What modern engines would you choose?

Juan · Post by **Juan** » Tue Aug 26, 2008 7:02 pm

Depending on the engine, and it's RPM range, you will need to swap transmission (for an OD unit), axle gears and/or tire size.

CGarbee · Post by **CGarbee** » Wed Aug 27, 2008 3:36 am

Another reason for swapping out the transmission is the difficulty in bolting up the stock transmission to a different engine. The input shaft lenght, diameter, and spline style and count as well as the diameter of the bearing retainer and the bolt pattern are different from those used on a modern Dodge, Chevy, Ford, Cummins, Detroit, etc... Much easier in a lot of cases to get a modern, fully synchronized transmission that bolts right up to the engine of your choice, then, all you have to do is some driveshaft work (and/or swap out the PTO if you have a winch truck or convert the winch to hydraulic power).

The thing that really comes out in a lot of these answers is that in order to do an engine swap "right", you also have to consider the rest of the truck and renew, replace, or upgrade a bunch of other components to ensure that you end up with a balanced, safe, vehicle.

More "go" needs more "whoa", so you need to make sure that the brakes are up to the task. Steering that is ok with a stock truck may not be adequate at 60-75mph as is the lighting.

In my case, the engine swap was part of a renewal that went from bumper to bumper.

A stock truck is a wonderful thing, a well modified truck is too. The more time you spend thinking about what you plan to do with your truck, and how you will get there, the better off you will be. This thread, and others on this forum concerning upgrades, swaps, and other related topics is a great help in the process that didn't exist when I did my first conversion.

peter e mark · Post by **peter e mark** » Wed Aug 27, 2008 4:26 am

As in any engine swap, the "componant alighment" has to be correct. In simpler words, the bell housing of the engine has to match the shape. and bolt holes of the original tranny. But the issue certainly goes beyond the componants mechanically fitting each othe. If the replacement engine has different "power" characteristics, as in much more powerfull, the power capacity of the tranny has to match, otherwise the tranny will iether not perform, wear out , or as seen on the racetrack sometimes, blow up ! There are those among us in this group who concern themselves with such issues quite pointedly, and who have already contributed to this thraed. May I recommend M SERIES REBIULD. for further input on this question

mp_tx · Post by **mp_tx** » Thu Aug 28, 2008 1:27 pm

Getting ready to pick up my Cummins 4BT/NV4500/NP205 M37 from the shop in a few weeks..... Can't wait to get her on the road.

Josh · Post by **Josh** » Thu Aug 28, 2008 2:21 pm

more importantly then engine, is driveline.

Ditch those POS axles, and get Dana 60's with a sane gear ratio, then, do a married NP205, with the NP203 to get your crawl ratios back (and a better selection to boot!), and stick it behind any 4 or 5 speed you want, and you have a short, light, bulletproof driveline that wont break constantly.

Personally, something ID LOVE to see is a built 230 with a blower of some sort on it.

Im sticking with my 360 though. Its in, it works, and I wont drive it enough to make up for the difference in cost for a 4BT cummins for at least 5 years.

meerkat · Post by **meerkat** » Thu Aug 28, 2008 5:41 pm

Gentlemen, thank you for the education you just gave me in three pages I'll be reading repeatedly now. What a great site, and what a great group of folks you are.

peter e mark · Post by **peter e mark** » Thu Aug 28, 2008 6:13 pm

Forgive me josh, but may I ask what you mean by married np 205 and np203? And what is POS axles? :

Lifer · Post by **Lifer** » Thu Aug 28, 2008 6:43 pm

A "married" NP 205 or 203 transfer case is one that attatches directly to the transmission instead of being driven by a short shaft. A "POS" axle is a "piece of sh!t" axle. Don't ya just love our language and acronyms?

Josh · Post by **Josh** » Thu Aug 28, 2008 6:47 pm

POS=Piece of Sh*t. I HATED the stock axles. Not enough brake, not enough gear, too soft a steel in the shafts, leaked oil out of every joint constantly, even with new seals and proper torque (thats ultimately what killed my rear and prompted my D60 swap, the left hub seal failed, and I didt know it till the pumpkin started to hum).

As far as the 205/203 thing:

http://www.fullsizebronco.com/forum/sho ... hp?t=45488

Thats what I'll be doing with mine. Then, bolting it right to the back of the tranny. Wont be any longer then my current, long tailshaft NP435/ divorced NP205 combo, but, it will give me the 2:1 LR of the 205, and then the 2:1 LR of the 203 range box, for a combo of 4:1.

Do the math, the stock low range is this:

6.5ishX2X5.83=75:1 crawl ratio

Now, with my planned setup:

6.7X4X4.1=110:1!!!!!!!

And, with the 42" tires I have planned, and the 4.1:1 axle ratio, I can run 60 MPH with the 360 purring allong at 1950 RPM.

peter e mark · Post by **peter e mark** » Fri Aug 29, 2008 3:16 am

Thanks guys, and now , of course, i shall have to crawl under my vehicle and take notice of what transfer case arrangement i have...As for axles, I will address that issue when, and this is further down the road , I consider that Locker installation on both the front AND rear ! Long Live 4 Wheel Drive !

wvcharlie · Post by **wvcharlie** » Fri Aug 29, 2008 4:28 am

All this discussion about engine swapping has come at the perfect time for me. Hopefully someone has an answer to my question. My stock six cylinder finally gave up and I happened across a 1965 318poly V8. I figured it must have been divine providence since my M37 is a 1965 also. I am in the process of rebuilding the 318. I was planning on just getting the adapter kit and bolting it up to the stock transmission. Those are no longer available so I then decided there was no point in keeping the stock transmission when I could just get a more modern 5 speed transmission. My question is does anyone know if a later model year( 80's or 90's) bell housing will bolt up to the earlier 65 318? I have looked through a lot of forums and found only vague references to later model Dodge Dakota transmissions. Any info would be helpful and as usual this forum is filled with great people and lots of information. I hope some of you make it to the Mid-Atlantic Power Wagon Rally. It is being held about 15 miles from my house. My M37 will be out of commission but maybe they won't give me too hard of a time if I show up in my M725 ambulance.

peter e mark · Post by **peter e mark** » Fri Aug 29, 2008 5:29 am

Hello Charlie, You may have some luck speaking to that group of contemporary restoration geeks commonly referred to as HOT RODDERS . I would say they are well versed in the civilian engine to transmission matching procedure. But, pray tell, what happens when you find a suitable tranny? Now you must hook up to you transfer case? Axles? Brakes? Beware of hot rodder mentality....

wvcharlie · Post by **wvcharlie** » Fri Aug 29, 2008 6:55 am

Peter,
Have no fear. I like to keep my vehicles stock. All my other vehicles I have restored back to completely stock military form. There was no hope for the stock six cylinder. I had a rod bearing go bad while I had it out a few weeks ago. I limped back home with it knocking badly. When I pulled the pan, I found the rod journal was trashed and I also found pieces of compression ring in the pan. That had to have left some bad gouges. Since someone had already converted the truck to 12 volts, I figure it should be a fairly easy swap. If I can find a bell housing and transmission to bolt up directly to the 318, then all I would have to do is get a new short shaft made to hook up to the transfer case. I am not looking to make this truck into a 70mph interstate runner. I just want to get up the hills with a little more power, since all we have is hills around here. It will look stock on the outside.

peter e mark · Post by **peter e mark** » Fri Aug 29, 2008 7:24 am

You're soul is saved ! And may I suggest you look for a stock engine. I happen to know where one is, here on Long Island, New York. Where are you geographicaly? Well, it's up to you of course...Peter

CGarbee · Post by **CGarbee** » Fri Aug 29, 2008 1:31 pm

wvcharlie,
I'll be at the Mid-Atlantic rally with my Cummins powered M37. We'll have to go for a ride...
I have a pair of running takeout T245 M37 engines in the backyard already sitting in a M101A1 trailer that I can hitch up to the M37 for the ride up to the rally in case you want to go back stock.