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M38A1 Engine Tune Up
Posted: Mon Apr 29, 2019 4:52 am
by ikalimnos
Great day today and found some time to check the points on my M38A1. I was lucky enough to find a motor pool issued instrument for checking dwell angle and I am using that as a much more accurate way of setting points. 47deg is the correct setting according to Willys manuals and I find that to get that I need to set the points a little tighter than with a filler gauge.
In any case, it was good fun and the engine is revving up happily!
Posted: Mon Apr 29, 2019 8:00 am
by wesk
Your Military Dwell Meter Kit is in very good shape. It is also good practice to check for maximum governor advance at the correct RPM while test set is connected.
The civvy Auto-Lite / Prestolite service manual has a lot more information for you that is not included in the M38A1 manuals.
You should visit my photo album page 2 and open Ignition Systems Sub Album:
http://www.willysmjeeps.com/v2/modules. ... _album.php
Then open & review tech data for IAU series distributors:
http://www.willysmjeeps.com/v2/modules. ... php&page=1
Take note of which advance curve applies to your Part Number distributor
You should have the IAU4006AUT distributor. If you do then the advance curve you use is: 1046
This chart can be confusing. Your Zero Advance RPM of 300 would actually be the your initial setting of 5 Degrees BTDC. At 425 RPM you will have one addtional degree of governor advance or a total of 6 degrees BTDC. At 1050 RPM you will have an additional 6 degrees of governor advance giving you a total advance of 11 degrees BTDC and so on.
Posted: Mon Apr 29, 2019 8:57 am
by ikalimnos
Thanks for the additional information. The reason that all the instruments are in good shape is that they were kept in storage until the late 2000s when the last M38A1's where taken out of service.
The kit I am using where never actually out of the box...
Posted: Mon Apr 29, 2019 10:18 am
by wesk
You are making me envious!
Posted: Mon Apr 29, 2019 10:23 am
by ikalimnos
wesk wrote:You are making me envious!
Dear Wes, you will be happy to know that we are many of us here extremely dedicated to preserving these wonderful pieces of automotive and military history. Greece and USA have always fought side by side as allies and brothers. We intend to keep alive this great tradition anyway we can...