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Wayne, Journeyman
Category: Agriculture and Farm Equipment
Satisfied Customers: 9532
Experience:  34 + years as a mechanic
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I have a 3306 Caterpillar in a farm tractor. I am getting

Customer Question

I have a 3306 Caterpillar in a farm tractor. I am getting compression in the radiator and pulled the cylinder head to check the head gasket. Everything looks good so far. I am wondering about the precups and injector/glow plug cups. I am not sure how to remove the injectors or precups. Is there a pressure test for this? Cylinders look excellent so I don’t suspect any problems there. There are no visible cracked on sleeves, block, or cyl. head.
Submitted: 1 year ago.
Category: Agriculture and Farm Equipment
Expert:  Wayne replied 1 year ago.

HI I'm Wayne

I will help you with this

do you have a air compressor on it

Customer: replied 1 year ago.

No air compressor on it>

Expert:  Wayne replied 1 year ago.

Hi Thank you for that

Ok, no compressor, then I suggest to take the head

to a machine shop and get it magnifluxed for cracks, that you would not see

and tell him to pressure test the cups

I hope this helped you

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Customer: replied 1 year ago.
Sorry its taking so long to respond. This has been a spare time project. i did send the head in to be magnifluxed and checked over. They said the head is straight, the fire ring seals look good, there are no cracks, and the precups passed a 40 psi test. Not sure thats enough psi to see if compression is leaking past. However, the head is back and i have orings and shims to replace on the precups myself. I am not sure on the procedure or torque specs for installing them. I did find a tool to remove and install them. Can you help me out ? Thanks
Expert:  Wayne replied 1 year ago.


here is a video on how to do it

click here

Newer CAT engines that still used PC chambers went to a single piece chamber and you must remove it and replace the seal ring underneath it that seals it into the combustion chamber of the head at the same time you change the o-ring around the top of it that keeps the coolant in. Use copper anti sieze on the threads and clean the sealing surfaces with wire brush etc so you get a good seal top and bottom. Torque to 140-160 foot pounds. Injector hold down nut torque to 100 foot pounds

Removing PC chambers is not to be done lightly. You can take the threads out of the head if you're not lucky/living right! If it has to come out, then sometimes an impact wrench will get it out with less trouble than a breaker bar once it's broken loose. If it doesn't spin right out, then go back and forth, a few minutes spent loosening it up can save you a bundle purchasing the helicoil repair from CAT that is needed to fix them when you take the threads out with the chamber.

Hi. If this helped you,

please remember to rate my answer 3 or more stars.

If more info is needed, use the reply button -