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Caterpillar D7 3T

ChrisUK

Well-Known Member
Joined
Dec 23, 2020
Messages
133
Location
England
That old D7 is in pretty good shape, considering its age. I thought I had major corrosion problems with my 931B, it's good to see someone else dealing with the same problem!
A sandblast and a coat of paint would make that old girl look like new.
Thanks @OzDozer, this one is staying in it’s working clothes, we will see how we get on with the engines and brakes first though
Cheers
 

ChrisUK

Well-Known Member
Joined
Dec 23, 2020
Messages
133
Location
England
A bit more cleaning up and chasing threads out, proper gasket too !
Some donated spark plugs are on their way.
Starting engine petrol tank has some “extra” holes, I will have a go at repair before adding to the shopping list.
I know of a fine gentleman that has a small selection of items ready for retail.
Cheers Chris.
9C1EAA03-19FF-4436-A9E1-0B6C0111B132.jpeg751EFA61-98CA-4C46-B231-2A520A7D4563.jpegFF33E102-F662-43D8-B00A-BA541E47E37E.jpeg
 

ChrisUK

Well-Known Member
Joined
Dec 23, 2020
Messages
133
Location
England
Starting engine re fitted, it’s a tight squeeze with the Bray dozer equipment fitted.
Thought I had the job sussed, the idea was to get it into place then feed the gasket down between the two faces but not so, I hadn’t taken into consideration how far the flywheel sticks out of the back of the crankcase.
Some profanity used, pulled it back forward and rotated it out and there was just enough room to fit the gasket.
Awaiting a few parts still but at least it’s back on.
Chris
B22BABF4-4706-43ED-845C-FB8F42DD45D5.jpeg32CE17DB-34C9-4975-BFC9-CA0819A97245.jpeg
 

ChrisUK

Well-Known Member
Joined
Dec 23, 2020
Messages
133
Location
England
Bit of a D73T update.
Have been slowly getting bits together to get it all going.
Fuel tank has been cut open, cleaned out and welded back up with a new bottom.
Carb has been made up from a total of three.
I have so far been supplied with 2 magnetos that do not like producing a spark.
Before I lay out more money on getting one re done or even find another known good one I thought it wise to try and see if the starting engine would run.
I stripped down the worst of the 2 mags and removed the coil as it is no good.
I borrowed a couple of automotive type external 12 volt coils and wired them both in using the points in the magneto. The reason for 2 is not finding a good enough way of attaching the HT output of the coil to the mag pickup rod and therefor being able to use the mag as a distributor.
The way I have it rigged is that both plugs fire at the same time so like a wasted spark type system.
I know many will frown on this but it has proved useful as the starting engine now runs after 30 years.
Cheers Chris. 7240D9D3-49F1-461D-BE11-F11CC6B62F8E.jpeg
 

Costnsg

Well-Known Member
Joined
Dec 10, 2023
Messages
63
Location
Arkansas
Occupation
Retired
You must love restoring old dozers to take on a project like this. I thought my D5B was old. Haha

I recall my dad buying what was then a very old D7 to use on the farm and I'm almost sure it was a 3T. That one was all cables, no cab, and I recall a hole in the side plate just forward of the left track where the hand crank was inserted to start the pony engine. When I was 12 yo my dad put me on that thing to clear land and left to go do other things. I remember being scared of it, scared of killing the engine, scared of the track popping off the completely worn out undercarriage (which it did and my dad was not happy). None of that mattered and off I went. I had been operating farm tractors and trucks from 9yo. My kids don't know how easy they had it. I know I was 12 so that would have been about 1970. A few years later I was very impressed when I operated my first power shift. Pretty sure it was a 7E.

Sorry for the trip down memory lane. I couldn't help myself.

Wish you the best on your restoration!
 

epirbalex

Senior Member
Joined
Aug 5, 2017
Messages
568
Location
Akitio
Occupation
peasant
Bit of a D73T update.
Have been slowly getting bits together to get it all going.
Fuel tank has been cut open, cleaned out and welded back up with a new bottom.
Carb has been made up from a total of three.
I have so far been supplied with 2 magnetos that do not like producing a spark.
Before I lay out more money on getting one re done or even find another known good one I thought it wise to try and see if the starting engine would run.
I stripped down the worst of the 2 mags and removed the coil as it is no good.
I borrowed a couple of automotive type external 12 volt coils and wired them both in using the points in the magneto. The reason for 2 is not finding a good enough way of attaching the HT output of the coil to the mag pickup rod and therefor being able to use the mag as a distributor.
The way I have it rigged is that both plugs fire at the same time so like a wasted spark type system.
I know many will frown on this but it has proved useful as the starting engine now runs after 30 years.
Cheers Chris. View attachment 309003
Good trick , do you still have the condenser in there ? . More wires in that photo than on a dozen T3's or the T4 I recently sold for a guy .
 

ChrisUK

Well-Known Member
Joined
Dec 23, 2020
Messages
133
Location
England
You must love restoring old dozers to take on a project like this. I thought my D5B was old. Haha

I recall my dad buying what was then a very old D7 to use on the farm and I'm almost sure it was a 3T. That one was all cables, no cab, and I recall a hole in the side plate just forward of the left track where the hand crank was inserted to start the pony engine. When I was 12 yo my dad put me on that thing to clear land and left to go do other things. I remember being scared of it, scared of killing the engine, scared of the track popping off the completely worn out undercarriage (which it did and my dad was not happy). None of that mattered and off I went. I had been operating farm tractors and trucks from 9yo. My kids don't know how easy they had it. I know I was 12 so that would have been about 1970. A few years later I was very impressed when I operated my first power shift. Pretty sure it was a 7E.

Sorry for the trip down memory lane. I couldn't help myself.

Wish you the best on your restoration!
@Costnsg These stories and memories are good and what it’s all about, thanks, Chris
 

ChrisUK

Well-Known Member
Joined
Dec 23, 2020
Messages
133
Location
England
Good trick , do you still have the condenser in there ? . More wires in that photo than on a dozen T3's or the T4 I recently sold for a guy .
@epirbalex yes the condenser is still in the mag. The wiring job is a very temporary measure and was just to see if we could get it to run, will no doubt get a better mag in the future,
Chris
 
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