3406B 7FB inframe overhaul average cost.

Update on 3406B issues.

Finally got this thing apart yesterday...been a lot of distractions this week that kept me from working on it continuously.

Pulled the head, it's cracked in between a valve and nozzle, so that's junk.

Found #5 piston scored bad...been scrubbing liner for some time. Found 3 small cracks in 3 pistons too. The best thing though, is the ONE hole with the IPD parts in it. The last owner swore this thing was "totally rebuilt" 410k miles ago when I put this engine in the truck last June. There's his total rebuild job right there. One hole.

Goes to show you, you can't believe a word anybody says hardly anymore.

So today it's parts ordering day. I got an old crackerjack 50+ year veteran coming to clean the deck up and cut and shim the liners towards the end of the week, and we'll begin re-assembling it.

SmokinCAT...you believe in that aftermarket Italian head you say? You think it's any better or worse than an Interstate McBee? I could care less about what Cat thinks about cores, it's not even a thought in my head, I just want to make sure I buy an aftermarket head that's trusted.

 

There's no hole in that piston, that's a puddle of oil you're looking at, the picture is deceiving. But you're right in the other statements. It's over-fueled and it did get hot due to that cracked head blowing compression in the coolant, caused a hot spot/pocket, #5 suffered the worst of it.

 

Yesterday's progress; got all the liners out. Tough when you're all alone...underneath, on top, bar it over, etc...another hand's always nice but not available.

Not visible in the picture, but this head has 8 cracks in it, between exhaust valves and one between ex. valve and nozzle. She got hot.

My theory. I never saw that (brand new) water temp gauge go over 200*F in all the time I was experiencing this issue. However it was fluctuating rapidly from 200F down to 185F within a one second interval, continuously cycling like that. No thermostat will ever open and close that quickly. That was expansion and contraction...Another thing I figured is the water temp probe always stayed submerged so it never showed a problem, while the back end of the engine was probably making steam, hence the heat/no-heat situation and the explanation for the scored #5 liner/piston and the packings are fried.

But in the bigger scheme of things, I'll be in good shape once I put it all back together next week. New head, all new head bolts and rod bolts, rod bushings and balanced while I'm at it. New oil pump, whatever it needs I'll give it to her. I'm pretty lucky I made it as far as I did seeing all the damage. Could have been worse.

 

In one of my parts quotes from my KW dealer, it has a core charge of $1384.17 if that helps.

Mind if I ask what aftermarket head you went with? I went with an HHP from Michigan. Best warranty out of any aftermarket, even better than Cat themselves.