GM 270 ci Engines

[jim sewell]

I am trying to find the differences between the engines if any that were fitted to ,

C60X
Staghound
CCKW 6X6
C15TA
The crankshaft on the staghound is different than the CCKW in the Front pulley mounting and crank dog
The staghound block has 4 bolts on the rear main bearing where as the CCKW has 2 bolts
Have not examined a C60X engine but It's engine number starts with 270 #### , same as the CCKW , whereas the staghound starts with ACR#### or ACL#### ( I assume means left and right hand engines ) why did they have left and right hand engines ?
Are the pistons the same ( does some one have a parts book which will give a number for a std piston )
I have seen staghound engines fitted to CCKW and C60X so obviously the blocks are the same .
I would appreciate some information so as to satisfy my curiousity
Regards
JiM s.

[Lynn Eades]

I dont know about this specific situation but some times the factory produces reverse rotation engines. in marine aplications motors are sometimes supplied as left and right. the differences being in camshafts and crankshaft drillings. I have also seen a reverse rotation Chrysler 318 in a Clarke forklift.

[Hanno Spoelstra]

Hi Jim,

The thread GMC 270 engine in CMP vehicles might be of interest to you.

Regards,
Hanno

[David_Hayward (RIP)]

CHEVROLET STAGHOUND ARMORED CARS
FLINT, MICHIGAN # 2 PLANT ASSEMBLED T17E1/ E2 SERIES

“ARMORED CAR, MEDIUM, 4 x 4, CHEVROLET, M6 (T17E1,etc)”,
approximately 3,800 produced 1942-1944

Engine #s: # ACR 1001 and # ACL 1001 and up [for "Armoured Car"? and “Right” and Left” respectively]
[presumably to # ACR4802 and # LCR4802]
Transmission #s “1” for 1942, “2” for 1943, “3” for 1944 – AC- 1 and up

I assumed that the engines were handed because of linkages, manifolds, etc. and not because they had opposite-rotating cranks. However did they counter-rotate into an common transmission coupling?

[Hanno Spoelstra]

Originally posted by Hanno Spoelstra
The thread GMC 270 engine in CMP vehicles might be of interest to you.

Also see C60X workshop manual.

H.

[jim sewell]

Thanks Gents for your replies .

From what I can gather is that the Stag engines had the same rotation as each other but as stated earlier by David that it was the ancillaries that determined if it was a left or right and this would have included the sump with its cooler fittings .
These engines would have been packaged as a left and a right engine and if replacement was required then the correct engine was selected and fitted in the field if necessary .

The compression ratio for a stag engine and a CCKW are the same ( 6.75 ) and the piston part numbers for the CCKW and the C60X are the same .
Do not have any part numbers for a stag std piston .
I have heard that the stag exhaust valves have a greater valve margin ( thicker head ) but have no prove , again would like a part number of a stag exhaust valve .

as you a probably aware the stag engine was coupled to two hydramatic transmissions and then on to a common final drive unit .

[David_Hayward (RIP)]

Chevrolet elected for the G.M.C. 270 engine made in Pontiac, Michigan, with the Chevrolet Gray* Iron foundry in Saginaw, Michigan, casting the cylinder blocks and probably the heads: Pontiac was busy with the demand for GMC trucks and also the Canadian contracts, and so Flint Motor Plant co-produced the engines with Pontiac and each plant machined blocks that were delivered to them with minor differences. The two 270 units, Right and Left, produced 97 b.h.p. at 3,000 r.p.m., but with 24 volt ignition and not 6-volt and with fluid couplings to a common transfer case [model 3670164] which, with the axles [front Chevrolet 3670077 with Bendix-Weiss drive ends and rear Chevrolet 3670075], were made by Chevrolet, with steering gear [Saginaw 580-DH-3] made by the Saginaw Steering Gear Division Plant in Saginaw, Michigan, though transmissions were built by the Detroit Transmission Division in Livonia, Michigan. The Handbrakes were mechanical, actuating on the transmission, and the chassis was equipped with 14.00 x 20-inch tyres all round.

Whether Pontiac, MI and Flint Motor Plant, MI produced handed engines I have no idea though it strikes me as being very unlikely.

*I am sure it is in fact spelt G-R-A-Y and not G-R-E-Y...how do you Canadian friends spell the colour?

[David_Hayward (RIP)]

Whilst Walkerville/Windsor Transmission Plant did not produce any GMC 270 engines, they did produce indigenous 248 cu. in. 33.19HP GMC engines from August 1940 to June 1941: 6,573 in 1940 and 10,464 in 1941. These units were projected to be used in DND-pattern trucks by GM of Canada in the summer of 1939 but were in fact only used in certain GMC and Maple Leaf trucks. I believe that some of these were acquired by the DND. Serials ran # G-1001 and up for 1941 Model Year, after which all 248 units were imported from Pontiac, MI. In addition there was of course the Chevrolet-based 224.1 cu. in. six that was used in Canadian Pontiacs and some GMCs.

[jim sewell]

Thanks for you input David .

I will endevour to find a Staghound parts book and check the engine part numbers against the other vehicles the 270 engine was used in .

Jim S.

[jim sewell]

I set out originally to find the differences ( if any ) between the engines fitted to CCKW'S , C60X and Staghounds .

After researching the various parts manuals I have come to the conclusion that there is very little difference in the three engines in their different applications , the crankshaft being the main one .

Jim S.

[marco]

Hi Jim,

I am not an expert on C60X or C15TA engines, but I have rebuild a Staghound AC which took me 10 years to finish, so I know something about the engines used in this car.
Serial numbers start with ACL-1001/ACR1001.
Don't know how many engines were made but I have a (spare) engine with serial ACL-9306.
Actually, there is no difference between ACL and ACR stamped engine crankcases.
The main difference between L&R engine assembly's is the location of the generator but ACL as well as ACR stamped cases have lugs on both sides to mount the generator.
So you can take an ACL stamped engine and assemble a right hand version from this.
Both engines have the same (right-hand) rotation.

Pistons, connecting rods+bearings, main bearings, camshaft gears and cylinder heads are the same as used on GMC-CCKW engines.
All the rest is different.

Stag standard piston no is G122-03-38698, ORD A281976, YT-2136841.
The standard GMC CCKW piston is exactly the same piston, although the part number may be different.

The Stag crankshaft uses a 4-bolt rear main bearing and has 8 threaded holes on which the flywheel is fixed.
It has an extended "front end" suitable to mount a double pulley to drive the (very important!) generator.

Exhaust-valve clearance is slightly bigger (at 0.016") because of the engines running hotter in the enclosed engine compartment.
Stag exhaust valve number is G85-01-02421, YT-2135403.

Stag engines are not governed and due to the specific parts as camshaft, carburetor and ignition, run up to 4200rpm.
A Stag can do 62mph.
At least, mine does...

Best regards,

Marco

[Hanno Spoelstra]

Originally posted by marco
I have rebuild a Staghound AC which took me 10 years to finish

Marco, welcome to this forum!

For those of you who want to know on what Marco spent ten years of work, see http://www.12mbdragoons.com/stag01.html

Regards,
Hanno

[Gunner]

Hi Hanno/Marco:

I don't know if you are aware but there is a 12 MD DVD available of pre-war and wartime 8mm footage filmed members of the unit. I got my copy from the 26 Field Regiment, Royal Canadian Artillery Museum in Brandon Manitoba (the Brandon Gunners have many 12 MD vets as the 12 MD's last garrison in Virden, Manitoba was converted to a battery of 26 Fd Regt in the 1960's. The museum in Brandon has a great number of 12 MD artefacts.

The army cadet corps in Virden is badged to the 12th Manitoba Dragoons and perpetuates their history.

Cheers! Mike

[jim sewell]

Marco
Thanks for your input , one is always learning and the use of this forum allows one to do it with ease .

I was quite impressed with your staghound as they are a mighty beast , I certainly would not like to collide head on with one travelling at 62 mph !!.

There is a running one in a museum not far from me and I would like to see it go through it's paces one day.

Regards

Jim S.

[Neil Ashley]

I found the serial number 270136265 on my C15TA at the weekend. The plates had been removed a long time ago.

Judging by the fact that it is a single pulley engine I would assume however that this is a standard engine out of a GMC Truck.

I have had to fit myself the correct type oil filler / breather and shorteh the dip stick so I can access it through the side door.