Brand new Delco HEI
#42
Tech Contributor
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Lars
Last edited by lars; 02-11-2019 at 04:47 PM.
#43
Le Mans Master
Thread Starter
Crane makes this little adjustable stop for the vacuum advance. Now I have 5* distributor degrees advance. All in at 6.5"
#44
Le Mans Master
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jackson (02-11-2019)
#45
Tech Contributor
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As I mentioned in post #2, we (GM's component divisions and personnel) were all kicked to the curb by GM in 1999. After that AC-Delco morphed into a purchasing group, buying stuff from all over the world. I have no definitive or insider information about where AC-D purchased service/replacement distributors, but my first guess would be Taiwan or mainland China. I welcome any corrections if someone has a newer vintage distributor with a stamp indicating its country of origin.
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jackson (02-11-2019)
#46
Le Mans Master
Thread Starter
The housing, still available seperate. No marks. Comes pre greased.
#47
Melting Slicks
What are you putting this in? For years I've read to look for 375 center and 41 weights, I gave up since old vehicles in salvage yards just aren't there like they used to be.
#48
Melting Slicks
[QUOTE=Big2Bird;1598855262]
[/QU
OTE]
I missed seeing the numbers stamped earlier. I'm excited about this, but after reading 375 and 41 is supposed to give 22 degrees?
[/QU
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I missed seeing the numbers stamped earlier. I'm excited about this, but after reading 375 and 41 is supposed to give 22 degrees?
#49
Race Director
Jeff, were you able to see any breakup at higher rpm's? What rpm do you think a new GM HEI is good for?
Last edited by jim2527; 02-12-2019 at 10:36 AM.
#50
Le Mans Master
Thread Starter
I will run it complete with coil, load, and on a scope. I imagine we can exceed the dwell necessary for complete coil charge up.
I would imagine Mike can calculate that out.
The point of this exercise is to measure without prejudice.
#51
Le Mans Master
Thread Starter
The next step is to shim the shaft, allowing for expansion. Since the housing is aluminum, and the shaft is steel, there should be a difference of expansion rate. If you read about the desired gap, you will get answers all over the map.
Originally, they came with one .030" shim. However, how do you know? You heat it up.
SO, at the risk of promising Mrs. Bird a new stove, let the test begin.
Originally, they came with one .030" shim. However, how do you know? You heat it up.
SO, at the risk of promising Mrs. Bird a new stove, let the test begin.
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jackson (02-13-2019)
#52
Le Mans Master
Thread Starter
#53
Le Mans Master
Thread Starter
I assembled an old housing and shaft that were together as a mated set, degreased them overnight, and assembled. The gap is .052". at 70* ambient.
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jackson (02-13-2019)
#55
Le Mans Master
Thread Starter
After baking 1 hour at 200*, the gap was immediately rechecked, and a change of .006" was determined.
If your distributor is ever this hot, chances are it's toast.
Conclusion: I will go back to .010" clearance, and never fret again. I also surmise that .008" to .010" is fine.
This is where all the metal gurus can agree or disagree. I just don't see an issue, nor do I see a need for .020" - .030" gap that some would argue is necessary.
I would suggest using a shim pack with the thickest shims possible, as a .001" shim could wear out and drop in the chaos below.
If your distributor is ever this hot, chances are it's toast.
Conclusion: I will go back to .010" clearance, and never fret again. I also surmise that .008" to .010" is fine.
This is where all the metal gurus can agree or disagree. I just don't see an issue, nor do I see a need for .020" - .030" gap that some would argue is necessary.
I would suggest using a shim pack with the thickest shims possible, as a .001" shim could wear out and drop in the chaos below.
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#56
Le Mans Master
Member Since: Sep 2001
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https://cimg7.ibsrv.net/gimg/www.cor...61aad7ae46.jpg
b2b
Either you're single or
Your bride is VERY tolerant or
You just don't give a flip
regardless, thanks!
b2b
Either you're single or
Your bride is VERY tolerant or
You just don't give a flip
regardless, thanks!
#57
Le Mans Master
Thread Starter
Mrs. Bird is quite tolerant of my antics. I consider myself a very lucky man.
#58
Safety Car
On the earlier small cap points distributors my 69 CSM recommends shimming .002" - .007" for mainshaft end clearance. I run .005" and have never had a problem or scoring on the shims due to lack of clearance.
#60
Le Mans Master
Thanks for posting all of this! I wish there were more of these tech-talks on the forum, though a search through the archives often uncovers some gems.
You are indeed quite fortunate to have found Mrs. Bird, if she tolerates science in your house.
You are indeed quite fortunate to have found Mrs. Bird, if she tolerates science in your house.