3.8L V6 Head Tightening Sequence
#1
3.8L V6 Head Tightening Sequence
OK guys, I know some of you wont respond because this is a car but give me a break. I have posted over 870 times and this is the first time I have ever posted on my wife's T-Bird. (At least it is a Ford)
I am about ready to put my rebuilt heads back on and question the procedure in the original Ford shop manual for my 1986 T-Bird. I agree with the tightening sequence up to step "e" where it states to back off the attaching (Head) bolts 2 to 3 turns. Then step "f" states to repeat steps "a" through "d." I can't believe that they want you to completely loosen the head back up and release the tension on the head gasket and then go through the entire torque procedure all over again. It seems as though you are now torqueing down a used head gasket. Does anybody have any ideas or suggestions?
I am about ready to put my rebuilt heads back on and question the procedure in the original Ford shop manual for my 1986 T-Bird. I agree with the tightening sequence up to step "e" where it states to back off the attaching (Head) bolts 2 to 3 turns. Then step "f" states to repeat steps "a" through "d." I can't believe that they want you to completely loosen the head back up and release the tension on the head gasket and then go through the entire torque procedure all over again. It seems as though you are now torqueing down a used head gasket. Does anybody have any ideas or suggestions?
#2
Since I do not know for certain, I'd hazard a guess that what you describe is what they want you to do.
There have been various methods and specs for head torque sequence for different engines over the years.
In general, one can assume the engineers described the torque sequence for a reason, even if that reason is not obvious to us.
Unless you can find definitive information describing where a revised procedure has been issued, I'd go with the original shop manual (assuming OEM head gaskets or equal replacement)
There have been various methods and specs for head torque sequence for different engines over the years.
In general, one can assume the engineers described the torque sequence for a reason, even if that reason is not obvious to us.
Unless you can find definitive information describing where a revised procedure has been issued, I'd go with the original shop manual (assuming OEM head gaskets or equal replacement)
#3
Been awhile since I did a 3.8, but here's what I remember.......
Make sure you use new head bolts. If I was doing it, I'd use Fel-Pro
as a head gasket and Fel-Pro only on a 3.8.
I believe the latest books want you to do the torque-to-yield method.
It's where you bring it up to a certain torque and then turn it a certain
amount of degrees. (90?) At least that was the method the Ford books recommended.
Don't worry about torquing it down and then untorquing it. You have not
heated the gasket up yet because you haven't started it. That helps to lubricate the threads a little better before final torquing.
Good luck. Done proper and you'll have a good engine again.
#5
Man, you must have been searching some old threads to find this thing. Im put the engine back together using the old torqueing sequence that came with the manual. I did a lot of searching on this subject before I put the engine back together. We have had this T-Bird since new and it has been a great little car except for this head gasket problem. (2nd time around)
I wanted to do a lot of research before I put it back together. We have moved since I put the car back together and all of the notes on the subject are in a box somewhere and I don’t know where that somewhere is. My memory is about as long as my little finger but the info that I got was to torque the heads down to a certain spec and then back them off and retorque to a certain spec and then tighten them another 90 degrees.
Now 90 degrees to me is a quarter of 360 degrees or a circle. In other words a quarter of a turn. I did this procedure on two bolts and one of them was getting awful tight. I set the torque wrench at 80 lbs. and it was popping long before I was able to obtain the quarter turn. The thought of tightening and aluminum head to over 80 lbs. scares the heck out of me so I backed off from the whole darn procedure and retorqued the heads back to the original specs.
I might just go to studs if I have to go through this again, but I would be interested is seeing what your green book says is the latest procedure, so it would be great if you wouldn’t mind posting them. Thanks for the response.
I wanted to do a lot of research before I put it back together. We have moved since I put the car back together and all of the notes on the subject are in a box somewhere and I don’t know where that somewhere is. My memory is about as long as my little finger but the info that I got was to torque the heads down to a certain spec and then back them off and retorque to a certain spec and then tighten them another 90 degrees.
Now 90 degrees to me is a quarter of 360 degrees or a circle. In other words a quarter of a turn. I did this procedure on two bolts and one of them was getting awful tight. I set the torque wrench at 80 lbs. and it was popping long before I was able to obtain the quarter turn. The thought of tightening and aluminum head to over 80 lbs. scares the heck out of me so I backed off from the whole darn procedure and retorqued the heads back to the original specs.
I might just go to studs if I have to go through this again, but I would be interested is seeing what your green book says is the latest procedure, so it would be great if you wouldn’t mind posting them. Thanks for the response.
#6
actually i forget how i found it.. think i was just trotting around the site... but ill get the book scanned for ya... and like kruse had said..
i do remember reading in the book they recommend using new head bolts every time, and from what ive read over the years on other sites felpro gaskets are the only ones that seem to hold up on the 3.8L's. i would also recommend trying an old school trick that some of the Hi-po v6 guys are bringing back.. and spraying the head gasket with copper paint..
ill get those pages scanned in soon as i can..
Make sure you use new head bolts. If I was doing it, I'd use Fel-Pro
as a head gasket and Fel-Pro only on a 3.8.
as a head gasket and Fel-Pro only on a 3.8.
ill get those pages scanned in soon as i can..
#7
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