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MG MGB Technical - Removing the engine

Apologies for the maybe stupid question - I'm mechanically a midget person!

I need to change the clutch in my '78 GT - it's a standard B series 1.8 car. I plan to pull the engine and the gearbox at the same time. Obviously I need to drain the engine oil but the Haynes manual makes no reference to draining the gearbox oil (which I would do if it were a Midget). Do I need to do that on a B?

Thanks.
JH

No, you shouldn't need to drain just for the purpose of lifting out, it's only a few extra kgs. But if you plan to do any jobs like the front oil seal or changing the filter on the o/d while it's out, then it will need draining, ultimately, whether before removal or while suspended from the engine hoist.

Martin
Martin ZT

Because the angle of the engine and gearbox durring removal can get quite severe, oil will gush out of the gearshifter tower and make a blooody mess if you don't drain it. Same on the way back in. jm2c
Paul Hanley

Hi
Do yourself a favor when removing or installing the lump, jack the back of the car up as high as you safely can. I see so many people with the car on level ground and the engine hanging from the hoist at some crazy dangerous angle. With the rear end of the car up in the air it is a straight in shot with the engine relatively level on the hoist and a lot less work.
FWIW Alyn
Alyn

JH,

Why go to the aggro of taking out the gearbox - it is easier to just take out the engine if all you are doing is changing the clutch.
Chris at Octarine Services

Agreed, unless the box has to come out for another reason, and even then you can do it separately. It's a fairly tight fit though and can be tricky to get exactly aligned so you don't damage the clutch putting it back. You need to be able to get a jack under the box.

If you take it out all together, drain the box as others say, the angle becomes acute and it will spill out the back. I was going to refill mine before putting it back recently but changed my mind when I looked at the idea closer.

2 pairs of ramps are useful with the car jacked onto them opposite ways round so it can't move off. Then it's level and you have clearance to get at everything as needed. A moving crane is nearly essential as the car can't be moved under a hoist.

A useful tool is a "paddle" of wood about 6" wide and 3ft long which is great at the front for guiding the engine past the rack and rear on top of the gbox for guiding it through the tunnel - careful of the plastic breather!
Rich

Apologies if my post seems contrary, but I never drained my box until after it was out of the car, and I don't recall any leaking out while removing it.
The only place from which it should be able to leak would surely be the breather if all the gaskets are secure? And if it could leak past the remote housing it shouldn't need a breather.
And as the breather is near the front of the gearbox, it is unlikely to reach that high when tipped back at an angle.

In hindsight, I should have left the gearbox in the car to do the clutch change as I might not have then started a full restoration!

Martin
Martin ZT

Chris,
I've always heard it's easier to remove the engine/gearbox as a unit. So, you're saying it's easier to leave gearbox in? What should you watch for in doing it that way?
Dave
David Steverson

I've never had any problem removing the gearbox and engine as a unit -- it always came out and went in rather easily. And my experience has been similar to Martin's -- I've never drained the gearbox and never had any oil come out whilst lifting it (even before I learned the trick of jacking up the rear of the car!)

The most annoying thing I find about the job is getting the engine and trans mated. It's fiddly enough with both out and with plenty of room around. Personally, I can't see arguing with it in the car when it's so easy to pull them both out. My 2¢....

While it's out, it's a good idea to renew the motor mounts (and trans mounts if you pull the trans) and don't forget to check and/or renew the clutch release fork bolt and bush.

Cheers!
Rob Edwards

Later cars seem easier than Mk1s with their narrow tunnel. Maybe that's where the recommendation to take the lot out came from.
I've done several, though only 1 Mk1, and if it's just a clutch, I definitely wouldn't take the tranny out as it saves so much time, so long as you're careful.
A crane on the rocker studs for the engine and a trolley jack under the box.
The tricky part is aligning the backplate with the bellhousing. That means having to get the box as high as possible as the 2 must be parallel when they start to connect (which is a different position to when they are both home).
It can be helpful to take off the engine mountings to allow it to move around more. Then let it connect under it's own weight; if it doesn't go don't force it, just keep moving the box/engine/shaft slightly til it does.
They do vary though, my Mk1 was definitely trickier than a late car I helped a friend with which connected first time as we started to line it up before we even realised it. Rich.
Rich

I've done it both ways - with and w/o pulling the tranny.

It isn't that much harder to pull and replace the engine tranny combo than just the engine. If you plan to replace the front tranny seal, it's obviously easier on the bench than in the car.

I've had times when the tranny shaft slipped easily into the clutch. Another time it took a 1/2 hour of wiggling to get the engine and tranny to mate. Obviously getting the clutch properly aligned with the pilot bearing is essential. Properly aligning and bolting the tranny to the engine is much easier on the bench.

Having the rear of the car higher would make it easier to insert the engine tranny combo. However it would be more dificult to get the rear of the tranny over the rear cross member. Once it is in, then the front would need to be raised to crawl under to connect the clutch, etc.

With an overdrive trans it is a pain for one person to handle the installation as getting the rear of the trans over the crossmember requires having the engine slightly forward. The rear of the trans is then lifted and the engine pushed rearward. The extra weight and size of the o'drive makes that process more dificult.

The engine tunnel is smaller for '67 and prior which makes it harder to install the transmission bolts in situ. If you plan to have the engine out for awhile, it is dificult to move the car with the trans in place as you must support the front of the trans while the engine is out.

If I was in a shop with a helper and I wanted to use the least time to minimize my costs, and I expected not to move the car and to have the engine back in within a few days, and I didn't plan to touch the rear engine mounts, tranny seals, u joints etc. I would pull the engine only. It is faster. Otherwise I would pull both.
Barry

If it has been a few years and many miles since the engine was out, you should take out the tranny too as the rear motor mounts are probably in need of replacement. You can also easily check the U joints at the same time, get better access to the clutch hydraulics, clean and paint as necessary etc.
Barry Parkinson

<<If you plan to have the engine out for awhile, it is dificult to move the car with the trans in place as you must support the front of the trans while the engine is out.

If I was in a shop with a helper and I wanted to use the least time to minimize my costs, and I expected not to move the car and to have the engine back in within a few days,>>

No problem! Our early repairs were all at the roadside and pulling the engine meant taking off everything ready and towing the car to a DIY garage that hired the floorspace and crane by the hour. We took out the engine and put it in the boot, tied up the box with cord through the bellhousing bolt holes and towed it home for a rebuild, reversing the pantomime a couple of weeks later with the rebuilt engine. Looked like a speedboat with its nose in the air :-)
Rich

Leaving the gearbox in place saves undoing the propshaft, the gearlever, the clutch slave and most importantly the crossmember!

You have to undo the starter motor and bellhousing bolts anyway to get the clutch out.

Putting it back in is easy - jack the gearbox up till it is trapped by the top of the tunnel, slide the engine back and down till the gearbox shaft goes through the clutch release plate, pop in two long bolts on opposite sides of the bellhousing / backplate and use these as guides while you slide the engine back, keeping the engine parallel to the gearbox by lifting or dropping it as necessary.

Get the clutch properly aligned (need to do if the box is out of the car as well) and it should slide back easily - putting the car into top gear will hold the input shaft still while you rotate the crank pulley to get the splines lined up.
Chris at Octarine Services

This thread was discussed between 28/03/2005 and 29/03/2005

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