Mark71

So I am in the middle of rebuilding my HEI with a Summit Pertronix kit. Here's the questions:

1) It appears that the weight base is "jammed"... By this I mean, if you look at the pictures 1 and 2 you see the maximum movement I can get out of the upper plate on top of the lower one. Look for the red arrows in pic 2 and you'll see what I mean... Shouldn't it move freely all the way to the tip of the red arrows???

2) The third pic shows the weight "land" that seems to have already been broken but fell out as I was working on the distributor. Can anyone tell me where I can buy a new one or how to make a replacement??? Please tell me I am not totally screwed on this!

Thanks,
Mark

MDchanic

Okay, I'd have to go out and take my cap off to check on the movement of those parts, but I can't imagine how they would be free to move just a bit, and then stop.
Hopefully, someone else can clarify that from memory.

As for the other part that fell out, I will admit that I am not clear on exactly what part it is.
Would it be possible for you to identify it from this exploded view from the Parts Manual?



- Eric

2blu442

Hi Mark
I'm used to people putting the Pertronix in their point distributors but not the HEI. Is this an upgrade, a hotter setup?

I pulled an HEI distributor out of the garage and fiddled with it. What I found is that if I rotated the weights then the two studs only moved to the middle. If I rotated the two arms the rotor fits on then the two studs went all the way. Is that different from what yours is doing?

The last picture reminds me of parts in the center of the distributor cap. Attached are a couple pictures of the factory distributor I have. Did yours look like this before removing the weights?

P1010079.jpg

P1010082.jpg

P1010081.jpg

Mark71

Hey Eric... I updated the pic below to circle where that little black plastic tab is. Basically, the weights (when not advancing the timing) just sit on those plastic "lands". There's no proper word for them - they aren't bushings and they aren't pads... I cannot find them anywhere, but then again, I have no idea what they are called.

You can see in the pic, I still have one that is ok...

Mark71

Just a Pertronix coil, cap and rotor. The weight set is from Summit, as is the vac advance canister, sensor and wiring.
Thank you sooo much for the detailed pics, that helps a bit. I think mine is behaving oddly. The arms the rotor fits on move only with significant force. And they don't move all the way (see the pics). I'll see if I can make a video and post it or something.

Of course, mech. advance was working (and seemingly properly) before I removed the distributor. So then maybe I am worrying about something I don't need to worry about???

The last pic is of that simple, stupid weight pad that mounts into the distributor rotor plate (where the distributor rotor is mounted to). They are just some simple thing to keep the weight from landing on metal when it swings back from an advance position.

2blu442

OK, call me an optimist. But I would hope you could still find that little black plastic piece at the GM dealer. They used the HEI in a lot of cars and years. You could take your distributor in to match the size, but I'd hope they're the same for many applications. John

MDchanic

Hmmmmm...

I'd say two things:
First, if the centrifugal advance seemed to be behaving well before, it should be working fine, and I wouldn't worry about it. Take it apart, clean and lubricate what you can, and it should be fine.

Second, while it would be worth it to see if the dealer has one of those little parts, the fact that they're not shown in the Parts Manual illustration does not bode well for finding them.
I'd try gluing the original back on with a liberal amount of RTV or a lesser amount of JBWeld, or, if there's just not enough to work with, I'd let it slide - most advance units in most distributors don't have these and they seem to work fine.

- Eric

Mark71

Problem 1:
Ok, so a liberal amount of WD 40 and lots of working it back and forth and now things seem to move like they should. So that solves problem 1.

Problem 2:
I am going to try those suggestions. I also found a weight kit from Mr. Gasket that seems to have those plastic things and some plastic "bushings" as well. I don't really care, I just want the thing to work right.

Newly discovered problem 3:
In all of this I didn't notice, but when I pulled the distributor, it was longer than I expected. That is, it looks like the oil pump drive shaft came out with the distributor. It is locked in there pretty good, so I am not going to mess with it.

Is there any chance I am going to get it to drop back in as one unit again??? Am I totally boned on this???

Please, please tell me I am not totally screwed!

bigD

no you aren't totally screwed, it might take a bit more fiddling around to get it back in but it will work fine. usually there is a c clip on the oil pump drive shaft to keep this from happening. as you can see the shaft is a simple hex design and will go back in just fine.

Mark71

Ok... Thank you for bringing my heart rate back down a bit. My wife would kill me if I told her that I screwed the motor up enough to have to take it out. Not only that, but I want to drive it a bit more on this motor! I've got a motor build just getting started and that takes up enough space!

Any idea what's holding the drive shaft into the bottom of the distributor? Is it just "olded" in there?

MDchanic

It's just wedged in there with gunk.

Pull it straight out, maybe wiggle a bit. WD40 won't hurt.
Just don't crush it with the Vise-Grips or you'll have to spring for like $7.00 for a new one.

- Eric

Mark71

But if I take it out... Wouldn't it be hopeless to try to get it back into the motor without just dropping it through to the oil pan?

MDchanic

Long needlenose pliers.



- Eric

Mark71

Heh... for some reason, I thought it would just drop straight through to the pan because there's nothing to stop it. I had read a thread or two here and folks were pulling motors because of a distributor rebuild. Made me a little nervous.

Anyway, I'll let you know when I get problem 2 (that annoying plastic pad) worked out.

Thanks again, guys!

MDchanic

Nope. The shaft receptacle in the oil pump is a dead end.

Just set it in there and make sure it pushes in all the way down.

- Eric

Mark71

I ran into a couple more questions:

1) The weight posts (posts where the weights mount onto) on my distributor seem to have a little "notch" in them, at the bottom... Is that normal (see pic 1) or is it wear???

2) The distributor shaft has some endplay in it. As near as I can measure it is just about .125" (or 1/8") according to a dial gauge. Is that normal? Since it is so exact, I assume it is.

3) Not so much as a question, but a rant. The distributor cap and rotor set I got from Summit doesn't fit. Or better said, the rotor doesn't fit. Take a look at pic 2... The front of the rotor mount needs to sit in that little space. The white on the left is my original and the black on the right is the new one. Oh well, I guess I'll be getting a new one at NAPA.

Mark71

So, from this post, I think my end play is more than it really should be.
https://classicoldsmobile.com/forums...e-replace.html

I found a shim kit from Jegs that should work to help reduce that, but because of the counter-clockwise rotation, I am not going to worry about trying to get that down to perfectly .015". I'll probably just try to reduce it down from .125" to .065" or so.
http://www.jegs.com/i/JEGS+Performan...40085/10002/-1

Mark71

So I am bringing this post back to life for the reference of future novices.

I just reinstalled my freshly rebuilt distributor. I used a Mr. Gasket #929G advance kit, with the wider bushings and the heaviest (gold) springs. The weights seem a little lighter than the originals... but oh well.

I started up the motor (let it warm up and come to operating temp) and set the timing according to timing tape. I wanted to target 20* BTDC which was originally set on my 350.

Using the heaviest (strongest) springs:
Initial timing - 20* BTDC
All in (no vac advance) - 32* BTDC

Doesn't sound bad so far, right? Here's where it gets a little concerning. It reaches 30* BTDC at around 1700 RPM!! Doesn't seem like much of a curve...

It reaches the full 32* by 2200.

So here are the questions, we'll call them 4 and 5 (as I asked 1-3 already):

• 4) Shouldn't it approach maximum advance more slowly? Is it even worth road testing in this condition or will it just ping like crazy???

• 5) Could changing the advance curve change the amount of TOTAL timing that my distributor is capable of? I mean, before I got 14*, now I seem to only get 12*... Or could that be the fault of the heavy springs?

Thanks again for all the help so far!

RetroRanger

Mark

maybe the wieghts are to light and your mechanical advance is moving 2° at idle so you dont see 14° any more you see 12° . the all in by 2200 rpms supports that theory

try it w lighter weights or no weights or heavier springs to confirm

IDK if its good to see it advance that quick usually 3k is a ref rpm I see in other posts.

in your other post I wrote my final timing set-up ~15 initial, ~28 w no vac at 3k (72 350 w HEI)

to test your initial and mechanical settings ride around w no vac advance if it pings back the initial down in 2° increments and retest if no abnormal noises, plug in the vac advance and test again..I think I gotta get an adj vac advance my intial and mech are good but I think I have too much vac advance (~26°)

Dean

Mark71

Hey Dean - I just re-read your comments from my other post. I am going to try to get things setup like you have them and work from there. I am a little concerned, though, because I used to be at 20* initial and 34* total. I'll spend some more time on it tomorrow and post any results I come up with.
-Mark

Mark71

So I had some time to work on it. I ended up putting stock-style weights back into it. The Mr. Gasket ones were causing "binary" advance - it was either 0* advance or 10. No in-between. Another thing I realized is that the distributor was only giving 14 degrees total advance before because it was "stuck" (see the previous posts in this thread). Now I seem to get around 20 degrees total.

I've had a few problems with those stock-style weights as well (came with the kit from Summit). I'll post about that later. For now, here's what I am seeing:


To translate, Advance is the total advance at the RPM. Mech Diff is the amount the mechanical advance added since the previous RPM. In a graph it looks like the image I attached.

It seems like the jump of 11 degrees from 700 to 1500 is pretty large. Right now I am using two medium springs because it is all the Summit kit came with (I'll explain that later). Is that a problem or somewhat normal? How does this curve look otherwise? At all normal?

RetroRanger

LOL I dont know !!!

I posted my data for reference good or bad IDK. I bought the car this summer my knowledge base has come from reading here. I would like it if someone more knowledgeable than me chimed in w thats fine or you gotta change it

I agree it does seem like your mech advance comes on suddenly and quickly mine wasnt quite like that. My reading suggests it should be all in by 3k (mines close to that). I am concerned about my total advance of 56°

I used the moroso advance kit (made in USA CT to be exact) it comes w nice(r) wieghts than some of the other kits Ive seen (spectre for one) I ended up w 1 mid spring and 1 lite spring, 2 mids showed to little mech advance 2 lite springs showed advance at idle.

My car is stored for the winter so i wont be able to look at it any more till ~aprilish

I *think* if you were at 20° initial before you might run that again tho if you freed up some mech advance you may find that your total advance is too much now

I would be interested in how much a stock 4 wire HEI *should* have for mech advance and what total timing should be (ini + mech + vac)

Mark71

Haha! That's great. Oh well, sometimes you have to learn by trial and error.

Hmm... yeah, sounds like a lot - but I have no idea what it should be exactly. On the other hand, it isn't unheard of or anything... I know mine was up around 45° before. I haven't even hooked it up yet.

Do you still have the part number, by any chance? I tried to get a Moroso kit, but was told it wouldn't fit counter-clockwise HEI setups.

My car doesn't get a winter break. It doesn't go out much in the winter, but it still gets started up and run once every two weeks.

Yeah, my total advance is definitely increased, but after all I put in a re-curve kit. So I guess it is ok that I am getting more of a range now. Plus, from my reading on some Chevy sites, it seems that SBC's usually do well somewhere between 8 and 15 degrees BTDC. I know it isn't the same motor, but still a V8 product from the same era.

I have searched and searched on the question of what a stock 4 wire HEI should have advance-wise. There are a lot of ideas and opinions, but many of them seem reasonable.

RetroRanger

heres the moroso kit i used

http://www.amazon.com/Moroso-72300-A...pr_product_top

youll note the one review of the kit was written by me

AFAIK the kits are all the same but you may need to flip over the components to match chevy or olds CW or CCW distributor turning direction

Mark71

Excellent. I just ordered that kit. I'll let you know what I find out from here.