[Frank R]

[QUOTE=ponyakr;6059098]"...how the hell do you start a car that has 36 degrees advance ..."


It had 20 initial plus 12 mechanical. 32 total.

[Formulajones]

Most guys these days are running CD boxes, and you can buy them with the option of timing start retard for those that want to run their distributors locked.

[Cliff R]

We make and install a stainless steel bushing to replace the soft factory bushings for the advance pin. I will also weld up the slot if/as needed to provide the exact amount of spark advance required for the application.

Most stock springs and weights start out right off idle and provide a smooth steady advance curve all in by 3000-3500rpm's. There is seldom any need to do much more than maybe open up the springs eyes slightly or use one lighter spring on one side to get to full advance sooner, if that is what you are looking to do.

I remove every single aftermarket advance kit on distributors that come in here for repair and put the stock parts back in them. Then I'll adjust the curve and install springs if/as needed to get the timing in smooth and steady.

If you aren't using vacuum advance your engine is missing some timing that it needs for best efficiency at light engine load. To this day I'm not sure why some folks eliminate the vacuum advance thinking that a quicker timing curve brings in more timing for best efficiency in the "normal" driving range....it does NOT. Most of these engines will enjoy initial timing around 10-14 degrees, a 20-22 degree curve, and another 10-15 degrees from the vacuum unit. So that's 30-36 total timing at full load and 40-50 degrees at cruise. Some fine tuning after your engine is placed in service is typically required to nail down the best settings and there is considerably efficiency (fuel economy/engine power) waiting for you as well with some effort spent in this area.

Here's a quick trick I use to dial in the advance curve before putting the distributor in the engine and having to wonder how much timing it is going to add, then have to yank it back out and modify, etc.

Keep in mind that 10 degrees on the wheel is 20 degrees at the crankshaft.

I modify the vacuum units if/as needed in similar fashion by MIG welding up the slot and using a round chainsaw file provide the travel required. Precision drill bits are used for measuring the amount of travel. Points or HEI they are done in similar fashion.

The tricky part once you get the amount of travel set is to find springs that start the curve when you want and get it all in by the desired RPM's. The springs showing up in these aftermarket kits are pretty much HOPELESS for this purpose and they go "soft" pretty easily after some use.......hope this helps some......Cliff

[steve25]

If anyone is curious here's how a stock Mid 1960s 400 4bbl Distributor came set up from the show room floor.

With the lower compressions we are forced to run these days you will be well in the ball park for your street motors needs if you started off with this set up.

[Sun Tuned]

The reason the aftermarket springs lose tension so quickly is that they aren't properly heat treated(tempered) AFTER they are maunufactured.

This is an absolutely necessary step. I have it done and pay extra for it for the ones I have made. They aren't cheap but they do hold tension really well because of it.

If you don't, they can and will lose tension fairly rapidly especially after being under the hood for several cycles.

[ponyakr]

"...the aftermarket springs lose tension...quickly...they aren't properly heat treated(tempered) AFTER they are maunufactured...they can and will lose tension fairly rapidly especially after being under the hood for several cycles..."


So, does that mean that ALL springs that come in new aftermarket dist are bad, & will fail quickly, including DUI, MSD, & Pertronix dist. OR, do they put good springs in their dist, but bad springs in their kits ?

https://www.summitracing.com/parts/msd-8428/overview/

https://www.summitracing.com/parts/pnx-d9001/overview/

Does all this mean that good springs are not even available to the general public ?

If this info is so(and I'm NOT saying it isn't) I don't see how anybody is still using an aftermarket dist, of ANY brand. But, I have to ASSUME that millions have used 'em, WITHOUT quick spring failure. What am I missing ?

[rohrt]

Originally Posted by unruhjonny

which issue of HPP was that article in?
I ask so that I can dig it up.

I think I have still have the magazine on my desk. I used it to do the same thing. I will try and remember to look tonight.

How I adjust my mechanical limit.
http://forums.maxperformanceinc.com/...3&postcount=11

[unruhjonny]

Originally Posted by rohrt

I think I have still have the magazine on my desk. I used it to do the same thing. I will try and remember to look tonight.

How I adjust my mechanical limit.
http://forums.maxperformanceinc.com/...3&postcount=11

thanks!!

[rohrt]

Aug 2013. Black Bandit TA on the cover.

[unruhjonny]

thank you very much!

[dataway]

Very interesting thread.

[TCSGTO]

Originally Posted by ponyakr

"...the aftermarket springs lose tension...quickly...they aren't properly heat treated(tempered) AFTER they are maunufactured...they can and will lose tension fairly rapidly especially after being under the hood for several cycles..."


So, does that mean that ALL springs that come in new aftermarket dist are bad, & will fail quickly, including DUI, MSD, & Pertronix dist. OR, do they put good springs in their dist, but bad springs in their kits ?

https://www.summitracing.com/parts/msd-8428/overview/

https://www.summitracing.com/parts/pnx-d9001/overview/

Does all this mean that good springs are not even available to the general public ?


If this info is so(and I'm NOT saying it isn't) I don't see how anybody is still using an aftermarket dist, of ANY brand. But, I have to ASSUME that millions have used 'em, WITHOUT quick spring failure. What am I missing ?

I noticed this a long time ago and have saved a stash of factory springs. The only aftermarket springs I have found that will last for a while are the heaviest ones in this MSD Kit

https://www.summitracing.com/oh/part...8464/overview/

Even those will weaken over time.

[Cliff R]

+2 or 3 on the aftermarket springs and why I don't use them. The distance between the eyes is incorrect as well and requires that they be "stretched" out too much to get them over the pins further adding to their early demise........FWIW......Cliff

[kyle_blake]

i pulled my points distributor from engine and also my spare one from toolbox.

so the brass fitting from the morso kit is exactly the same size as the plastic bushing located in both distributors (plastic) ... that is stupid, i didn't buy the kit a long time ago to give me the same mechanical advance any other pontiac points distributor. i'm so surprised! Like it's an advance kit, let me advance the mechanical more than the built in "18" degrees found in each distributor!!!

Well guess that means the brazing/welding/grinding down the brass a bit or removing the whole bushing is some way to add more mechanical advance!

See pic ...

So the picture of the "black/grey" finish moroso weights, doesn't properly rest against the center cam! Is that an issue? The other distributor stock weights ( 37 # on underside ) close properly against center cam..

Does it matter really if the weights don't come to rest against the center cam at idle?

Anyway so i tried silver and bronze spring with moroso weights. Will fire it up and see if it can keep a steady idle and no start adding advance until hopefully 300-500 rpm above idle.

[Formulajones]

I don't remember much of this thread, but what I generally do is toss the plastic bushings, they are useless. I use the bronze and solder that on, takes a few seconds. Then I either file the bushing or slot for more advance, or weld up the slot if need be. It can be tedious and time consuming to set these up properly, and many people don't understand how it works, but the rewards and benefits are worth the effort. Then there is modifying and setting up the vacuum advance when you're done with this part. Another highly misunderstood function that is beneficial.

[kyle_blake]

By the way Cliff is right, these moroso springs are way to short for the span across the poles.. i think moroso passed these off as pontiac when they are most likely for another application .

[Cliff R]

Related and I posted about it on another thread we just got a Proform distributor for an Olds V-8 in here and it was seriously messed up. For the most part it was a copy of a Pontiac HEI but the advance mechanism allowed too much timing too quickly and it continued to add timing well past where it should have stopped when the weights hit the "flats" on the center cam. Welding in a positive stop and correctly engineered factory springs corrected that issue. The VA was adjustable and seemed to work fine but the "black" iron gear they put on it was just about worn slam out after 200 miles!

About two weeks prior to that we got in a Summit brand distributor for a Pontiac V-8, it was as bad if not worse and when really bothered me was that they machined the "notch" for pump drive clear up into where it was drilled for the roll pin making it pretty weak in that area. The shaft was pretty soft as well, easily scratched with my pocket knife.

Another issue with both of them was no grease used in the mechanical advance mechanism, just light oil so no telling how long before they would start having lubrication issues in that area.......Cliff

[Sun Tuned]

I think it's a pretty safe bet to say these repop HEI's are going to continually be all over the map till they hang it up for good.

I've even seen the same manufacturer change 3 times the way they do the advance assy. At first I thought this was just product evolution, but now I see it for what it likely really is.... "we got their interest in buyin em, so now how do we make a cheaper piece of junk for more profit margin out of an already cheap unit to start with?" I don't think it's gonna work very well anyhow.

As far as springs go, ponyaker asked back up in the thread. No I don't guess that they're all junk, but a lot are. Truth is I don't use aftermarket curve kit springs and haven't in at least 25 years. I use either stock GM springs or custom springs I have made to my specs or a combination thereof as required. And even the original GM springs to a spring application engineer will look incorrect for the distributor. I had the guy that makes mine tell me this. He says "you know these are slightly wrong for the spanned distance they're using them on?" He said they will work but there must have been a reason they did it that way because technically by the lettter of the law they're actually a bit short for the length spanned.

The curve kit stuff is simply whatever knockoff or off shelf run of extension springs they get the best deal on. Since they found what they tend to believe works that's what they stick with. Again the end user is the quality control and suitability for fitness specialist.

Small runs of springs are rather expensive to have done. This is way I do it here, and this way I get exactly what I need. But it does get pricey when you get 5-6 different applications made unless you order them 10,000 at a time, and then still you're looking at a pretty good investment that's gonna sit for a good while. 1000 distributor springs will last a long damn time to be frank about it. Especially when you have 5-6 different sizes being made. I feel for and understand Cliffs investment in carb springs for sure.

The drive gears on these knockoff distributors is really what gets me. In between the "root" of the teeth they're not smooth like the factory gears were. These things have little raised striations in the root of the gear teeth. I don't know what their being Hobbed with but I really don't want any on an engine of mine.

Friend of mine owns a Dyno shop in California ( and an old one that's been there a long long time at that) and had a customer bring a chevelle in that had a knockoff Hei in it had been in there for 8000 miles or so and it had practically smoked the cam gear on the cam in that length of time. It showed up for several other issues and was a new build from Oregon, but they had to do a pretty good bit of work to it to get it up to snuff.

Gotta watch some of this stuff. There's a reason it's priced at 1/4 the entry fee fo the good stuff in the first place.

[Cliff R]

For sure 200 miles on a distributor gear isn't making the grade. Below is a pic of the bronze gear on my distributor after 10 years of hard use on a much harder billet steel roller cam.

I put the Proform gear beside it for comparison.

As I've mentioned numerous times a LOT of this stuff we see folks buying for these engines really isn't that great. We don't see a lot of negative feedback from it as very few of these engines really get much time put on them. So ratings for many of these parts are going to be all over the map no matter how good or how bad they really are......FWIW....Cliff

[389]

Originally Posted by Formulajones

Most guys these days are running CD boxes, and you can buy them with the option of timing start retard for those that want to run their distributors locked.

Or use a points distributor and just remove the springs to the weights.. The points will retard the timing when the engine shuts off.. On the 462 I got from Cliff, I had my locked out distributor starting at 2 degrees, once the engine started the weights would come all the way around and give me full advance that was 38.... Running full 38 all the time really made that 041 cam streetable..