PaulUptime

Sigh... Labor day project... and I have a few questions I couldn't find searched answers to...

While driving down to Carlisle last weekend I experienced some strange engine surging, loss of power and a car that ran like crap on what is always the best trip we make with it every year.

The bright side however was all the excellent assistance I was given on the funfield - for which I'm very grateful. There were a number of factors that needed to be addressed - timing, wrong type plugs, carb set too lean, vacuum leaks incl. at the carb gasket. All valid, all now addressed. (Hopefully) I'm at my final stage. Once home I noticed the ground wire to the distributor breaker advance plate had broken.

Part of me would like to drop in a new MSD tach drive billet distributor but I see an LS conversion on the horizon that would make a new disty an expensive short term option. I also don't want to spend on something I might otherwise be able to fix - which brings me these few questions, please:

1. Might this be a '65 Corvette or could it be a generic replacement?
There are no markings/numbers on it at all.



2. Will a B9 vac advance work?
Bought a new vacuum canister B9, but original says B1. OK to use or should I stick with the old one which was working, but thinking it would be a good idea to put new.



3. Must I use an "arbor press" or some such tool to remove the bushing and therefore the shaft?
After removing the bottom drive and tach gear I thought the shaft would come right out. I did remove a very thin clip atop this bushing but it seems the shaft can only come up a few inches before the tach drive gears on the shaft are stopped by the bushing.

I need to (silver) solder the new wire to the breaker plate and this would be better done apart, plus I'd also like to clean/inspect and lube esp. behind the breaker plate which shows some red plastic from where a rotor nicked the inside of an ill fitting MSD cap.

I don't have an arbor press and really want this done today - so unless there is an alternative I'll skip removing the shaft and do my best to solder with it assembled.







4. In this pic you can see I also purchased an advance curve kit to get the new springs, but I'm hesitant to use it until I'm sure the disty works once back in the car. The shape of the weights is a bit different than my originals but close enough they fit, and I think the weights and springs should be about the same. I plan to clean up the plate surfaces and polish smooth with an emery cloth before reassembly.

From the picture above, should I use that small brass bushing that was included, or leave it out? I presume it would go on the pin just above it in the picture, pressed on with pliers. It's purpose seems to be to limit the vacuum advance?

5. Lastly, there is a hole opposite the tach drive setup that was just plugged up with silicone but this looks like where a zerk fitting should go. Should I tap and fit a new zerk, and if so what sort of lube is recommended?




Thank you thank you!

Bluestripe67

Paul, After looking at all the pics I think you need a new main shaft and a complete rebuild. The gear section that meshes with the tach drive gear is chewed up I believe and does not look good at all. If you want the best bang for the $$, send it to Lars for rebuild. He will do it justice. Dennis

PaulUptime

Thanks Dennis.
Haven't met Lars but would do that in a heartbeat if it didn't involve being denied the car for a few weeks at the end of an already short season. If I can't get it going today, tomorrow I'll be picking up an MSD 8572 and hopefully just be done with it.

Easy Rhino

Here's my take - worth every penny you are paying for it.

If you got to and from Carlisle with that dizzy, you can fix the ground, reassemble it, and enjoy the fall. You don't even have to do the MSD now.

However, that dizzy is tatty, and I would recommend having it rebuilt when the snows come. A worn bushing can wreak havoc on your timing.

PaulUptime

Tru'nuf. That 8572's looking closer now, but just the same I think I'll get 'er together and back in today. Would be better if I knew a way I could get the shaft past the bushing for a better reference.

Frankie the Fink

Lars has my original "024" tach drive distributor from my split window for a rebuild right now. The MSD will work but indexing is tricky, you have to buy the tach drive cable adapter and I would want the GM "socket style" distributor cap. So -- you are looking at from $395-$425. A little excessive when the "turn-key" Pertronix distributor in my '61 was all of $209 (they don't make a tach drive dizzy). I'll just wait on Lars to get mine going again.

PaulUptime

Frankie - when you say indexing is tricky, do you mean if you have ign. shielding? (I don't)

I'll see if anyone in the Toronto area can rebuild it, but perhaps sending it to Lars over the Winter would be best.

I hear you on the price too - specially when I'm within a year or two before putting this motor in my boat and LS'ing both my '75 Silverado and the Corvette.

lars

That's an original GM Corvette tach drive distributor - it is not one of the cheap Chinese repro's.

The B1 is not the original unit, and is a bad choice, requiring 18 inches of vacuum to pull in. The B9 is even worse, as it has a 21-degree advance curve in it, which is grossly excessive for a Vette (or any other car on current pump gas). Get a B26 and limit it's stroke as outlined in my paper.


There is no press required - the shaft slides right out. The fact that your gears are sticking on the bushing is indicative of severe gear damage. Stick a rod up the bottom of the distributor and tap the mainshaft. This may result in the mainshaft coming out with the bushing jammed onto it. Once out, you can knock the bushing down off the shaft and re-install it with the install tool for the bushing. Be sure to inspect both the uppor and the lower bushing for damage caused by the metal filings/debris that have been shed off your gears.

Don't use the weights in any aftermarket kit - they are junk. Not only will they give you a very bad advance curve shape, but they are not heat treated, so the pivot points will wear out within a few thousand miles. If your stock centrifugal curve is very slow, you can install one of the gold springs with one of your stock springs to get the curve to come in around 2800-3000 rpm.

Your distributor is missing its advance stop bushing, so you will need to use the brass bushing in the kit. It does not limit vacuum advance - it limits mechanical advance. You will need to lay the bushing on its side and give it a gentle tap with a hammer to smash it down a little - in the as-provided condition, the bushing does not fit tight enough, and it will fall off your shaft and short out your points. Smash it down, and then install it by hammering it onto the pin. If you can install it with pliers, it's too loose.

That's not a grease zerk hole. It's the hole where your crossgear thrust button used to be. More than likely, the button wore out, and disintegrated. This debris has dropped down through your lower bushing, and likely scored the bushing and the mainshaft. Your crossgear has been riding against the inside wall of the distributor housing, and you now likely have a worn area in there around the hole that looks like a counterbore. This wear is causing your crossgear to start locking up, and this is what caused the damage to your mainshaft gears (and why you can't get the shaft out of the bushing). You need to do a complete machine repair job to your housing, fabricate a custom thrust surface insert, and replace your mainshaft and crossgear.

Lars

PaulUptime

You answered all my questions. Thank you Lars!
Man I wish I was closer to you. Need to send some Cdn beers over!


So, at the very least it looks like I have some parts to return. The original centrifugal weights do indeed look better than the stamped ones that came with the Mr. Gasket kit. That, and the B9 vac are all I could find locally.

I'll try getting that shaft to come up and through now. It will give me an idea what's going/gone on with this dizzy. I got the car 15 years ago with no owner history - it had been pretty much cobbled together for a radio contest (that I was glad to have won!)

It had a 454 at the time which spun a bearing, never ran that well and with little effort sold it and put a lighter, more efficient, quicker and more cost effective (at the time) new Edelbrock Performer 350 crate engine in that did come with a dizzy, but of course wasn't tach drive so I reused the distributor that came with the car, the one you see in my pics. Time to go!

If I can't find anyone local that could do a one or two day turnaround and considering all the other issues with it, I'm going to return the parts I can, cut my losses and get that billet MSD w/adapter. I'll lose the Pertronics II I recently put in, but it'll plug directly to my 6AL.

You've helped make up my mind: A nice, new - no nonsense hopefully - billet, modern manufactured dizzy is going to be the smart thing to do.
Contra or in favour, I'm open to comments!

Frankie the Fink

If you don't have ignition shielding you are prob OK with the MSD. The repro dizzy's don't have the 'dimple' to help align things so getting it right between the shielding and other obstacles takes some finesse...without the shielding...not so much.

tbarb

It's so easy to fix for penny's if you are willing to learn and some time. Much cheaper than hundreds of dollars for aftermarket hot rod parts that DON'T run better.

These distributors are the least maintained parts on the car.

wilcar

I agree about the ill fitting msd dist cap with male hei terminals. I have one on a 65 dist and is very poorly made. I had to file it just to get it to fit straight. Plus there is no slot tang on it to secure it to the dist body. I will be going back to a stock ac delco window dist cap.

Frankie the Fink

So you can see why Lars has my '63 dizzy. Cleaning things up and swapping worn parts out is easy....getting the optimal advance curve takes some finesse and special equipment.

I did it on my '61 with a digital, dial-back timing light after a LOT of trial and error....a Sun machine makes it a lot simpler and less stressful.