Info needed on V-8 864

[Mack man 1973]

The trans in mine is kinda odd it has a fuller rto 12513 13 speed it was factory that is what the build sheet shows . I haven't seen to many v8 with a fuller behind them I've always seen mack trans .

[bulldogmack58]

On 10/19/2014 at 7:14 AM, Superdog said:

displacement was the same,it was how they were set up,the 865 was a Maxidyne engine,engineered to be used with a 5 or 6 speed,with an operating range of 1200 to 2400 rpm ,they had 2 versions I know of for sure,most common was the 325 hp one and there was a derated 285 hp one,also

The 866 was designed as a Thermodyne engine,for use with transmissions having 10 or more gears,mostly paired withe the TRDL1070 Mack 10 speed and the TRTXL1070 12 speed Mack.Operating range was 1500 to 2300 rpm as I recall . Also offered in at least 2 versions I can remember,a 350 hp and most common was the 375 hp one.

Which one was the problem child? Or was it all of them?

[Bigdogtrucker]

None IF maintained correctly.They needed the heads re torqued every 100-150K of work and the valves adjusted.From what I've heard many people ignored the proper PM work and that led to issues...

[Mack man 1973]

The 866 in my truck has made it 41 years of service . The guy I got it from said it was a good truck for many years . So they were not all junk

[Bigdogtrucker]

Post a thread about your truck,pics and details!

[Superdog]

there were some with Fullers too.There was a FS797 at South bend that had a 13 speed and also factory air ride. I think it was a '73 also

[b61mack]

I have a 1964 factory service manual for the 864, the cubic inch on that engine is 863.94 but they call it 864 and 255hp, torque is 639 at 1700 rpm. the 865, 866 is 866 CID. when did the twin turbo 864 come out.

[theakerstwo]

I am going to say the twin turbo 64 came out in 1966.The Tulsa dealer here sold one in that year and I was told it was the first one sold west of the Miss river.

[39 Baby Mack]

On 10/17/2014 at 10:25 AM, mackdaddy said:

I have 3 of the B755's all with the L cab. I have never seen a B7553 but there must of been a few. And yes they would have been a twin turbo. Most interesting to me is that they built the 864 which should have been considered an experimental engine, through 1972! Begs to ask why? and who for? Both the 865 and 866 were in production then! I attached a word doc on the production and years.
Mack V8 Diesel Engines.doc

You can have a lot fun with numbers, can't you Dan?
Just was looking for photos of the 864s and came upon this thread on BMT.
Would a B-755 with an ENDT864 carry a model number extending out to fourth digit being a 3 to denote a turbo charger.
I've never seen model numbers carried out to the fourth digit. Or if they ever made a B75 with a turbocharged 864 would it be a B759. As in F715 versus F719?
I always thought that an H-61 with a Cummins engine in it (the only H model available from the factory with a Cummins in it) should have logically been called an H-71 as was it's western counterpart the W-71. The W-71 as far as I know was only available with a Cummins.
Just thinking out load, that has been known to get me in trouble!
Fun with numbers!

Ron

 

[39 Baby Mack]

Just double checked myself, there were actually three "B" models that had four digit model numbers. Had nothing to do with what we were talking but I was surprised to see that there were any at all.

Ron