Distributor Timing Curve

[Kurt]

Hello,

Does anyone know of a service manual for the M37 that lists the advance timing curve for a IAU-4007UT distributor?

Thank you, Kurt

[Cal_Gary]

Hi Kurt and welcome!
Sorry I don't know that distributor number nor the advance curve. Alan Bowes wrote a complete rebuild article on rebuilding the M37 distributor; however it has no information on the advance curve. Perhaps some of our other members can weigh in.
Happy to have you with us!
Gary

[just me]

I have the Autolite manual, I will look.
There is no IAU4007UT listed (1952 EDITION)
There is an IAU 4005UT
The curve for it is
0°@350
1°@370
3°@400
9°@1,050
10°@1,150
An IAD4007 curve is
0°@275
1°@380
3°@580
5°@800
6°@900

[Cal_Gary]

@just me, outstanding!
Gary

[PoW]

Pretty small increase, actually.

No vacuum advance mechanism in the G741 truck.

PoW

[Kurt]

WOW! You would think this is something top secret.....LOL

Was the IAU-4007 UT the only distributor used in the Dodge M37 and other models that used the same chassis?

Thanks, Kurt

[just me]

You may be close. Every page of the Autolite manual is marked Secret.

[PoW]

Every G741 variant I've ever seen in stock configuration has the same ignition system with the waterproof distributor and sealed vent line system..

For those that don't understand the Gov't system of classifying vehicles of the same basic type:

G741: M37 M43 M56 V41 M42
G742: M35 M44 M34 M49 everything built on the REO design.
G744: M39 M54 M51 M52 eTc, ending the 800 series.
G749: M135, M211, M215, M217, M220, M221, M222
G503: WW2 Jeep.

The G designator is applied to every tactical vehicle in the US motor pool.

"G" numbers are useful at NAPA stores, when asked for the model of just what you are trying to find parts for.

PoW

[Kurt]

FYI,

I found the timing curve in a Prestolite manual.

Thanks for your help

[cuz]

The IAU4007UT distributor is listed in the M37 ORD 9 SNL G-741 date 1954. The IAU-4005UT is also listed but for the 1st sn thru engine serial 20934. The IAU-4007UT starts at eng sn 20935 and on. The specs for both and advance curves are in the old 1960's AutoLite/Prestolite Service Manuals. The Army TM 9-1825B dated 1952 only lists the IAU-4004UT, IAU-4005UT & IAU-4006UT. The later units are not listed. The Prestolite service sheets date 1978 only lists the IAU-4006 thru IAU-4027 UT & AUT series.

IAU-4007UT xtrasm.jpg (221.3 KiB) Viewed 8423 times

IAU_ser_1.sized.jpg (80.65 KiB) Viewed 8423 times

IAU_ser_2.sized.jpg (38 KiB) Viewed 8423 times

[cuz]

Here's the advance curve sheet for the IAU-4007UT. It uses curve # 770.

Gov_Curves_8.sized.jpg (91.42 KiB) Viewed 8423 times

Here's a link to a downlaodable copy of TM 9-1825B AutoLite electrical Component manual dated 1952: https://www.scribd.com/document/5182534 ... -Auto-Lite