Engine building geek question:

[Zeke]

Originally Posted by speeder

And sure enough, it does say to oil the bolt flanges. Missed that previously.

IMHO, the dry feel friction you felt was not the threads but the dry flanges. Doesn't matter one bit, still the same problem of achieving the exact torque. So, will you remove one at a time? I assume these are not single use bolts.

It's been many years since I built an engine but IIRC if you remove all the bolts and start over you would need new head gaskets. A small price to pay for your confidence that things are correct. Since the engine is apparently out of the truck on a stand, it would seem easy to re do it.

Only my opinion.

[John Rogers]

I looked on the Ford Powerstroke forum which I used a lot when I had my 2000 F350 with the same engine. I also called the fellow I raced with who works at a diesel repair shop just east of San Diego and posed your question. He and the forum both said the head bolts are single use only as the stretch and due to the metal they are made of will not stretch correctly if you try to reuse them. He said he dips each threaded end in some engine oil (new and clean) and sits them on a shop cloth to let excess run off. He uses an acid brush to oil the seating surfaces just before they get closed up. He also noted to not remove a stud at a time due to the need to replace them and once you remove the head due to wrong bolt tightening you have to use a new head gasket.

[Steve Carlton]

Off with your heads!

Sounds like it would be easier to do it right now vs worry later. You can’t really base the decision on that engine’s history, as it’s based on engines that were assembled correctly (if there is a difference).

[sammyg2]

I have a spreadsheet at work that calculates the % of yield on different fasteners based on toque and friction factor.
The difference between dry and lightly oiled with machine oil is huge.
It takes almost twice as much torque to reach the same % of yield with dry threads.
But ..... if there was oil on the threads and it had a little time to soak in, consider them oiled.
Even if the majority of the oil was wiped away or pressed away or whatever, it's still there and working. It gets into the pores and that's where it does the work.

Here's an interesting study we did one time:
We took two identical centrifugal pumps driven by 40 hp motors. we assembled one pump with new SKF ball bearings with no lubrication whatsoever except the preservation film they were shipped with.
IIRC the radial bearings were 6310 C3 and the thrust were 7310 BECBM.

We assembled the other pump but soaked the new bearings in shell turbo 32 mineral oil for about 10 minutes prior to assembly.
We started both pumps under load with no lubrication.

The pump with the bearings we soaked in oil ran for over 24 hours but was obviously eating itself up by that time.
The other pump lasted less than an hour before vibration levels exceeded safe limits (approx .8 ips).
Most of the pumps at that plant ran on nothing but a very fine mist of oil that was barely visible.
And that's all they needed.

[John Rogers]

There was a great point made there about "shipping preservative or oil" and I remember when a couple mechanics in #2 engine room on the USS Enterprise reassembled a sea water cooling pump with new bearings and did NOT grease the new parts. The pump ran about 10 minutes before it seized and ended up ruining the shaft as the inner bearing spun! We had two of those pumps in each reactor plant and no more spare parts so we sweated bullets while off the coast of Vietnam until Ingersoll Rand could get us a pair of shafts and several sets of bearings! Fortunately the case was not hurt, not sure why, guess the outer race was nice and tight?

[Zeke]

Single use. Well, there you go. It's do over time.

[speeder]

Originally Posted by John Rogers

I looked on the Ford Powerstroke forum which I used a lot when I had my 2000 F350 with the same engine. I also called the fellow I raced with who works at a diesel repair shop just east of San Diego and posed your question. He and the forum both said the head bolts are single use only as the stretch and due to the metal they are made of will not stretch correctly if you try to reuse them. He said he dips each threaded end in some engine oil (new and clean) and sits them on a shop cloth to let excess run off. He uses an acid brush to oil the seating surfaces just before they get closed up. He also noted to not remove a stud at a time due to the need to replace them and once you remove the head due to wrong bolt tightening you have to use a new head gasket.

Are you sure that he was thinking 7.3 engines? I have the entire FSM pages for engine assembly, (posted a screenshot above), and it does NOT specify using new bolts. And it is very detailed. I’ve never used new head bolts. No one I’ve ever known or read on a forum used new bolts. If you go to a dealer parts counter and ask for all new head bolts for a 7.3 Powerstroke, they will look at you confused and ask, “why?”

Ford sells a comprehensive rebuild kit for the 7.3 under a Motorcraft part number that has not only everything you need like new pistons and every imaginable part, plus things you really don’t need, like a new oil cooler. It does not come w new head bolts, because you don’t need them.

So I’m going to say those people are mistaken. I’m OCD as all get-up when it comes to building engines and I would never cheap out on something like that. If new bolts are specified, I get them, period.