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 MGB Technical - Engine removal...oh my goodness!

Having prep thoughts before engine and gearbox removal. Have discovered that the 4 bolts on the top half of gearbox bellhousing to engine are missing - some type of blue sealant used - is it safe to take engine and gearbox out together? My thoughts concern uneven strain at this joint as removal takes place - can the remaining bolts hold it together?
Any comments/advice MUCH appreciated
/Moss Denmark
Moss

It will most likely be fine, but I would feel better with at least one of the top bolts in place.
Steve Simmons

Hi Steve, those are my thoughts too - have to find a bolt that fits...The result of the PO taking short cuts...what on earth the blue sealant has been used for I have no idea...
/Moss
Moss

Can't you remove the remaining bolts then remove engine and gearbox separately?
Simon Jansen

If you aren't going to carry out work on the gearbox then don't remove it as it is far easier to take out the engine on its own rather than take out the gearbox as well. Neither is it any real problem to mate the engine to the gearbox when putting it back in. For what it's worth I certainly wouldn't take out the engine and gearbox with the top four bolts missing this is a recipe for disaster.
Iain MacKintosh

I agree with Iain on both counts - the whole weight of the gearbox is going to be trying to pull the top of the bell-housing to end-plate joint apart. Either fit at least one bolt to the top, or remove just the engine.

Sealant is pointless, the bell-housing is open to atmosphere elsewhere and shouldn't have any liquids in it. If you get a seal or gasket go the oil runs out of the hole at the bottom of the bell-housing.
PaulH Solihull

I always take the engine & gearbox out together.

Separately there is a good chance that the clutch plate on the back of the engine won't be aligned to fit on to the shaft out of the gearbox and the two won't go back togther. You may need a clutch aligning tool.

John.
John Prewer

A previous owner likely removed the engine only, took the bolts out of the transmission (or jarred them out during the process accidentally) while the transmission bell housing could move downward with the engine out and then couldn't get them back in when the engine and transmission were mated up. They're quite long and there isn't enough room between the body and the bell housing with the engine and transmission mated up.

There are several discussions in the archives about engine removal and I'm certain you'll find that the great majority suggest removing separately. There are fewer headaches involved. For example, with engine and transmission mated up, many have found that the car has to be raised to allow the back of the transmission enough room to clear without raising the entire car. When you reassemble, replace the missing bolts and insert them in the bell housing prior to lowering the engine into place.
Rick Penland

John there is no chance that the engine won't align with the gearboz first motion shaft. Whether you take the engine out alone or both at once a clutch mandrel must be used to centralise the clutch disc otherwise you have no chance of mating the gearbox to the engine. Taking the engine out on its own saves a lot of time getting into gearbox mountings, slave cyls, gear levers, propshafts and such things that don't need to be touched. Besides refitting the engine is no problem at all and it usually slips back into place quite easily.
Iain MacKintosh

Hi all, thanks for all the response. Leaving the gearbox in and just taking out the engine seems to be the prefered method.

I suspect the blue sealant has been used as a glue because of the lack of bolts. If it is some type of glue, lets hope I can unstick the bellhousing and endplate from each other. A stanley knife will be usefull.

I have also noticed that a few bolts seem to be the wrong way round - too hasty when the engine was taking out last time...
/Moss
Moss

Iain,

I had a friend who tried in vain to get his engine to mate with the gearbox in the engine bay and eventually removed the gearbox, put them together and fitted both at once. I don't think he'll be doing engine only ever again.

I find the mass of the engine & getting it lined up when it is hanging on the end of a hoist MUCH harder than when the two are on the garage floor. To get the combination back in I jack up the back of the car and they slot in. I think the cars were assembled at Abingdon this way and for my money they did it for a good reason.

I guess its personal choice. Personal choice for me is also that the last time it was done a garage did it for me!!!!

John
John Prewer

Hi John,
On the one had I can understand the easyness of just engine removal, but I am rather concerned about not being able to line up when installing again. Then there is the issue of the missing bolts and nuts and the strain on gearbox - maybe I should take engine and gearbox out sametime after a bolt and nut fitted in the top of bell-housing - my initiating ceremony for things mgb! I have got to do it at some stage - I'm hooked on the tech stuff and finding out how everything works - and not just from a text book...
/Moss...here's a pic...

Moss

I never take them out together. Never had a problem putting them back. Takes no time. Two things I have learned. Support the gearbox on a jack so you can raise and lower the front of the box when mating it with engine and to support the box when engine gone. Use a clutch algnment tool before re mating engine with box. If it wont mate up at first usually a small rotation of the crankshaft by moving the harmonic balancer will do the trick.

The box weighs an absolute ton and coupled with engine weighs even more. I prefer to take out seprately

Allan
A J Ogilvie

Moss-
I'm with the group that takes the engine and transmission out as a single unit. True, you should elevate the rear of the car just to make things easier, but with the transmission out of the car you can do a quick inspection of its mechanisms and forestall any problems that might be developing, such as worn baulk rings (synchro rings). New seals are always a good idea on an old transmission, too. Better safe than sorry!
Stephen Strange

Now I am confused...should I, should I not remove engine alone or with gearbox...
Anybody know how much the things weigh - in kgs?
/Moss
Moss

It seems like we have personal preference here. I felt really out on limb until Steve posted (thanks Steve!).

I can't comment on the missing bolts, but the whole lot is REALLY well built, and there are a lot of bolts. The gearbox casing is substantial, and with stregthening ribs too. I've never heard of one cracking.

I don't like risk, so if I was in your position I would take the engine out on its own.

When putting it back the jack under the gearbox is a good idea. You'll find your own way, have fun, they are great cars and learning is part of building your own personal perference.

Everything is very heavy, you've got to live with that.

John.
John Prewer

Put a 1/32" @ 45 degree chamfer on the front of the first motion shaft with an angle grinder to aid alignment if you wish and just keep the gap between the backplate and the bellhousing parallel all the way round and the engine will go in just fine. You can get your hand in to align the first motion shaft with the clutch disc initially and then turn the crankshaft damper to align the spines if you need to at that point the engine should go right back. If it doesn't use a tyre lever between the front crossmember and the crankshaft damper to apply some pressure to help it on its way.
Iain MacKintosh

"You may need a clutch aligning tool."

Surely this is regardless of whether you remove both together or separately. You need the clutch alignment tool to centralise the friction plate when bolting up the cover plate. Without that you stand a very good chance of not getting the first motion shaft through the friction plate and into the pilot bearing regardless of whether you are assembling the engine and gearbox out of the car or in.
PaulH Solihull

Pilot bearing - how can one tell if this is ok? Could this been the cause of the noise - rattling from the clutch and shk shk noise? Whats the difference between a pilot bearing and a spigot bush - is it the same thing?
/Moss
Moss

John-
You're welcome.

Moss-
The big headache is not removing the engine from the car with the transmission still in the car. It's when you go to reinstall the engine! Reassembly is easier on a bench. True, it is possible to pull the engine separately, but to do so incurs the risk of damaging the first motion shaft of the transmission. As for those who feel that the first motion shaft of the transmission is essentially incapable of being damaged, I dare them to put their beliefs to the test by sliding their engine part-way onto the end of the shaft, and then releasing the hoist to simulate an accidental release!!! In addition, realigning the engine with the transmission still in place can be maddening for the unpracticed. To do so requires that the transmission be jacked up until it touches the transmission tunnel in order to clear the height of the front crossmember. Then comes the headache of getting the gap between the backplate and the bellhousing parallel all round while the engine is hanging from a hoist. For those with repeated experience, it's easy to forget how difficult it is for a first-timer, especially when he is working alone.

On a bench, reuniting the engine and the transmission with each other is an easy task as long as you have the transmission properly supported. When installing the transmission onto the engine, you should first put a thin smear of Lubriplate white lithium grease into the splines of the input shaft (first motion shaft) in order to prevent rusting. Always smear a very thin film of assembly lubricant onto the input shaft (first motion shaft) next. Never use plain grease for this purpose as it will seal the pores of the spigot pilot bushing and prevent the oil contained within it from lubricating the shaft. Do not use too much assembly lubricant as this can cause air to be trapped within the spigot of the crankshaft, creating a pneumatic lock that will cause the air trapped inside of the spigot to compress, keeping the input shaft (first motion shaft) from going all the way into the spigot pilot bushing, and make pulling it out a difficult task at best. Warping the clutch driven plate is a risk, so care in alignment is needed both when installing the clutch assembly and when mating the engine and transmission. The symptom of a warped clutch driven plate is a dragging clutch. This being the case, you will need a clutch alignment tool. The best tool for this purpose is an old input shaft (first motion shaft), although a plastic tool is available. If you do not align the clutch driven plate properly prior to attempting to mate the engine and the transmission, you will likely never make the engine mate to the transmission. If you do not have an alignment tool, then leave the bolts slightly loose, with just enough tension to hold the clutch driven plate in position (about two turns) so that the clutch driven plate can move into proper alignment. Be aware that if you use this method, you will have to remove the transmission in order to tighten the clutch securing bolts. Get the end of the first-motion shaft properly located inside of the carbon clutch release bearing, and, as the two casings are brought together, making sure that the flywheel is square with the transmission casing in both its vertical and horizontal planes, and that the two casings are aligned both vertically and horizontally with the same gap all round. Be prepared to rotate the crankshaft until the splines are properly aligned. Do not lock the transmission in gear. Without that, the shaft turns very easily, and making it easier for the splines to self-align. Remember that the longitudinal centerline of the transmission must be exactly aligned with the longitudinal centerline of the crankshaft. If it is off, even by a small amount, they will not go together. If you can only get the transmission to within 3 inches of the engine, then the problem cannot be the pilot bushing in the spigot of the crankshaft as the first motion shaft will not be anywhere near close to the limit of its travel within the spigot pilot bushing. It is more likely that the splines on the input shaft (first motion shaft) are not lining up with those of the clutch driven plate. If rotating the crankshaft does not produce the desired results, try engaging a gear, as this will allow you to align the splines by rotating the selected gear set by means of rotating the output flange at the rear of the transmission. The static inertia of the gears will prevent the input shaft (first motion shaft) from rotating too easily. If you find that this method is too cumbersome to succeed while working alone, then get an assistant to rotate the output flange at the rear of the transmission while you move the transmission forward onto the engine. Take care to ensure that the upper right bolt hole near the engine block oil outlet fitting and the lower left bolt hole where the brace for the exhaust system attaches are not misaligned. These holes are intentionally a smaller, closer fit on their bolts than the other bolt holes are. These two bolt holes and their bolts serve as locators, similar in manner to that of dowel pins, in order to maintain the concentric alignment of the crankshaft to the transmission input shaft (first motion shaft). If you put those two bolts in first, then the other bolts will slip right in with lots of clearance, and the splines of the input shaft (first motion shaft) and clutch, as well as the starter gear, will all be properly aligned.

Prior to reinstalling the engine along with its attached transmission, you can make things much easier for yourself later on if you have all of the attachment brackets for the wiring loom already bolted onto the transmission. Also, you ought to check both of the switches with an Ohmmeter before you reinstall them. This will serve two functions: If you are in doubt as to which switch performs which function, the right-hand switch for the reverse lights should give continuity on the Ohmmeter only when the transmission is in reverse; whereas the switch on the left-hand Overdrive lockout switch will give continuity only when the transmission is in third or fourth gears. If there is any intermittence in continuity at all, especially by wiggling the shift lever, you can fix the problem from inside the car without having to pull the engine / transmission package out all over again. On the other hand, if the switches are in good condition, it is usually a simple matter of adjusting the number and/or thickness of the washers. Normally, there must be two washers, otherwise it will not function correctly.

When you prepare to reinstall the engine, jack up the rear of the car and set the rear axle onto axle stands so that you will have adequate clearance for the tail end of the transmission. Leave the engine tilted with the transmission at a lower level in order to make it easier for your fingers to install the machine bolts of the front mounts. Do not make the classic Beginner’s Mistake of tightening down the front rubber engine mounts and then trying to install the transmission support crossmember onto the end of the transmission package. Instead, before attempting to install the engine, attach the transmission support crossmember onto the transmission and leave its 5/16"-18 X ¾" long mounting bolts loose. It is much easier to start the transmission bolts by hand, and then tighten the front rubber engine mounts with the engine hanging on the hoist before tightening the rear transmission mount.

You should note that there are two mounting holes with captive nuts on each side of the car for the machine bolts that secure the transmission support crossmember to the transmission. The reason for the two sets of holes is so that you can alter the position of the transmission support crossmember as appropriate. This feature is necessary because in the case of the three-synchro transmissions there is a difference between the distances between the front engine mount and the mounting point on the rear of the transmission of the standard transmission and the one that is equipped with an Overdrive unit. The transmission support crossmember needs to attach about an inch further forward for the Overdrive unit-equipped version of the transmission. Tighten the transmission support crossmember machine bolts using a half-height swiveling socket, with a four or five-inch extension. With this tool, you can get to those rear machine bolts a lot easier. However, if you are not fortunate enough to have a half-height swiveling socket available, the transmission support crossmember can be modified for easier installation. Slot the holes on the metal that the mounts sit on, and then drill two 24mm holes in positions that will allow a long extension bar with a socket to reach each of the machine bolts on the transmission mount. Next, bolt the transmission mounts onto the transmission, and then attach the “top hat” middle part. Bolt the transmission support crossmember and it to the top hat part. Using a long 3/8” drive extension you will be able to tighten the mounting bolts easily, before attaching the four transmission support crossmember-to-body machine bolts.

When new front rubber engine mounts and their brackets are installed, inspection usually reveals that the assembly is already bending toward the engine block. That means it is prestressed in compression, and as the engine rocks, the stress cycles from compression to tension and back again, ultimately leading to fatigue failure. This condition is at its most severe on the Left Hand engine mount bracket, since torque effect causes that side of the engine to lift under acceleration, whereas the Right Hand bracket tends to remain in compression, except during hard engine braking. If you fit a spacer of approximately 1/8” (.125” / 3.18mm) thickness between the bracket and the engine block at the large machine bolt, you will prestress the bracket in such a way as to prevent the cycling through zero, which reduces or eliminates fatigue failure. This compressive preload also keeps the rubber mount plates parallel, greatly increasing the life of the mount itself. If the mounts are correctly shimmed, then the force on the rubber mounts will be at right angles and they should not sag, even over a long period of time. The need for these shims is determined by the dimension across the mountings in the chassis, which varies due to build tolerances. You can determine if they are needed by examining the mounting rubbers. The sides should be at 90 degrees to the ends when under the weight of the engine. If they slope towards the engine at the top, then you need to add shims. If they slope away from the engine, then you need to remove shims.

Determining if you need to shim the rubber engine mounts is a simple matter because the rubber blocks deform if the engine is too low - the top and bottom faces will not be at right angles to the plate. Simply add shims equally to both sides until both of the rubber blocks sit square. If there are clearance problems with the bellhousing or the exhaust manifold / steering column, simply changing a shim from one side to the other will move the engine in the opposite lateral direction while leaving the engine at nominally the same height.

At first appearances, the installation of the rubber bushings into the transmission mount seems to many to be a formidable task. The smaller of the bushing’s two flanges is 1¼” in diameter and about ¼” thick, while the hole through which it must pass is only about ¾” in diameter. It appears to be a job that requires a man with at least three hands. However, installation of the rubber bushings into the transmission mount is not as difficult as it initially seems to be. The hole through which it must pass is only about ¾” in diameter. First, this task can be made considerably easier by heating the rubber in hot water in order to soften it up, and then using a lubricant will make the procedure yet easier, as well as protect the rubber from chafing. Secure the yoke in a vise. Tie off one end of a thin cord, in the direction of one end of the yoke. Loop the cord, and then pull it up through the yoke hole. Pass the loop around the bushing, and then place the edge of the bushing flange into the yoke hole. As you do this, it helps to use your free hand in order to oblongate the bushing. Initially, pull the cords almost parallel to the bushing groove. As more of the flange begins to enter the hole, change your direction of pull downward, until eventually you are pulling straight down. In this manner, you will gradually peel the circumference of the flange through the hole. Tying off the cord leaves one hand free to manipulate the bushing, and also to change the pull angle of the cords. Obviously, the wiser you are at choosing your tie-down point, the better this procedure will work.
Stephen Strange

Stephen - many many thanks for the instructions, advice and guidance. My printer is on overtime...and your text makes it very clear which procedure to follow. In the beginning I was 'leaning' to just an engine removal, but now, after all the comments on previous experience, I am going to remove both engine and gearbox. And now after a thorough look at the gearbox mountings I find that the PO has not done a proper job as a bolt is missing and one of them is actually stuck half way out and I can't seem to budge it(up to him of course back then-his car, time and money, and so on).

The tie rod at the thread end is also bent upwards.

The propshaft to gearbox flange bolts are in the wrong way - the nuts are on the propshaft flange side which means I cannot take the bolts out as there is not enough room to pull them clear. One of the nuts is actually missing.

The engine rubber mountings are lopsided.

These things together with the missing bolts on the top half of the bellhousing/rearplate and the blue sealant makes me think that an 'engine removal only' was attempted earlier and there were problems because things did not fit back as when they were taken out - does not account for the gearbox mounting problem but still an issue I have to deal with...
/Moss
Moss

The nuts on the propshaft only fit one way and they are installed correctly. They were designed so that you don't need a wrench on the bolt head when tightening. Their heads also prevent their removal without first removing the driving flange from the rear of the transmission. I'm still a firm believer that the engine can be removed by itself . A spare first motion shaft is an invaluable tool as the clutch alignment tools, made of plastic, aren't that accurate. If you have an overdrive transmission, removing it with the engine is a real pig. The bolts, at the rear, are near impossible to access. RAY
rjm RAY

This may be the case but on the drawings Moss (no relation)and other parts dealers show the bolts going in the other way at both ends of the propeller shaft, not from the gearbox/diff side of the flanges - this would also make sense when having to take the prop off the geabox/diff flanges...
/Moss
Moss

This is also the case in 'Haynes' in section propshaft.
Moss

Most of the above is based on what ifs. These will in all probability never happen. There is nothing like preparing for the job and then just going out and doing it. The more time you put off thinking about it the worse it gets. Quite frankly there is no way that I would pull an engine and transmission as one if I only wanted to work on the engine. The additional weight of the transmission is formidable and makes for a very heavy lift plus the whole thing must be tilted to a considerable angle to permit removal and clearance of the slam panel. When I had to do work on my gearbox I removed the engine first and then the gearbox and on refitting fitted the gearbox first then the engine. This makes the whole thing much more maneagable. In any case because of the missing bolts you will have to remove the engine on its own so why not just go ahead and do it and see how easy an operation it is. When refitting the engine as has already been said jack up the gearbox until it contacts the tunnel then fit the engine. As you are not going to drop it there is no chance of bending the first motion shaft or damaging the clutch disc. The first motion shaft is a particularly tough piece of steel anyway and I don't really think that you have any chance of bending it. The way I look at this job is why remove a patients lungs as well when you only need a heart transplant.
Iain MacKintosh

For 4 synch boxes, the bolts at the rear of the gbx are special D head type, they are a tight fit in the flange, and they go from front to back. They cannot be fitted or removed with the flange in place. This is only for the gbx flange, not the diff. If somebody has fitted standard type bolts then it doesn't matter, but the correct ones are as Ray stated. Relying on aftermarket parts suppliers or books for accurate info is a big mistake, and even the factory books can be suspect, since they frequently cut & paste drawings of earlier methods.

And I've R&R'd hundreds of engines only, much easier.

FRM
FR Millmore

Well said FRM, quite frankly I've never heard so much nonsense in my life as taking out the gearbox as well when just wanting to work on the engine. Not in an MG at least. Unless of course one has so much time on their hands that they don't know what to do with it. It's certainly a case of the more you think about a job the worse it gets
Iain MacKintosh

Well, thanks for all the comments on this and that...
With regard to MY propshaft flange bolts it is quite obvious that the bolts and nuts are aftermarket standard not original.
With regard to those who hear nonsense, well, don't listen!
With regard to engine alone or with gearbox time will tell and I'll keep you all up to date...
With regard to wasting time, it is my car number three so I have all the time it takes....!
/Moss
Moss

I don't think your question of whether the pilot/spigot bearing could cause the noise has been answered.

Given the diagnostics you have already given us the answer is no. The only time the bearing is being used i.e. the two parts turning relative to one another is when the crankshaft is turning at a different relative speed (or direction ...) to the gearbox input shaft, which mainly happens when you are sitting at a standstill with the engine running, the car in gear, and the clutch down (there are other circumstances but you get the picture). If you still have the noise when the car is rolling but the engine is stopped, the gearbox is out of gear and the clutch pedal is up, then both parts of the bearing aren't moving at all, let alone relative to each other. Ditto when you are driving along with the car in gear and the clutch pedal up, then both parts are turning at the same speed.
PaulH Solihull

Thanks PaulH. I had concluded this after watching John Twist's youtube vid on the MGB gearbox where one can see which parts move in certain situations.
/Moss
Moss

If I were to remove both engine and gearbox in one go in your situation with the missing bolts, I'd take a bolt or two out of the bottom of the bellhousing, put them in the top of the bell housing, then remove the whole lot. Then get the remaining bolts you need and reassemble the box and engine properly before putting it all back together.

Ive removed my engine both ways, and didn't find it made much difference either way. Both ways work.

When mating the engine back to the transmission after removing the engine alone, I jacked one back wheel just off the floor and rotated the wheel with the gearbox in 4th, and the two units fell together very easily.

FWIW, if I need to remove my engine next time without needing to do any work on the gearbox, I will take out only the engine.

Erick
Erick Vesterback

Maybe I was lucky, but I put a bit of grease on the gearbox shaft splines as well as the nose, the friction plate spines and spigot bearing, left the gearbox in neutral, and they just pushed together.
PaulH Solihull

Update - ceiling height in my 'workshop' not higher enough to allow the hoist to lift the engine clear of the engine bay....I need 2m 30cm, only have 1m 90cm...
Thankfully the ceiling is plywood sheeting....the story continues.....
/Moss
Moss

Moss-
Block the front wheels and raise the rear of the car.
Stephen Strange

Stepehen, good advice, however, the legs of the hoist I'm using need to go under the front crossmember which means the wheels have to come off, which means height is an issue - I've started on the ceiling, so a week or so and I'll be ready. Yes I am slow! But then full time work plus young family means an hour here and an hour there...but not a problem
/Moss
Moss

It may be simpler to replace the 'Hoist' with a modern arm type engine lifter with a hydraulic ram to lift the arm.
If you put up a picture of your hoist arrangement, then we may be able to give you some advice.
Geoff F.
Geoff Farthing

Sounds like it already is, if the legs have to go under the cross-member. Maybe the problem (one of them) is the end of the legs are too wide to fit between the wheels i.e. it is a big hoist. I had the opposite problem - no difficulty getting the legs between the wheels, but the end of the arm was nowhere near the middle of the engine even on full extent. I had to go in from the side and physically drag the whole hoist plus engine sideways against the run of the wheels to get the engine off the gearbox, and that also needed the wheel that side to be removed.
PaulH Solihull

Well spotted PaulH, it is a new model. The problem is simply space. Got to move a few things around in the 'workshop' - a bench, the celing height. Yes I know it sounds rather extensive but it is worth doing in the long run - might as well do it properly. From Nov 1st to 1 feb the car is off the road (insurance conditions) - so have my winter project. Thanks for all you comments - very much appreciated. It great forum thanks to all those who contribute...
/Moss
Moss

This thread was discussed between 29/09/2010 and 15/10/2010

MG MGB Technical index

This thread is from the archives. Join the live MG MGB Technical BBS now