D4600/D318 swap in 9K CAT 12

Djmayer

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I have a 9k grader with low compression and blue smoke. I’m thinking about a D318 engine swap vs rebuild the old motor.

Looking for a little info:
1) can someone outline the changes I’ll need to address? For example: is swapping to a new oil pan
2) What should I expect to pay for a used power unit? I see cores selling for $500 but I don’t see any running engine out there in this class
3) is it worth considering to find a “good” D4600 to put in.

Dave

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Sun, Aug 16, 2020 8:39 PM

ccjersey

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I would say it won’t be easy. I would start with a parts book for the early 8T graders and the one for your 9K and compare gasket part numbers for block to clutch housing and oil pan to block. If those match up, then you’re down to physical dimensions like distance from clutch housing back to the bolt holes in the chunk in the middle of the rear axle. For sure you need a grader oil pan to support the engine.

I have seen a mention here of a 212 that had been swapped from the D3400 to a D311 or the other way around but don’t really know how comparable the #12’s were across that 1947-1948 model change. The oil pan may be the only difficulty. That said there should be some grader engines out there as many of them as were made.

D2-5J's, D6-9U's, D318 and D333 power units, 12E-99E grader, 922B & 944A wheel loaders, D330C generator set, DW20 water tanker and a bunch of Jersey cows to take care of in my spare time😄

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Sun, Aug 16, 2020 9:28 PM

Djmayer

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Reply to ccjersey:

I would say it won’t be easy. I would start with a parts book for the early 8T graders and the one for your 9K and compare gasket part numbers for block to clutch housing and oil pan to block. If those match up, then you’re down to physical dimensions like distance from clutch housing back to the bolt holes in the chunk in the middle of the rear axle. For sure you need a grader oil pan to support the engine.

I have seen a mention here of a 212 that had been swapped from the D3400 to a D311 or the other way around but don’t really know how comparable the #12’s were across that 1947-1948 model change. The oil pan may be the only difficulty. That said there should be some grader engines out there as many of them as were made.

Thanks for the suggestions. Sounds like I have some research to do.

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Mon, Aug 17, 2020 4:29 AM

JoeG

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Reply to Djmayer:

Thanks for the suggestions. Sounds like I have some research to do.

If you got a D318 out of a grader it wouldn't be that bad. The oil pan and bell housing are the main mounting points that you need to be concerned with so a crawler or stationary engine would be a bit more work to fit up. The tin will bolt up easily. It is a bit of work, but it would make a nice grader when you were done for sure. I was pretty lucky that my D4600 was in good shape, may have to fire it up today and listen to it run now that I have read this.

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Sun, Aug 23, 2020 12:11 AM

Djmayer

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Reply to JoeG:

If you got a D318 out of a grader it wouldn't be that bad. The oil pan and bell housing are the main mounting points that you need to be concerned with so a crawler or stationary engine would be a bit more work to fit up. The tin will bolt up easily. It is a bit of work, but it would make a nice grader when you were done for sure. I was pretty lucky that my D4600 was in good shape, may have to fire it up today and listen to it run now that I have read this.

Is the distance from the bell housing to the axle mount the same between the D318 & D4600 (on a grader engine)?

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Tue, Aug 25, 2020 11:21 PM

ccjersey

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You’ll have to find out and let us know!

Like I said earlier I’ve heard of an old/new engine transplant in a 212 but never in a #12.

D2-5J's, D6-9U's, D318 and D333 power units, 12E-99E grader, 922B & 944A wheel loaders, D330C generator set, DW20 water tanker and a bunch of Jersey cows to take care of in my spare time😄

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Tue, Aug 25, 2020 11:24 PM

Djmayer

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Reply to ccjersey:

You’ll have to find out and let us know!

Like I said earlier I’ve heard of an old/new engine transplant in a 212 but never in a #12.

I may have found a power unit for a 12 grader but it may be October before I get to see it I’m person.
I’ve been promised it’s a “runner” but I’ve heard that before.

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Wed, Aug 26, 2020 1:15 AM

td-alan

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Reply to Djmayer:

I may have found a power unit for a 12 grader but it may be October before I get to see it I’m person.
I’ve been promised it’s a “runner” but I’ve heard that before.

Hey just curious about what serial number your machine is ! Thanks Alan

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Wed, Aug 26, 2020 8:40 AM

JoeG

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Reply to td-alan:

Hey just curious about what serial number your machine is ! Thanks Alan

If you are asking me my Cat 12 is 9K 9071 and was a government owned unit, I bought it on the GSA auction. It needed a ring gear and the pony was full of water, well ice really, it was February here. I also put the decompression rod seals in the valve covers and new gaskets there but other than that, it is in great shape. it was rebuilt in 1968 at Schenectady Army Depot according to the metal plate on the cab, and the hour meter shows 1,400 hours, which may be correct. It came off a federal wildlife refuge near here and surely didn't see much use.

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Fri, Sep 4, 2020 6:26 PM

Djmayer

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Reply to td-alan:

Hey just curious about what serial number your machine is ! Thanks Alan

My Cat 12 is 9K8140.

[attachment=60392]114_1426.JPG[/attachment]

My understanding is that makes it from 1944. Bought it about 14 years ago from the widow of a guy who called it lucy. I'm thinking you can guess why. I've done a bit of work to get it a bit more reliable:
Rebuilt the Pony & starter (my understanding is the PO pulled start it with a truck for years)
Replaced the Radiator
Replaced some fuel, brake lines, Fuel linkage and other bits and pieces

it's a hard starter. Seams to have low compression and I'm debating if this motor should be rebuilt or replaced. any advice on running a compression test, or a leakdown test?

BTW: I back near the Grader, and its 17" from bell parting line to the center of the oil pan bolts on the final drive.

Dave
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Wed, Sep 9, 2020 6:37 AM

edb

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Hi Dave,t
there are no compression figures given in Cat literature as they do not believe in it--however, I have this scan for the later D300 series engines that you can deduce from it what you like--I feel from studying the scan that anything much below 500 PSI would be getting into the hard start area.

Worn liners and rings , but also poor seating valves and definitely sunken valve heads cause compression to be low.
Cat have fairly specific ranges for valve head position in relation to the head surface--see scans below for the D4600 engine that is in your machine.
You will need to print the valve spec pages and align them to transfer the engine type over to the second page for all the data to make sense.

A leak down test will help you determine where possible leakages are as in rings by listening into the removed engine breather's tube, and valves by listening in the intake and exhaust manifolds with the cylinder being tested with its piston at Top Center on compression stroke.

Hope this helps.
Cheers,
Eddie B.
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