Spacer Tube gearbox cross member for ‘J’ Type

[trolleybus]

Been searching this on the forum but can't find the definitive answer.
What length do I need for the Spacer Tube gearbox cross member for ‘J’ Type Overdrive.
Are they the same length as the BW65 Auto that I am swapping out?
Shorter or longer?

[johnnydog]

The manual gearbox (non drive) and 'A' type overdrive gearboxes have the same studs - 138491
The auto gearbox (BW35) and 'J' type overdrive have longer studs - 158537, as the J type box has the adaptor plate -158442, and also the spacers 158538.
Unfortunately, I don't know the length of the studs, but I can check on my auto (BW35) in the morning.
Whether a BW65 has different studs lengths, I'm not sure, but there is no mention of it in the parts book (dated 1974), but it predates the fitment of the BW65 boxes.
I can dig out my later parts book in the morning and get back to you with any differences of the stud lengths for a BW65 relative to a J type if that helps?
Or maybe an email to Chris Witor may help?

[johnnydog]

I have measured my 73 2.5 PI auto cross member mounting studs.
The visible thread depth is 65mm long.
The spacer is approx 33mm deep.
I have measured some spares I have. There appears to only two sizes - 30 and 70mm thread length (one for spacers and one without)
The spacers are all the same length. This equates to approx 5mm thickness of metalwork in the body.
Bear in mind this is for a BW35 - I have never had a BW65 so I can't comment on their fittings - but you never know, someone out there may have the answer...
Hope this helps.

[tony]

I've also put this on the other forum.
J type spacers, inch and half long. bolts two and three quarters long.
Tony.

[trolleybus]

I've also put this on the other forum.
J type spacers, inch and half long. bolts two and three quarters long.
Tony.

Thanks Tony this is very close to what CW is listing for the auto box at 1.3", he doesen't list the length for the J type. I think I will stick to the ones I have.

[johnnydog]

If its not standard, I think I would fit the shortest spacers you can without causing any clearance issues. There has been discussion in the past about the angle that the front UJ turns through with the longer spacers, causing premature wear. The longer the spacers are, the lower the rear of the gearbox sits and the angle of rotation for the front UJ is sharper.

[Mike Stevens]

Somewhere, I have got a note about the various spacers used, including these. It came from CW but isn't on his website, so I think it came from Six Appeal some years ago. I'll have another look for it tomorrow and see what it says...

Cheers,
Mike.

[Mike Stevens]

Found it!

The 'J' type spacer (158538) is 1 9/16".
Automatics (138167) 1 3/8"

These were in Six Appeal some time ago together with other spacer sizes. Sadly the single sheet copy I have doesn't say when it was, but it's on page 12!

Cheers,
Mike.

[Mike Stevens]

If its not standard, I think I would fit the shortest spacers you can without causing any clearance issues. There has been discussion in the past about the angle that the front UJ turns through with the longer spacers, causing premature wear. The longer the spacers are, the lower the rear of the gearbox sits and the angle of rotation for the front UJ is sharper.

Having had non-overdrive, 'A' type and 'J' type cars, I can't say that I recall the height of the gearlever being any different between them. This would suggest that the height of the gearbox relative to the transmission tunnel is about the same for all 3, so maybe the drive angle is also the same.

The method of supporting the 'J' type using that offset adapter may well be the reason for the longer studs/cross member. I suggest therefore that the longer studs do not dramatically affect the drive angle into the front prop UJ, but is solely to give space for the mounting arrangement.

However, I do agree that it is a bit of a dog's breakfast!

Cheers,
Mike.