Hodakaguy M38 Misc Thread

[HodakaguyTom]

Also happened to notice the thick carb base gasket you have isn't the M38 "diffuser" type called for in the September 1955 edition of the ORD9 Manual (page 68, WO-A923, G740-7372543), designed to help atomize fuel flow to the intake and insulate the carb from manifold heat.
Shown here:

Thanks Mate! I'll snag one and get it installed. Appriciate the assistance.

Hodakaguy

[HodakaguyTom]

More progress and some fun!

Started the day by changing out the rubber cowl seal on the windshield frame. First up remove the top and fold down the wondow.








Lools great with the windshield down.




Removing the old seal, it's screwed onto the bottom of the windshield frame. Removal is easy and quick.




Houston we have a problem. The new seal is shaped a bit different and the holes dont quite line up with the old seal. Hmmmm.....not sure now which seal is correct for the M38. I re-installed the old seal for now until I verify.




Since the weather was so nice we decided to take the Jeep for a quick spin to the fuel station and back. Before we left I did a quick check of the timing....it was way to far advanced. The adjusting nut on the distributer was pretty loose so it probably moved on its own. With the timing set we gave everything a look over and found/tightened several other loose bolts.





And we're off. The timing made a big difference, engine is running a lot better now and has the pep I expected (it was low on pep when I test drove it around the block after the carb rebuild). We decided to run with the windshield down this trip. Fun stuff!




After getting fuel we drove around to a few yard sales....so much fun.






















Back at the house and time to get a bit more work done. Our jeep came with a decontamination unit but the previous owner had it just laying loose under the passenger seat...rolling around loose probably isn't the best idea. There are wooden blocks attached to the body just ahead of the tool box lid, these were installed at the factory specifixally to mount the decontamination unit.

Passenger seat removed, you can see the wooden blocks In this Pic.




Here I'm cutting a rubber piece to install between the Decon mount and body.






If you ever want to drill holes in rubber use a piece of tubing in a drill. Unlike a drill bit a piece of tubing leaves a nice clean hole. Use a bit of water as lubricant as you drill the hole.








And mounted up. I placed the unit as far back as I could while still allowing the tool box lid to open freely. I'll remove the setup.amd paint the mounting bracket OD soon.










Hodakaguy

[RonD2]

Another Army MWO-TB that might be of interest: https://forums.g503.com/viewtopic.php?t=192723

[wesk]

That MWO is loaded in my Photo album:





The PS Magazine TB, MWO listing mentioned in the referenced G503 post is in our downloads pages: http://www.willysmjeeps.com/v2/modules. ... tit&lid=96

If you have seat belts installed and anchored to the floor there is no need for the slide bolt mod.

[RonD2]

If you have seat belts installed and anchored to the floor there is no need for the slide bolt mod.

Unless you want to faithfully replicate your M38 as used during Army service?

[HodakaguyTom]

Thanks Guys
...a huge help as always!

Hodakaguy

[HodakaguyTom]

Cowl seal revisit. I had ordered the replacement cowl seal from Army Jeep Parts and had contacted them after the first test fit. They said the new seal is the correct seal and that our old seal is a cheaper incorrect reproduction. After looking at some pics it does look like the new one is correct and follows the windshield frame correctly.

With new information in hand I set to swapping seals again.




I warmed the seal up in the sun and it allowed the screw holes to line up correctly.






I used a bit of lighter fluid on a paper town to wipe off the white molding residue, leaving a nice black seal.






Very happy with the results. If you need a seal I would recommend this one from. Army Jeep Parts.












Note: With the old seal the latches were almost impossible to close (like the seal was to thick), with the new seal I can snap the latches down by hand now with good tension on the latch...perfect!

Hodakaguy

[RonD2]

Note: With the old seal the latches were almost impossible to close (like the seal was to thick), with the new seal I can snap the latches down by hand now with good tension on the latch...perfect!

If or when necessary, tension on the windshield latches is adjustable with the slots on the pivot brackets.

[HodakaguyTom]

Note: With the old seal the latches were almost impossible to close (like the seal was to thick), with the new seal I can snap the latches down by hand now with good tension on the latch...perfect!

If or when necessary, tension on the windshield latches is adjustable with the slots on the pivot brackets.

Thanks Ron.

Hodakaguy

[HodakaguyTom]

Maintenance day. Although the Jeep is running fairly decent it is still starting hard and could be running better. Time to check/verify points, timing, plug gaps and valve lash adjustments.

The M38 is waterproof and equipped with a sealed ignition system, utilizing sealed plug wires and a waterproof distributer.




Distributer opened up and the upper housing held out of the way with a piece of bent wire.




The coil is enclosed inside of the distributer assembly.




Adjusting the points to .020". As found the points were tight. Points were in great cond, same with contact surfaces on the Cap and Rotor.






Timing marks on the crank pulley and timing cover.






With the rough timing set it was time to adjust the valves. I bent a piece of tig rod to use as a feeler so I could feel when the piston was at TDC. The bent wire allows you to reach over the exhaust valve and reach the top of the piston. You can also set TDC on cyl #1 and then rotate through the firing order, I like to use the feeler as an extra verification.






Valves were pretty close to spec. A couple exhaust valves were about. 001" - .002" tight, and a couple intake valves were slightly loose. All reset to .016" now.




Cleaning and gapping the plugs. All 4 plugs looked pretty good. Cleaned and ensured gaps were set at .030". This Jeep came with civilian plug adapters already installed which allows you to run cheaper civilian plugs while retaining the waterproof feature of the M38.










Gapped and cleaned.






Back together again.




The engine started right up and was idling nice and smooth. Now it's time to check timing with the timing light At idle. To do this you unscrew the shielded plug wire on cylinder one and install a non-shielded adapter so the pickup will function correctly on the timing light. After timing is set and distributer is locked down Rev the engine up and watch the timing mark, the mark should advance with increasing engine RPMs. If your mark doesn't change you have an issue with your advance mechanism. All looked good here.










Out for a quick test drive and it's running and starting great. Sucess!






Hodakaguy

[wesk]

On the condenser lead there is a flat "L" sahped retainer that should be alligned with the tab at the top. Check your distributor cap firing order wiring. Should be clockwise 1, 4, 3, 2 with 1 being at the 7:00 o'clock position on the cap. When other orders are used the distributor becomes very difficult to rotate far enough to get an accurate ignition timing setting.

[whydahdvr]

Reading through these posts and seeing your pictures you've done an awesome job documenting and detailing your jeep, the work your doing, and the exact changes - and techniques used - that you've made. Very impressive!

[pacho]

Hi Hodakaguy,
Congratulation for your jeep, looks very very nice.
I am learning from yours photos, I have to make this kind of job too, please continue.
I saw in your post a spark plug adaptor. I have a m38a1 and i not sure if work good. I will appreciate the diferent opinions about this device.
COngratulations again and enjoy it.

Regards
Pacho

[HodakaguyTom]

On the condenser lead there is a flat "L" sahped retainer that should be alligned with the tab at the top. Check your distributor cap firing order wiring. Should be clockwise 1, 4, 3, 2 with 1 being at the 7:00 o'clock position on the cap. When other orders are used the distributor becomes very difficult to rotate far enough to get an accurate ignition

As always Wes your info and knowledge is much appreciated. I did notice that the distributor is about at the max travel to get the correct timing so this does explain that. I will fix this next weekend and get the wiring in the correct order.

Thanks again!

Hodakaguy

[HodakaguyTom]

Reading through these posts and seeing your pictures you've done an awesome job documenting and detailing your jeep, the work your doing, and the exact changes - and techniques used - that you've made. Very impressive!

Thanks Mate, I'm glad your enjoying the posts. I enjoy making them

Hodakaguy