help request 1990 fld 3406b cat top speed 55mph on 1550rpm

If memory serves me right. .87 (old RTO14613) x 3.42 x 516 (revolutions per mile for that tire) = 1535 then 1550 RPM X 60 = 93000 take 93000 divided by 1535 gives us 60.6 MPH at 1550 If it's a newer RTLO transmission, then it's .73 ratio in top hole then it come out to 72MPH at 1550

That's a lot of memory for an old guy, but I think I calculated right

RPM x 60 (divided by) transmission gear ratio x rear end ratio x tire revolutions per mile = MPH

Use this to figure out what any tire size changes or rear end changes will have on MPH

 

Step one on 3406B power issue is change fuel filters.

 

Fuel filters, ratio controller diaphragm, fist full of 5K5959’s and a spare Jake switch for the back of the pump are the never leave home without list for my B and C.

 

Next one is confirm the governor control lever on the pump is breaking over onto the spring when the pedal in the cab is to the rug. If you’re not sure what I mean grab the rod on the pump and pull it all the way back toward fuel on, you’ll see what happens at the lever on the pump. Make sure it does that off the pedal. It’s possible to lose travel in the linkage between the pedal and the pump for any number of reasons. That’s a good one to eliminate before big bills start.

 

Are you able to wind it up to 2100 in any other gear ? That engine likes to be wound up . It isn't like these new engines 1550 she is just getting started .

 

Up here we had to run the B’s in train tractors 1700 to keep egt’s within reason and put enough oil and water through them to get the heat out. They’re loaded up pretty good most of the time at 140,000, like run all day with 18-20psi of manifold on them. A 425 would only put up 22-23psi when they gave them to us.