distributor fitments

[bluecab]

Hi'
looking for advice on distributors: my machine shop is just about done with my motor and are looking for a distributor to install.
Will a MSD fit under the stock air cleaner?
Opinions?
Advice?
All welcome..

David

[Schurkey]

For any "street" use, including high-performance street use (not all-out racing) the simplest, easiest way is to drop in a rebuilt Delco HEI distributor, and then use a Toronado air cleaner from a late '74--'78 car. You'll need to bypass the resistor wire that powers the coil on the stock ignition system. Adjust the centrifugal and vacuum advance to suit your vehicle, and you've got as good an ignition as you'll need for a vehicle with a license plate.

DO NOT fall for the "brand new" HEI-style distributors commonly available; they're Communist Chinese and may or may not take standard replacement parts. At any rate, the quality is suspect right from the time you open the box. You are better off with a "usable-but-used" Delco HEI than a brand-new Chinese HEI.

I have used MSD spark-boxes starting in about 1979 with good success. That is to say, reasonable reliability and the assurance that I've got more ignition than I need. I've never used an MSD distributor, but I have heard many complaints of the internal parts rusting. It may be that MSD has resolved this issue. Last I heard, MSD was in receivership.

I wouldn't touch a Mallory distributor with a ten-foot pole. I have a photo and part number for the distributor gear on a Chevy distributor where the roll-pin hole is so far off-center on the main shaft that the replacement gears aren't drilled all the way through--the end user is expected to custom-drill the replacement gear.

On any street-driven vehicle, be sure the distributor you select has vacuum advance. Failure to use vacuum advance will reduce fuel economy, increase emissions, and reduce part-throttle driveability. It could potentially lead to reduced spark-plug life, and increased engine temperature.

[bluecab]

Hi,
Just saw your response! Thanks.
Can you advise a GM part # and where to look for one?

Can I walk into the local NAPA and get one?

Is it easy to tell the Chinese knock offs from real GM units?

Thanks again,

David

[Schurkey]

Hi,
Just saw your response! Thanks.
Can you advise a GM part # and where to look for one?

Can I walk into the local NAPA and get one?

Is it easy to tell the Chinese knock offs from real GM units?

Thanks again,

David

My preference is to wander into any local Treasure Yard, and buy three or four of them at ~$20--$40 each. I'd be willing to pay towards the high-end if I get to select them from "the pile", as I can pick the most complete, least-varnished units of those available. I'm looking for COMPLETE units, including spark plug wires, caps, rotors, coil, module, etc.

With three or four hand-selected cores, I toddle home to disassemble, clean, and carefully inspect. The only things that really matter are that the distributor mainshaft and bushings are in usable shape (no excess wear to the bushings, no scoring on the shaft,) distributor drive gear has no excess wear, and the centrifugal advance weights and pivot pins aren't worn out. Everything else is gravy. Installing a new pickup coil can be wise, as the pickup coil is about the only common failure item that requires distributor removal to fix. You'll need some heat-sink compound (available at any Radio Shack) to reinstall the module. Verify that the wire harness and noise-limiting capacitor are in good condition.

http://www.chevelles.com/techref/ftecref5.html

The only "hot-rod" part you need other than what it takes to tune the centrifugal and vacuum advance, is a low-resistance bushing between the ignition coil and the rotor. It installs into the distributor cap under the coil.

BE SURE YOU'RE BUYING A DISTRIBUTOR THAT FITS YOUR (OLDSMOBILE) ENGINE. Olds uses an O-ring seal rather than a gasket, but to a novice, looks similar to a Pontiac distributor.




Buick distributors also look similar, use an O-ring, but are "skinnier".


I don't know of ANY Made-in-USA "new" distributors for Oldsmobile. Perhaps MSD or other boutique brand, and even then you're going to have to be careful.

Production-line rebuilt distributors should be available at any parts store including NAPA.

No matter what you buy, you're going to have to tune the advance curve to suit your vehicle--or pay someone to do it for you.

Dave Ray does good work, I'm told.
http://www.davessmallbodyheis.com/
His specialty is using HEI parts in original-size distributor bodies, so you could keep the original air cleaner.

Sun Tuned has an excellent reputation, too.
http://forums.performanceyears.com/foru ... p?u=143447

[xgecko]

I have the 8566 Billet Aluminum distributor from MSD as part of my Atomic EFI setup (the rotor is locked to allow timing control from the EFI). It was not cheap at $281, but I feel it was well worth it for my application.

Either of these units will work well and use small diameter caps. I suspect they will fit fine with the stock air cleaner. The Ready to Run unit is ideal as a replacement for the stock unit as it has the Vacuum Advance on it.

While you may or may not have the same experience I had, I purchased a 'cheap Chinese' HEI unit for $38 and it worked fine. At $38 I felt it was a better choice than a used unit, and I have to say it looks great and worked just fine. While I cannot speak to the variability or longevity of the unit, it fit without problems and the car ran fine when I used it. At $38 it was not much of a risk, and since it worked out for me I would do it again. If the unit were much more expensive I would not do it again.