GM Semis

[Bob B.]

You could make a pretty good case that GMC intended the V-6 to be either gas or diesel almost from the beginning. From what I understand, the V-6 family was intended to replace all the GMC built straight 6 gasoline engines along with the Pontiac and Oldsmobile V-8's that GMC was using the late 50's. Concurrently there was another program to develop a 4 cycle mid-range diesel engine, and at some point it merged into the V-6 program. The result was the Toro-Flow. Very true the Toro-Flow had problems (particularly the early versions) but so did most of the other big bore, short stroke mid-range diesels of the era, like the Cummins V-6 and '555' V-8. We could have a pretty good discussion about what was wrong (and right!) with the Toro-Flow. I may have mentioned in the past that I volunteer at a railroad museum, and we have a functioning D478 Toro-Flow in a bus. I'll post more about my experiences and what I have learned over the years about these oddball diesels in the next few days.

[factorystock]

Originally Posted by Bob B.

You could make a pretty good case that GMC intended the V-6 to be either gas or diesel almost from the beginning.

GMC wasn't the only one with this interesting concept, White Trucks called it a "giesel". This was a 470 cu in gas V8. One premium feature that the White engine had and the GMC gas engines did not have, was the "wet sleeve"

[Bob B.]

Originally Posted by factorystock

GMC wasn't the only one with this interesting concept, White Trucks called it a "giesel". This was a 470 cu in gas V8. One premium feature that the White engine had and the GMC gas engines did not have, was the "wet sleeve"

That there was an idea that didn't pan out! The 'Giesel', sometimes called the 'Mustang VIII', was a small Cummins V-8 diesel modified to run on gasoline. It had lower compression pistons, spark plugs in the injector holes, and a Holley 2 bbl. carburetor. Needless to say it wasn't very efficient and sales were very low. I don't know if the engines were manufactured by Cummins or White. The Giesel was only around for a year or two.

[factorystock]

Originally Posted by Bob B.

We could have a pretty good discussion about what was wrong (and right!) with the Toro-Flow.

The improved version was the Toro-Flow 11. This article shows what was done for durability over previous versions. Maybe too little, too late?

[Bob B.]

Originally Posted by factorystock

The improved version was the Toro-Flow 11. This article shows what was done for durability over previous versions. Maybe too little, too late?

Possibly, but the new head gaskets and revised max R.P.M. governor setting addressed 2 issues the engine had. The Toroflow certainly had it's share of problems but so did most of the competitive mid-range diesels of that time, like the small Cummins V-6 and V-8's, the Ford Dagenham and Dorset, and the Internationals. In fact about the only reliable mid-range diesels back the 60's were the Detroit 53 series engines. A lot of the problems were caused by operator error. Engine overspeeding, poor quality fuel, improper maintenance, and overloading. Overloading was also caused in part by dealers, who would spec. trucks with a Toroflow to win fleet bids. Toroflow diesels were inexpensive compared to a lot of heavy duty diesels but equaled many larger diesels in H.P. and torque. Around the time the Toroflow II came out the engine was also dropped from the higher GVW trucks. Eventually the 220 H.P. DH 637 V-8 Toroflow was discontinued as well.

[C10 - C90 Bill]

Originally Posted by Bob B.

In fact about the only reliable mid-range diesels back the 60's were the Detroit 53 series engines.

Good 'ol Detroit.

[C10 - C90 Bill]

The thing that puzzles me about a Diesel in a '60 or newer GMC Conventional is their choice. The Detroit was the engine of choice in a GMC. Yet, the only way to get a Detroit in these trucks was to buy a Chevrolet (offered later on in the years of the '60-'66 trucks) In my opinion, they should have offered a 4-Cylinder Detroit in them from the beginning.

When I was driving my '62 6500 with the 478 Gas, there was a Chevy C-50 or C-60 in our same neighborhood at the same time. It was about a '65. It made me feel I had the lesser of the two, lol.

[Bob B.]

Originally Posted by C10 - C90 Bill

The thing that puzzles me about a Diesel in a '60 or newer GMC Conventional is their choice. The Detroit was the engine of choice in a GMC. Yet, the only way to get a Detroit in these trucks was to buy a Chevrolet (offered later on in the years of the '60-'66 trucks) In my opinion, they should have offered a 4-Cylinder Detroit in them from the beginning.

When I was driving my '62 6500 with the 478 Gas, there was a Chevy C-50 or C-60 in our same neighborhood at the same time. It was about a '65. It made me feel I had the lesser of the two, lol.

That's a good point! In 1962 Chevy introduced their first diesels and they were all powered by 53 Series Detroits, both 4 and V-6's. The 53's didn't show up in GMC trucks until the 1965 DB5900, a one-year oddball version of the Chevy E80 that was replaced in 1966 by the HV/JV 7500. The 4-53 was also offered in the GMC 4000 series conventional in 1966 only. So while GMC always had the larger 71 Series Detroits, in the mid-range trucks they certainly seemed to favor the Toro-Flows. Only reason I can come up with was the the Toro-Flow was a Truck And Coach Division 'internal' product. Chevy had no allegence to either the Toro-Flow or Detroit, they were both produced by other GM divisions. Good for Chevy, I think the 53 Series were the best mid-range diesels of the era.

[C10 - C90 Bill]

Originally Posted by Bob B.

That's a good point! In 1962 Chevy introduced their first diesels and they were all powered by 53 Series Detroits, both 4 and V-6's. The 53's didn't show up in GMC trucks until the 1965 DB5900, a one-year oddball version of the Chevy E80 that was replaced in 1966 by the HV/JV 7500. The 4-53 was also offered in the GMC 4000 series conventional in 1966 only. So while GMC always had the larger 71 Series Detroits, in the mid-range trucks they certainly seemed to favor the Toro-Flows. Only reason I can come up with was the the Toro-Flow was a Truck And Coach Division 'internal' product. Chevy had no allegence to either the Toro-Flow or Detroit, they were both produced by other GM divisions. Good for Chevy, I think the 53 Series were the best mid-range diesels of the era.

We were talking '60 to '66 the other day, but the same for '67 to '72. It would have been great to see GMC have a 4-53 available in one. Same for the '73 and newer as well. The first time I saw a 4-53 in a '78 Medium, I remember saying "It's about time"!! Finally, but only 18 years late. Only lasted 2 years though as I believe the EPA phased them out. Would had been a nice 20 year run though. And think of all the cool trucks that would still be around today with that great Detroit power.

[special-K]

I'm not sure the exact year on this one. Mid '20s I think. Maybe first year

[Bob B.]

Yes, the 4-53 was available in Chevy and GMC C series mediums from 1978 to about half-way through 1980, when it was replaced by the Detroit 8.2L. There was a lumberyard near me that had a few C-6500's with 4-53T's in them. Man they were noisy, sounded like they were going about twice as fast as they actually were.

[factorystock]

Originally Posted by Bob B.

Man they were noisy, sounded like they were going about twice as fast as they actually were.

I agree, that is what I recollect as well. It seems they were always being rev'd out to get the torque from of the small 212 cu inch engine.

[KQQL IT]

Gasoline forever

[C10 - C90 Bill]

Nice looking 7500 Tandem.

It's either a '68 or '69.

[special-K]

This thread fuels my love for old GM Trucks! It's been a real gas looking at all the pictures. (gaggin' on the corn over here)

[KQQL IT]

My favorite 54-55.5 AD trucks

Few fb grabs

[Bob B.]

An Astro 95 with a KT 450 Cummins. Wonder how many of those were built.

[KQQL IT]

Originally Posted by Bob B.

An Astro 95 with a KT 450 Cummins. Wonder how many of those were built.

At least one, and probably one of one.

[special-K]

Isn't that orange dump gorgeous? Sure is sharp anyway

The Cummins KT is a well respected engine for sure. Sure seems odd to see an Astro run one. That Mayflower gas job is hard to imagine these days. Twin tanks on this side. I wonder about the other side.

I wish I could see a picture of this Budweiser boat hauler

[Bob B.]

This is for C10-C90 Bill, special-k, KQQL-IT, and factorystock. I hope the rest of you enjoy it as well:

[factorystock]

Originally Posted by Bob B.

I hope the rest of you enjoy it as well:

Thanks for posting, nice crisp engine shot. Good observations, indeed engine destined for a tilt with the LV chalk markings. Note how the silver "W" engine is not painted Chevy orange, must be a shock to car people. IMO, must be a pre '66 photo, '65 was the last year of the 348 and 409 for Chevy, in '66, Chevy offered the new 366 and GMC 401 and 478 in their heavies.

[C10 - C90 Bill]

Impressive.

I was trying to see mine there with the Road Ranger behind it, lol.

Thanks for the picture.

[Bob B.]

Originally Posted by C10 - C90 Bill

Impressive.

I was trying to see mine there with the Road Ranger behind it, lol.

Thanks for the picture.

I was looking closely at the first V6 in the picture. 'LV' is written on the oil pan, and notice it has a crank-mounted fan, long heater hoses, a hydraulic clutch, remoted control shifter on the transmission and no air brake compressor. Just what you would expect the engine to have if it was going into an LV5000 (tilt cab with vacuum brakes). Behind that V6 is a Chevy High Torque 409. Since the GMC V6's were all made in Pontiac and the 409's came from Tonawanda I suspect the picture is of an engine dress line at a truck assmebly plant, not an engine plant.

[KQQL IT]

Neat comparison

[KQQL IT]

Since I'm finding gold