go in a Magnette. I am going for smoooooth power and reliability. I want a modern piston/ring design rather than the monster lumps the factory supplied. Anyone have a source they really like or advice?
The engine will have several modifications for reliability including lightening, balancing and upgrading as necessary (I've done a few of these in the 5-main format).
No, 10,000 rpm isn't in the cards, just smoooth cruising. /ubbthreads/images/graemlins/angel.gif

03-18-2006, 01:30 PM
If you want to go with REALLY spiving jugs, Wiseco, in Mentor Ohio will MAKE 'em any way you want. Not cheap, but decidedly "custom."

03-18-2006, 01:35 PM
Ja, Arias, Keith Black, Ross, etc. will all do that, I was hoping someone has experience with "off the shelf" stuff that wasn't cast in India from the same molds used since I was born.

03-18-2006, 01:59 PM
Try AE Pistons. A set around 9:1 comp ratio would be nice for a street car (but you can get higher). Here's one source that probably has them (but AE are pretty easy to find from various suppliers):


03-18-2006, 02:09 PM
AE seemed too "mundane", from the way I read the post... but they're all I've ever used in B engines. I got a set of jugs made for a V-12 Ferrari from the Mentor outfit, faster and cheaper than from It'ly.

Sorry for the gap in my understanding there, Mike!.

Dave Russell
03-18-2006, 02:17 PM
IMO, Deves makes about the best rings that you can get.

As far as pistons, Venolia makes some of the strongest, lightest, most precise pistons that you can get. However, they are forged instead of cast & require a bit more cold clearance than cast pistons. After a very brief somewhat noisy warm up they are as quiet as any others. The price may not be that much more.

I believe AE is a cast piston. Requires less cold clearance, is heavier, & not as strong. Maybe all that you need though.

03-18-2006, 02:31 PM
If you want to spend that sort of dough, get something made from a hyereutectic alloy, they are low expansion so you can still run the same piston:wall clearance as stock. That way you get the benefit of a forged piston, but no slap.

They are not exactly cheap though - mine ran about 2x the cost of a set of Hepolites, and because they were custom I ended up waiting 3 months for them.

03-19-2006, 05:09 AM
I have heard that hypereutectic pistons (>12.5% silicone) are very susceptible to detonation failure.

Any truth to that, or is it just Chicken Little talk?

03-19-2006, 11:47 AM
I've only ever heard of it being a problem for high boost turbo engines with poor detonation control. I doubt that that's what we are talking about here though.

03-20-2006, 12:07 PM
OK, so, is the consensus that ALL new pistons are of a new design (including 3-main units)? Perhaps I'm showing my ignorance but are the 3-main pistons actually different from the 5-main units other than wrist pin? Maybe It's not the issue I thought it was. I know the rods are two different flavors. If the wrist pin diameter is the same as the 5-main pistons then I should be able to use them?

03-21-2006, 11:52 AM
JE makes anything you want and they have a forged street stock alloy that has a lower expansion rate that is designed exactly for the hot,hottest, pump gas, street motors. those are what i am considering for my 10:1 comp triumph tr4.

Matthew E. Herd
03-21-2006, 10:51 PM
If it's any interest, my pistons are JE forged (and it took forever to get them). But I am running a 1500 midget at 10.5:1 + CR and using Sunoco Ultra 94 with absolutely no problems. 93 Octane works fine in a pinch too. No problems with knocking, and the car really screams.

03-22-2006, 10:34 PM
No, you can't run 5 main pistons in a 3 main engine. You need the correct wrist pins.

I LIKE the 3 main 1800 engines a lot. I've raced several cars with them.

03-23-2006, 02:01 PM
So, Bill, what pistons do you use and are you happy with them?

03-24-2006, 11:30 PM
I have run AE (Hepolite) .080" over cast in my 3 main back-up 10.5:1 race engine and never had a problem. Great for the street too.

For the race engine (MGA Twincam) I use custom built Ross Racing forged as with 12:1 and a 7800 RPM red line, you don't want them coming apart on you. That's overkill even for a hot street engine though.

03-25-2006, 08:18 AM
I've had NO problems with AE's in five main mills, even built some 10.5:1 "street" engines with 'em too.