Home » Public Forums » GMCnet » new engines for the GMCs
| Re: new engines for the GMCs [message #316358 is a reply to message #316311] |
Thu, 20 April 2017 20:57   |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
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HP - instrument manufacturer that sells computers now and again.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: new engines for the GMCs [message #316364 is a reply to message #316311] |
Fri, 21 April 2017 00:35 |
Francois
Messages: 161
Registered: October 2012
Location: Southern California
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Speaking as someone who has recently rebuilt my transmission, (relying on YouTube and other written guides) I do see a problem with a high horsepower modification. For my tranny, I was able to find plates and seals. I even grabbed a Ragusa pan for the unit. The thing shifts great, stays cooler, doesn't leak and I call the rebuild a success. But there was one part I was unable to get - the drive chain. I tried a dozen transmission shops, a dealer and the rest of our usual sources. I know Manny has a few, but I don't blame him for keeping those for his rebuilds.
Straight to the point, I figure the drive chain could more easily stretch and fail in a high horsepower/torque environment. I already had the maximum play allowable, but had to put the used chain back in because I could not get a new one. So I'm kind of babying it. Good shifts at 5-7 mph and 23 - 25 mph, but I keep thinking about that stretchy drive chain.
Sure, who wouldn't like fuel injection and variable valve timing and maybe even a computer controller ?? But I do think that the best new engine would be one that comes matched with a modern transmission. I am pretty sure these 40 - 50 year old transmissions are going to start to go fast if we mate them to much môre powerful engines.
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| Re: new engines for the GMCs [message #316438 is a reply to message #316311] |
Sat, 22 April 2017 07:08 |
Chris Tyler
Messages: 458
Registered: September 2013
Location: Odessa FL
Karma: 7
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First thing [which I think we can all agree on] whatever improvement in milage - if any- via any of the setups mentioned- will likely NEVER pay for themselves even if you do all the labor yourself.We do these things because we can and are inveterate tinkerers but we have to keep reliability and usability in mind with the sometimes esoteric ideas we come up with
Couple of years back was working on a "science project"with my BIL re trans mods and swaps for the GMC. Items considered doable included lower 1st/2nd gearsets, lock up converter, switch pitch converter conversion and some internal tweaks. His business has taken off to the point he can hardly keep up with the HP builds while I was sidelined with complications from 2 hip surgeries so they havent been fully realized.
Regarding 425 torque capacity, his feeling is that the drive chain is the weak link but can be upgraded
Also looked at the 4WD case/blocked rear idea- its doable but would require extensive mods and cubic money
I am a huge fan of the LS engine series and think this can work...if you want to spend the money. An iron block LQ9 with a stroker crank will get you around 400 cid fairly easily. Add small turbo[s] even to a 5.7 and you will have a torque monster. I know for an absolute fact you can make 556 #/ft at 3500 on a bone stock LS1 at 10# of boost and still get 35 mpg hwy in a corvette
Im also a huge fan of turbos. Set up for low end boost vs HP {IE small housings and wastegates] you could hget by with a smaller engine under cruise conditions
Another option would be the conventional SBC/383 stroker. I had one with twin turbos in a mid engine vega
Even a 350 single turbo works well for a tow rig
I understand Jim B was looking at a turboed Olds 350 a while back
For myself, Im content with the 455 I have for now, especially since I dont use the coach much lately. However, as I have mentioned before, at some point I will probably add 2 small turbos and a early model fuel injection system to it as I have everthing i need already laying around
76 Glenbrook
[Updated on: Sat, 22 April 2017 07:12] Report message to a moderator |
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| Re: new engines for the GMCs [message #316477 is a reply to message #316311] |
Sun, 23 April 2017 07:55 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
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Well, I want someone to look at a wrecked Ram Promaster diesel and see if the driveline might transplant. The allowable GVW on them is in line with a GMC. The option is Manny's upgrade. The idea of a Tonowanda Turd in my GMC is not gonna happen.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: new engines for the GMCs [message #316482 is a reply to message #316311] |
Sun, 23 April 2017 09:29 |
Mike S
Messages: 82
Registered: February 2017
Location: Vero Beach, FL
Karma: 3
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First, This isn't about mileage or even cost. Anything that goes round and round will wear out.
My GMC burns about 1 quart of oil every 500 miles, and I am OK with that vs. the cost of a rebuild.
Second, the last 455 casting was done sometime in the 70's. When I helped out at my buddies engine shop, about 50% of the engines that came in for a simple rebuild, took some kind of major component. That's why the top shops are quoting $7500 for a rebuild. It is not customer friendly to say $5000 and to then come back and say you need another $1500 because your block won't take a rebuild. The rarer the more money.
Third. The LS would be a perfect motor, if it would bolt up with just an adaptor(that are out there cheap), a custom oil pan and front mount(easily fabricated). You could sell those parts for around $500 and be OK making them. So a $500 kit, $2500 late model low mileage junk yard engine,$400 wire harness and $300 computer tune and your running.
I will make a kit to bolt up the LS to the 425 transmission. But It needs custom front mount, rear mount, oil pan, trans pan, and an adaptor between the differenial and the trans. I am looking at $1800 to $2000 for those parts. And to fit our coaches, you are going to have to add 3 inches to the height of the step near the transmission to make it work. And it is getting real close to the hatch. it may even need to be raised a little to clear the truck intake.
So what are the other choices?
To me there are 2 that make sense.
First the more expensive. World Product sells and engine called the LS hybrid. It is small block Chevy based bottom end, set up to take LS cylinder heads. Again, it is not cheap. The first quotes on the short block exceed $5500! With a fresh set of heads and all the other component, It will probably be near $10,000 for complete engine ready to drop in. But you will get easily 450 HP and 500 torque.
As always speed costs.
The other option is GM sells a motor they call HT383. Google it. It has almost the exact horsepower and torque of our stock 455s. The front mount and pan prototypes will be done soon. you will have to raise the hatch, and I will let everyone know how much soon. Jegs has the motor for $4500. It has a 2 year 50,000 mile warrantee. Add a Fitech fuel injection and you would have a great motor for our coaches. Keep in mind all your front accessories need to be changed. But GM does sell a kit with everything you need, brand new, for about $1000.
How much is brand new worth vs. 40 year old everything!
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| Re: new engines for the GMCs [message #316501 is a reply to message #316482] |
Sun, 23 April 2017 15:21 |
Hal StClair
Messages: 971
Registered: March 2013
Location: Rio Rancho NM
Karma: -12
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The WP Motown block is a whole different motor in comparison to the LS series'. They may use the LS heads but have the traditional SB lower end. The deep skirt LS block still looks like a problem to me. The small block pan is only there to capture and store oil and is an easy uncomplicated piece open to modification so thats a simple mod.
You'll probably have issues with the oil filter but a remote mount would be easy. Don't know how your fan will land in comparison to the 455 but a modified or new shroud may be required. Power steering and A/C lines will probably need addressing too as well as alternator and sensor wiring but nothing earth shattering. These are a fairly simple problems but would need to be addressed. The simpler the swap the more people that would attempt it. I'm certainly not the one to 'dis' this project and love that you're taking it on.
The 383 has been around for a LONG time. I have a 364" stroker in the garage I've never run. But, the Olds blocks will certainly out live the Chevy's as they were built using a higher nickel content block so, bottom line, 'you spend your money the way you feel best'. If you think gas is a better direction than diesel, go for it. I'll be watching with great interest.
Hal
"I enjoy talking to you. Your mind appeals to me. It resembles my own mind, except you happen to be insane."
1977 Royale 101348,
1977 Royale 101586, Diesel powered,
1974 Eagle Bus 45',w/slideout,
Rio Rancho, NM
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| Re: new engines for the GMCs [message #316526 is a reply to message #316311] |
Mon, 24 April 2017 08:14 |
Chris Tyler
Messages: 458
Registered: September 2013
Location: Odessa FL
Karma: 7
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I think Hal is right regarding diesel as being the best for milage, reliability and durability.
While Ive have wanted a diesel to play with do some time dont know I want one in the GMC. How is the noise factor with that?
Of course, it would sound better with a little turbo whistle, kinda like the duece and a halfs in the army. [mechanic told me they put the turbos on those to lesson the blck smoke emissions and they didnt really make any more power with them. Hmmmm....]
MikeS, as discussed on FB: The HT383 should work fine, may even fit under the stock hatch depending on the manifold you go with. I had a vega with the mid engine, twin turbo 350/425. BIL has it now and will be reomving the engine to put in my Monza and a built 700R4, but we need to change oil pans. I can send you some pics to give you an idea what to use. I THINK it would clear a 3.75 stroke but not sure
He is contemplating a big block for the car, if he goes that route the pan will be for sale.
The issue with the WP block and longer skirts could be a problem- It looked like the deeper skirts on the LS was going to be as well, but the double tilt idea might get around it
THE LS hybrid is a great concept for HP use, but I dont think it really offers much for our application at the lower RPMs we need. I think the low end airflow on hte Vortech type heads on the HT383 would be as good or better
76 Glenbrook
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| Re: new engines for the GMCs [message #316530 is a reply to message #316311] |
Mon, 24 April 2017 08:42 |
Mike S
Messages: 82
Registered: February 2017
Location: Vero Beach, FL
Karma: 3
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I will let others play with the diesels. Manny is the only one who can work around the torque vs, 425 trans. I have heard they have sheared the torque convertor bolts. If I have heard wrong someone let me know.
The HT383 would be right there on power. With some options on upgrades. If I needed a engine tomorrow, It is what I would do.
I speced the Hybrid with pistons to work with the stock truck heads. The CI increase to 427 would add all the low end torque we could ever need. And should make a really nice torque curve.
I'm going to start with a pan that will clear the 4 inch stroke. That way all options could be on the table. From turboed 350 to 440 small block
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| Re: [GMCnet] new engines for the GMCs [message #316534 is a reply to message #316530] |
Mon, 24 April 2017 09:13 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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The torque converter bolt issue is an operator caused one. About the same
time in production that GM went to METRIC wheels on trucks and HD 4 x 4
stuff, they also went to METRIC in their transmissions. Some of those
METRIC torque converters found their way into TM-425 aftermarket. They use
METRIC bolts on the torque converter. Due to inattentive technicians, or
inexperienced technicians, USS bolts left from OE torque converters found
their way into the assembly. They "kinda" fit for a couple of threads, and
then just lock up without clamping the flex plate to the torque converter.
Bad stuff happens quickly, here. I have fixed a couple of these in my shop,
and advised some owners over the phone with similar problems. The mismatch
is complicated by rebuilders painting their converters the wrong color, and
installers assuming that a converter is USS instead of METRIC because of
the color. Verify the converter by testing the bolts before assembly.
Jim Hupy
Salem, Or
78 GMC ROYALE 403
On Apr 24, 2017 6:43 AM, "Mike Sadlon" wrote:
> I will let others play with the diesels. Manny is the only one who can
> work around the torque vs, 425 trans. I have heard they have sheared the
> torque
> convertor bolts. If I have heard wrong someone let me know.
>
> The HT383 would be right there on power. With some options on upgrades. If
> I needed a engine tomorrow, It is what I would do.
>
> I speced the Hybrid with pistons to work with the stock truck heads. The
> CI increase to 427 would add all the low end torque we could ever need. And
> should make a really nice torque curve.
>
> I'm going to start with a pan that will clear the 4 inch stroke. That way
> all options could be on the table. From turboed 350 to 440 small block
>
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| Re: new engines for the GMCs [message #316538 is a reply to message #316311] |
Mon, 24 April 2017 11:12 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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The M-35s we had ("Deuce and a half" field grade truck) were about half turbo and half normally aspirated. The turbos outran the others and hauled more weight... although that was above the listed capacity. And, the turbocharger screaming away right under the passenger side floorboard would give you a headache after an hour or two at freeway speed. About the time I got Out, we started receiving trucks with Allison automatics in them. We called them the 'Ladies' Deuce'.
The M-35 is about as indestructible road vehicle as you'll find.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: new engines for the GMCs [message #316561 is a reply to message #316482] |
Mon, 24 April 2017 17:40 |
TR 1
Messages: 348
Registered: August 2015
Location: DFW
Karma: -7
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Mike,
I'm going to preface my reply with this statement: I too love LS motors. I have an 89 Mazda RX7 that I swapped in an LS6 a few years back. I also daily drive an 05 GTO, (LS2) and my wife daily drives a G8 (L76) that has 200K miles on it and counting. They're great motors. That being said, I don't see any real advantage at this time in swapping one into my GMC. You can rebuild a 455 with all new parts except for the block and crank. Both of those items are able to be inspected and deemed "Good" or "Not Good". There is no advantage to a brand new block over a good 40 year old block. When my 455 needs a rebuild, I will rebuild the 455, and anticipate having no issue doing so for some years to come. (FWIW, I'm 41, and plan to have our GMC for at least the next 25 years...) If 455s/455 parts become scarce, I would probably then switch to a Caddy engine. It is a true bolt in, and you should be able to reliably get parts for them for a very long time, as Cadillacs have been, and most likely will continue to be collectible.
If I had the $ now, or if gas prices go through the roof, I would opt for a diesel. The 6.5 swap Manny and other such as Hal have worked out, looks to be a great option. If the 6.5 is not refined enough for you, Cummins is planning to release a line of crate engines. The 5 liter Cummins V8 looks like an awesome fit for the GMC, but I'm sure it will cost boatloads for a Cummins crate.
Also, if you go this route as opposed to the 6.5, you would be pioneering literally everything. Having done a few engine swaps in addition to the LS motor in my RX7 over the years, I can tell you there is a lot to it. Lots of detail work in addition to the big things like getting it to fit. And at least for me, to go through all that, there have to be some significant gains... And I don't see that with an LS over the 455.
For example, LS motors, if taken care of are easy 200K motors... -IF- they are pulling around a truck that weighs 5K, and sometimes tows a trailer. GMC is 10-12K pounds, and has a pretty large frontal area to boot. I would guess they are more like 100-150K in motorhome service. 455 is similar... Maybe a little less, but not enough to warrant the effort of putting an LS in my GMC. And a good LS rebuild is not much less than a good 455 rebuild. Say 5K for a decent LS rebuild. Yes you can do it cheaper. I can spend less rebuilding a 455 as well. But you'll get what you pay for either way.
Now, if you absolutely have to have an LS in your motorhome, you want to start with a truck motor. The 2 crate engines you mention above are not really for HD truck use... They're more light duty truck or muscle car. If I were to LS my GMC, I would at least go with a Gen IV, iron block LS motor. The rectangle port heads (often called L92 or LS3 heads) are damn near magic when it comes to flow, torque production, etc. I would probably opt for the 6.2 so look for an L92 or L99 engine. Even better would be the Gen V L86. These add direct injection, variable speed oil pump, etc.... Lots of little tweaks to increase efficiency. This is arguably (arguable with Ford and Mopar guys  the most efficient gasoline engine available for motorhome use. And even with all that, it's only marginally more efficient than a 455 when pulling 12K pounds.
Now, for your swap, you mention physically bolting on the trans, and modifying the oil pan and engine mounts, modifying the interior step and maybe raising the hatch height. When forcing an engine into a vehicle it was not designed for, that's only the beginning:
Finding Radiator/heater hoses that work with this swap
Adapting the gauges, buying new gauges to work with the LS
Adapting the LS wiring harness to "interface" the LS brain with the GMC. ignition switch, etc.
Buy new ECU ($$$$), or modify truck ECU. Disable anti theft key, (VATS) other ECU changes to allow the engine to run without the rest of the truck it came in
Are you going to run a catalytic converter? If yes, modify GMC to run cat. If not, reflash ECU to remove cat emissions system from diagnostics.
You going to run stock manifolds or go with headers? Either way, you need to modify the exhaust on GMC
No evaporative emissions system on GMC. Modify GMC to add it or reflash ecu to remove it from diagnostics
Modify GMC fuel system. LS motors are high pressure, returnless fuel systems stock.
What are you going to do with engine oil cooling?
Gen IV and up LS motors use an electronic throttle, you'll need to figure that out, though there are options (Electronic gas pedal or switch to older ECU and reluctor wheel with mechanical tbody)
How do you run the mechanical TH425 on an engine designed for a computer controlled transmission? Again, there are options, but it needs to be considered
Modern truck is going to generally have a higher amp alternator (150 amp or so?). You'll need to verify your GMC can handle that current and modify accordingly
AC system will need custom hoses made. LS AC runs through ecu, so you'll need to modify GMC AC system with necessary sensors.
I love my cruise control on long trips. I consider it a must. Need to figure that out.
Will need some way to interface with the ECU... OBDII connector?
Hal mentioned cooling fan, shroud modification, etc above.
So after all that, you end up with a GMC with an LS motor. You get 8-10 MPG, with an engine that lasts ~100K miles, has around 400hp and tq, and costs $5K to rebuild.
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX
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| Re: [GMCnet] new engines for the GMCs [message #316563 is a reply to message #316561] |
Mon, 24 April 2017 18:09 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Happy as I am with my Cad500, and being too old to launch into another
"upgrade", I'm not about to get into this discussion. But, I recently had
a surprise that influences the longevity of the 455: NEW crankshafts are
now available, removing them as an unobtainium part! One source:
https://www.summitracing.com/parts/esp-104554260/overview/make/oldsmobile
Ken H.
On Mon, Apr 24, 2017 at 6:40 PM, Mark Sawyer
wrote:
> ...
> You can rebuild a 455 with all new parts except for the block and crank.
> ..
>
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Ken Henderson
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www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: new engines for the GMCs [message #316571 is a reply to message #316311] |
Mon, 24 April 2017 20:17 |
Mike S
Messages: 82
Registered: February 2017
Location: Vero Beach, FL
Karma: 3
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Since most of you out there do not know me, maybe a little background is in order.
I am 55. I learned to weld and fabricate at 13, Worked on a farm as a youth(boy the things you learn there). Had my first street rod at 15. Built my first Rod at 16. Had 3 periods a day of machine shop 1 year. Rebuilt my first motor at 17. Spent 2 1/2 years at college studying mechanical engineering. Left college to work for an ARCA race team. Built a motor that qualified at Daytona ACRA race 7th. 1981 ACRA national champions, I was the only full time paid guy on the team. Multiple local short track championships. Been boat racing for over 30 years. Tunnel, offshore, hydroplanes, P1, and lots of lake racers.
Engine transplant history
1995 Buick Roadmaster wagon-2001 5.3 ls
1972 Chevy Greenbrier(chevelle) wagon-1995 LT1
1972 Chevy El Camino-1992 throttle body 350
Friends 1967 Toyota LandCruiser Tuned port 383
Friends Jeep CJ 5 383 Holley Projection
Jeep CJ 7 Glass tub Chevy 4.3 V6
1930 Model A ford Pickup- 4 wheel drive 4 inches off the ground. Built in 192 with 1987 1 piece pan 355 ci 6 inch Rod Motor
I had my own Semi repair garage for 3 years. We were a Consolidated Freight primary vendor.
I worked on my first GMC in 1984, We had a doctor whose coach we maintained for 5 years. That's when I feel in love.
First meet Alex Sirum in 1985, when I spent 2 winters working in the marine business in Okeechobee.
I was one of the first 150 people hired at Steel Dynamics. We built a steel mill in a corn field. Worked 10 years as a millwright. One of the most technical/mechanical jobs you can have.
I have a little experience.
Again, this project comes from a conversation with Jim Bounds and backed up with Jeff Sirum.
We are going to need another motor if these coaches are to last the next 40 years. When I built the first street rod in 1977, I was not going to just rebuild the model a engine. I could have. And people are still rebuilding Model As, But engines options had gotten much better in the 46 years since the original.
If I needed a new motor in my Coach, has motor technology improved in the last 43 years, YES
Would I do something right now, I don't know.
Jim would love to have a new crate engine to put in his customers coaches. To quote Jim, "If I had a good crate engine, I would never rebuild another 455."
He has done other conversions, most of us know that. It takes a lot of time to develop a new package. He has employees and customers and obligations. When we talked, he said he would be interested in buying kits if they could be made.
I have a great relationship with Jeff Sirum. I retired at 55, but I wanted a small shop to help out retirement money. I am already doing all Jeff's fiberglass parts. And we are making new molds for parts that are not currently available. We have the Dash Cover, New improved molds for interior cab sides. Next is a new cab interior cap mold. And after that we are going to be able to keep the stock dash with a new "birdcage" part.
The "small block" pan and front mount will be easy. Like I said above, If I needed a motor replacement, I would put in the HT383. On longevity. Everything that spins has a life span, any bearing engineer will tell you that. reduce the load, like reduce the vibration or amount of out-of-balance and you will increase life. The new motors go 200,000 miles because of technology, they only have to go around 1/2 as much. Look at the gearing in you truck. they can go down the road at 1500 rpm.
Half what our coaches do.
Do I believe long engine life is possible with good maintenance, Sure Do. you can cook down a brand new motor with just 1 small coolant leak. Ben there done that. More engines fail from poor maintenance than just wear out.
Would I be comfortable with a 100,000 mile motor, Heck Yeah, if it never gave me any problems. How many miles are we averaging a year in our coaches? I am averaging 7,000 miles. I think that is on the high side of average. So at the end of the next 14 years, I need to replace the power plant, I will do it with the newest Mr. Fusion.
I agree, the LS conversion is not easy. It's why only one person I can find bolted one up. And he had to mill down the block. Not really a bolt in.
I have had interest in the LS from outside the GMC community. I will build the pieces. They won't be cheap because there are a lot of them. And will it fit our coaches well? NO. Would they work great? Probably. Will somebody want one? I don't know.
I kind of hope, "If I build it, they will come."
Once I build the hard parts, if someone wants to partner up on the first LS build, I will do it. We will figure out the parts needed and put it out to the world. Anything can be done with enough time and money.
Mike
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| Re: new engines for the GMCs [message #316589 is a reply to message #316311] |
Tue, 25 April 2017 09:33 |
TR 1
Messages: 348
Registered: August 2015
Location: DFW
Karma: -7
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Mike, I'm sorry if I came off as saying you were not capable of doing the swap. That was not my intention. My point in listing all that stuff out was to illustrate the point that engine swaps are a lot of work... And that the 455 and Cad 500 really are good motors for our application. You are 100% right, at some point we will NEED a new engine option... I also agree with you that the LS motor is the best gas engine out there right now for the job. But good god, it's a lot of work to get it in there and working, then add all the ancillaries as well...
But you are also correct in saying that the more options we have, the better off we will all be. I'll tell you, if I were going to do an LS swap on the GMC, and I needed to modify the interior anyway, I would probably look the possibility of using a 4L80 to get the extra gear and lockup converter.... I believe Hal's diesel setup uses a 4L80 or similar, and some sort of transfer case to get power back to the front...
Hal, could you maybe describe how your setup works?
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX
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| Re: [GMCnet] new engines for the GMCs [message #316590 is a reply to message #316589] |
Tue, 25 April 2017 09:41 |
Dolph Santorine
Messages: 1236
Registered: April 2011
Location: Wheeling, WV
Karma: -41
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Senior Member |
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I understand where everyone is coming from regarding the engine, but I think what will kill the GMC Motorhome in the end is transmission parts availability.
I just completed a rebuild on a 1922 Overland. Pistons, rings, gaskets - all available, as they will likely be for the 455 or the 500 in half a century.
Transmission parts, not so much.
Dolph
DE AD0LF
Wheeling, West Virginia
1977 26’ ex-PalmBeach
1-Ton, Sullybilt Bags, Reaction Arms, 3.70 LSD, Manny Transmission, EV-6010
“The Aluminum and Fiberglass Mistress"
> On Apr 25, 2017, at 10:33 AM, Mark Sawyer wrote:
>
> Mike, I'm sorry if I came off as saying you were not capable of doing the swap. That was not my intention. My point in listing all that stuff out
> was to illustrate the point that engine swaps are a lot of work... And that the 455 and Cad 500 really are good motors for our application. You are
> 100% right, at some point we will NEED a new engine option... I also agree with you that the LS motor is the best gas engine out there right now for
> the job. But good god, it's a lot of work to get it in there and working, then add all the ancillaries as well...
>
> But you are also correct in saying that the more options we have, the better off we will all be. I'll tell you, if I were going to do an LS swap on
> the GMC, and I needed to modify the interior anyway, I would probably look the possibility of using a 4L80 to get the extra gear and lockup
> converter.... I believe Hal's diesel setup uses a 4L80 or similar, and some sort of transfer case to get power back to the front...
>
> Hal, could you maybe describe how your setup works?
> --
> Mark S. '73 Painted Desert,
> Manny 1 Ton Front End,
> Howell Injection,
> Leigh Harrison 4bag and Rear Brakes,
> Fort Worth, TX
>
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| Re: new engines for the GMCs [message #316591 is a reply to message #316311] |
Tue, 25 April 2017 11:06 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Senior Member |
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I took a look at the ProMaster diesel, and I don't think it'll fly. It looks to require serious surgery in the front of the coach. Plus, the one I saw fits the MV four cylinder, not the V6. I got the impression the V6 only appears on the home market in bigger trucks, though I might be mistaken there. At any event, it isn't going to be like stuffing Mustang running gear in a Ranger.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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| Re: new engines for the GMCs [message #316593 is a reply to message #316589] |
Tue, 25 April 2017 11:45 |
A Hamilto
Messages: 4508
Registered: April 2011
Karma: 39
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Senior Member |
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TR 1 wrote on Tue, 25 April 2017 09:33Mike, I'm sorry if I came off as saying you were not capable of doing the swap. That was not my intention. My point in listing all that stuff out was to illustrate the point that engine swaps are a lot of work... And that the 455 and Cad 500 really are good motors for our application. You are 100% right, at some point we will NEED a new engine option... I also agree with you that the LS motor is the best gas engine out there right now for the job. But good god, it's a lot of work to get it in there and working, then add all the ancillaries as well...
But you are also correct in saying that the more options we have, the better off we will all be. I'll tell you, if I were going to do an LS swap on the GMC, and I needed to modify the interior anyway, I would probably look the possibility of using a 4L80 to get the extra gear and lockup converter.... I believe Hal's diesel setup uses a 4L80 or similar, and some sort of transfer case to get power back to the front...
Hal, could you maybe describe how your setup works? IIRC, Hal used the engine/transmission/transfer case because that is what he had on hand (4-speed).
A similar setup with 5 or 6 gear tranny would be better. More gears in the tranny is always better. Continuously variable is ideal, but not many sizes have ever been made, and nothing big enough to drag a GMC class A.
If anyone ever decides to make a drop-in front-wheel-drive engine/tranny combo (with other than the THM-425) 6 speeds should be the goal.
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. It's not economically viable but it's certainly unique.