Overhauling a C-12 with no experience

No special tools required to overhaul a C12. A good quality tension wrench is essential, a cat turning tool would make life easier but you can just turn it over off the balancer if you dont have one.
The best place to start would be to buy a genuine service manual from cat, it has all the information on how to pull it apart, put it back together, how it works and what the bolt torques, and clearances should be. when you consider the cost of a manual verse the cost of an overhaul they arent really that expensive.
There are only a few real tricks to watch out for when building a C12-
#1 Make sure you use new head bolts and tension the head down once, loosen it and tension it down again- this helps prevent internal coolant leaks that C12 are known for. Make sure you use the correct head gasket, there are two types and it depend on what block/head combo you have.
#2 Replace the injector lifters, do this any time you have the head off, they have a habit of flogging the pin out, dropping the injector pushrod out and damaging the cam. Cant get to these with the head on. Also when you refit the followers they are in two sets, the rear set has one extra bolt at the back underneath the head casting, dont forget to put this bolt back in as it seals off an oil gallery, you will have low oil pressure without it, and cant put it in with the head on.
#3 C12s can be hard on cam bearings, if you are doing a full inframe you should pull the cam to check the cam bearings, they crack in the lower half of the bearing, ususally in the front three or four bearings, they can also spin the rear bearing if they are left too long in service. You would need some special tools if you have to change the cam bearings, fitting them can be tricky if your not careful, most people would get the dealer to come out and remove/fit the bearing for them.

 

Yes, as Jas stated, buy a genuine Cat service manual. Don't be surprized if the manual is a couple hundred dollars, but well worth it! An inframe for shop to do is about 40 hours, so plan at least double that if you have no experience. Be patient and don't rush. I would leave the cam alone, because to pull that out then the whole front cover and gear train has to come out and that is not for a beginner. Write down your engine serial number and make sure you order all your stuff by that.

 

I would. No such thing as too much information.

 

Anything on the overhaul chart will be in the service manual anyway, if its a genuine manual that is. Make sure you get the right manual for your serial number, all C12s arent the same.
You may also be able to find SIS (Cats electronic maunal system) for a better price, they sometimes show up on ebay. Its 7 or 8 DVDs in total. A little bit of looking around the net and you can find a keygen to make it work.

 

I just ordered my service manual $950nzd thats about $475usd it covers the C15/16/18.
My wife can read me a page every night before I go to sleep should be finished about June 2013

 

The in-frame overhaul manual for 72 dollars is the one you need. I just inframe overhauled my '94 pete 379 w/a 3406E with just the in-frame manual. The special tools they recommend are in this manual. I got mine from a local cat dealer and it was like 45 bucks.

 

Forgot to mention if your engine has Jake brakes there is an exhaust bridge update that should be done, the old bridges can cause the engine to drop a valve when they are worn. who ever sells you the parts should be able to fill you in on this and show you an updated one so you know if yours has be done already.

 

Found this via google search & am sure the OP is no longer here. But just in case, how did this turn out?