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Davemercer
United Kingdom
115 Posts |
 Posted - 07/11/2019 : 22:14:49
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Looking to improve on the difficult task of accessing head nuts successfully I see there was a thread back in 2018 about a slimmer nut with a 13 mm head which was thought to be available from Holland does anyone have any details of the supplier or indeed a similar or better alternative currently available.Thanks
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Simon Johnston
United Kingdom
5984 Posts |
Posted - 08/11/2019 : 07:16:09
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Dave,
Having had the head off and on a few time last year and this I can honestly say that the regular nuts are readily accessible if you use a crow's foot spanner. You’ll need one even if you use the 13mm nuts you refer to. This has been discussed on several occasions and I’m sure a search of the archived posts will turn up all the information you need.
Simon J
J3437 |
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Davemercer
United Kingdom
115 Posts |
Posted - 09/11/2019 : 17:24:38
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Thanks Simon for pointing that out I had assumed that a lower profile nut might provide easier access for a spanner or crows foot on extension.
Cheers
Dave |
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Simon Johnston
United Kingdom
5984 Posts |
Posted - 09/11/2019 : 17:40:46
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Dave,
I found that the only issue with the height of the nut was the difficulty in slipping it onto the stud as you need to lift the head slightly to get sufficient clearance. But once screwed onto the stud a regular open ended spanner will tighten it up to the point where you need to use the torque wrench at which point the crow's foot is needed. I found that a 15mm crow's foot, which is much easier to obtain than a 5/16W one fits perfectly satisfactorily. I had the head off two or three times in the last year so I can vouch for this working!
Simon J
J3437
P.S. If your head has been machined at any time to raise the compression it's wise to check that there is sufficient clearance between the studs and the cam stands. I found that there was only 4 thou on two of mine which seemed too tight to me and necessitated taking the head of and grinding down the end of the studs to give a bit more clearance. Amazing what you discover when you do the work yourself! |
Edited by - Simon Johnston on 09/11/2019 17:45:45 |
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Davemercer
United Kingdom
115 Posts |
Posted - 11/11/2019 : 20:15:51
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| Hi thanks again Simon , I will check that clearance issue when I refit the head hopefully all will be ok ....which will be a first ! Cheers Dave |
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David R
United Kingdom
289 Posts |
Posted - 12/11/2019 : 13:02:56
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Dave
I have been down this road in the past 2 years or so. The "Dutch" nuts are no longer available but can be made fairly easily. They are metric M8 flange nuts retapped to 3/8th BSF. M8 nuts need a 13mm spanner and I used smooth flange nuts rather than serrated ones. This gives the same area in contact with the head as the original discarded flat washers but with more clearance around the nuts.
I had previously tried using the original nuts and washers,tightening them up with a variety of spanners,including crowsfoot,ground down ring and open ended. If using crowfoot it is important to get the thinnest and narrowest ones - indeed true of any you use. Crowsfoot are obviously best because you can then use a torque wrench.
However,in the end I reverted to the the M8 flange nuts as I was far from satisfied the head was evenly torqued down.Indeed it failed at first. The problem is really with other than the front 2 nuts which are fairly easily accessible and for which I retained the original nuts and washers - 15mm spanners also fit these.
The clearance between the studs and the rocker gear is the problem. Yes,the head needs lifting slightly to get clearance to put the nuts on in the first place - I used plastic wedges but I have heard matches will do the job! However,I also removed all the studs and ground them down to equal the shortest as they were different lengths. Put a nut on first before you start grinding to make sure you can preserve the thread. I also made sure there were a couple of threads above each nut when bolted down,but clearance was definately improved.
I cleaned the threads in the block with brake cleaner and replaced the studs using Loctite 577 which seals against any water ingress. In the end I used a composite gasket as I had problems sealing a solid copper one,but that is a personal choice. I coated everything with Wellseal left overnight to get tacky before bolting up. I think I torqued to 35ft pounds,re-checking and re-torqueing for several days and using whatever of my spanners I could get on but ultimately using the crowsfoot ones.
Several months later the head still seems OK. One further point is that my block is originally M Type with stepped studs of the correct J2 diameter,but still with the smaller threaded block - I suppose this is a potential weakness but I didn't think affected what I did.
There are several previous posts which I found very helpful. Hope this is as well.
David
J 3355 |
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Simon Johnston
United Kingdom
5984 Posts |
Posted - 12/11/2019 : 13:56:48
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Dave,
As I had absolutely no problem using a standard 15mm crow's foot spanner this made me ponder on why you and David R seem to have found access difficult and then I recalled that I have special intermediate brackets with slots cut in them to make it easy to get a spanner on the nuts. See photo below.
David's comment about discarding flat washers also reminded me that I used ARP moly steel washers and ARP Ultra Torque assembly lube. It seemed to me that torquing the nuts against three different surfaces - cast iron, steel and bronze - would give varying degrees of tightness for the same notional torque setting, so using these washers seemed to be a way of avoiding that. It’s interesting to note that the factory drawings for the P Type show spring washers being used, perhaps in order to give a consistent surface against which to tighten the nuts.
Simon J
J3437
P.S. Regarding lifting the head slightly to get the nuts on, as I had used an engine crane to lift the head into place it was just a matter of stopping it a few millimetres short to enable the nuts to be fitting before finally letting the head settle onto the gasket. The factory apparently used wooden wedges!
P.P.S. I just torqued the nuts once to 35 lb/ft and didn’t retorque them.
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Edited by - Simon Johnston on 12/11/2019 14:26:28 |
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Davemercer
United Kingdom
115 Posts |
Posted - 12/11/2019 : 21:01:31
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Thanks again Simon and also David , plenty to digest with such comprehensive replies , and your ideas will no doubt be of interest to others having the same issue.
Thanks again
Dave |
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Richard Hardy
United Kingdom
2138 Posts |
Posted - 13/11/2019 : 07:46:49
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I have never heard of anyone until now using an engine crane to lift on a 4 cylinder head!!!!! Was it made of bronze?!!
David, there should be no real access issues with spanners. You can grind the top leading edge down on a ring spanner and loop over the top if your head studs are not to long. The original MG issue ring spanner was pretty thin.
You cannot expect to allow the head to go all the way home usually before placing the nuts on. All very straight forwards really
Rich
Rich
Vintage MG Parts |
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Simon Johnston
United Kingdom
5984 Posts |
Posted - 13/11/2019 : 08:05:06
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Rich
Old age, and a badly broken arm, take their toll. I simply don’t have the strength to lift a head into place. You young uns have no idea what’s ahead for you!
Simon J
J3437 |
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Richard Hardy
United Kingdom
2138 Posts |
Posted - 13/11/2019 : 21:50:19
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Ah ok Simon, perfectly valid excuse then !
Rich
Vintage MG Parts |
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JLP
United Kingdom
92 Posts |
Posted - 19/11/2019 : 06:04:46
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A couple of questions:-1. How is the torque wrench connected to the various ring and open ended spanners? 2. The cut away rocker support that Simon has adopted, seems to be a very practical solution to the problem. Are there any disadvantages to doing this?
Jeremy |
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Simon Johnston
United Kingdom
5984 Posts |
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JLP
United Kingdom
92 Posts |
Posted - 19/11/2019 : 12:37:03
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This is the modified 3/8"BSF spanner that I have been using for quite a few years, so I am pleased that the principle is generally accepted. I will not now pursue the crow foot type of torque wrench.
Thanks Simon for your solution to improve access to the nuts by modifying the rocker support. It seems an excellent idea.
Jeremy |
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Richard Hardy
United Kingdom
2138 Posts |
Posted - 19/11/2019 : 21:54:16
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Clever simple idea but do remember Jeremy,you will not be getting the same torque readings as when torquing directly above the cylinder head nut.
Rich
Vintage MG Parts |
Edited by - Richard Hardy on 19/11/2019 21:54:43 |
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Simon Johnston
United Kingdom
5984 Posts |
Posted - 19/11/2019 : 22:11:05
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Jeremy,
To be clear, I didn’t 'modify' the original brackets. These are new ones fitted by Barry Foster , along with the 'splash plate' into which the cam cover securing bolts are screwed. This has the advantage not only of eliminating the possibility of oil getting thrown out via the breathers but also enables the cam stand caps to be lifted, and the camshaft removed, without taking the radiator off (or drilling a hole in the firewall!)
Rich Hardy used to do cast intermediate rocker stands which give easier access to the head nuts and a similar (if slightly more elegant) splash plate. I don’t know if they are still stock items.
Also the crow's foot isn’t a type of torque wrench - it is simply a shorter version of your converted spanner, but its shorter length means that for all practical purposes you can ignore its effect on the actual torque applied. Also, it’s easy enough to position it on each nut such that the torque wrench is more or less in the same position in relation to the nut and thus gives pretty much a consistent torque.
Simon J
J3437 |
Edited by - Simon Johnston on 19/11/2019 22:14:58 |
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