3406B Advice

I haven’t met an engine yet that doesn’t pull better over 1500

 

It would be interesting to have your final feedback when you will do it.

 

GWell it can still be all over the board. Depending on how good shape plungers and barrels are, lift pump, having all the air out of the fuel etc. I say all that because a B model will still run pretty fair with a minor issue. Rather than find and fix this day and age most just want to turn it up. I think this stems from putting a “tune” on the electronic motors. Very few realize how good a 425 runs if it’s right. If you combo is right it ought to lay out 500-550. Now that said the 5EK at 550 is gonna be stronger the mechanical just won’t produce the torque that an E will.

 

Back of head to left rear block corner. Some new heads come drilled some don’t.

 

Why? And should it be machined out for it?

 

It helps cool the rear of the block. I always mark and drill mine. Being honest I’ve read somewhere that’s it’s not necessary on the new CAT heads but I can’t help myself habits and #### like that lmao. I’ve read the newer heads have as much as 30 percent more flow. Back when that PIP first come out it was to prevent dropping 5&6 liners. I have seen it drop the rear of block by 15 degrees. So I stick with it. I also run a 6NZ oil cooler as well as a dual thermostat housing on my mechanicals. Up till a few years ago I insisted on a genuine PACCAR 4 core radiator and charge cooler. They just seemed to handle the heat better. Today they are same #### as rest in my opinion. I also refuse to run a heater hose to the right rear of block. It’s probably coincidental but I’ve seen too many scores pistons on #6 the night yiu turn the valves on. Again I’m not saying that it’s sure death I just don’t take unnecessary chances since I hate working on #### these days.

 

It must have been early 90s when Cat came out with that procedure? I had my truck in the Cat truck shop in Boise for something like valve and bridge adjustment or something. They told me about drilling the head, and did the work at no charge as I recall.

Those were good days!.

 

I just don’t know why they aren’t drilling them from the factory.