Engine Woes

Brett · Post by **Brett** » Wed Mar 03, 2010 3:42 pm

I did a compression test on my trucks original engine the other day, and the results were not good from front to back my readings were 60, 70, 95, 105, 110, and 105. I had been meaning to do this for a while and just wanted to assess things before I got too far along in my extremely slow project. Anyway I pulled the head to get a little bit better idea of what was going on. There was a significant ridge in all 6 cylinders, But nothing else that I could see. So with the realization that this engine is going to need rebuilt and the other issues that need solving(fuel pump, charging system, wiring, cooling the distributor with a non-original carb etc.) I think I'm going to do an engine & trans swap. I'm thinking that the most practical route will be to buy a complete vehicle and transplant the entire drivetrain. I'm wanting to go with something a little more modern and try to get an overdrive trans as well. Some of the things I've been thinking of are
GM 6.2 Diesel w/ 700r4
GM TBI 350 w/ 700r4 or NV4500
GM LS 5.3 w/4L60E
Ford Fuel Injected 300 I6 w/ mazda 5spd or E4OD
Ford Fuel Injected 302 or 351 w/ AOD
Dodge magnum 318 or 360 w/ 5spd or Auto w/OD

What are your thoughts on these good and bad? what will fit? Should I stick with a 2wd trans or look for a married t-case with pass. side outputs? any other suggestions?

Brett

Master Yota · Post by **Master Yota** » Wed Mar 03, 2010 5:08 pm

Small block GM will be the cheapest - by far - but its also boring if you're looking for wow factor... Same goes for the 318 - its been done lots of times already, with excellent results - but its kind of like white bread....

The 5.0L Ford would be an excellent choice - its a compact unit, lots of aftermarket support and easy to come by.
The Ford 300 6cyl. is too long to fit under the hood.
The GM 6.2 diesel would be a decent choice, but would need the overdrive trans - either manual or automatic.
The magnum 360 is a pig on fuel, but usually comes with the desireable NV4500 transmission.

If your plan is to use an automatic trans - get a married tcase, as its too long to "practially" keep the intermediate shaft and stock tase in the same location

All Ford tcases are drivers side front output - so that limits you to 2wd. transmissions only unless you want to purchase adapters to use other tcases with a passenger side front output. Dodge used a passenger side front output tase until 1994 and Gm used them until 1988 (1991 in some applications).

You may be better off keeping the stock tcase as the rear output is off centered as well.

The 700r4 is at its rated capacity just hauling the truck around empty; I would consider a performance rebuild with heavy duty internals to be a mandatory requirement. The 4L60 is the same transmission, just computer controlled.

If your're open to another diesel engine option, the Land Cruiser 3B 4cyl would be an alternative. They usually come with a 4spd. trans in either automatic or manual (the H55 5spds are available) and the tcase has an offset rear output to the same side as the M37. They are also a good candidate for a turbo instalation.

The Cummins 4bt is also a good idea, but they seem to be rather expensive. They can be out-performed by virtually any V8 in every area except fuel economy. The savings in economy however will never pay for the added cost of the swap, in my opinion.

My first M37 had a Gm305 with the SM465 4spd. and the stock tcase and driveline. It was an easy swap, was cooled fine with the stock rad, and needed no custom parts other than a transmission crossmember built out of square tube. It was a blast to drive, and still got fuel mileage in the mid teens with the stock gears.

Hopefully this provides some food for thought, and good luck with your plans!

SOTVEN · Post by **SOTVEN** » Thu Mar 04, 2010 5:30 pm

"I think I'm going to do an engine & trans swap. I'm thinking that the most practical route will be to buy a complete vehicle and transplant the entire drivetrain." SO, ARE YOU GOING TO TRANSPLANT THE ENTIRE DRIVETRAIN, (FROM ENGINE TO AXLES) OR JUST ENGINE TRANNY AND PERHAPS TRANSFER CASE?

Brett · Post by **Brett** » Thu Mar 04, 2010 6:54 pm

I plan on keeping the t-case and axles. I took some quick measurements today of a chevy truck with a 5.3 and a 4L60E and water pump to trans output yoke was about 60" Which isn't far off from the stock engine and trans. I'm still a long way from pulling the trigger on something though, so my mind will probably change a time or two before its all said and done.

Brett

powerwagontim · Post by **powerwagontim** » Thu Mar 04, 2010 7:20 pm

Why not just rebuild the engine you have? It will still end up costing less than a repower, and the truck will stay true to its pedigree.
Tim

Brett · Post by **Brett** » Fri Mar 05, 2010 7:47 pm

If my truck were otherwise complete, There might be some more validity to that argument. Here is how I see it. Best case scenario a rebuild is gonna cost $1000 to $1500 just for parts and machine work. My original wiring is a total loss. My stock fuel pump needs rebuilt. My truck has an non-original carb. With current carb there is no way to cool the military distributor. Also, my gauges and charging system are in need of serious attention. Going that route would cost me at least $2k to $3k, for a level of performance I probably won't be thrilled about. On the other hand I could buy a running vehicle with the engine and trans I want, and need only a few minor things beyond that. Also I think I will be able to offset some of the cost of this with the sale of some of the useable original parts I have.

Brett

cuz · Post by **cuz** » Fri Mar 05, 2010 8:39 pm

My truck has an non-original carb. With current carb there is no way to cool the military distributor.

You can still maintain a sealed distributor and vent the distributor using manifold or vacuum pump boosted vacuum by plumbing the suck (Vac) line to the distributor and plumbing the the fresh air in line to the aircleaner. Just insert a fitting in the line between the vacuum source and the distributor that is soldered shut and then drilled with a .040 drill. This will restrict the Vacuum to a reasonable level.

The primary need for the vent line is to remove the gaseous by products of the spark generating system which can be corrosive and explosive. The secondary benefit of the vent line is during very hot weather operation it helps lower the coil's operating temperature. The reason it is plumbed the original way is to keep water out of the distributor when fording. You could just drill two larger holes and install your own design vented plugs or you coul use two 1/8 P threaded axle housing vent plugs in the distributor vent ports.

SOTVEN · Post by **SOTVEN** » Sat Mar 06, 2010 2:21 pm

Brett wrote:If my truck were otherwise complete, There might be some more validity to that argument. Here is how I see it. Best case scenario a rebuild is gonna cost $1000 to $1500 just for parts and machine work. My original wiring is a total loss. My stock fuel pump needs rebuilt. My truck has an non-original carb. With current carb there is no way to cool the military distributor. Also, my gauges and charging system are in need of serious attention. Going that route would cost me at least $2k to $3k, for a level of performance I probably won't be thrilled about. On the other hand I could buy a running vehicle with the engine and trans I want, and need only a few minor things beyond that. Also I think I will be able to offset some of the cost of this with the sale of some of the useable original parts I have.

Brett

I UNDERSTAND YOUR POINT BRETT. I TOO ONE DAY WANT TO OVERHAUL MY M37 TOWARDS THE "EVERYDAY" DRIVER THAT IT HAS BEEN FOR AS LONG AS I OWN IT. THE ORIGINAL SETUP HAS SOME COOL FEATURES LIKE THE WATERPROOF DISTRIBUTOR AND PLUGS, THAT UNFORTUNARELLY CAN NOT BE TRANSDPLANTED TO A MODERN POWERPLANT. ON THE OTHER HAND A MODERN ENGINE/TRANNY COMBO WILL ANABLE THE VEHICLE TO MOVE QUITE EASIER AND APPARENTLY WITH BETTER MILAGE. PERSONALLY I AM MORE THAN IMPRESSED WITH THE ORIGINAL SETUP WHEN IT COMES TO OFFROAD ABILITIES. ON ROAD HOWEVER IT LEAVES A LOT TO BE DESIRED. I DO NOT WANT TO GO OVER 55 TO 60MPH, AND THE ORIGINAL ENGINE IS CAPABLE OF THAT, BUT AT RED LINE RPM. ALSO ACCELERATION IS MEASURED IN MINUTES RATHER THAN SECONDS. FINALLY GAS CONSUMPTION IS AS DESCRIBED IN THE PAST "IT WILL OVERCOME EVERY OBSTACLE, BUT GAS STATIONS". SO JUST LIKE YOU I WAS ORIENTED TOWARDS A V8 WITH A 5 SPD MANUAL. (I CAN NOT CONVERT TO DIESEL DUE TO STUPID GREEK LEGISLATIONS) SO I AM THINKING OF A 318/360 CARBURATED. IT SEEMS TO BE AN EASY ENGINE TO WORK ON IF A FIELD REPAIR IS NECESSARY, AND THE FACT THAT IT HAS BEEN DONE BY OTHERS IS AN ADDED BONUS FOR WHEN IT COMES TO FIGURING OUT ISSUES REGARDING THE TRANSPLANT. FINALLY IT IS A "DODGE" TO "DODGE" UPGRADE. HOWEVER, I DO NOT OVERLOOK THE GEARING ISSUE. THE CURRENT DIFFS ARE WAY TOO SLOW, SO A 4.89 SWAP MIGHT ALSO HELP IN COMBINATION WITH THE O/D TRANNY. I GOT CARRIED AWAY HERE. WHAT I WANTED TO SAY AS MY OPINION, IS THAT YOU MAY FIND A DONOR VEHICLE FOR 500 TO 1500 BUCKS ON CRAGSLIST. (I PICKED UP AN 87 CHEVY 2500 WITH FISHER PLOW AND A 350 TBI FOR $900!!!) HOWEVER, I WOULD NOT TRUST ANY USED ENGINE AND TRANNY TO PUT INTO AN OVERHAUL.WHAT IF IT IS A "DEAD HORSE"? YOU WILL DO ALL THE WORK OF TRANSPLANTING, AND THEN YOU MAY END UP WITH A MOTOR THAT NEEDS TO BE REBUILT. IMHO, I THINK IT IS BETTER IF YOU BUY A REBUILT ENGINE/TRANNY AND NOT HAVE TO WORRY ABOUT THEIR CONDITION INCE INSTALLED. SOME REBUILDERS OFER REPLACEMENT WARRANTIES. AND PRICES VARY. YOU MIGHT WANT TO CHECKOUT EBAY. SEARCH THE MOTORS YOU ARE INTERESTED IN, AND SEE HOW MUCH THEY GO FOR. I BELIEVE THAT IT IS BETTER TO INVEST MORE IN YOUR PEACE OF MIND, RATHER THAT ADDED THINGS FROM A DONOR VEHICLE THAT CHANCES ARE WILL NOT ACCOUNT FOR MUCH IN THE END, WHATEVER YOU DECIDE, GOOD LUCK