Head re-torque

I mentioned on an earlier post that I was getting some tiny bubbles around the headgasket between Cyl #2 and #3.

So tonight I re-torqued the head, starting at 40lbs, no movement. The at 45 three moved. Kept stepping up till I reached 65ftlbs.

Did I apply too much torque. Two of the three that had moved, well they took quite a bit to torque to 65. Hope I didn't stretch anything.

Since the head has obviously come down I probably need to re-adjus the valves right?

Jay

Spec is 50-55 ft lb
Yes the valves should be re-set.

I did this a month ago and solved my leak problem.

Yep, like Peter said, they need to be reset.

My manual says 45, so that's where I have mine. Should I torque it down more?

According to the factory repair manual, torque specs are 40-50 Ft. Lbs. Not sure what going to 65 would do.

I don't mean to hi-jack your post, but what is the proper retorque procedure?

Should you go around and loosen each nut a bit and then go around and torque to spec or just go around and torque to spec?

you should loosen them before the retorque, I do them one at a time

if you start where they are ...you will end up way off on the torque

well dang it! I did not loosen them first.

Brian do you think I'd be better off performing this again tomorrow after loosening them all or am I risking ruining the headgasket with another "crush" ?

Nah, if you only tightened them to 65, you'll be just fine.

Go ahead and check the valves for specs.

B

When you loosen them, you don't loosen them all at once. You back the one you're going to re-torque about a quarter of a turn and then re-tighten to the click at your desired torque. I use 52 pounds. Then warm up the engine to full temp and reset the valves hot. Best of luck. Basil

I would not go to 65 unless you have ARP studs, just do one at a time and go to 55 or so, I like to do the valves warm as Basil stated

I really don't see any way to damage the gasket

Jay,

You won't damage the gasket... but you are stretching the head bolts. Over tighten and you can pull the bolt past its elastic limit. You'll know when this happens because they have a tendency to snap at that point!

ARP bolts for the head and mains are a cheap investment in a hyper quality product.

Steve

Yes, the valves need to be reset after retorquing the cylinder head.

Yes, you should slack of the fastener being retorqued (1 at a time) 1/8 to 1/4 turn. This will take "sticktion" out of the picture.

ALWAYS check the book for the torque value BEFORE torquing it. If you don't have a book, get one. If you're in too much of a hurry, ask here. I don't know which books everyone is looking at, but I've just looked in both the green & black Bentleys (ie Factory specs.), Chiltons, and Autobooks manuals. They ALL say 45-50ft.lbs. for the cylinder head nuts. I have no idea where the higher values are coming from.

In the MGB racing world, re-torquing is a regular event, like once a weekend. Yes you must back off each nut about a quarter turn to re-spread any lube that's present and then bring up to torque. Do this one at a time! If you don't know the history of the car and it's service then I suggest you remove each nut and lube it, oil or anti seize, before tightening, again one at a time. If at 65 Lb-Ft. the nut did not turn then no damage was done to stud or gasket. On factory studs 45 Lb-Ft. is about max. I use 55 with ARP studs with a graphite lube.

it is easy to strip the threads in the block...I've had it happen twice.

then it's get out the helicoils and sweat that you are drilling straight.

In addition to pulling threads at high torques, you can also generate cracks into the water jacket in the pushrod side of the block which is "throw-the-block-away-time". Ask me how I know. Also, the higher the torque the higher the bore distortion with resulting blowby and poor ring sealing.

All I can say, is holy-moly, 65 lbs, you're lucky those factory studs didn't snap.

What Dave Headley said about reapplying lube to the nuts. That keeps the torquing smooth and even. That being said, don't buy replacement studs unless they are the ARP because many don't pull straight and even in the block and will pull threads out. The ARP studs also have a hex drive for installing them and torque noticably smoother.

Trying to do a bit of research before asking my queston (to follow), I came across this on another Forum:-

I do it dry, don't back off before retorqueing, and never have issues.

The goal when tightening the head nuts is to achieve an even and consistent clamping load on all 11 studs. Doing it dry would require the cleanest possible threads on both nuts and studs. Anything other than new parts would make this difficult or impossible. Oil will give pretty consistent clamping on initial torque but will tend to cook out over time. I use a graphite based anti-seize lube on the threads and the hard washer to minimize friction and give consistent clamping and it generally stays put over time at least on race engines.

chris Wrote:

Well guys the motor is coming out.

Between the wonderful oil leak at the front seal, the headgasket leak and questionable studs, and now a camshaft that may have worn its intake lobes (exhaust valve travel noticeably deeper than intake valves) I think it is best to take the motor out and go through it all and install quality components everywhere.

This really shouldn't suprise me. The PO told me he had rebuilt the engine and after seeing all of the short cut things he has done and sub-par parts he installed everywhere else on the car I have a good idea I am not going to like what was done inside the motor.

It'll get a quality cam from APT or other reputable source, hardened lifters, and vernier cam wheel so it can be dialed in exactly where it is supposed to be, best bearings available, all new ARP fasteners etc.

Have to take the motor out to fix the gearbox he ensured me was "fine" too, 2nd gear synchro is gone.

Just more money right? Ha!

You have to catch a break somewhere in there! Geez!

Hey Dave Headley,,

How far a drive is your shop from Denver?

That's what happens with the simplest B projects. Went from a head-retorque to a full engine and tranny rebuild. :)

I think what is bothering me most is that I keep running into sub par parts the PO installed. First thing I tackled when I got the thing home was taking off the aftermarket rear leaf springs that had the car sitting up like a dune buggy in back. then after apart i found he hadn't replaced the bushings with new, just slammed the old deteriorated rubber ones into the eyes and bolted it back in. Then the front end was much the same and it now has new nylon bushes and rebuilt kingpins. Suspension feels great now. But the trans is ruining the driving experience and the motor has me worried to the point i'd rather take it out and have a proffesional go through for peace of mind rather than risk it devouring itself and causing more problems later.

I'd say that is the usual fate of any old car project where you are starting with a "pig in a poke."

Think of it like this (I do... sometimes it helps), you will be a lot more confident in the middle of nowhere after you do it!

Derek up North Wrote:

So the motor is out and my oil leak was easy to find. The front damper wheel bilt was just LOOSE, yeah, just spun the bolt right out! So then I get the motor out and pull the damper forward and it slides right off to reveal a huge chunk of its neck broken out above the keyway about the shape of a sharks tooth. Where the seal runs on the dampers "sleeve" it runs right over this gaping hole.

Now to take the motor apart and see if the piece broke out during re-assembly and there is a sharkstooth shaped chunk floating around in there ,, OR ,, they new the damper was badly damaged and just used it anyway.

Previous owners,,,,,,,,, I'd like to choke that guy if I met him again.

Oh and did I mention he used the wrong fasteners almost everywhere? Yeah you know nylock insert locknuts are neato torpedo but man I hate them when they are put in places they don't NEED to be forcing me to wrench a fastener all the way off to the last friggin thread.

Rant over, thanks for listening guys

Jay