Good afternoon,
A friend of mine is the proud new owner of D7 ser no 3T17630. He would like to convert it to direct electric start. Is 12 VDC an option? Any info would be appreciated. Also I told him it was built from 1944-1955. Can anyone be more accurate? Thanks.
Packrat

The 17A that followed came out in 1955 so your ending date for the 3T is pretty much right. As large an engine as they are I would say the 24V would be far the best. OM on here is the expert on changes to the DES so maybe he,ll chime in.

I show 1951 as production year for that model.

There are some die hards that will tell you 12V will work but I would recommend you go the 24V route to keep the amperage down.

There is no commercial produced drive end starter housing for this application so custom fabrication is required. Either a 40MT or 42MT starter motor will work and the helical drive gear is the same as what is used on the D2, D4, D6 conversions.

I worked on 3T25666 for many years and as far as I can remember it was built in 1958, just before the 14A came out. Those old Hercules pony engines were pretty dependable, tho.

I sure wouldn't trade my pony motor for all the stack of batteries I'd have gone through in the last thirty years, not to mention the corrosion, mess, jumper wires, and short tempers inspired by electric starters!

Jack

D7 3T 10050 I think it is.

i have a 17a with a pony motor and a 3t with a 24v starter. I like the starting motor the best by far, for sure if you have cold winters, if you do go to the starter i would go 24v and check into glow plugs if you live in the northern states, i think the starting motor would be better and cheaper in the long run.

Rick, the first 17A came out in 1955 and the 14A the same year so the 3T was dropped when it came out. I started as a mechanic for the Cat dealer here in 1956 and they both just came out (17A & 14A) the year before.

My Track- Type Machines 1925 - 1960 Book which i purchased from ACMOC says your D7 3T is a 1951 year . I hope this information helps .

I have a D7 17A , actually i have two a 1959 and a 1961 and i converted both over to 24 electric volt with starters from ACME auto electric here in Louisville, Ky. I do not have a charging systm on either tractor and have charged the one tractor batteries up twice in two years and it did not need charging then . Two I nterestate batteries at 1,000 cold cranking amp power the size of car batteries starts in the summer with no help of glow plugs or starting fluid (either) only in the cold months i use a small shot of starting fluid and she starts right up. I went to a clean dump site that i keep pushed over with the 1961 D7 and it started with no help. You maybe able to start your D7 50 times before charging batteries up. I don't need charging systm.

I have been operating Caterpillar tractors for 42 years and i do not like the pony motor , two much work , mag goes bad , condensor , carb , and you still have a battery and cables that corode plus showing up and the pony gas tank is empty and you have to drive 5-10 miles for a gallon and a half of gas . I love my electric start on all 6 of my machines and will never have a pony start again .