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MG MGB Technical - TIGHT FIT

The engine in my 1979 MGB was sitting too high. This caused the air filter of come in contact with the hood (bonnet). As the motor mounts reside in a a slotted plate, the solution was to loosen the two 9/16" nuts which bolts the engine mounts to the plate and slide the motor mounts downward on the plate.

Having no lift to raise the car up,I laid on the ground to work this out. The passenger side was not too bad to deal with, but the driver side with the steering column passing through the mounting plate was a much different experience.

For those who may be facing the same challenge, I share this with you. After using many wrenches of different configurations, I used a 9/16" 12 point ratcheting box wrench with a slightly offset angled head. The going was slow, but it was steady and not too maddening.

Who engineers this stuff???

Cheers

Gary
79 MGB
gary hansen

Blame American legislators, and bear in mind if MG hadn't come up with a solution at a minimal cost it would have seen the end of the MGB six years earlier.

It's really not that difficult to pull the rack to get as clear access to the drivers side as the passengers.

Did you have the locating plates under the chassis brackets the right way round? Did you even find them? They are to ensure the engine isn't installed too high.
paulh4

Paul, What the American gov't has done to the auto industry is ridiculous. Having worked in the industry for many years, I've seen a decline in quality, of parts, but have seen some very interesting innovations.

As far locating plates, I'm not sure if I follow this. The motor mount sits directly on the chassis bracket. The motor mount bolt passes through the bracket with a washer and 9/16" nut on the underside of the bracket. I did not see any locating plates. Whoever replaced the engine after the rebuild perhaps didn't use them.

If you have any pix of what I should have, I'd appreciate a look at them.

Cheers

Gary
79 MGB
gary hansen

Gary,

There are two things I can think of that could cause the height problem that you are having. I think you can get an idea of both of them from the attached photo (if it is large enough to see in its low resolution form).

Note that the studs are not in the center. There is a right and wrong way to place them, but it has been too long since I messed with it to remember which is right. I believe Paul knows because he helped me when I replaced mine.

Then, also notice that not all replacement parts are the same height. The photo shows the difference in the "pair" that I got. The supplier sent me another pair but I don't remember if the replacements were the tall or the short.

Charley


C R Huff

Charlie,thanx for the pix of the motor mounts. They look like the ones that are in my car.

My guess is,over the 12 years since the engine rebuild and 31+k miles later, the nuts worked themselves loose to a degree and the engine "torqued" itself toward the left and raised up to the upper limit. The mount was right at the top edge of the chassis bracket. The nuts were tight, but they weren't too difficult to loosen.

At a recent event, I compared my engine mounting with other MGB's and discovered the issue. One fellow told me the chassis brackets are slotted,and to just loosen the nuts and drive the mounts downward with a bar and hammer; crude, but effective. I got them down about 1/2" and that was the best it would do.

Cheers

Gary
79 MGB
gary hansen

The locating plate is square, with a hole offset to one side. They go over the stud under the chassis bracket. as well as being turned over, they can also fitted by being turned round the stud 180 degrees. However only one way is correct - and that is with the hole in the lower of its two possible positions, i.e. below its centre-line, which ensures the stud is low down in the chassis bracket slot. I'm attaching a drawing from the V8 WSM, but the same applies to the RB 4-cylinder. A bit difficult to visualise until you are under there with the locating plate in your hand.

I oiled the top of the chassis plate and the bottom of the mount stud plate, then from above using a hammer and drift could slide the mount stud plate down so I could get the locating plate on correctly.


paulh4

Paul, I reviewed your drawing, many thanks.. I do not recall seeing anything that looks like the plate in question. I wonder if the locating plates were eliminated when the engine was rebuilt. If the plates are there, I did not recognize them. I do see by the drawing how it works in maintaining the engine's location.

Again, many thanks for your input

Cheers

Gary
79 MGB
gary hansen

This thread was discussed between 24/12/2016 and 28/12/2016

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