Cylinder head nuts

[Midget 1500]

One of my MG Midgets is the one with the Triumph Spitfire engine (In my case, it is a Toledo 1500 engine, fitted under warranty, when the original engine seized up).  I've owned the car since 1984 (But met the second owner of the car, years later, who confirmed why it has what I knew to be an engine originally from a Toledo) and during the intervening years, have carried out numerous alterations, such as fitting an overdrive box.  The very first item was an oil cooler, as the suspension cross member obscures the sump and the Midget 1500 was apparently more prone to engine maladies, than the Spitfire 1500 (I am sure the lack of overdrive will have made a difference).

Is there any special tool, that allows you to cheque the head torque, without removing the rocker shaft?  I know there are crows foot devices but you have to be careful how you use those or else the torque is modified.  Many years ago, I had a VW Golf GTI and there was a long socket, with an open side, which was used for tightening up the nut on top of the front suspension (An Allen key held the bolt steady, which was actually the part of the shock absorber and the Allen key went in through the side of the socket).  Something similar could work on the Triumph engine.  

As I type this, I have just remembered that I have a VL Churchill tool catalogue (It's years since I looked in it), though none of it is now going to be available.  I'd be interested to know if there is a way of checking the head torque, without removing the rocker shaft?  It's not something I do all the time but it would save a bit of time when I do!!

[dougbgt6]

On a Triumph half the head nuts are accessible to one side of the rocker cover and take the cover off to get at the rest. Or did I misunderstand what you're asking?

Also once you've re-torqued you'll have to do the tappets again!

Doug

Edited May 24, 2023 by dougbgt6

[JumpingFrog]

I've never seen or heard of a tool to torque those head nuts without removing the rocker assembly. If you're re-torqueing them because you've fitted a new head gasket, you probably want to check the valve clearances too? If the gasket has compressed, the valve clearances will also have changed.

I would be inclined to leave head nuts alone after the first re-torque, the only reason for the re-torque is due to compression of the gasket early in its life, I don't think they're prone to working loose on these engines?

Edited May 24, 2023 by JumpingFrog

[Midget 1500]

It's the rocker shaft I was asking after.  A few years ago, I fitted a new camshaft and de coked the head at the same time.   I have a TH5 cam and they didn't seem to be very durable.  It appears that they are often re profiled cams and this is the reason.  The new one came from Jigsaw Racing (Mark, who has retired, due to ill health, was most helpful) and it is made from a new billet.  For various reasons, I don't suppose I have done 500 miles since (Last year, I used it just once).  The head was re torqued (I know the valve clearances have to be re checked when this is done), after initial running but I was thinking  about doing it again, before I take it out this year.  It just occurred to me that it would be quicker if I didn't need to remove the rocker shaft as part of the process.

This is my first post and it seems to have ended up in the wrong section.  Can it be moved to the engine section?

[KevinR]

As Midget1500 has indicated, using a crows foot fitting on a torque wrench can give an incorrect reading.

Ideally, if you have a torque calibrator, you can set the torque wrench up to include the crows foot in the breaking torque.

If you don't have a torque calibrator, then the error introduced by the crows foot can be minimised by setting it at 90 degrees to the shaft of the torque wrench, rather than inline with the shaft.

[Pete Lewis]

as you must re check the tappet clearances after a retorque removing the rockers isnt such a bad idea 

Pete

[Midget 1500]

3 hours ago, KevinR said:

Ideally, if you have a torque calibrator, you can set the torque wrench up to include the crows foot in the breaking torque.

 

What an excellent idea.  As it happens, I have torque wrench checker (I sell some torque wrenches and it helps to make sure they are right; I once had a batch that were poor, so they went back to the supplier), so this would be one way.  Don't have a crows foot though, at least not yet.  I'd rather a ring spanner type one but not sure if there is such a thing.

I am getting the impression that, as I have always done, people just take the rocker shaft off each time the head torque is checked.  I know it's not a frequent task but I had wondered if there was another way, that would save some time.  I guessed there would be more knowledge, on this forum, than others.

Edited May 24, 2023 by Midget 1500

[PeteH]

IF, you do have a crow-foot for the job and a "Break" Torque wrench. One way of checking the torque would be to torque up a Dummy nut to the required torque and then using the crow foot check the "break" setting and adjust as necessary?.

Pete

[chrishawley]

6 hours ago, Pete Lewis said:

as you must re check the tappet clearances after a retorque removing the rockers isnt such a bad idea 

Out of curiosity I had a look at a 1500 head this afternoon. The 5 nuts in question are pretty inaccessible on any approach when the rocker assembly is in place. I couldn't picture any sound method of getting a wrench on the nuts which didn't involve removing the rocker assembly. I'd be inclined to stick with that.

[Midget 1500]

1 hour ago, chrishawley said:

Out of curiosity I had a look at a 1500 head this afternoon. The 5 nuts in question are pretty inaccessible on any approach when the rocker assembly is in place. I couldn't picture any sound method of getting a wrench on the nuts which didn't involve removing the rocker assembly. I'd be inclined to stick with that.

Yes, I looked at my spare engine today  (Rocker cover not done up) and the push rods are quite close.

[Josef]

19 hours ago, Midget 1500 said:

Jigsaw Racing (Mark, who has retired, due to ill health, was most helpful)

Jigsaw are not completely gone. They’re still selling on eBay as lemans-r.

[Midget 1500]

On 25/05/2023 at 06:36, Josef said:

Jigsaw are not completely gone. They’re still selling on eBay as lemans-r.

Good to know.  Just been in touch with them and they say there is no alternative to removing rocker shaft, so it's a case of doing as I have always done.  After this check, I hope I won't need to do it again, for a very long time.  I try to rotate the cars but would tend to use the 1500 for longer trips (Or the V8, which really excelled itself when I took it to Classic Le Mans and then further south), where it's overdrive gives it an advantage.  The 1275 is great for the twiddly roads but it starts to buzz at much over 60mph.  The 1275 is less highly modified and potentially the more reliable engine and since most of my trips are on local, twiddly roads, perhaps it may have more than it's share of the work....but I still leave notes in them, to remind me of when they were last used. 

Edited May 26, 2023 by Midget 1500

[Midget 1500]

I did the job yesterday and it was less of a faff, than I remember, to remove the rocker shaft.  All the nuts were OK and when I refitted the rocker shaft, none of the valve clearances needed altering.  I hope not to be removing the rocker shaft for some time; this was a case of the engine had done say 500+ miles since the initial start up re torque and I just wanted to make sure it was still OK.

I did the 1275 Midget, for the same reason, only a few weeks ago.  That doesn't need to have the rocker shaft taken off first but owing to the rocker shaft partly being held down by the head nuts, there are two torque settings involved, so in it's way just as much of a faff.

It's still a lot easier than doing valve clearances on a Lotus twin cam (Elan engine).