I always tap my injectors with a rubber mallet to reseat them before torquing the hold down bolt. I have had great results doing this.

 

What is interesting about this discussion is that the factory simply torques these hold down bolts with a calibrated torque tool only once (in a ‘cold’ condition inside where the temperature is probably in the high 60s to low 70s; the bolts are likely oiled and free from any debris that would cause the torque tool to stall prematurely. I think this procedure is similar for the installation of head bolts, crank/cam bearings and all other critical bolted systems.
So, while I like the idea of hot torquing these bolts, simply because it’s not hard to do, I also believe that a careful approach to the torquing process for these bolts, if followed properly, should produce a quality installation which should last for many miles. My original OEM bolts had over 580k miles on them when they were replaced but not due to any specific failure - mainly winter was just around the corner and all my work must be outside in the elements plus I used new bolts from Ford.
And I know many probably do this work during some cold temperatures so hot torquing would be fine in this scenario just to make you sleep better. Some still change their oil/filter at 3k instead of say 7500 miles - that’s fine as well.
Do consider that both the bolts and head are steel and likely have very similar coefficient of expansion factors; so, if torqued properly they should not loosen after many miles running hot.
Like everything else you can always fine a bad bolt in a large quantity of bolts causing someone a problem.
Sorry for the long discussion, not a rant, just another $.02.
Thanks for what all you guys do here on FTE, have always helped me work thru my issues.

 

Well, you're right. The "shouldn't" loosen...but they do....kinda like wheel lug nuts. Vibration and hot/cold cycles are a factor. When I did my first job, my first injector bolt was finger tight....certainly not factory spec.

 

I agree with Byron, I don't think it's so much the temp and expansion of the bolt, I think it's the injectors getting seated deeper with use, thus loosening the bolts. When I get into mine I'm going to mark the bolts to verify if they actually come loose.

 

I certainly do not disagree BB & Walleye, they do loosen up as so many here have noticed. Just making some observations. Hot torquing if time and circumstances allow is good, no doubt.

Thanks,

Larry

 

So if hot torquing results in about 1/4-1/2 turn past cold torque it seems one could just do the cold torque by the book and add 1/4-1/2 turn to achieve the same result without warming the engine. Either way, they'll be torqued beyond book spec., whether good or bad. I was going to check mine last time I had the covers off but found some conflicting info so I just left them alone to not risk doing damage.

 

I get the reasoning, but its not quite the same. It's still being torqued to the same amount of force cold and hot, not bumped up to say 160 in# when cold and in theory being at 120 when hot.

There's a lot of dissimilar thermal expanding materials involved; from the copper washer, bronze cups, steel hold down bolt threaded into cast iron heads, coolant, all the different sections of different metals making up the injectors, oil, fuel, and the injector orings when at operating temp where they will be when we are actually driving have different forces at play on the hold down bolt than just sitting at say 60* in the garage during a torque session.

We all probably know how different just an oring will react when we bend it at around 60* and again at 120* let alone at 30* or less on a cold start and 205* on the road like they will see this winter on a drive

Whether the extra partial turn is coming more when at temp from the more pliable o-rings squishing into the cups better or the difference of the steel bolt's threads expansion in the cast iron head or wherever else is anyone's guess

 

I am getting ready to re-torque my injectors.
It will be interesting to see how many have loosened up in the 3000 miles I have driven since rebuilding them.
When installing them I tapped with rubber mallet to fully seat them (could hear when they bottomed out) and I also tried the "bring them to torque spec and go another 1/2 turn" method. Based on the noise I am hearing that didn't work but I will know better when I get the valve covers off.
Could the crush washers have something to due with the injectors loosing torque over time?

 

Jimjokjv,
I’m interested in what you find. I can certainly see how the copper washer might impact the torque, especially after the system has seen some hot/cold cycling along with some ‘banging’ of the injectors during run time. I also like one suggestion to use a dead blow hammer to rap each injector, maybe after checking the torque on a few bolts, then before the hot torquing. You can rap on the injector bracket that pulls the injector down - keeps from rapping the injector solenoid.
I also thought about using some blue locktite (for smaller fasteners). For this to work however, the threaded holes must be clean along with the threads on the bolts.
Keep us posted.

 

Will do.
It may be a couple of days though as we have heavy rain in the forecast. A blessing when you live in the desert!

 

What about a buzz test before final torque. I still have not made up my mind about the hot torque yet. But very interesting. How was the injector rebuild? Complete dissammebly or just oring. New cups? Following. Will be doing mine soon next year. Like a very to the IRS. Only want to go once and only because need to.

 

https://www.ford-trucks.com/forums/1...l#post17654499

 

yes and no.
For 242 yes, for 243 it's more oil tolerant so prep isn't as critical for full strength.

 

Thanks. Very Nice. What about the injector cups, Did or would you install new cups as well?

 

No on the cups, mine still looked very good.