[Strokinfirst1]

Hey guys long story short rebuilding my engine, Ive called every machine shop within a 100km radius of me and everyone that has experience with these engines has more or less been suprised i want to do hardened valve seats and says its pointless and a waste of money becase the heads already have hardened seats and the tiny crack dont go into the water jacket so its a non issue, Obviously this contradicts everything ive read online so looking for some input as the cost of rebuilding the head nearly doubles putting hardened seats in.

And one of the guys supplies the major aftermarket parts supplier locally so he has done hundreds and hundreds of these heads.... and another guy does all the engines for a guy who specializes in these truck and sends him 15-20 heads a month to be rebuilt...

its hard not to listen to them as they are the ones locally rebuilding these heads nearly everyday. Would love some insight into this

 

[TooManyToys]

Technically true.

We have seen engines go from 500,000 to ~800,000 miles without removing heads and with no coolant leaks. They have to have cracks; we can see them at 100,000 miles in some cases. More concerning to me are the cracks at the injector holes.

But, they are a pathway for compression to escape, although I don't know if anyone has ever documented the amount; it would be hard to document how much is lost due to cracks or normal ring/bore wear.

I see the cracks as occurring due to the induction hardening process, and if inserts had been used at the time of manufacture and no induction hardening, we would not have them at all.

There have been respected shop people in the past who have said they redo heads with cracks, put them on the vehicles, and never have issues with them again. And they had done a lot of 6.0 rebuilds in general service. Although I never followed him, Jeremy Johnson, "lubeowner" who builds trucks for pulling, comes to mind.

I don't think it's something that "sounds" right, and many enthusiasts will run to the keyboard with their hair on fire. It makes me uncomfortable, too. INT says it's OK; Ford says it's OK. But we don't trust them anyway.

When I did my engine at-home refresh, I dye-checked the heads and saw no evidence of cracks at 75,000 miles. If I had, since it was never intended to be a lifetime engine, I would have let it go. But, if it were a business, the decision would probably be what clientele I was catering to. If I had the equipment on hand, business or personal, my drive for perfection would have me put in the inserts. But, that's me. To a general customer, I'd probably say the same as you were told.

 

[bismic]

First off, I have the utmost respect for talented machinists and machine shops. It is absolutely amazing what they can do. The good machinists take great pride in what they do and what they know, and they should!

That said, and it is only local experience I draw from, but when a machine shop has their arm twisted to do something that they recommend against, their attitude for the job seems to change. My experience has not been a personal one, but an industrial one. Does this impact the overall quality of their work - who knows, but in precision work, I think it might. It is just the way we imperfect people are. That said, on jobs for individuals, it may not matter at all, especially if a good rapport or relationship is established first.

 

[Strokinfirst1]

ok awesome thanks you for the input, i think im gonna lean towards not getting the inserts done for now assuming my heads are in decent shape. and Bismic your right i can deffinatley see that being the case just hope I didnt put a sour taste in his mouth already

 

[krazyk]

If this is a quality machine shop that specializes in diesels you will spend as much on a complete head rebuild as you will buying new o-ringed heads from KDD. I emphasize complete rebuild. That means all new valves, springs, real guides, resurface, proper valve job, checking for cracks, tanking, etc. I have made this same mistake a few times and regretted not buying the new heads from KDD.

 

[FordDoctor]

I can't remember ever seeing a valve/seat failure on one of these engines other than those caused by other valvetrain failures. The only argument to that is that I don't get to see high mileage engine work or modified engines at the dealership.