How do I know what HEI distributor to get?

[joeydurango]

I'm in the process of tuning up my '72 K10. It is a 350 w/ HEI, but it isn't the stock engine - it's some crate 350 from, I can only guess, the 80's or 90's. Still has the QJet, no crazy cam or anything, seems pretty stock-like.

I've been checking out the timing and neither the vac advance or the mechanical advance appear to be working. Tomorrow I'm going to pull the cap off and check out the condition of the springs and weights, but I suspect things are worn in there, and stock-ish distributors don't seem very expensive.

Reading up on things, it seems that some distributors were made specifically for certain engines, and sometimes not so much; looks like there are differing amounts of mechanical and vacuum advance available, total degrees of advance, etc. I figure there must be an HEI setup that is pretty much plug-and-play on a stock-type 350... but not sure. Anyone know, and if so, have a link to what works? Thanks!

[Grumpy old man]

Plug and play stock 350 off ebay .cheap !

[El Dorado Jim]

I bought a new one from Summit, $90.00 plug and play!

[joeydurango]

Thanks guys, I guess I was reading too much into it!

[volksworld]

basically the stock hei has an advance curve for a smog motor...so if you're going to use one count on a spring and weight kit and an adjustable vacuum advance...thats the route i took....i'm sure an aftermarket distributor would have a more performance friendly curve...just be wary of chinese quality control...lars grimsrud (hope thats spelled right) has good tech articles on hei advance over on some corvette forums

[FlameOut]

Remember though, on the K10, the 350 sits further back, so that big cap HEI will leave you about a 1/4" clearance from your firewall

[RustyBucket]

I'd take the one you've got apart and see why the mech. & vac. advance isn't working. Doesn't cost anything to take it apart and look. Might cure it with lube & clean up. Advance curve kits and adjustable vac. canisters aren't much money.
I bought a new EBAY chinese one for my '72 Jimmy that worked when IT wanted to .. ran me crazy for a week.

[joeydurango]

Yep, working on the truck right now, planning on taking it apart first to see what's up. Since it is a '72, it does have the charcoal canister (early smog stuff). If I do buy a new HEI, I guess I can always check the total timing after the install and determine if I need to adjust the advance curve. I looked around on eBay and I am leery of the super-inexpensive Chinese ones. If I get a new one, I'll gladly pay a little more for better quality.

And Bill, you aren't kiddin', there's no room back there... going to be fun pulling that thing apart, much less out of the bay.

[geezer#99]

No need to pull it.
Pop off the cap and twist the rotor. If you hear the weights move and snap back into place then they're good.
To check the vac pot just hook a hose to it and use your lungs to draw a vacuum. Watch the reluctor plate for movement.
Don't get lulled into the 'if it costs more it should be better' thing.
A test was done years ago between a 40 buck hei and a 300 buck MSD one. Turns out they were exactly the same thing right down to the part numbers and tolerances.

one thing to look at.
You might need to lift the back of the motor to get that hei out of there.

[Z10]

I just installed the Pertronix "Stock Look" distributor in my 350 ZZ4. The casting looks identical to a factory unit. Nice piece and about $210. Check it out.

http://pertronix.com/prod/ig/flame/d...t/default.aspx

[Chknlyps2]

There are a couple of links to different threads and to write ups in this thread that might be of some help tuning your HEI http://67-72chevytrucks.com/vboard/s...d.php?t=700192

[joeydurango]

Okay, so I got the cap off earlier and pulled the rotor just to see what the springs and weights looked like. The weights have a little wear on their pivot pins, but not much, certainly not oval. But things don't seem okay in HEI-land, really, because when I manually push the weights out, the whole advance assembly is extremely difficult to move, and the springs don't have even close to enough power to pull the weights back. Essentially I can't even move the "advance plate" (not sure what it's called) through the entire movement available in the slots. In the attached photo, the two parts marked with red arrows don't move independently except under heavy force. I assume this is bad.

Also, when I rotate the rotor slightly, no movement happens at the weights - I have a little movement, but it is all in the helical gears at the bottom of the shaft. Is this okay?

[Chknlyps2]

Originally Posted by joeydurango

Also, when I rotate the rotor slightly, no movement happens at the weights - I have a little movement, but it is all in the helical gears at the bottom of the shaft. Is this okay?

No, the weights should swing out when you twist the rotor. It looks like the springs and pivots are corroded. I would take it apart, clean, check for wear and then lightly lube the pivot points to see if it could be made to function.

[Ontcalimo]

Flame thrower sell HEI for our trucks. They are pretty good.

[joeydurango]

Originally Posted by Chknlyps2

No, the weights should swing out when you twist the rotor. It looks like the springs and pivots are corroded. I would take it apart, clean, check for wear and then lightly lube the pivot points to see if it could be made to function.

Thanks for your help. I guess I should clarify - I knew the weights are supposed to swing out when the rotor is twisted, and I knew it wasn't good when that didn't happen. What I don't know is if a little play in the helical gear drive is to be expected, or if it should be solid with no movement...

The weights' pivot points are free moving. It's the big, central pivot - the one that pins the "weights plate" and the "rotor plate" together - that is essentially stuck in place.

[joeydurango]

Originally Posted by Z10

I just installed the Pertronix "Stock Look" distributor in my 350 ZZ4. The casting looks identical to a factory unit. Nice piece and about $210. Check it out.

http://pertronix.com/prod/ig/flame/d...t/default.aspx

Z10, nice! Seeing as this truck is pretty original overall, and both the PO's and my current goal was to make it even more so, that might do the job perfectly.

Edit: Doh! I missed the fact that the "stock-look" distributors aren't listed as HEI. So, color me confused - are all of Pertronix's distributors HEI and they just do a bad job of categorizing on their site, or what? I thought anything without points was HEI.

[Security guy]

Years ago I had bought a 'Skip White' aftermarket distributor for about $75... worked great, never had a problem. I haven't looked them up lately, but a new distributor can be pretty cheap. I wouldn't spend a lot on one unless you had a big horsepower motor, but in your case, I would pull the distributor and clean it good to find out why the weights are not moving correctly

[Chknlyps2]

Originally Posted by joeydurango

Thanks for your help. I guess I should clarify - I knew the weights are supposed to swing out when the rotor is twisted, and I knew it wasn't good when that didn't happen. What I don't know is if a little play in the helical gear drive is to be expected, or if it should be solid with no movement...

sorry... The HEI in my 396 has just a little backlash in the cam gear you can feel but not much.

Originally Posted by joeydurango

Z10, nice! Seeing as this truck is pretty original overall, and both the PO's and my current goal was to make it even more so, that might do the job perfectly.

Edit: Doh! I missed the fact that the "stock-look" distributors aren't listed as HEI. So, color me confused - are all of Pertronix's distributors HEI and they just do a bad job of categorizing on their site, or what? I thought anything without points was HEI.

Pentronix does make an HEI http://www.pertronix.com/prod/ig/flame/dist/hei.aspx and the coil is integrated into the cap like a stock GM HEI, all the ones I have seen called "HEI" have had the coil in the cap. The Pentronix "Stock Look" needs an external coil mounted somewhere like in the stock location on the intake.

That Pentronix "Stock Look" would be way cool if it took off the shelf cap & rotor so you could do emergency quick fixes if needed.

I have a MSD electronic ignition distributor in my square body 4x4 that takes an external coil, it is slimmer than an HEI and would look more stock if it didn't have a red cap.

[joeydurango]

Chknlyps2, thanks for clarifying the HEI difference beyond no points. Got it, makes sense. I'd rather stick with HEI than have the stock look with an external coil... before I go for a new one though I will dig deeper into the old one, although with a blown vac canister and corroded advance cam, a new one for ~$100 doesn't look terrible.

Thanks for all the info generously given, everyone, this is why I love this site!

[snipescastle2]

Most HEI distributors, rarely get lubed in the area of the advance weights, you can usually see a lot of rust under the rotor that's a dead giveaway. Under the weights, there are small nylon pads that the weights set on, if you clean everything up good with brake parts cleaner and add a dab of tune up grease to each of those nylon pads, you would be surprised how much of a change that makes.but, if your going to that much trouble, might as well get the advance weights/springs kit at the same time...make sure if you replace the ignition module in the distributor, that you use the packet of thermal grease on the bottom of the module, or it will fry very quickly.....
Ben

[diggerbob]

I had an accel HEI from Autozone on mine that I tried to recurve for my motor. I finally got tired of messing with it and bought a DUI HEI. I told them my compression ratio and a few details on my cam and they hooked me up. Runs like a champ.

[Z10]

[QUOTE=Chknlyps2;7521331]: .

That Pentronix "Stock Look" would be way cool if it took off the shelf cap & rotor so you could do emergency quick fixes if needed.

I'm not sure if the cap is the same but it sure looks like it. The actual aluminum casting looks to be a direct copy of the original.