Spark plug ejected Ford 5.4

[Colt45ws]

Originally Posted By: The_Eric
Originally Posted By: Colt45ws

There is a place advising using a very high torque value on the spark plugs to prevent them from loosening, but, Ive checked and the stock value of 10ftlbs is about all you want to give a 4-thread head. Taking into account the strength of the cast aluminium.
An 8 thread head is much better in that respect, and 18-22ft-lbs is doable. So, I did tighten the plugs on the F150 to 18ft-lbs.


The place you're referring to tested a head to 100lbs without ripping threads out- I think it'll handle 28lbs just fine. I've done several this way and ALL have felt rock solid.



Yeah, and I found a bolt torque calculator and ran through a few different numbers and 11 or 12 was all it would give the heads with 4 threads, IIRC.

 

[Run]

Update! Truck is back on the road. The boss is lighter of some cash. Its running like nothing ever happened. Now should I get the oil changed or wait it out until the end of the OCI? Hmmmm....

 

[Colt45ws]

Give it at least a couple thousand for the garbage to wash out of the system and into the filter.

 

[The_Eric]

Originally Posted By: Colt45ws
Originally Posted By: The_Eric
Originally Posted By: Colt45ws

There is a place advising using a very high torque value on the spark plugs to prevent them from loosening, but, Ive checked and the stock value of 10ftlbs is about all you want to give a 4-thread head. Taking into account the strength of the cast aluminium.
An 8 thread head is much better in that respect, and 18-22ft-lbs is doable. So, I did tighten the plugs on the F150 to 18ft-lbs.


The place you're referring to tested a head to 100lbs without ripping threads out- I think it'll handle 28lbs just fine. I've done several this way and ALL have felt rock solid.



Yeah, and I found a bolt torque calculator and ran through a few different numbers and 11 or 12 was all it would give the heads with 4 threads, IIRC.


I'm thinking there was another member who did some calculations an ended up within a pound or two of the value listed by the website in question?

Wasn't that in the last thread on Ford spark plug threads? I know you, me and someone else was talking it over...

 

[Colt45ws]

That was me that re-ran the calc with a doubled yield strength over the inital number.
First post where I find 11-15ft.lbs. is safe
I posted one before this where I got 21-28 ft.lbs. but it was with the 8-thread engagement length.
Second post where I doubled the Yield strength of the head; as if it was heat treated ( which I seriously doubt) and got 21-28 again

I just don't see 100ftlbs out of any of these heads and I don't know how they tested that. If they cracked the torque wrench at like 20, then spun it to 30 and cracked it again, etc, etc, it would be suspicious to me because you have to be moving the bolt to get a proper torque. So you'd have to back the bolt off, then retorque to the new number.

 

[Merkava_4]

Alotta good videos on YouTube about it. Check out FordTechMakuloco and South Main Auto.

 

[The_Eric]

Originally Posted By: Colt45ws
That was me that re-ran the calc with a doubled yield strength over the inital number.
First post where I find 11-15ft.lbs. is safe
I posted one before this where I got 21-28 ft.lbs. but it was with the 8-thread engagement length.
Second post where I doubled the Yield strength of the head; as if it was heat treated ( which I seriously doubt) and got 21-28 again

I just don't see 100ftlbs out of any of these heads and I don't know how they tested that. If they cracked the torque wrench at like 20, then spun it to 30 and cracked it again, etc, etc, it would be suspicious to me because you have to be moving the bolt to get a proper torque. So you'd have to back the bolt off, then retorque to the new number.


I see what you're saying. I still feel that they are on the right track. They seem to be pretty concerned with making a quality repair once the plug has blown out and also concerned with keeping them from blowing if they haven't yet.