IAT vs. IGT distributors

[Deleted User]

I'm looking for some input here on distributors. I have a couple of IGT distributors and a couple of IAT distributors - all needing some kind of attention. Since we're looking at the demise of the last IAT vacuum advance can we have, I'm wondering the merits of each.



Since the only difference in an IAT 4009 A and B distributor is the vacuum advance actuation point, we'll just group them together. My manual lists a straight IAT 4009 distributor with no suffix too.



I noticed something curious, the IGT distributors curve out with a 35 degree mechanical advance at 3400 rpms. The IGT A&B distributors curve out at 18 degrees mechanical at 4000 rpms. The IAT 4009 (no A or B suffix) curves out at 20 degrees at 4000 rpms. All these degrees are in crank degrees, half them for distributor degrees.



What engine was the straight IAT 4009 found and why does it have such a higher mechanical advance? Also, why would the IGT be a little higher in mechanical at a lower rpm?



I suddenly have alot of distributor questions, huh?



Mark

Unknown

Quick reply Mark

The September 1953 Hudson Merchandiser provided the CORRECTED distributor curves for the 4009A and B. I have copies of these pages which can be scanned if needed.

Application information from the 48-54 Master Parts Catalog

IGS-4213 A-1: 48, 49, 501, 502
IAT-4203 or IAT-4009: 500, 50A, 4A, 4B, 4C, 4D
IAT-4009A: 5A, 6A, 7A
IAT-4203A - IAT-4009B: 4B, 5B, 6B, 7B, 4C, 5C, 6C,7C, 4D, 5D, 6d, 7D
IAT4207 or IAT-4016: Jet only
IGT-4204B-1: 483, 484, 493, 503, 504, 8A, 8B

[Deleted User]

Yes Ken, I would definitely be interested in the corrected curves.



By whatever means, posted here or e-mailed to me.



Thanks,

Mark

SuperDave

Ken, Please post here! I have found some data but some of it contradicts it'self.

Thanks, Dave

Unknown

The following are JPEG files of the scans.


http://members.aol.com/stepdown53/pictures/Curve1.jpg

http://members.aol.com/stepdown53/pictures/Curve2.jpg

http://members.aol.com/stepdown53/pictures/Curve3.jpg

SuperDave

Ken,

Thanks for the scans. I now have then saved in my pictures. It took a little hacking around to figure out how to get the first page printed including the entire page. by transferring into my pictures, I could then print the whole page. I wonder if that info is on one of Alex's CDs?

Think I'll send him a PM.

Thanks again, Dave w