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MG TD TF 1500 - TD Gearbox installation

I've had my TD transmission rebuilt, and now seek wisdom on the re-installation. I've managed to successfully thread the transmission spline into the engine. I've started attaching and tightening the bell housing/engine flange bolts. Many went in smoothly, but a few remain not particularly well aligned. The gearbox weight is supported on the rear engine mount (on the chassis crossmember), but not bolted in, nor shimmed in any way.

So I am now trying to sort out a good method for assuring alignment between the engine and bell housing flange bolts and the spline shaft and engine.

It is possible that my jacking support for the sump is not perfectly aligning the engine and gearbox.

I'm thinking that I'll back off (one turn or so) on the six bolts that are presently connecting the engine and transmission, remove the spark plugs, turn the engine by hand to test the "smoothness of rotation, and then rock the gearbox back and forth to try to install the remaining bolts (at the top of the flange).

My question is: is there a better approach to this final connection? (Never done this before). Any thoughts or guidance on this would be appreciated.



Walt
wlswift

What ever you do don't torque down the bolts to pull the trans in or you'll likely break the bell housing. If you use a new pilot bushing, a clutch disc alignment tool, and then draw the pressure plate down to spec AND the alignment tool comes out freely then the trans should go it without issue. Do not use the rear mount to support the transmission as you put it in until the bell housing flange is seated and the bolts are snugged.

Bill Chasser
TD-4834
W. A. Chasser

Walt - a bit late, but if you have to reinstall the transmission sometime in the future, a pair of the studs that hold the rocker arm cover threaded into the upper two bolt holes in the engine will help support the gearbox while you are getting the first motion shaft situated.

I am with Bill, don't tighten any of the bolts around the clutch housing to the engine until all the bolts are started by hand. Only then should you use a socket and ratchet to tighten the bolts. Cheers - Dave
DW DuBois

Walt, here's a view of what Dave is talking about. If the shaft is aligned properly in the pilot bushing the bellhousing should slide up flush. Bud


Bud Krueger

I suggest that you start over so that you won't be trying to overcome something that is misaligned.

> It's easier with one person under the car guiding the gearbox into place, and one person in the cockpit manhandling the gearbox into position. Additional people can give moral support.

> For future reference: Support the car by the frame with jack stands so that it can't move. Don't put the stands under the rear axle or front spring pans. (You can't change the location of the stands at this point.)

> Also for future reference: Support the engine solidly. I use a (Ford Tarus) scissor jack with a wide base bolted to it and a "floppy" top that presses against the sump. (You can't change the jack at this point.)

> Make sure that the pilot bushing is not mushroomed. Lightly grease it to help the input shaft slide.

> Make sure that the clutch disk is centered so that the input shaft will slide through it into the pilot bushing.

> Install the mount on the rear case of the gearbox before installing the gearbox: rear engine bearer bracket, support rubber, fork end, engine rebound rubber, clevis pin, and washer.

> As Dave and Bud noted, use two long studs to guide the gearbox into place as shown in Bud's photo. I cut off the heads of two metric 8X1 bolts with long shoulders and rounded over the ends.

> Grease on the 8X1 guides and on the locator pins.

> Raise or lower the engine as needed to allow the gearbox to line up. FYI - the rear mount on my TF gearbox is 1/2" or less above the cross member when the gearbox is bolted to the engine, and before I remove the jack from under the sump.

> If the toeboard is in the car, the right side of the bellhousing may catch on it. Just flex it out of the way.

> Put the gearbox into 4th gear.

> Insert the first motion shaft and contine to push the gearbox into position. May require a very slight amount of wobbling to "find the spot". Rotate the rear flange to spin the input shaft if needed to move through the clutch disk.

> As Bill and Dave noted - Don't use the mounting bolts to pull the bellhousing to the block. Keep moving the gearbox a few degrees and pushing until all of the locator pins in the block are starting to push into (or through) the locator holes in the bellhousing. Wiggle the gearbox some more to push the bellhousing flush to the block and the locator pins through the holes.

> Install the bolts finger tight. Check alignment and tighten the bolts. Use lower torque on the bolts that go into the aluminum sump.

> You will probably need to push the rear of the installed gearbox and engine left, right, foreward, or back to insert the bolts throught the rear engine bracket into the holes on the cross member. The rubber mount will allow it to move a little.

> Lower the engine and remove the jack.

> Tighten the rear engine bracket to the cross member.

Good luck,

Lonnie
TF7211
LM Cook

Thanks for all the inout. I tried responding earlier, but somehow the response choked my browser and it appears not to have been posted. Anyway - here's a later version, because at the tie of my earlier post attempt, I had not yet seen Lonnie's detailed post. I wish that I had posted the question before starting the attempt at re-insertion.

I'll respond mostly to Lonnie's detailed steps.

I used the same methods (support, gearbox mount) as described.

I did not use the two studs for guide - stupid of me:
wlswift

continuing after user error ....
I used the same methods (support, gearbox mount) as described.

I did not use the two studs for guide - stupid of me:
- didn't know where to get such studs,
- didn't know they were 8 x 1 metric - thought they were BSF unavailabilium
- had the helper raise and lower engine based on my visible and finger sensing the gap ( I stayed on my back supporting, wing;ing and jiggling the gearbox
- didn't have the 4th gear engaged. Duh. Thought of it much later when I realized that the no-go was caused by the first motion splines not aligned with the engine drive. The shift lever was somewhere in a box and it would have taken me an extra half hour to find it and shift.
- so I left it in neutral, removed the plugs and had my helper hand crank (slowly) the engine til the first motion shaft seated.

- at this point the flange was seated face to face - the locator pin was seated in the mating hole (are there really supposed to be two? That's why not all the bolt holes lined up!!!

- so now I head to the shop to finish up - I'm not going to pull it and start again, although it's prudent advice. I think that my align meant problem is caused by the lack of one locator pin, and the gearbox is ever so slightly rotated with respect to the engine that results in a misalignment of 2 or 3 of the bolt holes. I plan to barely loosen the bolts and rotate the box slightly to line up holes at 0, 90, 180, 270 (+/-) then start hand snugging til all feels good. I'll check it by using the hand crank.

I really should have done my homework before starting this. Thanks for all the support!

Will report later.
Walt

P.S. Also had to restore the prop shaft cowling flanges (horribly rusted) - if you think it's useful I'll post the method. $200.


wlswift

Most fasteners in engine and gearbox are fine-thread metric with Whitworth heads. Most fasteners in the rest of the car are BSF. Kinda drives you crazy!

2" 8X1 metric bolts should be available at a good local hardware store. Cut off the hex head and use as shown in Bud's photo. Makes alignment a breeze, especially if one of your locator pins is missing.

Most BSF fasteners for our cars are available at British Tool and Fastener and at the major MG parts suppliers. MG suppliers also have metric bolts with Whitworth heads for our engines and gearboxes.

Send me an email and I'll send you info on reinstalling the floorboards and tunnels.

Lonnie
TF7211
LM Cook

Walt, 8x1 is a very common thread in the engine/gearbox package. Home Depot tends to carry a number of 8x1 bolts and nuts. Bud
Bud Krueger

The important thing to note is that it is Metric Fine thread and not Metric thread.
Dave H
Dave Hill

Walt when you have an hour or two to kill have a look at 'The Original MG TD midget' site. There is a vast amount of accurate information on just about every aspect of the TD. The section on nuts & bolts tells you the location, size & type of every fastener on the car. Plenty of pics, well laid out & updated as more information comes to light about these terrific little cars. Cheers
Peter TD 5801
P Hehir

Peter thanks - just as you wrote, was on the page - searching for the appropriate torque for the bolts between the bell housing and the engine plate. Couldn't find exactly what I hoped for. The bolts are M8x1. Most of the torque specs for the M8x1's in the torque table give 19 lb-ft for the torque (into steel ) However, some of the these bolts go into the blind tapped aluminum sump and I did not spot a torque recommendation for the aluminum fit.

Anybody know of the correct or even just sensible figure? I really don't want to start rethreading the sump ...

Walt TD16817
wlswift

Not sure where these came from so I can't credit the source. Not sure if the info you need is here though.

Torque Values for XPAG Engines
Engine

Description Torque
GUDGEON PIN CLAMP BOLT 25 LBFT
ROD BIG END BOLTS 25 LBFT
MAIN BEARING CAP NUTS 63 LBFT
FLYWHEEL TO CRANKSHAFT BOLTS 50 LBFT
CLUTCH PRESSURE PLATE BOLTS 19 LBFT
OIL PICKUP PIPE TO SUMP BOLTS 6 LBFT
CAMSHAFT LOCATING PLATE BOLTS 6 LBFT
CAMSHAFT SPROCKET BOLT 50 LBFT
TIMING CHAIN TENSIONER BOLTS 6 LBFT
SUMP TO BLOCK BOLTS 19 LBFT
TIMING CHAIN COVER BOLTS 19 LBFT
CRANKSHAFT PULLEY BOLT 50 LBFT
CYLINDER HEAD NUTS 50 LBFT
ROCKER TOWER BOLTS (8 MM) 16 LBFT
ROCKER TOWER BOLTS (10 MM) 43 LBFT
OIL PUMP TO BLOCK BOLTS 6 LBFT
Other
Description Torque
WATER PUMP PULLEY NUT 10 LBFT
GENERATOR PULLEY NUT 35 LBFT
TRANSMISSION OUTPUT FLANGE NUT 65 LBFT
REAR AXEL HUB NUT 170 - 200 LBFT
FRONT AXEL HUB NUT 40 - 70 LBFT
WHEEL LUG NUTS 50 LBFT

Cheers
Peter TD 5801


P Hehir

Never used a torque wrench on those. Of course torque readings vary greatly depending if lubricated, dry, etc. I just comfortably snug, with less snugging on ones threaded into aluminum as they strip if you look at them. George
George Butz

The tapped holes in the sump are not blind - the bosses are open ended, and threaded all the way through. Thus it is useful to use longer set screws or bolts to reach the unworn threads at the inner ends of the bosses. It is possible to use set screws with 27mm of thread, or 27mm bolts with 19mm of thread, with 1.5mm thick washers under the heads. Even forgetting to fit a washer will not result in the set screw or bolt touching the ring gear.
R A WILSON

Peter, that list is from Gordan Clark and is one of the lists presented on Ttalk. See http://www.ttalk.info/ClarkPage.htm. Bud
Bud Krueger

Thanks Bud. I'll update my notes to reflect this. Cheers
Peter TD 5801
P Hehir

Hey Walt -

I received your message. I replied, but not sure that you received it. Send an email to me at my address at the top of this post. I'll capture your address and forward my message to you.

Lonnie
TF7211
LM Cook

RA
You are correct.
Back around 1985 when I started to re-assemble my TD I mistakenly used 5/16-24 bolts. (What did I know about mad metric in those days). The 5/16 bolts will screw in just fine. They were just a bit shorter than the MM. I rebuilt the tranny a few years ago and when going back in I saw the lower threads were buggered. I did use slightly longer 8 X1 mm screws after insuring there was no possiblity they could touch the fly wheel.

Jim B.
JA Benjamin

Forgot to mention, I made some suitable bolts from some old, but not stretched, little end bolts. I had to run an 8x1 die down to extend the thread, and then I cut them to length - I think I went to 28mm, as I ground a very small lead-in chamfer on the ends.
R A WILSON

Good idea for longer bolts. However if too long and they touch the flywheel it makes a really loud and bad noise. George
George Butz

After you install the longer bolt, I suggest that you remove the spark plugs and spin the engine with the hand crank.

I inserted a longer bolt to compensate for a partially stripped hole when I installed my TF gearbox. Don't remember which bolt. I questioned the process when I did it, so I tested the fit with the hand crank. I couldn't turn the hand crank. I shorted the length of the bolt until it cleared.

Lonnie
TF7211
LM Cook

Is there any danger of cracking the aluminum engine sump if it is supported with a scissors jack? Cushioned by a soft block of wood maybe?
John Quilter

I bolted a large block of wood to the top of an old Ford Tarus scissor jack. I left it loose so that it could pivot to remain flat against the sump as it was raised and lowered. Bolt a block solidly to the bottom of the jack so that the jack remains upright.

Lonnie
TF7211
LM Cook

Reactivating Bud
Bud Krueger

This thread was discussed between 17/10/2016 and 14/02/2022

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