Just Bought My First Mack

[hawk2881]

I just bought a 1975 mack with a V8 where do i look for the engine size HP and rpm range? next is what should I do to this truck befor putting it into service. The Maxidine engine brake seems real weak as well, do they normally not have alot of hold back power. The engine seems to run really strong and i plan to take it to the mountains and haul grinding's off my tub grinder, as well as haul my lowboy. Any idea's on what I should check befor getting 100 miles from home in the middle of winter, for I break down enough with my other equipment I dont need any more. Any idea's where i can get a service manual for the engine or the hole truck. To sum it all up I would just like some preventative maintance ideas on the engine and trans. I know to check the oils and stuff i mean mechanical stuff

[IdleUp]

I just picked up my 1990 Superliner last week - I'm sure the guys here will be able to answer any of your questions!

Mike

[Rob]

I just bought a 1975 mack with a V8 where do i look for the engine size HP and rpm range? next is what should I do to this truck befor putting it into service. The Maxidine engine brake seems real weak as well, do they normally not have alot of hold back power. The engine seems to run really strong and i plan to take it to the mountains and haul grinding's off my tub grinder, as well as haul my lowboy. Any idea's on what I should check befor getting 100 miles from home in the middle of winter, for I break down enough with my other equipment I dont need any more. Any idea's where i can get a service manual for the engine or the hole truck. To sum it all up I would just like some preventative maintance ideas on the engine and trans. I know to check the oils and stuff i mean mechanical stuff

Hello and welcome to the site. Excluding myself there are a few folks here that know these older trucks quite well, (I just guess a lot).

First off I see your truck is listed as an RS 700 series meaning that it has straight steel frame rails building a conventional ladder type frame from front to back, and an extended hood. You also mention Maxidyne, which is the engine series with an engine brake which would be called a Dynatard system. This is a Mack design and although most say they do not work quite as well as a "Jake Brake", if maintained properly they perform adequately in their intended application.

Pertaining to the V8 engine that you mention: It is a choice of three in that style of chassis if original to the truck: The first choice would be an ENDT865B. This will be rated at either 322hp, or 325hp depending on the calibration of the injection pump. The other choice of engines would be an ENDT866B engine that is rated at 375hp. There should be an aluminum tag riveted to one of the aluminum rocker covers on the engine with the specifications stamped into it.

Typically the 865 engine would have either a single stick five speed, or twin stick six speed transmission installed behind it as this was the "Maxidyne" series of engine. The 866 engine is of the "Thermodyne" series and typically had many more gears such as nine, ten, or so.

Parts for the two valve V8 engines are getting increasingly difficult to locate and acquire. On top of that, expense is ever increasing. If you plan to work that truck be cognizant of the cost of operation especially breakdowns. It has been said those engines were hard on head gaskets, but I've not seen that problem myself. My experience is that the injection pumps are very expensive to have worked on.

Ebay has a consistent supply of service manuals available and you want the TS-442 series. These are easy to use for the mechanically inclined. If you go that route, be sure to ask the seller the latest reprint date as that series of manuals ran for many years. You want to ensure that your chassis is covered.

I personally like the V8 engines. They are smooth, powerful, and seem to be dependable. I've not worked one myself, but remember them well when popular.

Good luck with this one.

Rob