Clarify starters for electric start conversion

D318? 4.5"x5.5" 6 cylinder comes up to ~525 cubic inches displacement.

The inertia drive would be a step backwards and $$. You want a commonly available solenoid shift starter instead. You just have to get the DE housing and helical gear drive to make it work.

I see farm tractors with similar size engines using the 50MT (JD5010/5020 with a 531) on up to the 855 Cummins etc. Probably depends a bit on compression ratio and engine design for example precombustion vs direct injection and high pressure injection vs the ~5-600 psi of the CAT injectors.

D318? 4.5"x5.5" 6 cylinder comes up to ~525 cubic inches displacement.

The inertia drive would be a step backwards and $$. You want a commonly available solenoid shift starter instead. You just have to get the DE housing and helical gear drive to make it work.

I see farm tractors with similar size engines using the 50MT (JD5010/5020 with a 531) on up to the 855 Cummins etc. Probably depends a bit on compression ratio and engine design for example precombustion vs direct injection and high pressure injection vs the ~5-600 psi of the CAT injectors.

Just a side thought.....

OM, do you recommend the 40 or 42 over the 50 because it fits better in the D4/6? I know there are issues with side panels and such and a 50 would be ugly due to its larger size.

Space isn't a concern on the grader.

Thanks ccjersey.

Would a 50MT be better for cold weather than a 42MT?

Bigger's better in my book, but I still have ponies on all of our stuff older than about 1960. I believe CAT uses a 50MT on the D333 which is basically the same size engine, but I would have to look at the 12E to be sure of the starter model.

If someone was going to be using the grader without exercising common sense about cranking duty cycle times, I would say the larger starter would be a good investment. If you are going to run it and have starting fluid or glow plugs installed in a decently maintained engine, the smaller starter is known to do the job ok.

Bigger's better in my book, but I still have ponies on all of our stuff older than about 1960. I believe CAT uses a 50MT on the D333 which is basically the same size engine, but I would have to look at the 12E to be sure of the starter model.

If someone was going to be using the grader without exercising common sense about cranking duty cycle times, I would say the larger starter would be a good investment. If you are going to run it and have starting fluid or glow plugs installed in a decently maintained engine, the smaller starter is known to do the job ok.

The original direct start option for the 8T was a 40MT starter (24v)
Cat is still using the 42MT 24v (replaces obsolete 40MT) starter on in line 6-cyl engines.
The 50MT is still current production (24v) and used on the D7's on up.

The physical difference between the 40/42MT and the 50MT is about 1/2 inch in length and 7/16 inch on the diameter.

The drive end housings are the same for the 40 & 50MT units....all three use the same helical drive.

If you feel you need the larger starter size (D7-D11) it will fit but you will have to match it with the appropriate batteries, switches and wiring to take advantage of it's
capacity.

raklet - I'd trust OM's independent and impartial judgement and knowledge over any company person who may be trying to sell a certain line.

Delco state that the 40MT/42MT is designed for engines up to 950 cubic inches, and the 50MT is designed for engines over 950 cubic inches .. however, this is in vehicular applications .. maybe tractor/industrial/agricultural applications had different recommendations.

Here is a Delco-Remy application catalog book that will provide useful additional info for you. Even though it is mid-60's, and has obsolete product info in it .. it still provides much useful info.
This book not only provides info on vehicular and industrial applications .. it also provides a lot of info on the Delco starter motors .. much useful wiring information .. design information .. identification info .. along with cable recommendations ..

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=250143625418

Here are the comparison dimensions of the 40MT and 50MT.

http://img54.imageshack.us/img54/2740/delco40mt50mtgv7.jpg

Thanks everyone. I'm clear on what needs to be done and will stand my ground against anyone trying to tell me other than what I've learned here. 😄