Sprint gearbox retaining bolts.

[sprintchris]

Hi all....yet another question.

At the point I need to refit my gearbox ( with overdrive ). It's such a long time ago this all came apart and various fixings have dissapeared. Can anyone confirm how many bolts/studs there should be to hold the gearbox on and the dimensions and location, the adaptor plate has holes galore!

I have had a look in the parts book and workshop manual but it's a little vague. I think there's three different bolts and several studs.

Many thanks,

Chris.

[xvivalve]

Chris,

I separated a gearbox from an engine recently, if you are lucky, all the connectors will be sitting where I left them in my yard. I'll have a look for them and photograph them for you. Unusually, there was a full compliment!

[Galileo]

Of the two gearboxes I've separated there was what can be best described as an eclectic mix of bolt diameters, lengths and studs and a bit of chewing gum...

[xvivalve]

The full compliment of fasteners comprises:

3 x stud and nut 1/2" AF
7 x bolt 1/2" AF
2 x bolt 9/16" AF

[tony g]

thread sizes will be 5/16 unf and 3/8unf

Tony

[sprintchris]

Thanks everyone.

Think I've worked most of it out now, the parts book shows three different bolts and a stud.

Looks like 1&1/8th bolts, 1&1/2 inch bolts (5/16) and two large bolts (3/8)

The large ones are easy to trace.

I measured the holes for depth, most are only 20mm deep so need to make sure bolts don't bottom out.

Keen to know the exact location of the three studs, got some unf stud I can cut to length.

Interestingly, are the short bolts all full threaded or do they have a shank?

The 1 1/8th bolts seem an odd size as there seem few on eBay and my local specialist doesn't stock them but does to just about everything else.

[Carledo]

The 3 studs go in the 3 topmost holes, those that go clean through the backplate and adaptor plate and into the engine block itself.

Steve

[xvivalve]

I'll send you the connectors I have with the other stuff and tell you where on the clock face the studs go.

[xvivalve]

The 3 studs go in the 3 topmost holes, those that go clean through the backplate and adaptor plate and into the engine block itself.

Steve

The ones on the one in my yard don't! They are all near the top, but they aren't all next to each other.

[Carledo]

The 3 studs go in the 3 topmost holes, those that go clean through the backplate and adaptor plate and into the engine block itself.

Steve

The ones on the one in my yard don't! They are all near the top, but they aren't all next to each other.

Picky, picky! There is a dowel pin between 2 of them and they WOULD be the top three if the engine were vertical! I think the rightmost stud is in the topmost hole and the other 2 spread to left of it. However you slice it, they are still in the 3 holes that go through to the block!

All Triumphs have this arrangement, not just the slant, OHV 4 and 6 cylinder engines are the same, 3 studs and a dowel at the "top" of the block.

Steve

[Jon Tilson]

Agree on the 3 studs through to the block. Needed for refitting boxes and taking the support weight before the input shaft is properly in I guess.

Not sure this works on a Sprint though as they are a bit lost in the adaptor plate....

Or is it late and am I talking rubbish? Dont forget the studs for the starter on the adaptor plate, which dont normally come off but
you dont get on an auto....

Which is of course irrelevant in your case...must stop rambling.

Jonners

[xvivalve]

These are the pins I've just removed from an adaptor plate from a car where everything else was untouched from new.

First, as you'd expect into alloy they are UNC not UNF

Secondly, two of the studs are short affairs and have UNC on one end and UNF on the other

I've a feeling the photo I'm about to attach may rotate, if it does the long stud is at 12 o clock through an unthreaded hole and all other pins are in relative locations. The two bigger threaded bolts go either side of the false starter bulge on the RHS with the two longer shanked bolts either side of those. I've just compared with a bare adaptor plate I have here in the house, in which there is only accommodation for 4 of the 5 shorter bolts!

I'll put them all in the post to you Chris...

Alun

[sprintchris]

Thanks Alun & everyone else too for all your help!

It's good to know there's lots of friendly people here on the forum always willing to help