D4 7U Engine Overhaul

Hello i'm new to the forum. I have a D4 serial number 7U39193. As best i can tell this has a d315 engine on it. It has developed a nocking noise and i have two questions. First what is the correct points gap setting for the pony motor and second where can i find an overhaul kit for the diesel engine?

It will have the D315 if the intake is on the fuel pump side and the exhaust is on the right side...........I don't think anything else would fit, though perhaps a D4400 would fit with some modifications, but that older engine would be rarer than the D315 and it has both the intake and exhaust manifolds on the right side opposite from the injection pump.

You will want to isolate the noise to a certain cylinder, but first examine the oil drained from the sump of the crankcase and or cut open the filters to look for metal particles. If you don't find any, If the engine will run at idle, loosen each injector line one at at time to find which one eliminates the noise (if any do). A bad injector "valve" will cause a horrific knock, but it will stop when you cut out the fuel to that cylinder. A bad rod bearing knock won't stop obviously, but best not to diagnose one that way, make sure there's not metal in the oil first, so you're not right there when a rod "makes a break for it".

It is very likely you will find that the engine has been rebuilt before, so before you purchase bearings, you will need to see what shape the crankshaft is in and what undersize it can be turned to, etc. Make sure you can get the bearings for the undersize that is planned (including the thrust bearing, front and rear main and intermediate (plain) bearing etc. Sometimes the cost of undersize bearings is so much that finding a standard crankshaft makes sense compared to turning one undersize. Several folks have had old bearings re-babbeted when new ones were NLA if you find yourself in that situation.

Some aftermarket companies list a bearing that also fits the 3304 engine, It is a lot narrower than the more expensive, but correct one for the D315/D318.

From my experience with overhauling a D318, there are no engine overhaul kits. A few companies advertise having them, but when you call them to ask about it, they say they no longer have many of the items you need in stock and can't get them anymore.

My overhaul had to be pieced together from multiple sources. A parts manual is a must in order to do this so you can give out the correct part number for the needed item.

If you need new bearings, the prices seem to be the lowest for either standard or .030 undersize cranks. I found out a complete set of main bearings for all 7 journals on a standard crank priced at $96. Only problem was my crank was no good and I could not locate another that was standard. I found a crank ground to .020, but the same main bearing set was $635. Next, I checked on a main bearing set for .030 undersize. I got six of the seven bearings I needed for just under $100, but the last bearing could only be obtained from a Cat dealer. I had to pay full price - $156.44.

Some of the places I obtained parts from are:

Regal Corporation
Florin Tractor
Weller Tractor Service

Check the sticky thread on Cat Part Sources to find contact info on these companies.