I am tearing down a 4BT for total rebuild. The previous owner had already removed the injection pump...without locking it at TDC. Its unknown if this engine has ever been opened up or turned up.
On removal of the timing case cover, checked/noted the index of the Pump Drive gear in relation to the Camshaft gear. The Cummins shop manual shows to use the 'F' letter on the pump gear. TDC was located by barring the engine until the timing pin went into the hole. At this point, I checked the index of he pump gear/Letter F. It was one tooth off. Crankshaft and Camshaft marks dead on. Any thoughts why someone would set the pump drive gear one tooth off. Due to clearance inside the timing case with cover on, the gear cant rotate after the pump is removed to jump a tooth.

The manual also says to be sure there is no oil/grease on the pump shaft when replacing the drive gear or it can slip. How can it slip since there is a woodruff key on the shaft and the drive gear is cut for the key ?

Finally, how can I get the injection pump to the proper time and lock it since it was removed with out locking at TDC

Thanks
8Valve

 

Welcome to DTR, 8Valve! The no oil/grease on the pump shaft has nothing to do with the rotary pump you're dealing with. The inline pumps use a press fit that has no keyway, hence the need for a clean, dry fit. Does your service manual detail both rotary and inline pumps? I can honestly say that I don't remember how the letters are supposed to line up, but if you trust the info from the manual, just slide the pump gear out and line the letter up while everything is at TDC. At that point, there's only one way the pump can go on (because of the keyway) The VE pump has slotted mounting holes to adjust the static timing advance...some people (like me) find that even that range of motion does not provide enough timing lead at higher RPM..sooo, jumping the gear by 1 tooth adds Xdegrees of extra advance to play with ---maybe the PO of your engine did that trick. Either way, the worst that will happen is it won;t run. Tons of white smoke and/or no start=retarded 1 tooth. Just don't forget to pull the timing pin in from the cam gear before you crank it...also, check to see if the lock on the pump was engaged at some point. Good luck! Hopefully someone who knows the gear letters better than me will chime in!


Sooo, what's the 4bt going in?

greg

 

Greg;
Thank for the info, I understand. The gear was probably jumped one tooth for more timing. The lock on the VE Pump was not ingaged when the PO removed it. Your saying just to turn the pump so the keyway matches the keyway on the drive gear ( while engine is at TDC) and that is the same as locking the pump at TDC and then removing it ? If so, thats a simple fix.

This is going to be a spare engine. I have a 4BTA CPL857 in my 1943 Dodge Carryall, 4BTA CPL 857 in my 1954 Dodge M37. This coming summer, a 4BTA CPL 1260 is going in my 1967 Dodge Power Wagon and I have a 4BTA CPL 1260 for the 1952 Dodge Power Wagon Swivel Frame I am building. Both the CPL 1260 engines are charge air cooled aftercoolers. I plan to convert them to Liquid Cooled aftercoolers like the CPL 857's on my other trucks. The design of the old power wagons does not lend to a charge air cooled system

Pictures on my image event site;
http://imageevent.com/moosecreekmaple Many albums on 'How To' for Power Wagons.

8Valve

 

I looked at EVERY photo. Great trucks, I salute your craftsmanship. Exciting journey. How much time did you take for the loop? Did the faster traffic do any damage to your paint?

 

Rare1;

The paint got some stone chips on the Trans Lab Highway which is a primative gravel road. The underside of the fenders looked like a sand blaster hit them after 539 miles on the gravel. Its a war wound, her Purple Heart. A little touch up and she is good to go. My trucks go off road 4x4'ing, they are not trailer queens. By the way, over all average fuel use on 3411 miles, which includes 539 miles of gravel and slow speed was 25.9115 mpg. The Carryall weighs 7300#.

8Valve

 

Rare1;
Sorry forgot your question, 18 days for the loop

8Valve