2 questions about weights and center bars in stock engines;

1) Many have stated the stock HEI weights and center bars from 'smog era' Olds engines provided only about 14 degrees mechanical advance. Anyone know the numbers stamped on these weights and center bars?

2) Anyone know what weights and center bars came in the Olds diesels?

 

Sorry, no.


Okay. Think about this for a minute and ask again...

- Eric

 

Contact Speedway Motors. If you find a Diesel distributor youd better hang on to it as its as rare as hens teeth and would ebay for 6 digits!

 

A diesel distributor is almost as rare as an old VW Beetle thermostat.

 

Duh on the diesel question!!!! Brain fart! My head was somewhere else. Just been focusing on all the various weights and such I had a momentary stupid moment. Maybe I should cancel my order of diesel spark plugs too....

OK, now that's out of the way. So anyway I'm looking into different weights and centerbars so I can run less mechanical advance without having to resort to welding up the slots. Would like to use factory parts if possible. So if anyone has any numbers I think it would be valuable info for those looking to shorten the advance curve of most aftermarket hei's.

 

I dunno - I've got a set of old diesel spark plug wires around somewhere - waiting for them to appreciate just a bit more before I reveal them to the world - not sure whether to put them on eBay or charge admission...

And those VWs, the thermostats may be hard to find, but the antifreeze is even harder - they called it unclefreeze, if I recall.

- Eric

 

Diesel distributors only come on non-windowed 403 block engines.

 

Yes, and we should all change our blinker fluid and muffler bearings too. Is it all out of everyone's system now? Much appriciate any real knowledge anybody has to share on the subject of stock HEI weights and centerbars.

 

Pretty sure I have one that would fit your needs. I tried to make positive stop and it went goofy, maybe I went on the wrong side? I believe at 20 base, it moves to 36 just around 3000 rpm with lighter springs. Good luck having it come in sooner with stock weights. I now use a Mallory breakerless, love how the base and total advance/rate are completely tuneable. I can bring in all my timing by 1600 rpm! Right now comes in just over 2000 rpm. Unless your DUI has a stop mechanism built in, you will need to braze up a stock set up. They all advance extra degrees when revved way up.

 

http://www.chevelles.com/forums/showthread.php?t=327577



Scroll down to find Rocky Rotella's cahart and PDF




Hope this helps. Getting down to 14 degrees in an Hei so I could get more initial was challenging.

 

That thread is excellent, and should take care of the OP's needs.

Please allow me to link separately to a very nice pdf version of the Lars Grimsrud vacuum advance specs, along with an article by Duke Williams about how to set up your vacuum advance, which is included in the thread you linked to:

http://www.lbfun.com/warehouse/tech_...ance_Specs.pdf

Thanks for posting that!

- Eric

ps: be sure to note that that is a Chebby-based article, and so assumes clockwise rotation of the distributor, with clockwise directionality to the weights - arrangements may need to be reversed for Olds engines.

 

Yes I have seen that chart before. Very useful info. The problem is is not knowing where to find the center bars that give you the desired advance you want! Figured if I knew what centerbars came in what particular application, I would have an easier time tracking some down.

Also just talked to a friend who says he has lots of spare weights and centerbars so hopefully he has some of the more desireble ones from that chart.

Eventually I will try some of these different combos and report back on my findings but that won't be until spring.

 

Yeah. They have numbers on them, but are not listed separately in the Parts Manual, so you can't tell what they come from.

- Eric

 

I'm curious as to what timing parameters you are wanting. Is 14* mechanical advance too much for your application?

 

Currently running aftermarket ( DUI ) weights and centerbar. I have the initial at about 12-13 and have about 35 total and is all in around 3k.

I'd like to shorten the curve so I can try running around 20 initial and still have 35 total. Looking for around 15-16 mechanical. With the right springs I'd like to have it all in a little before 3k.

 

OK, I see. The HEI on my engine has about what you are looking for. The center bar and weights give 16º mechanical advance according to my measurements, so I have the initial set to 20º for 36º total.

GM HEI Distributor #1103324
78-79 403 exc Toro and Firebird
Weights stamped 139, plate stamped 446

 

I'll have to see if my friend has a 446 centerbar. I know I have some 139 weights already. Seems like a good place to start at least and I can tinker from there. Thanks for the info.