Me and my dad just bought one of these as a project truck. Does any one have any experence with them. It has the mack 6 cyl ,auto tranny, and an inline style pump but I dont think it is a p-pump. How can we give it a little more power and RPMs.

 

What year?? 2 valve or 4 valve?? Pump could be a P7100, P3000, Nippondenso EP9 or a Robert Bosh. Pump have an AFC??

 

It is a 75 model probally a 2 valve. I don't know about the afc In the next couple of days I will take a pic and post it. We did figure out how the road speed Gov works and plan on turning it up to 70-75 currently it is set to 45. There is an air leak in it somewhere and it wont build up pressure that we have to fix first.

 

If you are turning that engine above the speed that it was designed for you are looking for trouble.They make a tough truck but you have to buy horsepower,you can't be fiddleing with adjustments and expect to get any great performance gains without sacrificing the life of the engine.Ron G

 

Stock it should turn 1900-2100......they can be bumped up to 2300 and run it all day, everyday for years. The 2valves dont like high Egt's....they tend break piston skirts or smear rings. Look for a engine tag.....I bet its a old 285 with a Nippondenso injector pump=lots of fuel.

 

If it pulls as good as we were told then we might just leave it stock. were looking at around a total of 30k truck and trailer weight when we get done. A full set of gauges are one of the first things that are on the agenda. What is considered high egts for this truck is it the same as the 5.9 in the 1200 range.

 

30k will be nothing.... giving the trucks age theres a good chance the fuel rate has been bumped up at some point. I wont recomend a safe Egt, however I will tell you our old 1977 R model wrecker(warmed 285)runs 1350ish post turbo with a good jag on her. The old 2valves are good simple engines and will,IMO run every bit as good as the E6 and E7's. How many miles since its last overhaul??

 

We don't know but there is only 85k on it now. One of the reasons we bought this truck is because it has a factory jake break on it.

 

Mack called their engine brake a "DynaTard" and it times out at idle so that it won't kill the engine like the Jacobs brake will.Mack made a great truck back in those days.....................today????.I am not impressed.It is sad to see them going down but I try to remember the good days and shut out the bad.Ron G