Distributor O-ring BBC question: [Archive] - MercuryMarauder.net Forums

View Full Version : Distributor O-ring BBC question:

BillyGman

10-26-2006, 08:46 PM

Sorry that this isn't a question about my Marauder, but I know that there are some Marauder guys here who are also Big Block Chevy guys as well. So I'm hoping to get an answer to this BBC question......:D

I pulled out the HEI Mallory distributor from my 632 C.I. crate engine awhile back, and I'll be re-installing one back in the engine soon (hopefully)now that the engine is in the car. But since I wanted to have more room back there, and because I didn't care for an HEI type distributor, I went and bought an MSD Pro Billet one as well as an MSD ignition box (a 6AL).

What I noticed right away is that the Mallory distributor that came with my crate engine doesn't have any O-ring(s) on the shaft housing,and looking at the way that it's shaped, I'm not so sure that an O-ring can even be used on it anyway. However, there definately is an O-ring groove on the MSD distributor.

So should I, or shouldn't I use one on the new MSD distributor? What determines whether o-rings are needed or not needed? Does it depend on how the block is machined in that area? This is a tall deck Merlin block that I have. If that matters.

younga1

10-26-2006, 09:00 PM

Billy,

My BBC's were original GM castings and none had an o-ring set up. I ran HEI and Mallory Dist. and never used anything other than the flat ring distributor gasket.

No leaks.

BillyGman

10-26-2006, 09:08 PM

Billy,

My BBC's were original GM castings and none had an o-ring set up. I ran HEI and Mallory Dist. and never used anything other than the flat ring distributor gasket.

No leaks.Thanks for your reply. But I'm more concerned with oil flow and pressure, rather than with oil leakage. I think that I remember reading somewhere that the reason the MSD distributors for Chevy come with O-ring grooves is because some Chevy blocks are machined to use them, and if that is the case, then they're needed for oil control in that area. But I'm not sure where I read that, nor if it had to do with small block Chevy engines only. I guess I should call the engine builder, and MSD about this.

Krytin

10-27-2006, 02:23 AM

Billy
If the Mallory HEI had no O-rings and the MSD came w/no O-rings I would not install any on my own unless you found something in the instructions or online from MSD - IMHO.

BillyGman

10-27-2006, 02:37 AM

Billy
If the Mallory HEI had no O-rings and the MSD came w/no O-rings I would not install any on my own unless you found something in the instructions or online from MSD - IMHO.That sounds logical. I just am curious as to why there are grooves for O-rings on the MSD distributor anyway. I'll contact them and post back as to what they tell me.

Loco1234

10-27-2006, 05:30 AM

Im guessing its grovved to accept o-rings because its a common part used for many applications including one that require o-rings....
This way they can make 1 part weather an O-ring is required or not....
Cheap...
Bottom line is on a MBNA's mind...

BillyGman

10-28-2006, 02:04 PM