671 Detroit Governors

[Skytramp]

Hi Guys;
     I am converting a 671 Detroit engine to run my mill, I have two, one that has had a major overhaul, and another one in an old truck.  I have the good one out and ready to set on the frame.  It has regular truck governors.  The other one has the constant velosity governors ( They ran a block mill off the driveshaft.)  I have to switch them around.  They look the same but I am sure they are different internally.  My question is, how much do I have to change, just the top or all the way down the side of the block, or somewhere in between?
Any and all help will be greatly appreciated;
Skytramp;

[UNCLEBUCK]

Hi Skytramp, I have the big detroit 671 complete service shop books and it shows 10 different governors . The list shows these types
1.) Mechanical governors
2.)Limiting speed mechanical governors
3.)Limiting speed mechanical governor(dual high -speed range)The dual range governor is used on highway vehicle engines that require a high maximum speed part of the time and a low maximum speed the remainder of the time
4.)Limiting speed mechanical governor(variable low-speed)where the same engine powers both the vehicle and the auxilliary equipment for unloading bulk productssuch as cement ,grain and liquids
5.)Limiting speed mechanical governor(fast idle cylinder)for auxilliary power as well as the vehicle
6.)Limiting speed mechanical governor(variable high-speed)/for auxilliary like cement trucks
7.)Variable speed mechanical governor
8.)Constant speed mechanical governor
9.)Mechanical output shaft governor/ for use on engines with a torque converter
10.)Hydraulic governors

I will try to zero in on what it says in the next day . I have to look at the book alot .
What is your reason for switching governors and not using the truck governors? I had a thread here last month about 671 troubles and there is a member on the forum here that use to drag race trucks with the 671 detroits. I will find who it was and am sure he could tell you in two words what to do ok. I got 2 huge new books for the 671 that came free with it and it shows complete illustrations for every part overhaul,its mind boggling .

[UNCLEBUCK]

Quartlow is the member to talk to . He grew up drag racing trucks with these goofy 2 stroke powerhouses .

[Quartlow]

I'm not so sure I would hassle with changing it, going from memeory all you should have to do is unbolt the whole assy and switch them. DD was great about making things interchangable.

I think I would be tempted to run the truck govenor, if your going to set the mill up to run against the govenor while cutting. highway equipment is set up so you have full control of the injector rack to control road speed. The only time the govenor is going to com into play is if you have it wound up tight on a flat streatch of ground, as soon as the rpms strat to drop the govenor will then open up and give it more fuel. If your only running half throttle a  limiting speed type governor will not try to maintain rpms. The motor is waiting for a throttle position change from your foot.

IF your running wide open while sawing a truck govenor will work, but it will only work right if your running wide open while sawing. Double weight govenors respond better than single weight ones.

That being said don't be afraid to run it wide open all day every day. Detroits like to breathe I wouldn't run it any slower than 2300 RPM's. In fact if it was me it would be running 2700 to 2800 rpm,s anything under 2300 your going to start having problems with it building up carbon deposits which will shorten the life of the engine. Every detroit I ever had the govenor was set wide open , usually resulting in a condion that gave you you up to 3400 RPM,s and no I was never afraid to take it there.  :D

If your not going to run it wide open and want to be able to slow it down for certian types of cuts you going to have to go with a SWVS: single-weight variable speed  used inindustrial and marine eqipment.

No matter what you decide, before you start it everyday get mad at it and beat it, it will longer and better :D I used to slam my finger in the door every morning :D :D