Repower or not

[W_A_Watson_II]

I can understand the fatigue failures of flexible frames, but the stiffer you build things the more likely they are to fail suddenly.

I like the flex, and it aids the M's solid axle leaf spring suspension to keep the tires on the ground.

I guess I should look forward to a frame swap on the M some day.

[Wulfman]

Creaky Frame Indeed

Driving around the beat up '52 parts rig I just got, the frame definitely creaks when flexed. I refurb'd a '65 CJ5 decades ago and I had the frame boxed - certainly stiffened it up and they were notorious for frames cracking under extreme use.

I do my wheeling up in Northern California - Rubicon and the lessor known but more extreme Fordyce trail (IMHO). When you are crawling through the rocks, you are not shifting, you are looking where to place your wheels and pick your line. Also, faster speeds make drive component failure more likely. The number one rule on the trail is, if you brought it in, you bring it out. That includes your 6Klb truck so I'm building mine for that specific task in mind.

I would highly recommend Ray's disc brake upgrade, atleast up front. I'am also following a thread that discussing using D60 axles inside the stock M37 axles tubes. Now that would be pretty cool to pull off.

[MoparNorm]

...
Side note, hope you are back on your feet soon, and our prayers are with you.

Thanks Will!
Doc put me down for one more week, still have 60% of the gas bubble in my eye, still wearing my "I'm explosive!" arm band to warn paramedics and emergency personnel...ha! ha!

[rush]

I think all the ambulance and radio trucks (M43 style) had an additional frame brace rail added to their mid sections. Next time you see one take a look under there.

roger, I have seen it on the longer wheelbase trucks. The drive train manual also show's the rails to be being slightly heavier gauge material.

[lebowski]

I think all the ambulance and radio trucks (M43 style) had an additional frame brace rail added to their mid sections. Next time you see one take a look under there.

[rush]

Frame issues?, wow must have been some "really" wild rides. Seems to me the m37 frame is pretty darn stout!!

[W_A_Watson_II]

Thanks Norm, his running boards look just mine, Ha Ha. Yea the frame has a lot of great flex, so I can see eventually fatigue setting. in. Perhaps I'd better go buy that spare basket case for the frame?

Side note, hope you are back on your feet soon, and our prayers are with you.

[MoparNorm]

If I can recall correctly, it was frame failure.
Sam didn't baby Jethro, it was one fun ride, but succumbed to the rigors of the trail.
Early Jeep frames had the same issues before they started boxing the frame. Less flexibility traded for more longevity.

I had the privilege to see Jethro in action in both CA and TX.

[W_A_Watson_II]

Based on my start with "Franky" My M37 is likely to follow in Jethro's foot steps, but I hope not.

What was Jethro's undoing or the main failures?

[MoparNorm]

...By the way you have (RIP Jethro), did it come to some demise?

grant

Sadly yes, it sustained a plethora of damage over the years to drive train, frame and body. Sam decided it was time to retire Jethro, a great truck!

[maineSS]

The 251 was rated at 115 hp- haven't seen any torque figures. The last years of civilian 230 production '59-60 saw the introduction of an 8:1 compression head with redesigned transfer/valve pockets that brought Hp up to 120 with the awful intake/exhaust system these engines have. The car users have improved output with dual carbs and split exhaust. When I rebuild my 230, it's getting the 8:1 head and triple Mikuni sidedraft snowmobile carbs, plus some valve work.

The stock slant six would give you about the same Hp/Tq at a higher rpm range. It was fitted in the Export M601 by Dodge, so it can be done. Access to the distributor would likely be difficult. The Slant can be modified to develop very respectable power levels for its displacement.

[rush]

Just out of curiosity how much better do the 251's in the ffpw's pull? And what kind of mods did the CDN M37's have to install the 2 inch longer motor?

[rush]

Sorry about the SBC thing, 318 would work great and is more avail. The slant six has been a thought for economy on fuel, higher rpm, fairly short overall length, and having a reputation for being bullet proof. There looks have even grown on me somewhat. Wierd! I have seen the truck "Jethro" in some other pics and even have one cut out and posted on my wall here. Way cool looking truck.

Thanks so far for the input from all of you. Looks kinda like of course the harder core wheelers want V8 power to get through those tuffer spots.

By the way you have (RIP Jethro), did it come to some demise?

grant

=MoparNorm;73141]First and foremost, Thank you for your service!

Secondly, go sit in the corner and wash your mouth out for mentioning SBC....ha! ha!

The most fun I ever had in an M37 was riding with Sam in "Jethro" (RIP Jethro!)
It was a 360 powered beast and a ton of fun. I would think that a stock 360 or built 318 Poly would give you all the torque the stock drivetrain could handle and work well with the mods you have planned.
I don't want to start a war here but the slant 6, although a wonderful, economy motor, would not be worth the effort in time or money.
If you're going to do it, do it so you can tell the difference.

[/QUOTE]

[MoparNorm]

First and foremost, Thank you for your service!

Secondly, go sit in the corner and wash your mouth out for mentioning SBC....ha! ha!

The most fun I ever had in an M37 was riding with Sam in "Jethro" (RIP Jethro!)
It was a 360 powered beast and a ton of fun. I would think that a stock 360 or built 318 Poly would give you all the torque the stock drivetrain could handle and work well with the mods you have planned.
I don't want to start a war here but the slant 6, although a wonderful, economy motor, would not be worth the effort in time or money.
If you're going to do it, do it so you can tell the difference.

[MasterYota]

Being in Florida I'm not familiar with wheeling in hilly country, so I have to ask why it would be necessary to be able to shift faster than the stock transmission does.

Thanks, Glenn

Up in BC, the hills are usually one of two things, steep, or long, or both. I found that M37's don't always have the best brakes, especially after they've become wet. Downshifting from 3rd to 2nd can sometimes mean making the corner at the bottom of the hill or not. Not having to double clutch a newer transmission can save precious seconds when caught unprepared with soggy brakes that don't do much for a 6000lb truck.

A faster shifting transmission also works well when mud is encountered. With a limited rpm band, and deep gearing, shifting the trans to gain wheel speed is needed to get the tires to clean out and foster forward movement. Sometimes its nice to upshift or downshift without losing momentum.

Everywhere is different though, that been my experience so far.