MG-Cars.info
MG Midget and Sprite Technical Proper re-torque procedure? BBS discussion at MG-Cars.info
MG-Cars.info
Welcome to our Site for MG, Triumph and Austin-Healey Car Information.
Parts
MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.
|
|
MG Midget and Sprite Technical - Proper re-torque procedure?
| With 600 miles on the odometer since the Anklebiter came out of rehab, I guess it’s time to re-torque the head. How should this be done? 1. With the proper sequence in mind, do I loosen the nuts one at a time and re-torque, or do I loosen them all before tightening them again? 2. If all of the nuts need to be backed off before retightening, does the head need to be loosened? 3. Outside of the valve cover, the nuts and washers have been painted. Do they have to be removed and stripped of paint? 4. Do the studs need to be oiled or lubricated in some way? 5. 40 ft. lbs? I'll check the valve lash after re-torquing. Anything else I should know? Thanks, Paul 
|
| Paul Noeth |
| Paul, Thank you for starting WW3, and so close to the holidays....haha A couple of camps ....tea vs coffee, biscuits vs toast, valvoline vs pensoil, hot vs cold retorques, showerers vs bathers...bla bla blah, you get the pic. 1st are the HOT torques, they belive drive it for 500 miles then get the engine good and hot, and retorque it while avoiding 3rd degree burns, the reason being.. the engine dosnt run cold, only hot so the torque spec should be be set at the temp the engine normally operates at 2nd group they are the evil cold torquers... a dasterly bunch of heathens, they like to retorque any time the temp is below 0 degrees...I think they do it this way because the haynes book told them to do it this way...they like cold coffee, pensoil, cold baths, and cold toast I never back my nuts off I just mark the nut with some paint, set the target torque then apply the torque .... done! Id check the head gasket maker for the proper torque...most are around 50psi, dont add a few extra ft lbs for good measure, you can over squish the firing rings of the head gasket and blow out the gasket in a hundred miles doing that, so stay with the head gasket makers recommendation...then recheck your valven clearance tolerance...agian hot, not cold... unless your one of those guys Good luck Prop |
| Prop and the Blackhole Midget |
| Is your head 9 or 11 stud If its 11, then the stud at.the front only gets around 10-15 ft pounds or it can do some damage Also remember the smaller studs in the center of the head that helps hold the rocker arm gear (5 studs ???) They only get a good stiffening snug up, not the full 50ftlbs load,,, or they will strip out!!! Prop |
| Prop and the Blackhole Midget |
| Personally, in over 40 years of playing with cars I have never retorqued a cylinder head, and it's never been any problem. Something in what I loosely call my mind tells me that if you use a composite gasket (with a soft layer) you must not retorque, but it can be done with copper type gaskets. But I've never really understood why. |
| Mike Howlett |
| I pretty much agree. At least on the old head gaskets. You put the head on, torque it, run it to temp and retorque again. That's it until the head has to come off again. But some newer hgs are said to need to be retorqued by some people. Whose hg did you use? Were there any retorque instructions? Prop. You forgot Vaseline vs KY Jelly. lol. |
| Lawrence Slater |
| I usually re-torque mine. No particular time/mileage, I guess I do it after I've got it running right or after the first run out. I do it when it's cooled down and always back off the nuts a little. I set my torque wrench and going in the sequence for tightening I back of by 1/4 (ish) of a turn then immediately tighten back up. One at a time. The nuts nearly always go past the original position on the re-torque. If you don't back them off a bit I find that the initial break away torque required to get them moving means they stop where they are. I'm not saying that the above what you should do, just telling people what I do myself!! |
| john payne |
| My only successful new HG install (third attempt) was my present Payen and like John says (back off a quarter etc) but I re-torque cold after a 5 min engine run in the garage. One of my original problems was not well cleaning and oiling the stud threads and nuts. Only other thing to watch is the poor new washers that can be supplied these days instead of the original hardened ones. I used the originals. I see your pic is of an A series so should be relatively straight forward and successful compared to the 'rings' gasket on a 1500. |
| Dave Squire |
| Iron head, retorque hot. The steel studs expand more than the cast head. So the studs are 'loose' when hot. Ally head, do it cold. The ally expands more than the studs. So the studs are 'loose' when cold. I can't see that changing even with modern head gaskets. |
| Lawrence Slater |
| some suggestions here http://arp-bolts.com/p/FAQ.php |
| mark 1500 on the road Preston Lancs |
| The BMC WSM says to torque the cylinder head, run it up to temperature and re-check the valve clearances. No mention of re-torqueing. |
| Dave O'Neill 2 |
| That's specific to ARP studs Mark. So maybe modern studs should be done according to the suppliers/makers instructions, and the car book should be ignored. Dave, that's true. But in the specs, they only give the valve to rocker clearances cold. So unless you know the hot clearances, you have to let it cool. I'm pretty certain that years ago, the h gaskets used to come with retorque instructions. But maybe the new HG's just don't need it. Does it do any harm to retorque? That the question. I've always torqued cold, and then retorqued when first hot. The only time I've had an hg fail within a couple of hundred miles, was when I snapped a stud and replaced it without using a new hg. Otherwise they've lasted years, and many 10s of thousands of miles. |
| Lawrence Slater |
| Of course, the other biggy not mentioned in the official Spridget w/s manuals, is the unmentionable rear hub nut torques. Don't mention that though, because down that road lies madness. lol. |
| Lawrence Slater |
| Ignoring copper head gaskets then some modern A-series gaskets do not require a re torque. They also have a covering so that the cellophane wrapper should not be opened until the gasket is to be used as the coating may dry out. So if your gasket comes wrapped then read the instructions. I get mine from Minispares. Alan |
| Alan Anstead |
| Thanks everyone. Prop, I appreciate the enlightenment. I had no idea this was a controversial subject. It adds to my confusion about brake fluid, synthetic oils, spark plug wires/EMI and why I even own the car. After reading all of the comments, it seems my big mistake was not re-torquing after running the engine though a heat cycle or two. For some reason I had the impression this was to be done after the engine was broken in. That said, I am all in on Mike Howlett’s comment, "I have never retorqued a cylinder head, and it's never been any problem." This car has been driven 600 miles over a several week period with no engine problems at all. I am thinking the best action would be no action. If it ain’t broke, don’t fix it. (I’ve been known to fix things until they no longer work.) …………. Should anyone care, here is the back story on the engine. This is the first car my wife and I bought after we married in 1972. The car was a junk yard refugee. The lower driver-side A-post hinge was swinging in the breeze, the road was quite visible through the floor boards and while the car ran, not much else worked. Insulation was melted off the wires in several places and it’s a wonder the car never burned to the ground. Having no clue, we paid $250 dollars for it and felt like Royals as we motored about the country side in our little British sports car. Around 1975 I rebuilt the engine because the bearings knocked, it had about zero oil pressure at idle, and belched a blue haze out the tail pipe. About 1,500 miles later the hydraulic line to the clutch rusted through and I parked the car until I could get around to fixing it. Fast forward to 2002 and the time came to either fix it or scrap it. We decided to fix it. Although I rebuilt the engine way back when, it never stopped burning oil. I had just parked it and never prepared it for storage. I later drained the radiator and block but that was it. I did not know what kind of damage may have resulted from the car setting all of those years, nor why it continued to burn oil after the rebuild. So I sought the help of a professional. I yanked the engine out of the car and brought it to Richey’s Imported Car Care in South Bend, Indiana. The owner, Richard Milburn, had been in business for as long as I could remember. (I had him inspect the block and rebuild the head in ’75). Milburn had been trained at the British Leyland factory and worked as a dealership mechanic before starting his own shop in 1966. In 2002 he was still racing his own ’66 E-type Jaguar in the vintage class. I was concerned he would retire soon so I brought the engine to him before I even started on the body work. (He did close up shop a few months after the rebuild.) After the tear-down, Richey said the engine looked fine. The cylinders were not scored, the rings were not broken nor did he find anything out of order. He could not explain the oil burning. He went over the engine top to bottom, new rod bearings, crank bearings, rings, honed the cylinders, and lapped the valves among other things. As part of the rebuild, he installed a Rivergate 5-speed adapter plate and rear oil seal modification. After the rebuild, I filled the crankcase with oil, squirted light oil into the cylinders and turned the engine over with the starter every six months or so. The engine sat for about a dozen years before I retired and found time to finally get the ankle biter out of rehab. Incidentally, the engine started the very first time it turned over. The idle was way too high so I shut it off, adjusted the setting, warmed it up again, set the timing, synced and adjusted the carbs and have not had a lick of mechanical trouble with it. Keeping my fingers crossed. Paul 
|
| Paul Noeth |
| Like Mike I have never retorqued in over 40 years with no trouble on both iron and ally engines. I do not think they were retorqued when built new, so see no reason to do it when the gasket is renewed. Trev |
| Trevor Mason |
| Paul Thats a great story, thanks for sharing it Is it still leaking or is it cured ? Prop |
| Prop and the Blackhole Midget |
| Haynes manual tells all - unless ARP. As it only takes 10 minutes or so, cannot see any harm in checking torque on head bolts. |
| Mark O |
| Prop, is what leaking? My steering rack leaks at the pinion and to fix it right I would have to remove the rack, disassemble and have the housing and pinion gear shaft machined to accept a proper seal. Not going to do that anytime soon. The engine seals, the oil pan, valve cover and rear axle seals do not leak. The engine still leaks a tiny bit of oil into the cylinders. I've used about a quart in the first 600 miles. I hope that gets better after I change the break-in oil for a lubricant with a higher viscosity. Paul |
| Paul Noeth |
| Opps sorry paul, I should have said burn oil not leak oil... common habit I guess ....haha Prop |
| Prop and the Blackhole Midget |
| Like Mike and Trevor, I don't re-torque unless a workshop manual or manufacturer's instruction says I must but, frankly, I'm trying very hard to remember when that's been the case; it might be that I've never done it.... there's tick in my head to do with a Renault 18, but it's lost in the mists of time. |
| Nick Nakorn |
| Nor me. I use the standard black composite gasket supplied by AH spares. Not had a problem. I just make sure the mating surfaces are scrupiously clean and flat. I currently run an 11 stud head but I don't think it makes much difference. |
| Bob Beaumont |
| I've been thinking back to when I strated re-torquing hot after first engine start. It was when I had my Ford Consul Capri. 116E engine. In the workshop manual for that, it definitely said to recheck hot, and that was a cast iron block and head. Haynes for Spridgets is at best ambiguous. In the A-series engine section it just says, -- " Run the engine until normal operating temperature is reached and then recheck all EXTERNAL nuts and bolts." --- Since 4 of the head studs are under the rocker cover, does that exclude them from recheck? The BL manual is also ambiguous. On first reading, it does seem to suggest that the intial COLD torque, is ALL that's required. I say that because it DOES say to run the engine to temperature and check the valve clearances, but DOESN'T mention the head studs; Although, the bit they leave out is to allow the engine to cool off again, and then check the valve clearances. But why do you need to check the valve clearances again, unless the head has moved relative to the block face? If they go to the bother of mentioning running the engine till hot, and then rechecking the valve clearances, doesn't that imply that the head should be retorqued too, because the hg must have been compressed enough to alter the valve clearances? However, there are those here that have only ever done a first cold torque, never retorqued, and not had a problem. That suggests, as proven over time, you DON'T need to retorque, whatever the books actually said or meant. At least as far as the bog standard head gaskets and studs are concerned. The next engine I'll re-build is my Sprite engine. So I'll experiment. I'll do the first cold torque, run it to hot, NOT retorque the studs, let it cool, adjust the valves, and then see what happens over the ensuing miles. |
| Lawrence Slater |
Here's what the BL book actually says btw.
|
| Lawrence Slater |
| BL/BMC may be saying to recheck the valve clearances because the valves 'may' have been refaced, so are likely to bed in |
| Dave O'Neill 2 |
| My experiance has been poor with the current off the shelf head gaskets, they used to separate when you removed the head and took all day to clean up and get ready for the new gaskets.... now they hardly leave any residue behind and look as clean as when they where installed...which I belive was a big part of my H. gasket problem With my new MLS H. gasket it was surprising how much spec it lost before I did the 1st hot retorque... most of the nuts where off by 1/4 turn I think its imperitive anytime you retorque the head you readjust the valves...even 1/16 of a downward turn im sure can equate to a 100 of an inch or more in the valve lash, plus if the torque was off by 1/4 of a turn at the front of the head and a 1/16 of a turn at the back of the head, thats going to do some wierd stuff to the state of your engines tune and performance as it relates to the valve lash...in my opinion Prop |
| Prop and the Blackhole Midget |
| My experiance has been poor with the current off the shelf head gaskets, they used to separate when you removed the head and took all day to clean up and get ready for the new gaskets.... now they hardly leave any residue behind and look as clean as when they where installed...which I belive was a big part of my H. gasket problem With my new MLS H. gasket it was surprising how much spec it lost before I did the 1st hot retorque... most of the nuts where off by 1/4 turn I think its imperitive anytime you retorque the head you readjust the valves...even 1/16 of a downward turn im sure can equate to a 100 of an inch or more in the valve lash, plus if the torque was off by 1/4 of a turn at the front of the head and a 1/16 of a turn at the back of the head, thats going to some wierd stuff to the state of your engines tune and performance...in my opinion Prop |
| Prop and the Blackhole Midget |
| " -- they used to separate when you removed the head and took all day to clean up and get ready for the new gaskets.. " I just removed the traces of an old Payen from my spare Sprite engine. It was stuck mostly to the head, and some on the the block as you described Prop. It was the silver variety. I must have bought and fitted it sometime back in the mid '80s, so it may only have been the longevity of it's service life that made it stick so much. As for the Valves. This is what BMC/BL say. But I think the main point is that they will be "finally adjusted" because it's a new head gasket, which may/will inevitably be compressed when you re-torque the head. Clear as mud then? 
|
| Lawrence Slater |
| ""will be finally adjusted"" By whom ? GOD ! or just pure blind luck I think the phrase by how its delivered means your going to adjust the valves at some point, just you wait and see buck aroo Prop |
| Prop and the Blackhole Midget |
| Valve re-adjustment. That's something I've done for years on worn/high-mileage pushrod engines. The reason is that the followers, pushrods and valves, when checked cold after a rebuild, will not be in their most settled positions and, as the engine is run, those items can rotate relative to each other and thus their aggregate lengths per valve tend to shorten a little; sometimes quite measurably. Think of the top of a valve stem (for example)as a worn asymmetrical slope rather than a nice flat perfect plain and there's lots of scope for readjustment after it has settled to its least stressed position. |
| Nick Nakorn |
| Nick, I found that to be true. The valve lash was set cold before starting the engine. After running the engine on and off for about an hour, I checked the valve lash. I did not re-torque the head. Some of the gaps opened slightly but a couple had opened a few thousandths. |
| Paul Noeth |
| None of that alters the fact that if you re-torque the head, assuming the nuts turn, you'll likely compress the gasket more, and hence close the valve/rocker gaps. In the end, it's still an open question. Retorque or not, and if yes, when? |
| Lawrence Slater |
| Indeed, 'if' one re-torques. I tend not to re-torque simply because it was never included in my training and never came up as a subject (though some students claimed it ought!). I think it's true to say that, as the studs 'relax' slightly, or as a dirty/binding thread unbinds, a few lbs/feet might be knocked off the torque reading, but I think we always assumed that manufacturers were well aware of that and so set their torque figures accordingly. But if all is clean and the studs and threads are in good shape then a tiny variance around the quoted torque figure will make no practical difference. I think manufacturers knew what they were doing in terms of holding cylinder heads on properly even in the 'old days'. But if a manufacturer actually instructs an essential re-torque, I'm happy to follow that procedure. I think a lot of the 'desire' for re-torquing came from the garage/repair industry who could charge money for it whether needed or not. So I don't think it's an open question really; if it were needed then I think it would be standard procedure. I'm not 'against' it but I'm not convinced it's a valid procedure either. Still, if there's data out there saying re-torqued heads last longer I'm very open to changing my mind. |
| Nick Nakorn |
| Any one asked miley cyress, she seems to be an expert on "twerking" Torqueing ... twerking, ehh - basically the samething Prop |
| Prop and the Blackhole Midget |
| "Torqueing ... twerking, ehh - basically the samething " it's no wonder you have so many head gasket issues Prop. |
| graeme jackson |
| If he torques his dick, he has more worrying issues methinks. lol. |
| Lawrence Slater |
This thread was discussed between 06/12/2014 and 12/12/2014
MG Midget and Sprite Technical index
This thread is from the archives. Join the live MG Midget and Sprite Technical BBS now