1550 RPM

[carolina oliver]

Recently installed a 77 gas into my 1550 replacing a 1550D engine. All working out well. But max RPM is 1700, would like to get 2000 or so. Any advice on how? TIA

 

[Oliver owner]

Recently installed a 77 gas into my 1550 replacing a 1550D engine. All working out well. But max RPM is 1700, would like to get 2000 or so. Any advice on how? TIA

The shop book for a 77 should explain gov adjustments. I’d just adjust whatever it says to adjust for the high speed and read your rpm off the crank pulley with a phototach. I can share pics of my shop book tomorrow afternoon if you don’t have it.

 

[Tramway Guy]

You might need to change the governor weights to those used on the hundred series engines…

 

[rrlund]

You might need to change the governor weights to those used on the hundred series engines…

I wondered if maybe that was how they did it. I know they increased the rpms a little with each new model, but didn't know how.

 

[ss55]

Recently installed a 77 gas into my 1550 replacing a 1550D engine. All working out well. But max RPM is 1700, would like to get 2000 or so. Any advice on how? TIA

A 77 engine was rated for 1600 RPM at PTO speed, the 1550 engine was rated for 2200 RPM at PTO speed. Pushing the 77 engine up to 2000 or 2200 RPM might need a different cam profile ( regrind? ) and a different distributor curve to still produce much enough torque at those RPMs. Odds are that on a 70 plus year old engine the distributor is due for a rebuild anyway, as well as due for a cam regrind. Air flow restrictions and vibration balancing could be smaller problems.

If you don't need PTO work the 77 engine can work as-is. If you do need full PTO speed a different engine or buying a field ready 77, 1550 or similar might be less expensive.

Pullers can get big power out of those engines at higher RPMs, but they are heavily modified costing cubic dollars.

https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1565&context=tractormuseumlit

https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1510&context=tractormuseumlit

 

[carolina oliver]

The shop book for a 77 should explain gov adjustments. I’d just adjust whatever it says to adjust for the high speed and read your rpm off the crank pulley with a phototach. I can share pics of my shop book tomorrow afternoon if you don’t have it.

 

[carolina oliver]

The shop book for a 77 should explain gov adjustments. I’d just adjust whatever it says to adjust for the high speed and read your rpm off the crank pulley with a phototach. I can share pics of my shop book tomorrow afternoon if you don’t have it.

The shop book for a 77 should explain gov adjustments. I’d just adjust whatever it says to adjust for the high speed and read your rpm off the crank pulley with a phototach. I can share pics of my shop book tomorrow afternoon if you don’t have it.

The shop book for a 77 should explain gov adjustments. I’d just adjust whatever it says to adjust for the high speed and read your rpm off the crank pulley with a phototach. I can share pics of my shop book tomorrow afternoon if you don’t have it.

Found my copy of 77 IT book, describes coupla things I'll try. THANKS to all of you who have made suggestions.

 

[Tramway Guy]

Trying to counteract the heavier weights in a S-77 with enough spring tension MIGHT achieve 2200 RPM, but in the long run could overload the thrust bearing in the shaft assembly. Alternatively, you could remove the weights and machine them down a little, equally and precisely of course.