Need help identifying Mack Dump Truck please?

[IH Tom]

Hello, I have a rig that I am getting running for off-highway use, and am looking to try to get some info on it. Door tag is intact, Model R773ST, Serial number *2067*. I believe the block number is either 8148543 or 6148543. Any info in regards to motor, year, etc. would be greatly appreciated! The owner says he believes it's a 6V71. Drove it for the first time today (without the air assist steering) and it sounds amazing!

[Mark T]

Tom Tom Tom.....you need to post some pictures if you ask a question like that ( lol )

[doubleclutchinweasel]

See..

 

[Vmac3]

On 12/1/2020 at 5:36 PM, IH Tom said:

Hello, I have a rig that I am getting running for off-highway use, and am looking to try to get some info on it. Door tag is intact, Model R773ST, Serial number *2067*. I believe the block number is either 8148543 or 6148543. Any info in regards to motor, year, etc. would be greatly appreciated! The owner says he believes it's a 6V71. Drove it for the first time today (without the air assist steering) and it sounds amazing!

This is what I was able to dig up. Hope this is correct. 

V

Chassis ID ML582 2067 Model R7 (R773ST) Build date 07/01/1970 

11GB3051P31 ENGINE ASSY,DETROIT DIESEL(8V-71NE)ENGINE ASSY,DETROIT DIESEL(8V-71NE)(REV S)

SPECIFICATIONS:

ENGINE SERIES: 8V-71NE

MODEL: 7087-7044

HORSEPOWER: 242 AT 1950 R.P.M.

MAX. TORQUE LB.FT.: 690 AT 1200 R.P.M.

BORE & STROKE: 4-1/4 X 5

DISPLACEMENT: 568 CU. IN.

[IH Tom]

That's awesome! Thank you very much for the info, greatly appreciated!!

[james j neiweem]

You will be needing all the gears in the tranny and then some.🙂

[terry]

Never realized the 8V71 was such a small cubic inch engine.   terry

[Hayseed]

16 minutes ago, terry said:

Never realized the 8V71 was such a small cubic inch engine.   terry

The 71 series is 71 Cubic Inchs per cylinder.

92 series is 92 Cubic Inchs.

53 series is 53 Cubic Inchs 

[Mark T]

1 hour ago, terry said:

Never realized the 8V71 was such a small cubic inch engine.   terry

They aren't very big displacement wise, but they popped every stroke down.....so for engines that didn't make torque like modern ones it was kinda like twice the displacement ( kinda )

[Rob]

And quite easy to get a lot of power from relatively inexpensively.

Nothing smoother on diesel engine generator duty than a two stroke Detroit Diesel.

[davehummell]

There was a larger bore and stroke if I remember 103 or 107 per cylinder. I hauled a lot of tonnage with a 318 with the 13 speed.  

[1965]

They had a 6-110 series, and the V-149 series. They also had the 51 series that I think was labeled at General Motors Diesel.

[Mark T]

I'm still think'n we're gonna need to see some pictures of this truck in question 

[tjc transport]

I agree. 

Pictures, or it didn't happen! 😁

[doubleclutchinweasel]

Just remembered something while reading all the Detroit comments...

Once operated a small tug boat.  Had a 6-71 Detroit in it.  Was labeled as "Gray Marine".  I can't remember if Gray actually built those engines based on Detroit's design, or if they started with the Jimmy and converted it to marine use.  Whatever.  It was definitely a 6-71 design.

The guys I worked with bought me a cap with gold braids on the bill, and for a while I acquired the nickname "Cap'n".

The superintendent told me they would provide a life jacket in case i fell off the boat, but would not supply a parachute if i jumped off.  Luckily, never had to do either.

[1965]

1 hour ago, doubleclutchinweasel said:

Just remembered something while reading all the Detroit comments...

Once operated a small tug boat.  Had a 6-71 Detroit in it.  Was labeled as "Gray Marine".  I can't remember if Gray actually built those engines based on Detroit's design, or if they started with the Jimmy and converted it to marine use.  Whatever.  It was definitely a 6-71 design.

The guys I worked with bought me a cap with gold braids on the bill, and for a while I acquired the nickname "Cap'n".

The superintendent told me they would provide a life jacket in case i fell off the boat, but would not supply a parachute if i jumped off.  Luckily, never had to do either.

Worked on a lot of gray marine 6-71s. I know they were in conjunction with Detroit in some way, they had  the cooling system with there daytank  (at least that’s what we called them) design that was different.