I've been wondering about a direct electric start conversion on a D4 7u versus the cost of a complete rebuild of the pony motor. I'm considering bringing my D4 into my shop/ storage this winter to fix a number of things and this might be one of 'em.

Also, if the direct start conversion happens, do you weld up the water passages in the back of the main engine block up or just plate over 'em with the battery box?

Can't really tell you how much either approach will cost. Depends on how much you can do yourself and what your sources for parts are......but I believe the costs for doing either will track about the same. If you had to farm it all out...to Cat for instance I'd expect a bill in excess of $3,500. (starter hole boring req'd)

Yes, the battery box base becomes the block off plate for the bell housing connections.

Check this website for conversion information.
email me if you have additional questions.
img400.imageshack.us/gal.php?g=header4oq.jpg

Last winter I converted a 70D motor grader w/ a 318 engine to direct electric start, of course with Old Magnets expert help !! It turned out very good, and I'm sure you would not be sorry that you did it.
Vernier

grump, it is cheap trust me, in the KINGDOM i had one pup motor on the 15B with a cat 4400. that pup motor was rebuilt and everything new and i just about ended at AA (alcholic's anonyoms(spelling??))
the direct electric start that old magent helped me with is trhe cat's meow, my d6 9u known as THE HOOD has started at -35c with one battery instead of two. if it was a pup motor i would still be attending AA meetings.
listen to old magnet, it is cheap and you will enjoy your cat.

ok, i'm off the soapbox now or did someone take it out from under me, LOL

thansk

Hi KoO,
You can get on that soapbox any ol time:D
Had no idea things were shak'n in the Kingdom.
Hang in there;) us "canooks" survive.

Thanks for the all the answers everyone. Now to start making two price and parts lists. .one for the conversion and one for the rebuild of the pony motor. But before I can make lists, where can I find quality parts besides bending over and backing in to my friendly local Cat dealer:eek:

Seeing as how I"m a retired machinist/ welder/ fabricator the machine work and fabrication doesn't bother me, nor does rebuilding the pony motor. Hopefully, I'll have access to a machine shop when/if this happens. Looks like now it's just a case of making up my mind which way I want to go before winter.

You can add option # 3 if you have a mind to:)
It's possible to have both on the D4, just need to find space for battery/s or portable battery start. If you go the 12V route, the 6V pony electric start will operate fine.

Not a lot of option on the pony parts. Rings can be had readily aftermarket, pistons seem to be Cat only. Cylinder sleeves are aftermarket. Valves can be substituted. If you can make your own main bearings (T-something aluminum) you can save a few bucks and customize the thrust clearances. Seems machine shops don't know what to do with that block anymore. The crankshaft can be a cost killer, most are cracked, weld build up/repair is pricey. Be sure to check thickness and for cracks on the bottom of the cylinders where they all rot out or freeze burst before investing. Rod bearings are a Cat item. Camshafts and gears seem to go forever.

On the Direct Start, keep an eye on ebay. I've seen some pretty good deals there from time to time. I prefer the Delco 42MT starter for the fit reasons described on my website.

Need any more projects to help you with your retirement, just let me know:D

Maybe I've been missing the boat or something here. Why isn't it possible to keep the pony (either with pull rope or electric start) and also use a direct electric start for the diesel? Seems to me like a starter could be bolted up front on the diesel at the same place the generator was located (accessory drive housing). I thought I read a post on this once. Someone used the delco starter and drive gear with the same number of teeth as the generator drive gear. Only thing I questioned was whether the starter had the correct amount of travel on the bendix to mesh properly with the gear located in the housing. If this isn't possible someone please figure out a way. It seems to be a much easier and more affordable way than removing the pony and tearing everything down to bore through the flywheel housing just to mount a starter.

I installed a starter on my 7u, also using Old Magnets info. I drilled the
hole using a Starret carbide hole saw. With a little cutting oil the housing
cut like butter. The batteries are mounted on the fender. I used two
12vt marine batteries for the 24vt starter. So far occasionally charging the
batteries hasn't been that big of a deal.
Old Magnet, did I read the post right?, using 12vt for the 6 vt pony starter
is ok. ( I'm a little leary of the idea, but I suppose if the pony starts in a few crank cycles its ok) If so, I could maybe convert the 6vt generator to 12 vt and use a selector switch for charging the individual 12 vt batteries.
Just for comparison I use the electric starter for temps above 50 degrees.
below 50 and with no pre-heat the main has a sluggish start up. Thats when
the pony comes in handy.

I havn't checked into details yet, but I read somewhere about a delco
6 to 12 conversion. Seems the amature might be the biggest issue.

Love reading these posts about direct electric vs pony start. In my humble opinion if you don't have glow plugs or pre heat for the early cat diesels your asking for trouble in cold weather. I know the direct electric start is cheaper to repair when something goes wrong, but if your pony is in good mechanical shape ie, good mag, good compression and good carb, there is no reason it should not fire up the main at just about any temp. Nothing like the sound of a pony winding up. They are a great piece of american engineering.