should i bug my rebuilder yet?
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Joined: May 2022
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From: Salt Lake City / Boulder, CO
So what is the best procedure for retorquing the head ? Does one want to simply retorque each nut in turn per the order in the service manual ? Alternatively, should one loosen / remove each nut one at a time and lightly oil the stud threads before the retorque ?
Schmitty
Schmitty
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Joined: Jan 2013
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From: Calgary, Canada
Yes, simply follow the initial torquing order in the service manual. That's necessary with the original style metal gasket, but with a modern style like the MLS gaskets made by Cometic retorquing isn't necessary.
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From: Oxford, UK
The service manual doesn't tell you to re-torque the head nuts. Still, it doesn't tell you not to do it and it tells you to remove nuts to fit lifting eyes. So it shouldn't do any harm and may be long term positive. I'd follow the standard order, centre out, one nut at a time, loosen about 1/3rd of a turn and re-tighten slowly but smoothly to target torque. It might be interesting to mark the initial nut orientation to see what difference it has made. I'd do this after a rebuild, not at any other time.
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From: Lake Cowichan BC Canada
I've always used grease on nuts/bolts to lubricate the threads to get an accurate torque.
The nuts/bolts should undue and do up easily with your bare hands, with or with out grease.
Any burs or damaged threads will affect the torque value.
I also apply grease to the face of the nuts/bolts and the washers they torque up against.
All of this is to allow proper slippage when torqueing to prevent galling on dry metal to metal contact.
A heavy oil will work, but grease is best, the grease stays put.
The nuts/bolts should undue and do up easily with your bare hands, with or with out grease.
Any burs or damaged threads will affect the torque value.
I also apply grease to the face of the nuts/bolts and the washers they torque up against.
All of this is to allow proper slippage when torqueing to prevent galling on dry metal to metal contact.
A heavy oil will work, but grease is best, the grease stays put.
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From: Calgary, Canada
This is important, as torque tables usually aim to bring the stress to 90% of the yield limit of the steel. Once the yield point is reached, then continued application of force results in permanent deformation of the steel, which isn't usually desired. Some modern cars do have "torque to yield" fasteners, but they are also single use. The studs in our Jaguars are not intended to be torque to yield.
One of my previous jobs was verification of the stress levels in fasteners for safety critical pressure piping joints. I attached strain gauges to the studs and then torqued them in the "as received" condition and then lubricated. The amount of stress developed is considerably larger in the lubricated test than the dry. Torque tables are always indented to be dry fasteners unless otherwise stated. If you do wish to lubricate the fasteners, you need to reduce the amount of torque you apply to obtain the same stress in the steel.
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Joined: Feb 2023
Posts: 143
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From: Jaco Beach, Costa Rica
in reference to my post #100...
after much searching i bought two temp sensors. and today i installed one of them. good news is that the one that was in the car was registering about 20C too high. i suspected this on my trip back from the rebuilders and even more so after verifying that there was a 20C difference between the gauge on the dash an my laser gun's reading.
bad news is that neither of the new one really fit. both had too many threads on them. it seems the hole in the thermostat housing into which they thread is a blind threaded hole and they were bottoming out too soon. soooo, ended up buying a couple of copper washers as spacers. this effectively reduced the threaded portion. it's now water tight. and ya, it's a hack and i don't like it. but maybe i'll forget about it in a year or two.
FYI, the thread types of the old and new (the one i eventually installed today) temp sensors matched but their hex heads did not. the old one was whitworth and the new two were probably metric. and the one i bought from moss after personally talking to their representative on the phone to make sure i was getting the right one had so many threads on it, i never even tried to mount.
in any event, the car on this warm day ran very well, and engine temps never moved above about 85C. and no heat soak or vapor lock or hard starting after a number of short five to ten minute stoppages. oil pressure was about 20psi at idle and 45psi at speed on this hot day.
things to do yet:
1) fix horn doesn't work. i'm hoping it's a wire that was left loose when the engine was pulled/installed. plan on tracking it down with multimeter, a couple of jumper wires and my spare 12v motorcycle battery.
2) front bumper looks to sag as it wraps around the front fender towards the wheel well. can't decide if i'm imaging it or not.
3) the small, orange, translucent plastic thing-a-ma-jig on top of the left front turn signal is now missing
4) power brakes are sticking on, but will release of the brake pedal is lightly tapped. it's a priority.
5) stopped by mech's shop today and scheduled a hour session on his lift for next monday. purpose is to inspect for things that i've thus far missed and maybe a quick lube as there are lots and lots of old-school grease fittings under there.
6) need to change oil and filter now that i've got close to 1000 miles on the rebuild. i'll be doing that.
7) remove HUGE double snouted air cleaner in order to mount two smaller pancake ones to facilitate carb tuning access.
probably won't update any more on this thread. the rebuilder's are now out of the picture.
thanks to all who have contributed.!
after much searching i bought two temp sensors. and today i installed one of them. good news is that the one that was in the car was registering about 20C too high. i suspected this on my trip back from the rebuilders and even more so after verifying that there was a 20C difference between the gauge on the dash an my laser gun's reading.
bad news is that neither of the new one really fit. both had too many threads on them. it seems the hole in the thermostat housing into which they thread is a blind threaded hole and they were bottoming out too soon. soooo, ended up buying a couple of copper washers as spacers. this effectively reduced the threaded portion. it's now water tight. and ya, it's a hack and i don't like it. but maybe i'll forget about it in a year or two.
FYI, the thread types of the old and new (the one i eventually installed today) temp sensors matched but their hex heads did not. the old one was whitworth and the new two were probably metric. and the one i bought from moss after personally talking to their representative on the phone to make sure i was getting the right one had so many threads on it, i never even tried to mount.
in any event, the car on this warm day ran very well, and engine temps never moved above about 85C. and no heat soak or vapor lock or hard starting after a number of short five to ten minute stoppages. oil pressure was about 20psi at idle and 45psi at speed on this hot day.
things to do yet:
1) fix horn doesn't work. i'm hoping it's a wire that was left loose when the engine was pulled/installed. plan on tracking it down with multimeter, a couple of jumper wires and my spare 12v motorcycle battery.
2) front bumper looks to sag as it wraps around the front fender towards the wheel well. can't decide if i'm imaging it or not.
3) the small, orange, translucent plastic thing-a-ma-jig on top of the left front turn signal is now missing
4) power brakes are sticking on, but will release of the brake pedal is lightly tapped. it's a priority.
5) stopped by mech's shop today and scheduled a hour session on his lift for next monday. purpose is to inspect for things that i've thus far missed and maybe a quick lube as there are lots and lots of old-school grease fittings under there.
6) need to change oil and filter now that i've got close to 1000 miles on the rebuild. i'll be doing that.
7) remove HUGE double snouted air cleaner in order to mount two smaller pancake ones to facilitate carb tuning access.
probably won't update any more on this thread. the rebuilder's are now out of the picture.
thanks to all who have contributed.!
I received a crate containing my brand-spanking new engine 4 days ago, and both myself and my mechanic were blown away at how beautiful it turned out...I'm certain it will run perfectly as well.
Best of luck!
Thread Starter
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Senior Member
Joined: Jul 2022
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Hey Huey, glad to hear my suspicions are confirmed re. your running temp. Fwiw, I got a good read on Robb when I consigned them to build my engine, and was pretty confident your sensor or gauge was lyin' to ya...plus, you made it back, which quite possibly wouldn't have happened were it really running that hot.
I received a crate containing my brand-spanking new engine 4 days ago, and both myself and my mechanic were blown away at how beautiful it turned out...I'm certain it will run perfectly as well.
Best of luck!
I received a crate containing my brand-spanking new engine 4 days ago, and both myself and my mechanic were blown away at how beautiful it turned out...I'm certain it will run perfectly as well.
Best of luck!
here's to hoping you're right
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osyris
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Jan 26, 2013 02:29 AM
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