Spitfire before i swap this od transmission into my mk3 what would you do?

[Bruce100]

I have a 1500 engine in it. I have already cleaned the transmission up, painted bell housing, etc Took a look inside from the top, all the gears seem ok.

My plan is to replace the gaskets, rear seal, copper washer.

https://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=113329

I am also aware I may need to swap the flywheel. I am replacing the clutch and throwout bearing while I have it apart as well, pilot bushing tool
I also have a drive shaft with a cv joint. can't get it apart, was going to perhaps buy a new one from Spitbits.

which gaskets require sealer? what else should I do?

 

[dklawson]

I am not following what is being replaced and what the current condition of the car is.

Are you saying you have just put a 1500 engine in a Mk3 and now want to attach the car's original 3-rail gearbox to it? If so, look at the following...
Compare the clutch friction disks. The 1500 & 1300 pressure plate/disk components are different. To use the 3-rail box you will need the friction disk for it, the one for the 1500 has different splines. Compare the disk diameters also. I don't have any at home to look at but I know they are different in diameter. I am not sure if enough of the 3-rail friction disk fits under the 1500 pressure plate.

Alternatively you could fit the 1300 flywheel to the 1500 engine as you suggest. That represents different problems though. The 1500 crank and flywheel use larger diameter bolts than the 1300. You will need to accurately drill out the holes in the 1300 flywheel to accept the 1500 bolts. However, drilling out the holes would allow you to use the 1300 clutch (complete) on the 1500.

Regardless of which combination you go with, fit a new release bearing to the gearbox before mounting it. Also check the condition of the slave cylinder and make sure it is in good shape. Basically, look at anything that may require replacement in the near future and take care of it now so you don't have to pull the gearbox again anytime soon.

 

[Bruce100]

Sorry for not being clear. I have a 69Mk3 that already has a 1500 in it, with a non OD transmission. Everything runs fine. I purchased a transmission with OD, and am planning to remove the non OD tranny and install the OD tranny.

 

[dklawson]

As long as the transmission is the same type (single rail to single rail or 3-rail to 3-rail) I think all you will need is the driveshaft for the OD gearbox... and possibly a different (longer) speedometer cable. If the OD gearbox is a 3-rail and you are replacing a single rail, you have to deal with the issues in my previous post and the different length driveshaft. I also have vague memories that there are different driveshaft flanges. However, I cannot remember if the flange has to be changed on the driveshaft or on the gearbox to get everything to fit together.

At one time the Canley Classics web site had a comprehensive list of the driveshaft (propshaft) lengths by application.

 

[Bruce100]

Thanks Doug,

I have a Driveshaft I bought with the Transmission, with the CV Joint. I can't get it apart to inspect/add new grease. I was thinking of buying the one from Spitbits

 

[Trevor Triumph]

Remember to check the flange that fits to the differential, also. In '74 the cars had a 1500 engine and the three rail transmission. Spit Bits seemed to have the answer- some bolts with bushings or "collars," I think Nigel called them. I remember doing this several years ago and it was troublesome- many had ideas that didn't work. Worth the trouble, I believe, knocks about 500 rpm off highway speed.
T.T.

 

[dklawson]

The bushings are required to put a 1500 flywheel on the 1300 crank. I did not need any bushings on the driveshaft when we put a later single rail box and driveshaft in our '72.

 

[Don_R]

Bruce, what year is the Motor?....... also....the CV driveshaft might have a larger diameter than the flange on the Diff...you might need the later flange for the Diff.

I ask about the motor because the single rail (marina) trans have a 20 spline clutch....the early 1500 with a 3 rail should be a 10 spline clutch, so you would need at the minimum a new clutch plate...

Did you get the trans mount plate from the donor car?...your mounting plate wont be drilled for the overdrive type trans mount.

 

[Bruce100]

The engine is A 74 Spitfire MIV USA
The gearbox/OD is a 20 spline
I have purchased a new Borg & Beck 20 spline clutch
I have the trans mount plate from the donor car
I have the CV Driveshaft from the donor car
I do not have the flange on the Diff from the donor car....

Can I swap the flange from my existing Driveshaft to the shorter CV driveshaft on the Differential side?

 

[dklawson]

I think you can make that swap. I know we changed a flange... I just don't remember if it was on the driveshaft or differential (my post above... #4).

Please confirm the following as I am speaking from memory... but I think there is only one size U-Joint for Spitfires. That suggests that you can move the flange from one driveshaft to another wherever a U-Joint is used.

 

[Don_R]

you only have 1 u-joint on the CV shaft......yes you can swap the flange.. ,u-joints are the same,....but then you would have to bolt the CV end to the trans.....

Don't think there is enough room in the tunnel for that..

 

[dklawson]

Sorry, the links took me a while to find. The first is to a thread where I was asking about converting a 1300 with 3-rail box to a single rail box. We changed the gearbox first, later we changed the engine as the 1300 turned out to have very low compression and head gasket leakage problems.
https://www.britishcarforum.com/bcf/showthread.php?50242-Spitfire-Driveshaft-Which-End-Where

and a related thread that mentions the flange swap
https://www.britishcarforum.com/bcf/showthread.php?68462-Spitfire-Trans-Swap

EDIT: I forgot to mention that there is room in the transmission tunnel for the CV joint on the front of the driveshaft. However, the conversion on our car was for a standard gearbox, not an overdrive unit so your experience may be different. We did cut the tunnel back about 4 inches to gain access to the flange bolts. We saved the part and I riveted "ears" onto it so it could be screwed to the tunnel similar to what later Spitfires have.

In hindsight while I remember discussing flange swaps during our car's conversion I don't think we had to do one as we ended up with a single rail gearbox and driveshaft both from a later 1500.