Toyota T50 Spigot Bush

[IslipMinor]

While I have the engine and gearbox out of the car, I want to replace the 1275 flywheel spigot bush for the T50 primary shaft support.

I have some pictures, but no dimensions, other than measuring the existing, rather worn one.

Does anyone have the complete dimensions for the special spigot bush for a 1275 flywheel please?

[philthehill]

Richard
I am surprised that you have a bush and not a caged needle roller to carry the front of the 1st motion shaft.
Phil

[IslipMinor]

Phil,

The one that came with the engine is solid phosphor bronze, but the pictures I have show steel with a bronze or oilite bush pressed in.

I was thinking of using a needle roller bearing, if the dimensions will allow it.

[philthehill]

Richard
I do not know the size of the spigot on the front of the Toyota 1st motion shaft but I have a needle roller bearing inserted into the rear of the Midget crankshaft that accepts the spigot of a Ford gearbox 1st motion shaft.
I attach a photo of the spigot bearing set up as it may give you some ideas.
Phil[frame][/frame]

[IslipMinor]

Phil,

Did you make any modifications to the crankshaft itself, or just make the bush/housing that presses into the end of the crankshaft that accepts the needle roller bearing?

[philthehill]

Richard
The needle roller bearing and spacer tube were fitted by Oselli to measurements I had determined from trial mating's of the Ford gearbox to the Midget crankshaft.
Those dimensions are most likely different for the Toyota T50 1st motion shaft
I am not aware that there was any requirement to machine the rear of the crankshaft.
Oselli carried out the same modification i.e. fitting the spacer tube and needle rollers to all three Midget crankshafts I have.
I can get one of the spare crankshafts off the shelf and take some measurements if you require.
Unfortunately I do not have a standard crankshaft to compare with though.
Phil

[simmitc]

I'm sorry that I can't help with the dimensions, but can recall fitting a T50 many yeras ago and confirm that the crankshaft bush was as described by Richard: steel mounting with bronze or similar insert.

[IslipMinor]

Just split the engine and gearbox and extracted the existing spigot bush using the well-known ‘hydraulic’ method of filling the void with grease, inserting a well-fitting rod and hitting the end of it firmly. After drilling through the back of the bush 1/2” diameter (the original 12mm bore at the front was very well worn), it came out like a dream! Never had to use the method before, but it definitely does what is claimed.

I got some dimensions from the MG Midget BBS, and 'our' bush is solid phosphor bronze. A quick measure of it shows that the bore in the crankshaft is 7/8” (or maybe 22m) so doesn’t look like standard, which I believe is 3/4”? Also the gearbox primary shaft was only projecting into the bush by ~8mm, which is not enough, and may explain why it is very worn on the original 12mm bore. A quick measure shows the projection could be up to 15mm, so once I have verified all the dimensions accurately, it looks like I will be making a ‘special’ for my 1380 to be 7/8” OD and allow at least 12mm of support in either a bronze bush or needle roller bearing.

I’m thinking of using a ‘2RS’ ( 2 x rubber seals) needle roller bearing to keep the lubricant in place – something like HK12162RS. A bit more expensive than a non-RS version, but would give peace of mind!

[philthehill]

Richard
Thank you for the feed back.
You will note from my photo that the needle roller 1st motion shaft bearing as fitted is in a bearing support / spacer that projects from the rear of the crankshaft and so allows the needle roller bearing to be fitted further back towards the gearbox.
As originally fitted the needle roller bearing would have only supported the front couple of mm of the Ford 1st motion shaft so I had to devise and fit the bearing support / spacer to get the correct support for the shaft.
It looks as if you may be doing a similar operation.
Phil

[IslipMinor]

Phil,

Yes, the existing bush projects out from the back of the flywheel by ~8mm, but could come out another 6mm to provide around 14mm of support, which is much more like it. A very rough rule of thumb is the support should be at least 1 x diameter, so a minimum of 12mm for the Toyota T50 primary shaft. After allowing for the chamfer on the end of the primary shaft, the actual current support length is just 7mm.

Just measured the bush OD and the crankshaft bore, and the bore is 0.878" diameter and the spigot bush OD is 0.879", so 0.001" of interference. Just about enough. Will make the new one with the same OD, but longer by around 6mm (just love mixed dimensions!) and to take a needle roller bearing, which is also metric.

[Declan_Burns]

Richard,
Here's a photo of the bearing 10M131A I got from ESM for the 1275 crankshaft. It measures 19.09mm diameter and is 15.66mm deep if that's any help to you. It sits further into the crank. The larger crank bore measured up between 22.2 and 22.3mm but that was only a rough measurement.
Regards
Declan

Diameter
[frame][/frame]
Depth
[frame][/frame]

[IslipMinor]

Declan,

Thanks. After measuring up everything, I have concluded that making one up is going to be the best bet. The bore in the crankshaft is 0.878" or 22.30mm, so just over a nominal 7/8" or 22mm - so that is the diameter that I will need to make one end to.

The needle roller bearing arrived today and is an HK1214RS, which if inserted correctly, will have the seal on the outside end to keep any lubricant away from the clutch splines.

After all, what could possibly be hard about having to bore one end of the bush to within 0.001" diameter to take the needle roller bearing , and turn the outside diameter other end to the same tolerance to press into the flywheel recess?

[IslipMinor]

The deed is done!

This is the original solid phosphor bronze bush, with insufficient support for the primary shaft.
[frame][/frame]
The 12mm diameter is worn to around 13mm.
[frame][/frame]
I started making the new spigot bush last night and finished it off this morning. For the eagle-eyed, the marks on the OD are from the chuck jaws as I first tried to use the tailstock to press the needle roller bearing into the bush, using a 16mm bolt turned down to 12mm to provide the alignment with the bush (the back of the bush, beyond the needle cage is 12mm), but it slipped slightly in the jaws, hence the marks. As the instructions for needle roller cages are NOT to use a hammer, I had to use a small press to press it into the bush.
[frame][/frame]
[frame][/frame]
Now fitted into the end of the crankshaft.
[frame][/frame]

[SnapOff Jon]

I need to fabricate a similar spigot bearing holder for the steel crank in my modified 1340 A series engine and was wondering whether anyone could let me have the photos that were originally posted as part of this thread..?

Even better - does anyone have a dimensioned drawing of the spigot adapter..?

Many thanks !

[StillGotMy1stCar]

I can't help with dimensions, but here are the images:-

This is the original solid phosphor bronze bush, with insufficient support for the primary shaft.

T50 1.jpg (35.94 KiB) Viewed 1519 times

The 12mm diameter is worn to around 13mm.

T50 2.jpg (34.78 KiB) Viewed 1519 times

I started making the new spigot bush last night and finished it off this morning. For the eagle-eyed, the marks on the OD are from the chuck jaws as I first tried to use the tailstock to press the needle roller bearing into the bush, using a 16mm bolt turned down to 12mm to provide the alignment with the bush (the back of the bush, beyond the needle cage is 12mm), but it slipped slightly in the jaws, hence the marks. As the instructions for needle roller cages are NOT to use a hammer, I had to use a small press to press it into the bush.

T50 3.jpg (35.77 KiB) Viewed 1519 times

T50 4.jpg (33.37 KiB) Viewed 1519 times

Now fitted into the end of the crankshaft.

T50 5.jpg (60.79 KiB) Viewed 1519 times

Regards John

[oliver90owner]

I had to use a small press to press it into the bush.

I use my bench vise as a press for light duty jobs like this. If I needed extra precision for lining up, I would use a machine vise, but have never yet needed to resort to such measures.

Regarding the chuck marks - they are not important (I have never cleaned up out-of-sight marks with either timber or metal items. The sliding fit of the boss would be loctited in place, these days. Some centre-punch marks might be necessary if the bush was a too loose fit.

This is not a particularly heavily loaded bearing - it only rotates when the clutch is depressed - and must be accurately concentric if turned using collets. I suspect the first bush may have been made by remounting in a 3 jaw chuck, so was not quite completely aligned or perhaps too loose and not lubricated sufficiently.

[philthehill]

Below is a photo of the original spigot bush (as supplied with the T50 to Minor fitting kit) fitted onto the T50 first motion shaft.

Toyota T50 3.jpg (390.08 KiB) Viewed 1506 times

Here are the fitting instructions for the Rooster Racing T50 to Minor 5 speed conversion.
The picture can be saved. rotated and enlarged so enabling the instructions to be read.

Toyota T50 2.jpg (482.25 KiB) Viewed 1503 times

[SnapOff Jon]

Thanks to everyone who posted responses - all very helpful indeed..!

I ought to own up that the car is a 1969 Sprite that I’ve owned for 39 years (so I do feel a bit of an imposter..!). That being said, my siblings and I have owned 7 Minors between us in the past (inc a convertible and a pick-up) - all great cars…

Would definitely get another if I had the space to keep it dry..

[SnapOff Jon]

… also - the crank dimensions of the steel crank I’m using are different to the stock item - this extends to the reamed out recesses into which the spigot bush is designed to fit. My plan is to take the partially built up engine to my local machine shop and get them to fabricate something that will fit the crank and house the needle roller bearing that features in the above photos..
Thanks again for everyone’s input !

[philthehill]

I think that you are very wise to get an engineering firm to produce a spigot bush/roller bearing and carrier for the rear of your crankshaft.
I had the same problem with the 1275cc MG Midget crankshaft used in my Minor and got Osselli to make and install the carrier/needle roller bearing as the photo below

WDF crankshaft 2.jpg (53.35 KiB) Viewed 1427 times