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Fmtv engine swap to a Detroit 50 series.
- Thread starter Goomer214
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The 50 series is apparently a 4 cylinder 60 series. These are big engines, very tall from pan to valve cover. That would be your biggest fitment issue.
I operate a few C7 engines and can absolutely understand why you don't want another. We use John Deere 6068 engines in the same application and they are flawless. They are very similar dimensions and power wise.
I operate a few C7 engines and can absolutely understand why you don't want another. We use John Deere 6068 engines in the same application and they are flawless. They are very similar dimensions and power wise.
coachgeo
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matters what your truck.... if the truck had a C7... then a swap to a computer engine is best to match better coordination with computer transmission. If your truck is older with mechanical engine ..... then a mechanical transplant would be best.
The older FMTV and MTV on the short lived commercial side used the Cummins 5.9 or was it the 6.3??? . Maybe both. Anyway this was an upgrade from the 3116./3126 IMHO the cummins 8.3 would be better match for a tune around; but not much or any more than 330hp, would be good swap. This puts it similar to the C7 rating but mechanical pump. That hp rating would not be pushing the 8.3 anywhere near the tip of its limits by any means so you should still get good "work" with reasonable fuel mileage and reasonable speeds. Keep in mind..... old enough truck will have no ABS.... so consider STOPPING when you consider how much go power you put in her. For newer trucks (Wtech III trans ECU) a more modern Cummins that is computerized could be swap for them and for C7.
BTW- If a person is meticulous on maintenance, the CAT will last you nearly as long as a so so maintained Cummings...at least that is what has been said.
Side note. You might want to dig up the old threads on this topic. There is some very heavy well detailed discussions in here on this already. Could give you a head start to view those.
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I know BAE systems briefly sold a civilian version of the fmtv called the SD brazo. Apparently it used a Cummins ISB engine.
New 6X6 BAE Systems SD Brazos Truck with subframe for Bliss Mobile - $99,999
This is a turn key expedition truck platform I just listed this on eBay. Here is the listing. https://www.ebay.com/itm/324046880230 The description is copied and pasted below. If you are interested in the truck, you can reach me by email using the address baetruck (at) labsupplycentral.com...
expeditionportal.com
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Well... Everybody has an opinion, but the 3116 (mechanical) and 3126 (electronic) CAT engines in the Stewart & Stevens and BAE Systems trucks don't seem all that bad to me. I mean there is a thing called "the oil line of death" on the 3116. If you have that power plant, you need to inspect yours today. Maybe even buy the replacement part and install it, then keep on driving. With regular maintenance and oil changes at least yearly, those two CATS should out last you... The C7 is even newer and the same applies.
The driveshafts... They are a whole "nuther" thing. The angle from the axles to the transfer case / transmission are marginal even when they were built Not a whole lot can be done about that, but the military tested it and accepted that design. When the universal joints and slip joints are well and regularly greased, they function just fine. The handling in some of the auction yards cause some problems. Bent or Out Of Balance (the weights get knocked off) are a BIG PROBLEM on these drive shafts. Spend the money. Remove them and carry them to a reputable company that does that sort of work - and you won't have that concern.
As far as a re-power, it just takes time and money. If you are creative enough, anything is possible. Cramming a 454 into a Chevrolet Vega is possible. And a blown 350 into a really small boat is possible too... Again, back to the opinion part though, for these trucks I'm personally not sure it is worth the effort. They aren't race cars (trucks). If you've ever passed a convoy on the interstate, they are generally running somewhere between 45 and 50. Yes, in their factory configuration you can easily make 60, but to be honest - you could spend your money on a faster vehicle that rides more comfortably - for less.
Off My Soap Box
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The later trucks used the intermediate MTV axle for the rear axle on the LMTV and eliminated much of the driveline angle problem. If the drivelines are serviced and balanced it's really not an issue. The u-joints are cheap - often about $40 to $60 in the surplus market - and can be considered a maintenance item.
And the C7 by all accounts is an improvement on the 3126..... here's a post that linked to a teardown video of a 3126 with 300k miles and frankly it looks essentially new inside:
With very few of these trucks exiting their military career with more than 15-20k on them...... most of us consider this is a non-issue since very few of us are likely to ever exceed the lifespan of the CAT engine if it's well maintained.
I'm told the military likes the CAT engines because they rarely leak. The military hates things that leak. It's an inspection/PMCS/leak classification/deadlined vehicle thing and if something leaks into the dirt there's a lot of paperwork and disposal of contaminated soil that has to occur, etc..... they hate leaks.
Also the C7 can be up-rated to 370 HP and 931 Ft/lbs. Mine is an absolute beast.
If you are going to buy a military truck, the statistics are very clear on this point - the FMTV is the most reliable military vehicle the US has ever purchased. Not by a little either - by about 4x.
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coachgeo
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they might have put 6.3 in the MTV and not the 5.9.... anyway though.... yes the 5.9 can be tuned up to similar specs as the C7..... but that tune would sacrifice the engine life and mpg a lot to get there. If can use less tuning needed to reach similar C7 specs. then your not pushing the engine further to its top edge. Hence considering starting with something like 6.3 or 8.3 might be better... less tuning needed
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Cummins are not known for long life , they are popular as diesels go because they are cheap to rebuild .
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M1084 is the MTV cargo with MHE - that what you are referring to?
Being an MTV it doesn't suffer from the steep rear driveline angle, only the front. Which again - really not that significant of an issue if attention is paid to balancing and maintenance.
Get a C7 truck if reliability is your goal. The C7 A1/R trucks got roughly double the MTBF as the A0 trucks due to the build changes and improvements.
Engine swap is just silly IMO. The C7's are excellent engines used in tens of thousands of school busses, fire trucks, RV's, and equipment. Maintenance is key as it is with anything. This is a pretty active forum and there's a couple facebook groups also - read through posts - engine failures are pretty rare - even more so if you disregard all the 3116's that have died of the oil line of death and focus only on 3126b's and C7's. The C7's got better oil pumps and an improved HEUI pump and there's a kit for about $200 in parts that adds an inlet oil filter to the HEUI supply line. Give them clean oil, clean fuel, and good air filtration and they are 500k mile engines easily. Inspect the air filter housing and all the rubber elbows on any truck new-to-you. They can rot out and then you are just sand blasting the cylinders. Probably what happened to that 3126 in the tear down video. 300k miles and no one saw the holes rotted in the intake couplers, etc. Mine had cracks large enough to stick your finger through on the hump adapter from the filter housing to the intake tube - my C7 A1R sat in the desert it's whole life only accumulating 1500 miles till it was auctioned so it was entirely due to old rubber.
Being an MTV it doesn't suffer from the steep rear driveline angle, only the front. Which again - really not that significant of an issue if attention is paid to balancing and maintenance.
Get a C7 truck if reliability is your goal. The C7 A1/R trucks got roughly double the MTBF as the A0 trucks due to the build changes and improvements.
Engine swap is just silly IMO. The C7's are excellent engines used in tens of thousands of school busses, fire trucks, RV's, and equipment. Maintenance is key as it is with anything. This is a pretty active forum and there's a couple facebook groups also - read through posts - engine failures are pretty rare - even more so if you disregard all the 3116's that have died of the oil line of death and focus only on 3126b's and C7's. The C7's got better oil pumps and an improved HEUI pump and there's a kit for about $200 in parts that adds an inlet oil filter to the HEUI supply line. Give them clean oil, clean fuel, and good air filtration and they are 500k mile engines easily. Inspect the air filter housing and all the rubber elbows on any truck new-to-you. They can rot out and then you are just sand blasting the cylinders. Probably what happened to that 3126 in the tear down video. 300k miles and no one saw the holes rotted in the intake couplers, etc. Mine had cracks large enough to stick your finger through on the hump adapter from the filter housing to the intake tube - my C7 A1R sat in the desert it's whole life only accumulating 1500 miles till it was auctioned so it was entirely due to old rubber.
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Third From Texas
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Do you currently have an LMTV?
Just trying to get perspective here. What makes you feel your Cat engine is going to die?
Just trying to get perspective here. What makes you feel your Cat engine is going to die?
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It is obvious from his posts if you look at them (there's only 42) that he hasn't purchased any military vehicles recently and only drove/owned an M35 quite a few years ago that he bashed around in the woods but didn't (in my opinion) find the limits of (I have much experience in the M35 and found some of it's limits). He has been in all the various 2.5 and 5 ton sub-forums here asking a lot of questions about suitability, what to look for, and other noob questions.
So no - he's making a lot of assumptive statements such as the original supposition that the CAT engine (with no specific model of the three possibilities in the FMTV platform) quote " is bound to dump."
Honestly given my review of all his previous posts and that specific statement I am concerned that his conclusions are based on a complete lack of experience and it may run deeper than experience alone given the demonstrated grasp of English, punctuation, sentence structure, etc.
My gut reaction is that based on him being here and posting the same basic on-the-fence noob questions for 10 years and still not buying anything is that the current trend will continue and he will probably not make a purchase anytime soon.