Overdrive compact A

[Norton]

Hello.
My 64 S type have moss box with longtail A OD.

But I have a compact A for another project and in need of information / tips.

The OD’s oil sump contained more than oil, some metalparts which I cannot identify. Anyone any idea? See photo.
The smaller narrower parts I’m pretty sure are from thrust washer behind uni-directional clutch. ( curvator and thickness ). But the thrust washer are present and looks good. From parts list / service manual I can’find any other thrust washer. Larger parts similar material ( non magnetic yellowish ) but I can’t find any similarities from parts list.

Small bent pin probaly unsuccessful used to lock planetary gear shaft.

OD not completely dismantelled, thrust ring assembly on sliding member with bearing still in one piece. ( the one with 4 studs on whitch operatng pistons act via bridge piece ). But no way theese pieces can have escaped from here.
Annullus still attached to rear casing due to stubborn speedo drive, but from manual / parts list nothing like theese chunks in that area.
Any idea anyone?

Speedo drive. Removed the retaining screw but can’t get it out. Hard to get a good hold on, any tricks?
( Have also posted on E type forum )
Thanks, Harald.

[Glyn Ruck]

Suggest you dismantle completely. Lay out & photograph.

Is the one way roller sprag clutch burst? Happens if reverse is engaged with OD activated. Reason for the inhibitor switch on the reverse selector rod of the gearbox. You can't reverse the car in OD without doing severe damage.

Regarding removing the speedo drive. If you have the retention screw out all you are fighting is an external O ring in the bore & disengaging the drive gear. The drive gear just slides out.

Either attach an old speedo cable outer and pull or attach an angle drive and pull. That should give you the leverage to remove the main drive unit & it's external O ring. I used an old angle drive to pull mine out. You look as though you have sheared the pin and exposed the inner cable seal. That brass collar should not be out until the main collar & O ring is removed. Screw the double threaded brass collar back in and use a speedo cable or angle drive as above ~ attach the speedo cable or angle drive to the outer exposed brass threads. I have just replaced the external O ring on mine due to a drip. We rebuilt everything but forgot to replace the O ring ~ I had it.

Sprag clutch.

Overdrive one way roller clutch.PNG (134.37 KiB) Viewed 1392 times

Speedo drive outer seal 83. Retaining screw is 84.

Speedo Drive seal 83.JPG (25.96 KiB) Viewed 1392 times

speedo drive inner seal.JPG (79.71 KiB) Viewed 1392 times

Speedo drive.PNG (172.95 KiB) Viewed 1388 times

IMG_20180314_162210 - Copy (2).jpg (504.16 KiB) Viewed 1390 times

[Norton]

Hi.
Thanks. Sprag clutch is ok. Speedo drive now removed. I was looking throug my bits & bob drawer looking for something that could fit either thread, also thinking about an old speedo wire but nothing. But there was an angle drive with the box when I got it, just didn’t think of it. With that attached I got some leverage and removed the drive. It was pretty tight though, even after o ring was outside. Annullus also pressed out, no surprises there, bearings also looks ok.
Emailing overdrive-repairs.co.uk. Good response, and they can supply spares. They suggests that chunks are from main case centre bush. Does anyone know whether it is just placed in position, or if it should be fixed in place with something? ( pressed in? )
I didn’t even know about that one, as the remains were resting in pieces down below.
See photo, no bush.
Parts list not very informative on such details. Searching youtube etc. there definitly is such a thing.

Now I am double checking what parts I need and try to put it back together. I’ll post the result or post more questions if / when needed.
Rgds Harald.

[Glyn Ruck]

It's over 20 years ago since I rebuilt my overdrive due to overseas expat assignment, only fitted recently. I remember the speedo drive because we did it recently.

Suggest you watch Elin Yakov's highly competent entire series of You Tube videos on rebuilding a Type A "Compact" overdrive. He covers everything in the greatest of detail.

Good luck! This pdf will help.

A Type Overdrive.pdf

(1.87 MiB) Downloaded 70 times

[Norton]

Hi. Have watched Elin’s videos. Good but it is an A-type, not a compact A-type. Also found one by Magnus Carlsson also A-type. Then one on compact A-type by Chris Schober.
Major mechanical parts similar but anchilliries different. ( pump, pistons, valves, springs etc. ).
Closer look on theese videos show some differences on planet gear carrier. A-type: flat front and aft. Compact A-type: an added «ring» on front. Like a large washer. Aft an extra dished ring ( disched washer ). Anyone any knowledge? Of course it might be production changes during time.
See photos. ( sorry they came out helter skelter but see description below each photo.)

Then my planet carrier looks like A-type front and compact A-type aft..
And from videos, A-type carrier have thrust washer on front ( whitch shaft passes throug ) but not on compact A- type.

Thanks for any information, rgds Harald.

[Glyn Ruck]

Over 20 years I've forgotten the differences between the Compact & the Longtail ~ sorry. I still have a longtail lying on a friends farm with engine & Moss gearbox. I remember the speedo drive because we did it recently.

Get hold of Dave Twigger at Overdrive Spares in Rugby. He knows more about Laycock DN Overdrives than most on the planet. He is a most helpful gent & more than happy to help even if he sells you nothing.

http://www.odspares.com/

[Norton]

Thanks, have emailed Overdrive Spares and got answer from Dave. Discovered some more issues now and will get back to him.
Rgda Harald.

[Glyn Ruck]

Have a chat to Dave on the phone sometime. He will chat for hours if you want him to.

[Norton]

Hi, just emailed him again with a couple of photos. It will certainly be informative to have a chat with the guy.

[Norton]

Hi. OD update.
Have emailed and talked with David Twigger of ODspares several times. Most helpful guy with expert knowledge. Also bought parts, NOS planetary carrier, planet gear shafts, planet gear bearings. There are two needle roller and one needle roller thrust bearing on each. Two of the shafts on mine were loose, rotating in carrier enlarging the holes and signs of heat build up. Apparently not fixed properly with the mills pins. New bearings of drawn cup type, old where open cage. Pressed in with spacers and end washers etc. Also main case centerbush, fixed with a large alloy rivet. Parts list / service manual not very helpful here. Allways presented as one part, and half alloy rivet remaind in hole of alloy case. So I didn’t know what I was looking at.

David clearyfied all this. He also explained that the pieces of washer I found inside are the corrugated ( no longer corrugated ) washer in front of sunwheel. «Don’t fit one, they allways break up».
I have earlier described differences on planet carrier. Mine had a dished plate at rear. David told me it is an oil flinger, doing no good but trapping swarf and impurities.

Everything cleaned and inspected, including the accumulator piston. Which was a pain to refit. Manual refer to some churchill tool. Would have been nice with a picture or drawing of all «churcills». To give an idea of what you are up to. Elin Yakov's youtube video showed me how to fit the UDC. He also presented the measurements of the UDC tool, I made my own out of a tin can. ( photo ).

Regarding parts lists and service manuals, it is somewhat annoying that same parts have different names in differen places..

Anyway, think I found out of it and its back in one piece. Anyone know something I have forgotten / not considered?

Before I fit it to any car I will rig up something to give it a test run. Youtube videos have given me some ideas. The chap I bought it from said it worked fine. But they allways do, don’t they?

Rgds Harald.