4.0L engine swap

[1942DodgeTruck]

I have a 42 WC15. The flathead in it is tired and I have been unsuccessful finding a shop near me to rebuild it. I have been hunting for a rebuilt or good running engine as well with no success. Which has me looking at different engines to transplant. Would the 4.0L out of a Jeep be a good fit for these pickups? I believe they are a little bit longer. I have Tig,stick and mig welders as well as a mill so making mounts etc. are well within my garages range. Wanted to see what your opinions were. 

[Plymouthy Adams]

sounds like a few nice tools....you need a tape measure in that collection.....?

[NiftyFifty]

I actually pondered this swap as well, but in all honesty by the time you factor in that you lose your bell housing, which is also the mounts for your pedals and master cylinder, you might as well go all the way to a V8 swap.....

 

Then if you’re going to do that, it makes more sense to just put in a whole new clip or at least a kit to upgrade front suspension and brakes to handle the new power.

 

This said,  I rebuilt a 251 and upgraded my front brakes and a bunch of other engine goodies and the T5 trans swap, and I really wish I could go back some days and drop the V8 in and deal with the pedals and brake master moving 

[greg g]

The Jeep engine is pretty long lots of measuring involved. Also with engine swap maybe trans swap and with trans swap you will need to address alternate emergency brake.  I saw a truck where the body had been mounted on a 4x4 Mazda by pickup truck. The fellow said the only frame mods involved body mounting. He got 3.5 by, fuel injection auto, 4 wheel discs, cruise control and ac in the bargain.

[kencombs]

I don't know of any inline sixes that are short enough for an easy swap.  But, I haven't measured one of the small Ford sixes from the 60s/70s.  The 250 which is similar to the 144/170/200 Falcon/Fairlane family is fairly short, certainly shorter than the Jeep..  Used one to replace a 170 way back when.  Nice engine, good power and used the same trans as the 289/302.

 

Still have the whole clutch/brake/rear mount issue though.

 

I wonder if a plate type adapter on a 'foreign' engine to mount the original clutch housing is doable?  In theory at least it sounds possible  Simple plate that bolts to the new engine with a new bolt pattern that also accepts the Dodge housing.  1/2" plate attached to the engine with Countersunk flathead bolts.   Lots of precision locating, drilling, countersinking and tapping.

 

That would solve the rear engine mount and driveshaft issues too.

 

 

 

 

[cavisco1]

There is a member on here that has a B series with an AMC 258 and 904 auto, same length as the 4.0L.  Firewall was not modified and uses stock fan. I think it was GRAMPS1951

Edited September 11, 2020 by cavisco1
Additional info.

[kencombs]

Last entry here describes the length solution.

 

Sounds just like the 25" flathead swap solution, move the radiator to the front of the support. 

 

Might ask him about the pedal solution.

[cavisco1]

The 4.0ls are very common in wrecking yards. If you go through with this swap, take lots of pictures and share.

 

Scott.

[Old CWO]

I have owned a couple of those engines and aside from some pesky rear main seal leaks, they are basically bulletproof.  I love them and think that an EFI L6 in a classic truck is a fantastic idea.  There was such a thing as 2WD Cherokees with the AX15 manual and I am pretty sure a Dakota stick shift will bolt up to the Jeep bell as well.  There is (was?) a standalone wire harness available to run the EFI marketed towards CJ5/CJ swaps.  I would think that is something you could take advantage of.

 

That being said, it's essentially the same effort to swap in a V8 which at the end of the day is a simpler path because of the deeper aftermarket parts and support.  I bet you could find a clean running Magnum 5.2 cheaper than a 4.0L.  Those hit that 230HP/300TQ range that gives plenty of pep without overpowering the rest of the truck.  Something to consider if you're dead set on a swap. 

 

There are people who can build these engines and if there isn't one local, you can always crate it up and truck ship it somewhere.  Even with the added transport costs it will still probably shake out cheaper and less frustrating than an engine swap.  Check with forklift repair places; Chrysler flatheads were in some forklifts and other industrial equipment for a number of years so that might be a lead for you.

[lostviking]

Looking online, I found an article by the company...that did this on a 47 1/2 Ton. They did move the radiator forward of the stock mount, but none of it looked that hard (for someone who can weld, unlike me). You could contact them. I read it a few weeks ago, so I don't have the link right now, but Google is your friend.

[gramps1951]

[gramps1951]

sorry about the prior post I had a hard time posting pictures here I didn't think it would be so easy. I'll take some pictures of my 1951 b3b with the amc 258 for those who want to see it thought I had to use photo bucket or some other software.  Neil

[55 Fargo]

On 9/11/2020 at 7:54 AM, NiftyFifty said:

I actually pondered this swap as well, but in all honesty by the time you factor in that you lose your bell housing, which is also the mounts for your pedals and master cylinder, you might as well go all the way to a V8 swap.....

 

Then if you’re going to do that, it makes more sense to just put in a whole new clip or at least a kit to upgrade front suspension and brakes to handle the new power.

 

This said,  I rebuilt a 251 and upgraded my front brakes and a bunch of other engine goodies and the T5 trans swap, and I really wish I could go back some days and drop the V8 in and deal with the pedals and brake master moving 

While I agree with most of this,

Front steering and suspension can be kept stock, if in decent form not a problem. No its not IFS, but on smooth roads its not a problem at all, its rough roads it becomes evident.

Brakes, well stopping at 65 mph is the same with a V8 or any other engine and if your brakes are crappy, well you get my point.

On disc conversions, you get all kinds of opinions. I have not driven any old Mopar with front disc brake upgrades so will reserve any comments. Some who have swapped were not overly impressed, not sure if they had some technical issues or not.

Driving environment versus engine type will highly influence your brakes, IE LA freeways versus Highway 2 in North Dakota no comparison in traffic volume or dangerous drivers. 

Some rely on dual MCs for peace of mind which can be dubious, having a decent functioning ebrake might be advisable. On C series truck MC is not on the bell so can be utilized in V8 swap as I did, at least for now.

On my 318/904 swap with 3.23 gears is night and day over flathead 6. With this lower powered V8 its plenty enough for my light truck. She gets up to 70 mph just as well as my Hemi Ram it seems.

If you stomp pedal off line she lays rubber from 1st right into 2nd...lol

Edited September 20, 2020 by 55 Fargo

[B1B Keven]

Front axle out of a 2wd XJ would cure the brake problem and keep the 5 on 4.5 bolt pattern.

 

[55 Fargo]

1 hour ago, B1B Keven said:

Front axle out of a 2wd XJ would cure the brake problem and keep the 5 on 4.5 bolt pattern.

 

Interesting idea, have you done this swap?

If so, how was the job and and hiw does it drive, ride etc?

 

[NiftyFifty]

On 9/20/2020 at 10:56 AM, B1B Keven said:

Front axle out of a 2wd XJ would cure the brake problem and keep the 5 on 4.5 bolt pattern.

 

is that a front steer or rear steer axle?  Makes a world of difference trying to figure that out for the steering box and pitman arm

 

As for stock brakes and suspension...those are only set up to control the stock powertrain, so once you add more weight and more speed then adding more braking power and handling is a must.

 

 

[HotRodTractor]

Interesting idea using a 2wd XJ front axle. Guys are already using the rear axle. I'm not sure it would be an easy or clean swap based on its layout.... 

 

[kencombs]

Looks

3 hours ago, HotRodTractor said:

Interesting idea using a 2wd XJ front axle. Guys are already using the rear axle. I'm not sure it would be an easy or clean swap based on its layout.... 

 

Looks like it would be a complicated swap.  Front steer?  Probably require a change of steering gear to one with a vertical pitman shaft.  Or some welding on the steering knuckle to add a steering arm.  Spring seats etc.     Makes disk adapter setup look easy, comparatively.

[55 Fargo]

While this looks like a "great idea", is it really though?

I asked poster who mentioned it whether he had done this swap or knows of any done.

It may work great, it may not or be a huge headache.

The stock front suspension on a B or C series truck while not IFS seems to do okay on nice straight smooth roadways. Lighten spring amount, all bushing,shackles, steering shocks etc, yields a decent ride.

Rough uneven roads and sharp curves you notice its limitations.

Powersteering or lack of, is a bit hard at a dead stop, once rolling no problem.

As far as 6s, Slant6s can be swapped in and have been, especially in a C series truck.

But if you are doing all this work, perhaps a V8 such as a 318 or 360 is the ticket.

On brakes, go with what you deem safe and reliable.

Stopping at 65 whether a flathead 6 or V8 aint no difference. Lots of V8s weigh less too.

 

 

[B1B Keven]

On 9/20/2020 at 10:25 AM, 55 Fargo said:

Interesting idea, have you done this swap?

If so, how was the job and and hiw does it drive, ride etc?

 

Nope, never done it. Would like to someday.

 

[Old CWO]

23 hours ago, 55 Fargo said:

While this looks like a "great idea", is it really though?

I asked poster who mentioned it whether he had done this swap or knows of any done.

It may work great, it may not or be a huge headache.

The stock front suspension on a B or C series truck while not IFS seems to do okay on nice straight smooth roadways. Lighten spring amount, all bushing,shackles, steering shocks etc, yields a decent ride.

Rough uneven roads and sharp curves you notice its limitations.

Powersteering or lack of, is a bit hard at a dead stop, once rolling no problem.

As far as 6s, Slant6s can be swapped in and have been, especially in a C series truck.

But if you are doing all this work, perhaps a V8 such as a 318 or 360 is the ticket.

On brakes, go with what you deem safe and reliable.

Stopping at 65 whether a flathead 6 or V8 aint no difference. Lots of V8s weigh less too.

 

 

 

I  totally agree with this.  A fully gone through stock steering and suspension is plenty fine for a classic pickup truck.  Medium and heavy duty trucks to this day use leaf springs and beam axles up front and log millions of trouble free miles.  

 

For those seeking power steering there is now an under dash universal electric hot rod unit on the market.  It looks like it might be great for B and C trucks with 12v conversions.  I have only seen them online and in magazines but am curious.

[55 Fargo]

2 hours ago, Old CWO said:

 

I  totally agree with this.  A fully gone through stock steering and suspension is plenty fine for a classic pickup truck.  Medium and heavy duty trucks to this day use leaf springs and beam axles up front and log millions of trouble free miles.  

 

For those seeking power steering there is now an under dash universal electric hot rod unit on the market.  It looks like it might be great for B and C trucks with 12v conversions.  I have only seen them online and in magazines but am curious.

Yes totally agree, of course the bih trucks use a beam front axle.

All new parts, less springs and possibly a steering damper of VW Beetle and sway bar, can make it a nice ride.

Power steering, not at this stage of life, but for older people or those with strength or mobility issues it could be a must.

In all seriousness with regard to powersteering, if I wanted it would find a donor to make it work ..

[lostviking]

Interesting build and dyno on a Jeep 4.0 stroked using a Jeep 4.2 crank.