new engines for the GMCs

> Has anyone looked into a lock up torque converter? It ought to help freeway
> milage. They make them for the TH-400
>
> Great to hear of some cheaper motor options, I'd love Manny's diesel, but
> I'd love to keep the extra $20-30k in my pocket.
>

>
> > The 6.0s and 6.2 have been the go to motor in the 1 tons since the demise
> > of the 8.1. And their GVW's are way above ours. The 6.0s what outwork the
> > Ford V10's in our service Fleet.
> >
> > _______________________________________________
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You need to look at it apples to apples. Manny's kit with motor out the door vs an LS with new motor OTD. Or see if you can source your own 6.5 and
buy Mannys kit (if he's interested in selling it that way) vs this LS 'kit' and used engine. The labor to install either engine would probably be
close either your own or paying someone. JMT
Hal
--
1977 Royale 101348,

1977 Royale 101586, Diesel powered,

1974 Eagle Bus 45',w/slideout
 
> Wasn't there a problem with 454 engines and rear bearings?

Please don't get me going on the 454...
There is a real good reason that they are out of production.
The only reasons the 8.1 is gone is that it was too expensive for Government Motors to sell and they were looking to end gas engine production.

Matt - the refugee of Detroit eco-wars.
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Still Loving OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
 
Mike, first of all, I applaud your effort. If folks didn't ask 'what if', we'd still be riding horses. Go for it. I've thought of the same kinds of
things myself.

A few questions/comments.

1- What happens in the tranny when you rotate the pan so it's no longer level? Will there be any issues with fluid pickup etc? Manny is your go-to
source for questions about that.

2- I have a 6.0 in my '07 GMC Serria pickup. It has a 3.70 final drive and it will indeed make a lot of power but it makes it at 4000-6000+ RPM.
With a 425 and 3.70 final drive, you're still going to be at 3000 rpm at 60mph and I don't know if that is the sweet spot for LS torque.

3- Hal StClair did a masterful job installing a diesel with motor tranny in his Royale. What he did was use the entire tranny and front wheel drive
system from a 1 ton 4wd. Not anywhere like a kit that you are thinking about but he has a modern overdrive 5 speed tranny and a final drive that fits
the motor. The RWD portion is blocked off at the tranny. The 425 is the major problem with updating the GMC imo.

4- What about rotating the MOTOR instead of the tranny? The fuel injection shouldn't care but you'd probably have to modify the oil pickup and still
modify the oil pan.

5- From a kit standpoint, raising the hatch is much more viable than modifying the step for most folks.

Just a few thoughts from another fabricator.

--
Kerry Pinkerton - North Alabama

77 Eleganza II, 403CI, Manny Brakes, 1 ton, tranny, lots of aluminum goodies.

http://www.bdub.net/pinkerton/

'03 Fleetwood Discovery 39L
 
That 6.0 is still moving my 1999 GMC Sierra 2500 down the road quite well. Has also hauled a 4-ton travel trailer quite well, also. About 176,000 on the clock so far.

Rated HP was rated 300 @ 4800. Torque was rated 355 lb-ft; no RPM stated. Even that should move a GMC MH quite well.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
~~ ~ D C "Mac" Macdonald ~ ~~
~ ~ Amateur Radio - K2GKK ~ ~
~ ~ Since 30 November '53 ~ ~
~ ~ USAF and FAA, Retired ~ ~
~ Member GMCMI and Classics ~
~ ~ ~ Oklahoma City, OK ~ ~ ~
~~ ~ ~ "The Money Pit" ~ ~ ~~
~ ~ ~ ~ TZE166V101966 ~ ~ ~ ~
~ ~ ~ '76 ex-Palm Beach ~ ~ ~
~~ k2gkk + hotmail dot com ~~
~ www.gmcmhphotos.com/okclb ~
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
______________
|[ ]~~~[][ ][]\
"--OO--[]---O-"

________________________________
From: Gmclist on behalf of Jon Roche
Sent: Thursday, April 20, 2017 15:50
To: gmclist
Subject: Re: [GMCnet] new engines for the GMCs

I really dont know a thing. Other then being around 6.0 ls conversions in grand wagoneers. Prefect for those, but I just dont get how that
junkyard engine can pull around our coaches. Works perfect for the wagineers, but we are twice the weight. Must be some more performace upgrades
you had in mind other then taking a stock tahoe engine and putting it onto the 425? And at what price?
--
Jon Roche
75 palm beach
St. Cloud, MN
http://lqqkatjon.blogspot.com/

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To see the collection of prior postings to the list, visit the Gmclist Archives. Using Gmclist: To post a message to all the list members, send email ...
 
> Like I mentioned, great motors but they need rpm for the towing you're talking about. To get to our weight levels you would probably need a 4.1
> gear. At that rpm your economy wouldn't be much different than the present combination. You might be up with Manny's kit for money expended.
> Hal
And nobody ever seems to pay attention to the fact that the belt driven stuff hanging on the engine turn 34% faster with a 4.11 final drive from the
OEM 3.07.

If you don't change pulley diameters to compensate, you will need alternator, AC compressor, power steering and water pumps, not to mention belts, 34%
more often.
--
73 23' Sequoia 4 Sale
73 23' CanyonLands Parts Unit 4 Sale
Upper Alabama
"When I grow up I am going to be a curmudgeon."
 
Jim,

Well in Dave Lenzi's 8.1 Vortec powered Royale it likes 450 ft lbs.

http://www.gmcmhphotos.com/photos/aa-miscellaneous-photos/p36474-d-lenzi-27s
-81-front-frame.html

http://www.gmcmhphotos.com/photos/aa-miscellaneous-photos/p52884-dyno-run-vo
rtec-81.html

Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808

-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of James
Hupy
Sent: Thursday, April 20, 2017 1:54 PM
To: gmclist
Subject: Re: [GMCnet] new engines for the GMCs

Wonder how a tm 425 will like 500 foot pounds of torque? Probably not much,
I expect.
Jim Hupy
Salem, Or
78 GMC ROYALE 403
 
Mike,

Have you determined if the axle from the final drive to the passenger side
clears the main bearings and crank / rod throws?

Regards,
Rob M.
The Pedantic Mechanic
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808


-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Mike
Sadlon
Sent: Thursday, April 20, 2017 1:50 PM
To: gmclist
Subject: [GMCnet] new engines for the GMCs

Some of you may be following this from the Facebook page. I have been
looking into the viability of the LS engines for GMC motorhomes. Problem
number
one was getting the LS engine to hook to our 425 transmissions. The Panrail
on the LS interferes with our differential. I solved the connection
problem by rotating the transmission up about 25°. That allows clearance
around the Panrail and diff. The next problem was the transmission now
interferes with the step area. It could be worked around but it illuminates
a True Bolt-in situation. I have identified an aftermarket block that
would get us 427 in.³ relatively easily. And still fit in the stock
location. The target for the horsepower of this engine would be 450 HP and
500
pounds of torque. They can have late-model fuel injection and coil on plug
spark system. I'm ready for questions

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You guys are so good, but nobody has asked a question I haven't though about.

First lets do the general question about moving down the road, then I will address Kerry's excellent questions.
It takes X amount of energy to move Y mass vs drag/ mechanical load. It's why we get the same mileage no matter what gear we put in. The ls motors at
best are 5-10% more mechanically efficient than the 455. That's less than 1 mpg. If I find a way to get around basic physics, I won't ever hang with
you guy again, I'm going into space.

That being said, it takes around 100-125 HP (some smart peoples best guess. For reference my HHR SS only needed 40 hp to run 80 mph)to move our
coaches done the road. So if we had only 125, it might run 65, but it would take days to get there. So, as long as we stay in a range where the motor
can make 100 hp we will move down the road. Extra HP just makes it more fun to get there. The nice thing is modern fuel injection will figure that out
for us.

So the short answer is it will be fine, any gear you run. Look at your trucks, it will pull down the road that 4 ton trailer at 1800 rpm until you hit
a hill and need more power. Then it adds fuel until it can't compensate, then it down shifts.
 
> ...
> It takes X amount of energy to move Y mass vs drag/ mechanical load. It's why we get the same mileage no matter what gear we put in. The ls motors
> at best are 5-10% more mechanically efficient than the 455. ...
>
> So the short answer is it will be fine, any gear you run. Look at your trucks, it will pull down the road that 4 ton trailer at 1800 rpm until you
> hit a hill and need more power. Then it adds fuel until it can't compensate, then it down shifts.

I'd tend to agree. Our diesel pusher has 330 HP and 850 ft lbs of torque. I have an aftermarket product that hooks into the coach computers and
displays lots of stuff including HP and torque in real time. Even with a 26000 (empty) coach with the aerodynamics of a concrete block, it takes less
than 100 HP and 250 ft lbs of torque to maintain 55 on flat ground. Hit a hill and both numbers and gallons/minute of fuel rate go up and the 6 speed
Allison downshifts if the RPM gets down near the peak torque RPM (1550 RPM)...depending on which transmission mode I'm in.

My concern is how much torque the 6.0 (LS) has at 2500 RPM without a smart tranny and lots of gears and a lockout converter. While I can assure you
that my 1/2 ton with the 6.0 will cruise at 60 at 1500 (or less), as SOON as I hit a hill, the RPM goes up either because the lockout converter
unlocks or it downshifts. It's so smooth you can't tell unless you're watching the readouts but it does. The thing is, I don't know what it would do
if there was a way to hold it at 2000 RPM and try to accelerate without downshifting. I'm suspecting not that well but probably at least as good as
my 403. I also get about 18-19 on the highway. BUT, if I put any load on it due to a trailer the mileage tanks. Even an empty flatbed car hauler
(weights about 2000 lbs)causes mileage to drop to 10 mpg. Put a car on the trailer and expect 5-6 mpg. It will still skoot with the weight but might
go to 3rd at 60 and 5500 RPM which just ain't gonna happen with a 425 behind it.
--
Kerry Pinkerton - North Alabama

77 Eleganza II, 403CI, Manny Brakes, 1 ton, tranny, lots of aluminum goodies.

http://www.bdub.net/pinkerton/

'03 Fleetwood Discovery 39L
 
> Mike, first of all, I applaud your effort. If folks didn't ask 'what if', we'd still be riding horses. Go for it. I've thought of the same
> kinds of things myself.
>
> A few questions/comments.
>
> 1- What happens in the tranny when you rotate the pan so it's no longer level? Will there be any issues with fluid pickup etc? Manny is your
> go-to source for questions about that. The trans rotates around the diff centerline. the new pan just need to maintain the same effective level from
> the centerline, and volume. It will take a custom pickup.
>
> 2- I have a 6.0 in my '07 GMC Serria pickup. It has a 3.70 final drive and it will indeed make a lot of power but it makes it at 4000-6000+ RPM.
> With a 425 and 3.70 final drive, you're still going to be at 3000 rpm at 60mph and I don't know if that is the sweet spot for LS torque. The ls
> motor has one of the flattest toque curves out there. it will make all the power you need at any rpm. Hook a trailer to that truck and it will still
> run down the road in OD.
>
> 3- Hal StClair did a masterful job installing a diesel with motor tranny in his Royale. What he did was use the entire tranny and front wheel
> drive system from a 1 ton 4wd. Not anywhere like a kit that you are thinking about but he has a modern overdrive 5 speed tranny and a final drive
> that fits the motor. The RWD portion is blocked off at the tranny. The 425 is the major problem with updating the GMC imo. Yes, I have followed
> Hal's build and he indeed do a masterful job. But it as far from a bolt-in as you can get. I would like a kit where average skills could install.
> And I agree about the trans, we don not have reasonable trans option. But I believe we have reasonable engine options.
>
> 4- What about rotating the MOTOR instead of the tranny? The fuel injection shouldn't care but you'd probably have to modify the oil pickup and
> still modify the oil pan. I looked at that as I was rotating the engine around to find a balance that I thought would work. That combination
> required require the motor to be at about a 40 degree angle. I just don't think the average customer would accept that.
>
> 5- From a kit standpoint, raising the hatch is much more viable than modifying the step for most folks. I agree whole heartedly. It was Jeff Sirum
> who pointed the step issue. I was just about to mock it up on the frame he provided to me. The valve cover and intake and hatch are within an inch
> of each other. I would gladly give the step for hatch. I hope I can fab a bolt in part for the step.
>
> Just a few thoughts from another fabricator. It was great meeting you in Dothan.
 
BTW, I'm so glad you're discussing this here. I'm just not going to get into a technical discussion on FB. In addition, there are many, many very
knowledgeable folks here that simply do not, and will never do FB.
--
Kerry Pinkerton - North Alabama

77 Eleganza II, 403CI, Manny Brakes, 1 ton, tranny, lots of aluminum goodies.

http://www.bdub.net/pinkerton/

'03 Fleetwood Discovery 39L
 
Well that didn't work as planned.
I though my answer to Kerry where going to be in RED.
OK so read it carefully.
 
To answer the transmission, most of the computers I am looking at have the ability to unlock or lock a Lockup convertor. It would just be a matter of
a relay to down shift the trans and the programing to make it work.
 
As I keep expressing, I'm a big fan of LS motors. I swapped an LS6 into my 1965 Vista Cruiser, have a 402ci LS stroker in a 1963 Corvette and my Chevy
half ton has one as well. As Kerry states, they are fine on the level but load them at low rpm and they tank on low end torque and mileage goes into
the toilet. Its not an issue about enough HP it's torque that really does the work.
I still think your oil pan mods will be a real tough nut to crack. The LS is a deep skirt block and the oil pump is located up front so the pickup
runs to the rear through the pan. Just a quick look at mine and I see a real issue getting the right half shaft under the pan. Maybe using a dry sump
system could get you the clearance but even then it will be touchy. Have you actually measured for this critical dimension? Interesting study though.
Hal
--
1977 Royale 101348,

1977 Royale 101586, Diesel powered,

1974 Eagle Bus 45',w/slideout
 
Hal, can you get to facebook page. even if you hate facebook. I need to set up a GMC photo account, but haven't taken the time.
All my pictures are up there, on how the LS kit is going.

But the SBC/LS Motown block really has me going.
 
The 427 hybrid short block gets my attention. not cheap, put all your low end torque thoughts go out the window.
There is no problem cubic inches and dollars does not solve.
 
> ... It was great meeting you in Dothan.

I remember you now Mike. (I cheated and looked at your FB photo) Aren't you the ex HP guy?

--
Kerry Pinkerton - North Alabama

77 Eleganza II, 403CI, Manny Brakes, 1 ton, tranny, lots of aluminum goodies.

http://www.bdub.net/pinkerton/

'03 Fleetwood Discovery 39L
 
> > ... It was great meeting you in Dothan.
>
>
> I remember you now Mike. (I cheated and looked at your FB photo) Aren't you the ex HP guy?


HP?
 
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