POPPY Posted April 20, 2014 Share Posted April 20, 2014 Good evening, Could anyone kindly let me know a healthy top speed for my Ford CMP LAAT F60 Bofors gun tractor. She has her original Flathead V8 and today I managed a top speed of 30mph at a struggle. (No Bofors gun included) when on a flat I select 4th gear, she feels under powered and takes forever to reach 30mph unless I decend down a hill. I have read in a book that top speed back in the day was 45mph. Mayby she is alittle tired after 70 years or I need to give her a service kind regards and Happy Easter. Mark Quote Link to comment Share on other sites More sharing options...
0 g0ozs Posted April 20, 2014 Share Posted April 20, 2014 Mark I guess it depends on gearing as well but my petrol V8 SUMB with a little bit bigger Ford flathead (4.2 vs 3.9 litres I think) and about the same weight (3.5 tonnes unladen) could quite happily get to 50mph on the flat, so 30 sounds a little underpowered. Iain Quote Link to comment Share on other sites More sharing options...
0 Lauren Child Posted April 20, 2014 Share Posted April 20, 2014 Thats about right. Remember the gear ratio of an artillery tractor is set for torque, so its not going to be a speed demon. You can reach 40 to 45 downhill, but about 30 climbing slowly to 35-40 (takes a while) if you are flat out. Its also worth noting that these rev faster for a change up than you may be used to. Try putting your foot down for a bit longer before changing up. It took me a bit to get used to. Quote Link to comment Share on other sites More sharing options...
0 Pete Ashby Posted April 20, 2014 Share Posted April 20, 2014 You will in reality be flat out at around 40mph on the flat, the 30cwt, 60cwt and LAA have fairly low ratio diffs. On our C30 we swapped them for C15A diffs which are slightly higher ratio. Iv'e not done it with a Ford but check your parts book to see if the diff carriers are compatible to a F15A, you will have to do both front and back or take your front prop shaft off to stop wind up. You could also try fit larger tyres as a quick fix, it mucks up the power/gear ratios a bit so you may find you need alter you driving style to match. Pete Quote Link to comment Share on other sites More sharing options...
0 Lauren Child Posted April 20, 2014 Share Posted April 20, 2014 (edited) Has to be said, fresh oil made a big difference to how she felt and revved when I got mine. A quick service may make it feel a bit more oomphy if you've not done one, even if it doesn't change the top speed. For reference a SUMB feels much snappier and faster even though it's the same engine. Edited April 20, 2014 by Lauren Child Quote Link to comment Share on other sites More sharing options...
0 POPPY Posted April 20, 2014 Author Share Posted April 20, 2014 Mark I guess it depends on gearing as well but my petrol V8 SUMB with a little bit bigger Ford flathead (4.2 vs 3.9 litres I think) and about the same weight (3.5 tonnes unladen) could quite happily get to 50mph on the flat, so 30 sounds a little underpowered. Iain Hi Iain, Thank you very much for your speedy reply ! Mark Quote Link to comment Share on other sites More sharing options...
0 POPPY Posted April 20, 2014 Author Share Posted April 20, 2014 Thats about right. Remember the gear ratio of an artillery tractor is set for torque, so its not going to be a speed demon. You can reach 40 to 45 downhill, but about 30 climbing slowly to 35-40 (takes a while) if you are flat out. Its also worth noting that these rev faster for a change up than you may be used to. Try putting your foot down for a bit longer before changing up. It took me a bit to get used to. Hi Lauren, Thank you for your reply! I feel much better now after reading your post ! I thought somthing may have been wrong with the low speed ! So that's good. And yes I know what you mean about them revving high ! I'm slowly getting used to her now. Ive got to sort out my dynamo that is'nt charging , then I should be ready for the historic vehicle show season HAPPY DAYS :-) Good to hear from you Lauren ! regards, Mark Quote Link to comment Share on other sites More sharing options...
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POPPY
Good evening,
Could anyone kindly let me know a healthy top speed for my Ford CMP LAAT F60 Bofors gun tractor.
She has her original Flathead V8 and today I managed a top speed of 30mph at a struggle. (No Bofors gun included)
when on a flat I select 4th gear, she feels under powered and takes forever to reach 30mph unless I decend down a hill.
I have read in a book that top speed back in the day was 45mph.
Mayby she is alittle tired after 70 years or I need to give her a service
kind regards and Happy Easter.
Mark
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