That just helps confirm to me that 122in lbs is not enough torque.

 

I only say that because I’ve installed LOTS of injectors and none have ever gotten loose. The set in my truck now have about 125k miles on them.

I’ll see if I can verify what torque they are when I install the 250/200’s soon.

 

How much attention has to be paid to cleaning out the bolt holes prior to install to prevent liquid lock from oil etc?

 

I have pulled/replaced a "few" injectors myself, and I wouldn't think all that much. The bolt, being on a slightly raised surface from the oil drains at the bottom of the head, doesn't have a bunch of oil built up around it like the glow plugs. I don't see much (if any) oil on the bolts when I pull them, either.

 

Plus the bolts don't bottom out in the hole so there's room for liquid to pool at the bottom of the bore.

 

I was trying to look up what Grade and size the bolts are but none of the descriptions given for Ford Part F4TZ9R523A say. The give a length but that seems to be it.
Anyone know for sure?

 

I thought the injector hold downs were closed bottom holes... oh well live and learn

 

They are a blind hole, it's just that the bolt doesn't bottom out in it.

 

I clean the hold down bolts and the threaded hole in the head. I think it’s pretty important

 

So if one had enough oil in it it could potentially hydro lock or give a false torque???

 

Sure, but even though there's a sheen on everything underneath the VCs from the oil splashing around there's very little that hangs around above the injectors. The VCs barely clear everything when installed (the gasket gives it just enough spacing to clear the injector solenoids).

With the holes on top it would take a lot to get any real fluid in there. The only time I've cleaned the holes out was at 310K miles when I put in new cups, injectors, and replaced all the hold-down bolts. There was some oil moisture in there and very little at the bottom of the bore.

If I still had the truck I would only remove the bolts (and clean the bores) if I had to remove the injectors. I would not make a specific effort to remove the bolts and clean the holes unless I was using threadlocker like @Tugly does.

 

So for more fuel on the flames of the subject...


The highest torque value i can find in any "manual" form for injector bolt holes threads comes from cup seating instructions off Riff Raffs site. 35 ft pounds to seat the cup, using the 2 injector hold down bolt holes in the head. So 420in pounds, spread across the 2 bolts, so 210in pounds per bolt. BUT..... That's not using injector hold down bolts, or an injector and all its parts, crush washers, or orings during thousands of miles of hard driving. It's for seconds during the cup seating install. So although the bolt hole threads in the head can take the torque momentarily, i still wouldn't go to 30foot pounds, (360 in pounds?) for the 1 injector hold down, that's still 150in pounds more than the cup install torque on one bolt. To much risk for me in my "shade tree mechanic" driveway. Now if i were taking it down the road to Jason as a customer knowing broken bolts would be his concern, I'd say have at it

How's that for dumping some gas, err i mean diesel, on the fire



And yes, torque values are different on dry vs lubricated (oil, loctite, water, soap) bolts. There's charts on that too

 

I do have an OBS friend that broke an injector hold down bolt last year. He go it out with an easy out, but it was on the number 1 cylinder and he was using a bad torque wrench. He got lucky.

 

At least there is one thing we all agree on. You can go over 120in pounds, and it makes the engine quieter if they were below factory spec

 

It's necessary by definition or I'd imagine people wouldn't feel the need to go back in and retorque in the first place. I'd think it should work well. Heat is used for removal of fasteners where threadlocker has been applied, but that doesn't render it ineffective. Safety wire would be another method, if access allows, though it doesn't sound like it.