MG TF Engine Mounting

[Jontune]

I have hit a problem while attempting to change the cambelt on my TF. One of the two 18mm bolts that hold the OS engine mount together had a rounded off head and I've just sheered my stud extractor leaving one end stuck in the mounting. My question is, is it possible to remove the engine mounting from the top / side by unbolting it from the block and the steady bar? Or will I have to take the subframe out?

[Rob Bell]

I have hit a problem while attempting to change the cambelt on my TF. One of the two 18mm bolts that hold the OS engine mount together had a rounded off head and I've just sheered my stud extractor leaving one end stuck in the mounting. My question is, is it possible to remove the engine mounting from the top / side by unbolting it from the block and the steady bar? Or will I have to take the subframe out?

Welcome to the forum! Nightmare that the bolt rounded off and the extractor sheared! This is the one of the pair near the cam cover? They're sizable and should take quite a lot of torque. Might be better to use an impact gun - I find that this tool gets you out of a lot of sticky situations. Can you knock on a smaller (may be an old imperial) socket? As the engine is still in the car, there may not be room to get an angle grinder in there to take the head off the long-bolt...

Yes, the whole mount can be removed. I've not done this with the engine in situ, but I am told it is possible.

[Jontune]

Thanks Rob, I'll try to remove the whole mount then.
I tried the 'small' socket hammered on and an impact wrench. Also I managed to grind the head off the bolt and it was after that I used a stud extractor with the impact wrench again. That wouldn't free it. The extractor sheared when I was using a wrecking bar. Unbelievable really !

[Mykel]

Yes, the whole mount can be removed. I've not done this with the engine in situ, but I am told it is possible.

It indeed can be done, but it’s a massive pita, to be honest. My good friend Markus once sheared off one of the mounting bolts on my car (yes indeed, the 14mm bolt!) and so I told him to take the bugger out and replace it or else …

All the bits and bobs on the top of the alloy crossmember have to come off and then he could just, I repeat just! remove the mount by undoing the four bolts (8mm with 13mm heads iirc) using a ratchet spanner.

Whilst brute force wasn’t helpful with the large bolts in the first place, when the ratchet spanner gets to work you will need to have your local Hulk handy. But beware not to snap the four smaller bolts, now THAT would be a real nightmare.

When refitting the 14mm clean the thread first. DO NOT apply any thread lock (even though the original spare ones come with it) and for goodness sake use a torque wrench, 145 Nm is less than you might think. Always remember, you’ll have to undo them next time.

[Jontune]

Thanks Mykel, I'll have a go tomorrow.
I'll let you all know how I get on.

[Bazzajay]

When tackling a bolt which hasn't been loosened for some time I always use a generous spray of Plus Gas, then leave it for 20 minutes or so. I find this works better than WD40. It's also an idea to try tightening the bolt before you loosen it, sounds illogical, but it often works.

[Geoff.F]

Stud removers are just that. They are a deep socket that passes over the thread and loads on the shank.
Bolt removers are available which comprise of a socket with tapered sharp clockwise splines that cut into the bolt head.
If you want to stop taking the corners off nuts/bolts then throw away yur cheap tools and go for Professional Snap-On tools especialy their "Flank Drive" sockets which load the hexagon flank (flat) rather than the corners.
Geoff.F

[mowog73]

Jontune, I was in the same boat you are now in many years ago.

The first time I tried to remove those bolts I was able to undo one but there other wouldn't budge. I broke a socket trying to undo it. I also tried to unbolt the mount from the engine block but none of the bolts would budge. I ended up cutting the head off the seized bolt and pounding the bottom of the mount from below until it move upwards enough to get a puller under the mount and pulled it off. I them removed the bolt by welding a nut to it and the heat of the welding heated the bolt enough to allow me to remove the bolt. It took me a month of free time to get the mount off and the bolt out.

The bolt was covered in white powder (aluminium oxide I believe). Yeah for dissimilar metals in a damp environment. I now use antiseize on every bolt going into an aluminium alloy part.

[Rob Bell]

When tackling a bolt which hasn't been loosened for some time I always use a generous spray of Plus Gas, then leave it for 20 minutes or so. I find this works better than WD40. It's also an idea to try tightening the bolt before you loosen it, sounds illogical, but it often works.

Agree completely with this - particularly the "nip up before loosing" - it may be enough to break and "stiction" caused by corrosion etc.

Jontune, I was in the same boat you are now in many years ago.

The first time I tried to remove those bolts I was able to undo one but there other wouldn't budge. I broke a socket trying to undo it. I also tried to unbolt the mount from the engine block but none of the bolts would budge. I ended up cutting the head off the seized bolt and pounding the bottom of the mount from below until it move upwards enough to get a puller under the mount and pulled it off. I them removed the bolt by welding a nut to it and the heat of the welding heated the bolt enough to allow me to remove the bolt. It took me a month of free time to get the mount off and the bolt out.

The bolt was covered in white powder (aluminium oxide I believe). Yeah for dissimilar metals in a damp environment. I now use antiseize on every bolt going into an aluminium alloy part.

What anti-seize do you use? I read somewhere that you shouldn't use copper-based grease because of dissimilar metals, but I don't really know enough about the subject?

[Rob Bell]

Stud removers are just that. They are a deep socket that passes over the thread and loads on the shank.
Bolt removers are available which comprise of a socket with tapered sharp clockwise splines that cut into the bolt head.
If you want to stop taking the corners off nuts/bolts then throw away yur cheap tools and go for Professional Snap-On tools especialy their "Flank Drive" sockets which load the hexagon flank (flat) rather than the corners.
Geoff.F

A flank-loading tool might still work on that rounded bolt? But I guess it depends on "how rounded"?

[mowog73]

One of the main purposes for the use of an anti seize is to protect against dissimilar metal corrosion. I use a general purpose anti seize unless I'm using it on exhaust nuts/bolts and then I use a high temperature anti seize. The use of a copper-based anti seize with aluminium alloy parts fine.

[Rob Bell]

One of the main purposes for the use of an anti seize is to protect against dissimilar metal corrosion. I use a general purpose anti seize unless I'm using it on exhaust nuts/bolts and then I use a high temperature anti seize. The use of a copper-based anti seize with aluminium alloy parts fine.

Thanks Mark - there is a lot of debate on this subject on the web - I've just been looking. It seems that Cooper does cause galvanic corrosion of aluminium. I guess this is worse in some applications versus others, but a reasonable alternative would be a PTFE-based grease.

[Rob Bell]

Found this thread quite useful (https://www.pistonheads.com/gassing/top ... &t=1585308) and this post in particular:

Thanks everyone; Most of my questions have been answered.

I have also been doing a bit more reading.
Galvanic cell voltages are;-
Stainless Steel & Mild/Carbon Steel = 0.5V
Stainless Steel & Aluminium = 0.58V
Mild Steel & Aluminium = 0.08V
Copper & Aluminium = 0.53V
Copper & Stainless Steel = 0.05V
Copper & Mild Steel = 0.45V
NACE recommend that in brine galvanic voltages should not exceed 0.25V, and in fresh water should not exceed 0.45V.

I was surprised that Stainless steel in Mild steel has a galvanic difference of 0.5V = very corrosive, whereas Mild steel in aluminium is only 0.08V = almost no galvanic corrosion. (Compared with Stainless steel in aluminium = 0.58V.)
I have not been able to find out whether the insulating jointing compounds recommended for dissimilar metals are able to withstand engine temperatures and oils.

But the proof of the pudding is that no one appears to have actually experienced any problems with Stainless and copper grease in Aluminium on our cars. So I shall leave my Stainless bolts in place.

So hence the advice to avoid s/s bolts in alloy castings where ever possible, and why some are so adamant about the unsuitability of using copper grease in aluminium parts. A more inert compound would be preferable, although, depending on the environment (dry versus wet, versus marine) you'll either experience no problems or big trouble, or somewhere in between...

[mowog73]

This information is very true when it comes to combinations of metal and galvanic corrosion but I don't think it relates directly to the situation where anti seize compound is used. One of the main reasons for using an anti seize is to stop/reduce galvanic corrosion. Although one type of anti seize may be better suited than another when it comes to the types of metals.

For instance, I have a bottle of Permatex copper anti seize. In its description it says: "Contains a high percentage of micro-fine copper flakes in a semi-synthetic grease carrier and is fortified with high quality rust and corrosion inhibitors." One of it's suggested applications is spark plug threads installed in aluminum. Copper anti seize seem to be better suited for high temperature applications.

Permatex also make an aluminium anti-seize, which is a blend of aluminum, copper and graphite lubricants. It too has a suggested application of spark plug threads installed in aluminum. This is not a high temp anti seize.

[Fraser]

When I had a Rover P6 with the V8 engine, I had to take the heads off to replace a headgasket. The V8 was an American design, and used head bolts rather than studs. These used a sealer on the bolt threads to stop them seizing which smelt very strongly of the old Evostick. Whether this was Evostick or something similar I don't know, but I used Evostick when bolting the head down. The right stuff may still be around as there are an awful lot of these Rover V8s around. This stuff would be suitable, I would think for preventing the corrosion found on the seized bolts on the engine here. I think the reason this sealer was used was because it did not provide lubrication, merely sealing. Torque figures are usually always quoted without lubrication of the threads.

[mgtfnut]

I use Ceratec now, made by Mintex, for brake slider lubing etc, but now use it for most fastenings.
Allegedly with ceramic compounds, it is certainly sticky and slidey. Seems to work well on mixed metal bits bolted together, screw threads etc.

[itsonlyme54]

Having had to remove the mount from the engine block last weekend from a friends car I can advise, yes its possible but not easy, you will need decent tools as the 5 13mm bolts into the block are going to be very tight initially, once cracked off they will move easily, you will need to release the engine mount to the alloy support arm to allow you to raise and lower the engine.
I removed the expansion tank and the outer camshaft cover, you need as much room as you can get, I have 15inch long ratchet spanners which allowed me to work from a distance.
The bottom mount bolt when the engine is lowered can be removed with with a long socket extension through the wheel or remove the wheel which makes access easier, I would recommend 6 sided sockets, you cannot allow the bolts to be rounded off, its a tough job but can be done.