Unusual Detroit 6046 6-71

[anthony urek]

Hi all, I am new here and hoping someone can shed some light on a Detroit Diesel 6-71 engine I have in my shed.
It is unusual in a couple of ways.
Firstly it has a brass tag near the rear stating 6046(see pic attached) which is GM's code for tank. However Grant tanks (M4A2) which ran the 6-71 twins did not have a tag here. They had a slightly different tag on the transfer case which also states the reduction ratio of the gearing in the transfer case.
Also the Grants and Shermans which ran the twin diesels have 2 motors that spin clockwise when looking at the flywheel from the rear of the motor. My motor spins anticlockwise from the rear and should do so according to the model number (671RA54) on another GM tag on the motor.
So am I right in guessing that this motor could be from a late Valentine? Which would explain the rotation and the need for a different tag on the motor as there is no transfer case to put one on.
The motor has the same exhaust manifold, front cover, water manifold and 3 air filters as found on the Grant tank but a different model number and rotation.
Hope this makes sense.

[rob love]

I was always under the belief that the twin detroits in the Shermans were counter rotating.

[tankbarrell]

Originally Posted by rob love

I was always under the belief that the twin detroits in the Shermans were counter rotating.

You're not alone, some refuse to believe they don't even when you show how they couple together!

[anthony urek]

Nope....both spin left in Grants.
Can anyone verify this once and for all.

[roy206]

the gm 6046 fitted in sherman and also m10 tank destroyer turns seen from front counterclockwise and the outcoming propshaft from the gearbox turns clockwise. your twinset is a runner right now?
see our complet restored twinset running

http://www.youtube.com/watch?v=adEy5j4XiJk

[Perry Kitson]

twin diesel set up was clockwise from flywheel end(manual states rotational directions should be veiwed from fan end, hence counterclockwise rotation in manual), camshafts were counter rotating, left hand engine counterclockwise from flywheel end, right hand engine clockwise from flywheel end.
Hope this is not too confusing.

Perry

[anthony urek]

Great video Roy!Beautiful motors! I jumped when you gave her a rev. It looks like both your motors are spinning anticlockwise from the front, is this correct?


But Perry, in your Sexton, you are saying your twins run opposite

[Perry Kitson]

Both engines crankshafts turn counterclockwise when standing in front looking at the fans. I think I only muddied the waters adding the talk about what the manuals say. Detroit Diesel always refers to rotation direction when looking at the engine from the flywheel end. The military refers to rotation direction from the fan end in the manuals. So the twin set up has both crankshafts turning the same direction, counterclockwise when observing from the fan end of the motors. The camshafts turn opposite direction because you are feeding the engines from opposing sides.
My Sexton uses the 9 cyl. radial.

Perry

[anthony urek]

Thankyou Perry for clarifying that.
Yes both engine cranks in the 6046 twin pack spin in the same direction.

Now back to my engine which spins the opposite way to the normal 6046 twins. Valentine maybe????

[cantankrs]

Anthony,

I'm pretty sure my 6046 army manual says that only the crossbox had the serial number for the 6046 power pack and that they didn't record the individual engine numbers. (Pretty odd idea that) So curious if your motor has the pictured plate affixed directly to it. Can you provide a more general view of the motor and include the plate in the frame?
Also a shot of the fan drive as that might clear up any Valentine possibility.

Alex

[anthony urek]

Hi Alex,
Here are some pics of the motor. The first one shows the whole motor with the two plates evident. The brass 6046 tag on the rear and the silver model tag behind the rear air filter. As I stated in the first post the 6046 tag is different to the usual 6046 tag on the crossbox as it does not list the reduction ratio.
The second pic of the front of the motor shows where the fan extension housing has been cut off and welded over. This motor was found on an abandonded irrigation pump. The exhaust has also been modified to facilitate an upward outlet. The water manifold is broken and is currently removed.
Cheers.

[roy206]

here is a picture from our twinset,as you can see the tagplate is mounted on the gearbox.