[GMCnet] Balance your system

[Mike Sadlon]

Let's have some fun!

Let's start with a base line, the stock 455 3.07 gear package.
One thing we don't talk about much is torque converters. And what I want to talk about the effectiveness of balancing your power train system.

This will not be about mileage. I think most agree, it's about 125 HP to run them down the at 60 mph. That is going to take X amount of Gas. To get
more MPG we need to burn the fuel more efficiently or use a more powerful fuel(diesel). If you know of a way to get fuel to burn more efficiently in
any motor that will fit in a GMC let me know. I remember reading that in the fuel injection age, the top engineers have only got about 5% more
internally efficient motors.

So for our project today,let's create a baseline. Let's call it torque for acceleration. TFA.
For the discussion we need to establish a few things. First, that we don't spin our tires from a WOT start. I know most can. 2nd, our stall speed on
our stock torque converter is 1800 rpm. If someone knows for sure that was not the origanal new number let me know. How do I think that is the correct
number. Go back to 1973, we were in a 55 mph speed limit. with the stock 3.07 gear 55 cruise would have been 2090 rpm. I have been told since 1975 on
a non lockup converter, stay 200-300 below your cruise rpm so the trans does not slip excessively and over heat. Higher gear more stall. Remember
this, it's important later. Also the torque multiplication of average converter 2.5.

Let's make our baseline.

torque at stall X first gear ratio X final drive ratio = TFA

1. Stock 455. 350(stock 455 at 1800 from Jim's dyno chart) X 2.48 X 3.07 = 2665 TFA

2. Stock Caddy. 400(from what I can tell form Cadco site Caddys make about 50 more across the range) X 2.48 X 3.07 = 3045 About a 15% increase. That
power you feel in the seat of your pants. No bolt-ons (headers intake)on the 455 will give you that much. Maybe 35-40 at that rpm range. So why didn't
GM just put in the Caddy. My guess, the peak torque of the Caddy at 500+ way more than they though would live in front of the 425 under the heavy load
of the GMC.

3. Add a gear to Stock 455. 350 X 2.48 X 3.50( a lot of people like this gear)= 3038
About the same as the Caddy. And according to sources the gear they wanted to put in but didn't. And the same lesser load on the transmission.

4. It's 2017 and we know we cruise a little fast let's use 65 mph. New cruise rpm 2470, so new stall speed is 2100 rpm. About 400lbs from Jim's sheet.
So with just a torque converter change it would feel like the Caddy. 3045 TFA

5. Lets add a Gear. 400 X 2.48 X 3.50 = 3472 That's a 30% increase! That's more than seat of the pants!

6. Let's get it all. I know I like to run at 70. Right at 3000 rpm with 3.50 gear. Lets put in a 2500 stall converter.
450(from jim's chart and right around max} X 2.48 X 3.50 = 3906 TFA That's a 47% increase and we never touched the motor!

FYI the switch pitch convertor is about 1800 low and 2400 high from what I find. And as side note, my switch pitch will not normally spin the tires in
low, but under the same conditions will spin in high.

So what is this all about?

Balancing your system. Most agree that GM didn't even do it right in the beginning. We got a 47% increase in feel, and didn't touch the motor. No
added load to the transmission. The only concern would be running in the slip range of the converter. and if you don't monitor your trans temp now,
you should be. And even cruising in the slip range won't be that bad. Remember stall is a function of load input.

Or as I like to look at it, it takes 47% less to move the same load.

Somebody said something about luging the HT383 that I am proposing. We are already luging our 455, not to mention the poor 403s.

Reducing the load on your engine, I don't care which one, is going to make it last longer.

Rock away!


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[Johnny Bridges via Gmclist]

Well, first, nobody said it won't work, it almost certainly will. As an economic substitute for the 455, currently it almost certainly ain't.
Whether it will be in the future is open to speculation. If you want to run the converter in a high slip situation, knock yourself out, I'd rather it
was above the stall speed. Lockup converters certainly weren't developed because they're cheap. Let's get close as we can with what we have. As to
lugging the engine, I'd really rather load the hell at low engine speed out of something with a lot of bearing surface to spread the load, as opposed
to a smaller area which does better at high engine speeds I'm never going to see in this service.
From a theoretical point of view you'd much rather have an electric traction motor a la locomotive, except the current ways of doing that are
prohibitively heavy for a road vehicle. After all, it develops maximum torque at zero rpm. Problem is, the very weight which helps the locomotive
hinders the GMC.
In practice, a far greater worry than engines is/are the THM-425. Some of the hard parts are no longer available. There are a hell of a lot more 455
Oldsmobile and 472/500 Cadillac motors available for rebuild than there are THM-425 transmissions. No one to my knowledge is making chains or
sprockets. It's turning 'backwards' so you have the option of cutting helical gears the other way, or taking the thrust at the other end. There
ain't any more of many of these pieces.
We can argue the Turds will fail... but there are parts. We can argue the 383 isn't designed for this service - but if it is short lived there are
plenty more. The elephant in the room is the THM-425. There ain't any more.

--johnny
--
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" - ol Andy, paraphrased

[Rob Mueller]

Johnny,

You have hit the crux of the matter, I visited Manny on the way back to
Sydney in April and he noted that when he started working on TH-425's he
bought enough spare parts to build 500 transmissions. I can't remember the
exact number but I am pretty sure at this point in time it was way less than
100.

I am of the opinion that back in the 60's and 70's Detroit over engineered
"stuff." One can get heaps more HP and TQ out of the engines of the period
and the rest of the driveline would take it IF you didn't abuse it.

I really don't understand the penchant to have huge HP / torque available in
a GMC, it's not a race vehicle; it's a vacation vehicle.

Double Trouble has a 455 Olds that was rebuilt by Ken Frey over 80,000 miles
ago and will cruise all day long at the speed limit (60, 65, 70, or 75)
through a tranny he rebuilt at the same time and a 3.21 to 1 final drive I
installed.

I have a "policy" of staying in the right lane unless I want to pass. When
I'm at a stop light I accelerate at a reasonable pace to the speed limit.

It has been noted that one needs the HP / TQ when climbing mountains,
however, just how often does one climb mountains?

To me it's all about reliability and longevity.

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

[Kerry Pinkerton]

Mike, Johnny, and Rob...I agree with all of you.

Mike, your 383 will definitely work...it's only 20 cubic inches less than a 403 after all. How well it will hold up? Who knows. Build one and test
it. I totally agree with your comments regarding final drive ratios. When I put 3.70s in my coach it REALLY woke it up.

Johnny is also correct. TH425 is the weak link. A 4-5 speed automatic would do wonders for drivability.

I drive like Rob. If I want to go fast, I'll drive the roadster.

--
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

[Johnny Bridges via Gmclist]

I've no problem with engine swaps as an exercise in ingenuity. It's from this sort of action we get progress. I've seen them both well done and
poorly done. It looks as though the one being discussed will show some ingenuity - tilting for clearance, developing (hopefully) cooling fan(s) up to
the job, etc. This kind of exercise is best done by an individual with the hotrod mentality - note the cost of some of the stuff done by the
commercial shops. Six figures because of the labor costs. Work it out under the shade tree and then kit it and it becomes closer to reasonable in
price. What's needed for the GMC though is a viable transmission because the one we have will soon be unsupportable.
The options appear to be extending the engine room rearward to accommodate a transmission behind the engine, or go to a transverse setup for the
powertrain. While I admire the ingenuity of the swappers, I'd sure like to see it applied to transmission swaps.

--johnny
--
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" - ol Andy, paraphrased

[John R. Lebetski]

In the real world, with high vacuum light throttle and 3.07, the first event is long torque converter slip to launch the vehicle and speed match. Then
the shifts come fairly quickly with not a huge amount of power transmitted through the shifts in terms of RPM drop (unlike a TH700 where lots of RPM
drops at 1-2) Then you are in 3rd at a relatively low speed and 1-1 other than converter slip %. This in not like today's vehicles with less
displacement and constant gear hunting 9 speeds. Driven as above they last a long time. However, pull off to a rest area and then try to merge back to
75MPH truck traffic from a short 90 deg ramp that has an uphill grade and you are at the other extreme. Here the trans has to take the WOT power but
at high road load, so shifts will be firmer, good to eliminate clutch pack wear but harder on other components. But these are short "blasts". Then get
into a 15min 6 deg grade situation and it's about long term heat disipation, initially engine but very soon the entire powertrain systems ability to
shed heat. This will be the real test to see if it can function as a total system design. Running out of capacity in any part of the system is the
limiting factor in getting up and down the grade. So with any transplant, you have start over with 'Desert proving grounds reenactment' to see what
is discovered. Hard to armchair guess what the results will be. Perhaps the new engine may have worse engine braking on the long downhills, and may
require higher tan expected numerical gearing to compensate.
--
John Lebetski
Woodstock, IL
77 Eleganza II

[Ken Henderson]

During all of this discussion, no one has addressed the other, definitely
related problem: The front suspension. Even if one does an engine change,
at considerable expense, and finds a way to replace the transmission, at
probably greater expense, the "One-Ton" is still needed. Seems to me, the
only really logical way to attack all three problems is to replace the
whole front clip. The only one I've ever heard address that is NASCAR
veteran Barry Owen, who's said he intends to build his own frame for his
GMC. I think others of our younger, innovative owners should combine their
efforts, perhaps with his, to tackle the whole job.

A completely new front frame, with properly positioned (perhaps "moveable")
pivot points for the A-frames, provisions for the correct motor mounts for
the "new" engine and transmission, designed to interface directly with the
OEM side rails, etc, would offer many benefits. Not the least of those
would be elimination of the too-common internal rust being found in the
front clips. With a new design, the front A-arms could be custom or from a
sure to be available "forever", donor. Increased caster capability would
definitely be a requirement. Use of more modern torsion bars, and,
perhaps, provisions for air bags would certainly be desirable. Since the
later GM torsion bars are available in a wide range of spring rates, it
might be worthwhile to use light torsion bars along with air bags to
provide some dynamic adjustability -- a major mod to the existing frame,
but relatively simple in a new design. A new frame might also include
provisions for a widely available donor radiator, eliminating the necessity
for the custom design we now have. The OEM front clip is sufficiently
modular that a replacement could be a direct bolt-in with no other changes
required.

Granted, it would be a MAJOR undertaking, but I'm not sure it would be that
much more than the three "MINOR" mods combined. The integrated approach
should result in far fewer compromises than the piece meal route everyone's
followed so far.

Ken H.

[Rob Mueller]

Kerry,

IMO the question is will the tranny that Mike suggested hold up being
transferred from a passenger car to a 12,000 pound GMC?

The TH-425 did it because as I noted it was overdesigned.

If I want to go fast I ride my 2003 Ducati S-4 Monster with 120 HP at the
rear wheel! :-)

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...@list.gmcnet.org] On Behalf Of Kerry
Pinkerton
Sent: Saturday, June 10, 2017 10:17 PM
To: gmc...@list.gmcnet.org
Subject: Re: [GMCnet] Balance your system

Mike, Johnny, and Rob...I agree with all of you.

Mike, your 383 will definitely work...it's only 20 cubic inches less than a
403 after all. How well it will hold up? Who knows. Build one and test
it. I totally agree with your comments regarding final drive ratios. When
I put 3.70s in my coach it REALLY woke it up.

Johnny is also correct. TH425 is the weak link. A 4-5 speed automatic
would do wonders for drivability.

I drive like Rob. If I want to go fast, I'll drive the roadster.

--
Kerry Pinkerton - North Alabama

[Mike Sadlon]

If we can, so we don't confuse the more lay people.

Let's try to keep this thread on our currant engine and trans package and the value that gears and convertor can add.

The sideways thread talks about the 4t80e, and I address some concerns there.

Ken absolutely completely and yes, yes yes. I will start a new thread based on your post.

A lot of things have changed over the last century, but one horse power is still a fact, one horse power.

[Johnny Bridges via Gmclist]

Ken is moving to the Final Solution. You need to have the front wheels in vaguely the same place... and fit in the available space. That space is a
lot bigger and more friendly when whatever you put there has only to fit the frame in the rear. The Germans already build a coach on the ProMaster
gas chassis. With the Mopar many-speed transmission, you wouldn't worry that it has to wind up pretty good to make pull. Or maybe Fiat/Chrysler will
show one with the V-6 MotoVittori engine...
Speculation is fun. Who has a welder and a sawzall and a wrecked van?

--johnny
--
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" - ol Andy, paraphrased

[rich...@comcast.net]

Ken: I agree. Clean piece of paper approach needs to be considered. Definitely an opportunity to learn from 40 years of field testing. I would be willing to build the welding jig for the new front clip. I suggest setting up a user group and start the collaboration.
Just an observation.
A while ago, I visited India on a service call to install semiconductor equipment at a solar cell factory over there. While there, I noticed a truck, that appears to be at least 1 1/2 ton size from a company called 'TATA' that was front wheel drive. I found out that 'TATA' only made the front half, and sold the incomplete vehicle to anybody who added their own rear frame, bed, box, etc. Don't know who 'TATA, buys their transmissions from,but I would guess it is ZF. One of the requirements for any project like this is to stick with a single supplier, like GM, for all the bits and pieces. If Mary Barra (CEO of GM) has her boys working on a front wheel drive truck, of adequate size, that would be the way to go.
I intend to enjoy our coach, but also to pass it along to our children, when we can't use it any more. I want to do the updates for them as well as for me. My list of things include:
ABS brakes
Better instrumentation
Diesel power

Blue Sky things
Siemens Electric drive system in the coach, just like Tesla


----- Original Message -----

From: "Ken Henderson" <hend...@bellsouth.net>
To: "gmclist" <gmc...@list.gmcnet.org>
Cc: "Johnny Bridges" <jhbr...@ymail.com>
Sent: Saturday, June 10, 2017 7:01:56 AM
Subject: Re: [GMCnet] Balance your system

[jhb1]

Have a look at this for your blue sky option

http://www.tm4.com

--
John H. Bell
77 Royale; QuadBag,Manny OneTon,Honda EV4010, FITech
Montreal Qc.

[Matt Colie]

richshoop wrote on Sun, 11 June 2017 20:23

> Ken: I agree. Clean piece of paper approach needs to be considered. Definitely an opportunity to learn from 40 years of field testing. I would be
> willing to build the welding jig for the new front clip. I suggest setting up a user group and start the collaboration.
> Just an observation.
> A while ago, I visited India on a service call to install semiconductor equipment at a solar cell factory over there. While there, I noticed a
> truck, that appears to be at least 1 1/2 ton size from a company called 'TATA' that was front wheel drive. I found out that 'TATA' only made the
> front half, and sold the incomplete vehicle to anybody who added their own rear frame, bed, box, etc. Don't know who 'TATA, buys their transmissions
> from,but I would guess it is ZF. One of the requirements for any project like this is to stick with a single supplier, like GM, for all the bits and
> pieces. If Mary Barra (CEO of GM) has her boys working on a front wheel drive truck, of adequate size, that would be the way to go.
> I intend to enjoy our coach, but also to pass it along to our children, when we can't use it any more. I want to do the updates for them as well
> as for me. My list of things include:

> ABS brakes <= Are common these days **
> Better instrumentation <= A Glass Cockpit is OE in Detroit **
> Diesel power <= Is still a problem as far as ROI in an RV **
>
> Blue Sky things
> Siemens Electric drive system in the coach, just like Tesla <= IC/EV maybe, but not EV only in the places we like to go

Rich,

Tata Was Telco - Tata Engineering and Locomotive. They, like Mahindra, were well positioned when India went to an open economy. Now that imports are
allowed, (they always were, they were just taxed into oblivion) the locals had to start making other than over priced junk (like 3kW diesel mopeds).
The do use a lot of foreign content, but are gearing up to bring those jobs home. And all with no local pollution standards.

You will not see a Tata anything in the states for a long time. Those cab-only don't even come close to passing the standards required for sale
here.

I would like ABS, and I actually had a line on a six wheel processor at one point. Then I got seriously looking into implementation and it was both a
cost and a mechanical impractical plan. <<Aw Chit>>
but the new families of turbo-charged engines should also be altitude compensated and that was the big gain of diesels. The real reason the big
coaches are diesel is that there are no more big SI engines produced.

Matt

--
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

[rich...@comcast.net]

Regarding the ABS, the one ton front conversion uses a bearing pack that can have a ABS speed sensor installed. I also think that an aftermarket ABS kit? would be a legal nightmare for whomever provided parts and hints. I still want it though. We had a Winnebago Rialta that had ABS. The ONE time I needed it, it did turn a real emergency stop into a non-event.
As far as the 'TATA' truck, I was considering only the transmission, not the very dirty engine as well.
One of the things I keep reminding myself is the design lifetime of a mid 1970's vehicle has to be 10 to 15 years. Ours are now 40+ and by hook and crook we can still get parts. Any significant upgrade has to be done with initial cost considered, but also the longer term parts availability. Using the One Ton Front Conversion as an example. Eliminating special bearing sets that are not made any more except by special order, and the special seals, and the service interval of less than 5,000 miles. Now the front end uses standard parts, used by 10,000's of trucks, made by many manufacturers, longer service interval, bigger disk brakes. That is what I think the measure of any upgrade project should be.

The one off upgrades that our very creative owners do however are not to be ignored. Until someone does the particular conversion there is no knowledge about the details. i.e. To do this engine swap it required the engine to be tilted, and a new oil pan fabricated, as an example. The person who did the conversion and shared what they found provides those doing other conversions with additional things to consider without wasting time and money learning the lessons all over again. I view the GMC Motorhome owners as part of an 'Open Source Hardware Project' where we all can contribute, benefit, and keep these magical things on the road.
----- Original Message -----

From: "Matt Colie" <matt7...@gmail.com>
To: "gmclist" <gmc...@list.gmcnet.org>
Sent: Monday, June 12, 2017 6:02:50 AM
Subject: Re: [GMCnet] Balance your system

[John R. Lebetski]

If you want to drive a TATA here, just buy a Jaguar as they bought them out several years ago.

--
John Lebetski
Woodstock, IL
77 Eleganza II

[Johnny Bridges via Gmclist]

Jaguar: "John Lucas, Prince of Darkness". Hopefully the Indians make more reliable electrics.

--johnny
--
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" - ol Andy, paraphrased

[Hal StClair]

It's the reason the Britt's drink warm beer-Lucas refrigerators.
Hal
--
1977 Royale 101348,

1977 Royale 101586, Diesel powered,

1975 Eleganza II, 101230

1974 Eagle Bus 45',w/slideout

[Mark Sawyer]

Hal StClair wrote on Tue, 13 June 2017 23:46

> It's the reason the Britt's drink warm beer-Lucas refrigerators.
> Hal

Lucas refrigerators and Girling door seals... ;)

Always amazed me that a country that gets as much rain as GB, makes cars that have so many issues with leaks....

Speaking of Jaguars, I was researching vapor lock a while back and came across a factory "Fuel Cooler" used on Jags in the 70s and 80s. Cooler works
by pumping fuel into a jacket that surrounds the AC evaporator line... Not sure what Jag drivers that did not opt to equip their cars with AC would
do when it was hot out, but there you go...

https://www.jaguarclassicparts.com/uk/jaguar-xjs-v139052-v179736-parts/air-and-fuel-delivery-systems/fuel-cooler/fuel-cooler-5-3-litre


--
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX

[Johnny Bridges via Gmclist]

And I got it wrong - Joe (Joseph) Lucas it was.

--johnny
--
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" - ol Andy, paraphrased

[Keith V]

Lucas the prince of darkness LOL

________________________________
From: Gmclist <gmclist...@list.gmcnet.org> on behalf of Johnny Bridges via Gmclist <gmc...@list.gmcnet.org>
Sent: Wednesday, June 14, 2017 10:44:23 AM

To: gmc...@list.gmcnet.org
Cc: Johnny Bridges

Subject: Re: [GMCnet] Balance your system

[James Hupy]

Years ago, I had a 500 cc BSA Gold Star single cylinder Motorcycle. It was
set up as a scrambles and flat track bike. I personally never experienced
this, but MANY other racers had the lonnnng spindly connecting rod part
company with the piston and crankshaft, and ventilate the engine cases,
whereupon it encountered the Lucas Magneto. It would destroy the magneto,
and the racers would always describe the engine failure cause as, "Magneto
Failure, due to the Lucas Mag". Those mags were so poor that you could not
see the spark they produced in bright daylight. You needed to shade the
plug to see if it was sparking. Such was the state of the electronics in
those days. There was a lively aftermarket for replacements during those
times. Some of the motoplat and Absvenska mags were great stuff compared to
the Lucas Mags. Lighter too.
Jim Hupy
Salem, OR
78 GMC Royale 403

[Johnny Bridges via Gmclist]

I put many many miles on that scooter's successor, the Victor Special. At 440CC it had a bit shorter stroke and a stronger connecting rod. And
leaked three different weights of oil at every seam. The old thumper was my favorite bike of many I've owned.

--johnny
--
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" - ol Andy, paraphrased