Mercury Marine engine advantage?

Is there any advantage to installing a 4.3 Mercury marine engine in a Willys over a 4.3 Vortec? i also see some people installing the 3.0 Mercury marine. Any thoughts? Thanks Todd

 

Mercruiser Marine engines are basically just factory balanced and blueprinted versions of the same variety of engines. This is done for the higher sustained r.p.m.s that a boat sees at cruising speeds. The electrical and carburation systems are also setup to be 'spark arresting' so as not to cause a fire or explosion in the enclosed bilge compartment of the boat....that is why the carbs and alternators cost more.....in an automotive applicationthey can be replaced with 'normal' stuff.

 

If the 3.0L engine is available, it's a good one. The 181 cid (3.0L) Mercruiser/GM Industrial is the same engine as the 153 cid Chevy inline 4, although it has a larger bore. The 153 swap is popular, and the 181 swap would be popular too if the engine were more widely available. You could buy a new 181 crate engine set up for industrial or marine use up until a few years ago. Has been discontinued by GM AFAIK, but parts availability should be fine considering it was available new so recently. Also shares a lot of parts with the 194/230/250 Chevy inline 6 (230 * 4/6 = 153; the 153 is 4 cylinders of the 230).

Get it if it's cheap - easy swap, easier than the 4.3L. See the write up about the 153 swap on the CJ-3B pages http://www.film.queensu.ca/cj3b/Tech/EngineSwaps.html - there may be more info about the 153 in Jeeps out there ... IIRC Nick's Dad has one in his Jeep.

 

I have the 153 Chevy four in my Jeep, and the fit is great. There is some much room around it to work on it. Great swap, if you can find a Mecury engine that is the 181 cubic inch motor, it would be a great swap. If you go the inline four, just make sure it is the rear sump model. My engine was an early model and I had to buy a rear sump pan and oil pickup tube to make it work. I love it, when I had the local Highway Patrol inspect it for my title work, he thought I had the orginal motor in it, so I just said yes! Stock as can be I said...

 

The 3.0/181 Merc seems like the perfect early jeep motor. 140 HP at the same rpm that the F head has 72 and the L head 62! That and the Merc will run at 4400 rpm FOREVER while the same is not true of the Willys motors.

I have a 181 I plan on swapping in my A1. BUT, all the marine engines are front sump, so you have to source a rear sump pan or modify the stock one and buy a Nova pickup. The 153 was also used in Postal Jeeps from around '67-71 or so, it will have a rear sump pan.

Also, the marine motor comes with the water cooled combination intake/exhaust manifold so you have to source the auto or industrial manifolds. I haven't looked that closely at the industrial intake and exhaust, but they are usually for engines that are governed around 3000 rpm, so may not be good for a jeep.

I found a Clifford intake for mine and figured I would buy or build a header, but the intake does not match the head perfectly. Looks like GM did a re-design at some point. So if I want to use the Clifford intake on the 181, I will have to weld up the flange and port it to match.

I have my eyes out for a 153 donor, but they are like the proverbial hens teeth around here. But I figure somewhere there is a Postal donor just waiting to be found!

 

If postal Jeeps have this engine. Check out this web site, http://www.scottysjeeptruckand4x4.com/.
Last time I looked it had acres of postal Jeeps, no that does not mean they have bullet holes in them!

Ed :tea:

 

Thanks for all the info. Todd

 

Just FYI - the postals with the 153 come from the end of the Kaiser era.

From this site http://www.offroaders.com/tech/jeep/Jeep-DJ.htm
DJ-5A (1968-70): Chevy four cylinder, Powerglide automatic

Note this site calls all the DJ model Jeeps "postals" but I would dispute that. To me, the postals are specifically made for postal service, with RHD, the odd postal body with sliding doors, and automatic transmissions.

DJ does not mean postal, although a postal is a DJ except for those CJ-8s delivered to Alaska, which I presume is a RHD 4WD vehicle.

According to this site http://www.righthanddrivejeeps.us/finding-rhd-jeeps.htm Jeep has supplied RHD Wranglers on special order within the past decade. AFAIK the 2WD DJ series ended when the USPS stopped sourcing them for general mail delivery.

Back to the topic - the postals in question should be easy to spot because they do not use the distinctive "bubble" grille. The bubble grille was fitted to allow the 2WD DJ platform to use the AMC 232 instead of the 153. Clearly AMC switched to their 232 which was produced in-house for their domestic automobiles. AMC would have had to source the 153 and Powerglide from GM, presumably at a premium to the 232 used with the various other automatic transmissions.

 

There are a couple of privately owned RHD TJs I've seen here around town.

 

I recently acquired on of the 3.0 mercury engines. I think it will be a great little flatfender swap. I have a couple of questions though. Do these engines share the same flywheel as the 230 i6 and SB Chevy? Also, does anyone know about tranny compatibility? Will a SM420 bolt up using the correct pilot bushing and bellhousing? And last but not least, does anyone know of a source for the automotive intake/exhaust manifolds for this other than clifford and the junkyard? I'm having a hard time locating parts.

Sorry if these questions have been answered before, but I couldn't find anything using the search feature or the web.


Thanks in advance,
Jake

 

If you have the 3.0 (140 HP) motor it has a different head than the 153 motor. The 3.0 head is a better design, but there are no street application intake and exhaust manifolds that I now of, unless you can still get the industrial manifolds from GM. These motors take a standard GM bell housings and flywheels. What I did to mount a Ford T18 behind mine was, I found used steel LAKEWOOD bell housing, ground off the threaded pads on the inside, drilled new pattern and welded in new nuts for the mounting bolts. I also got a new input-bearing retainer from Parts mike that he machines down for a GM throw out bearing and to fit the hole in the bell housing. I also got a power steering pump mounting bracket off of a Chevy 250 Six that mounts to these inline fours, so I can use my Saginaw power steering. These motors make such a clean installation, that I pulled out my V6 and replaced it with it. Also, there are marine engines that have a rear sump oil pump and pan; I think there was a change somewhere along the way. Good luck with you install.

 

Should be a nice combination. I have the 153 version in mine as it is a 1969 Postal DJ-5A built in May. A NP542 five-speed out of a 1984 C-60 schoolbus with a 350 Chevy bolted right up. Somewhat long for a 4wd application.
I would agree with Timgr regarding postal vs DJ except for the RHD exclusive comment. In the late 60's, early 70's our Postman drove to his route and then carried a bag, delivering door to door, no need for RHD. Mine is also LHD. Rural Route or street mailbox delivery were what used RHD.
Your cylinder head is different than mine, 8 port instead of 5 port IIRC. I got my intake/exhaust from a forklift salvage yard @ $150. Looks exactly like the same casting other than the GM Mexico logo. Sullaire(sp) made an air compressor using the same engine, only for many industrial applications the carb is an updraft and the exhaust would point straight up out of the hood like a pulling truck.
Best of luck with your project.

 

Upon further review today, my engine is actually a 2.5, which from the looks of it may be good news due to the intake/exhaust manifold choices. I also lucked out, because my boat engine already has a rear sump pan. Being it's a 2.5 with the 5 port heads, what are sources for intake & exhaust? I noticed when pulling the marine stuff that the intake and exhaust would have to share bolts, is the automotive version similar to that of an L-Head?

Also, one other question, after pulling the outdrive, I found that the engine was already equipped with a flywheel, which looks pre-drilled and tapped for a pressure plate. Is this the same style as the SB Chevy flywheels, and would it be acceptable to use it?

Thats great about the power steering pump. Now will be a great time to convert to saginaw, being i'm getting rid of the old l-head.

It's hard to believe a simple rear-main leak in the l-head caused me to go this far.

Thanks for all the help so far,
Jake

 

Well you can part out the 1962 ? through 1967 Chevy II's or the 1968 through 1970 Nova's.
Also the 1967 through 1970 Postal DJ which all came with the GM 153.
Yes, the automotive intake / exhaust uses an integral heat riser.

I expect the (2.5) should provide the best MPG that is readily feasable for any of the old school jeeps.
My estimation is about 25 to 28 mpg with GM 153 / 4.88 / O.D.

The 1967-1970 Postals used a full cradle crossmember for front engine support.
I believe that postal setup would be undesireable for the early CJ's.
So what are various GM 153 / 181 installers using for front engine support ?

 

We built regular mounts off the frame for Dad's '43 GPW when we put in the 153.
Some Postals did have the cradle/crossmember with the motor mounts bolted to it. Have one at the shop now. No biggie to eliminate that and build mounts off the frame like any other Jeep engine conversion. One we have is getting a Chev small block and a 3b body.

 

I have two GM 153 engines here; the one I am putting in is an older block and only has provisions for front mounts off the front of the block. My other motor is a later version and has mounting boss's on the side of the block, which is a better set-up. I am using the older motor because it has already been rebuilt, I am going to make a saddle type mount off the front of the motor, with rubber mounting biscuits from AA adapters to go to a metal pad coming off the frame. Words of advice, I did not know of all the differences in these motors when I had my first motor rebuilt. For those of you looking for a motor, make sure it is a later model motor that already had a rear sump pan, so the dip stick goes to the right spot (as my older motor has the dip stick hole in the wrong place) this after I converted it to a rear sump. Also, look for the blocks that have the motor mounting blocks in the middle of the block, this will work better, especially if you are mounting a heavy transmission like I am using (Ford T18). I am going to have to make a rear motor mounting system off the bell housings, just like you see on those older steel GM truck bell housings, this is to carry some of the weight, and take it off of the front mounts. Actually, if I had to do it over again, I would find me a mercury 181 cubic inch motor and build it. The one thing that I really like about these motors is that they are a very strong motor (good power to weight ratio), and they make a very clean installation (very uncluttered engine compartment). One more thing, if you need power steering, look for the pump mounting bracket off of an early model Chevy 250 six (non integrated head model).