Drive Shaft thoughts.

[cartooner]

I'm in the process of fitting a 2.9iV6 into a Mk1. Concerning the propshaft I have read a lot of posts. I think the original propshaft fitted with a flange from a MT75 prop would do well. Then
again there are people who think this will be a (too) weak setup. My original propshaft has a diameter of 51 mm. Since the engine and transmission are from a '94 scorpio(Granada in UK) I just checked the diameter of that prop. Remember this engine is three times as powerfull as the original 1700 V4!. To my surprise the diameter of the prop on the Granada is also 51 mm, so I guess this is beefy enough to use. Sadly enough this is only the front part of the shaft, the backpart is 63,5 mm in diameter, which raises questions again.

1/. Can I now safely use the original propshaft fitted with a MT75 flange, going with the theory
that a chain is as strong as the weakest link?

2/. Why is the backpart of the prop on the Granada 12,5 mm thicker than the front part?Doesn't make sense to me, because the 51mm part would snap or twist first.

Your thoughts please.

Any thoughts

[bazw]

for q2 it depends on the tube thickness as well as diameter so it might be smaller but will be thicker wall size so strength is retained

for q1 now see above you would need to know wall thickness's to decide

[madmark]

well i myself would just have the front part of the prop alterd to take the mt75!

the original transit prop must be thick enouph to turn those 4 wheels around

[cartooner]

As I read in a post by 'Gunslinger' in another topic ( Green Mk2), I will need a sort of a sliding
joint to compensate for axle movement. This sounds pretty logical to me, since the original prop has a sliding splined shaft at the front. Just replacing the front part of the prop with the
MT75 flange, does not give me that play. Has anybody installed a MT75 gearbox in a Mk1/2 without a sliding joint and does that give any serious problems? Will the rear-axle pull the prop
when it moves upward?

[bazw]

that joint is needed as you say it allows for movement without it the axle would be pulling and pushing the engine and box every time you drive it

[madmark]

what you need is a prop from a mk3 twin wheeler!

[cartooner]

what you need is a prop from a mk3 twin wheeler!

That's a big problem! They are very hard to find over here( Netherlands). I know I tried. Most of these went for export a few years ago and on scrapyards they are very hard to find.

[madmark]

i see your problem, the orginal v4 type uses the slide in the gearbox end ,
i think you need the slider type propshaft, even from a mk2 or 3 overdrive type then you can have the end changed!

[Squirrel]

I have fitted a Ford 3.0Ltr V6 with a Toyota 5 speed manual gearbox, to my Mk1. I have split the prop shaft just behind the gearbox with a carrier bearing mounted to the underside of the body and the sliding joint sticking out between the carrier bearing and the back axle/diff. This serves two purposes (1) accomodates axle movement and (2) relieves the additional stress the stronger motor has on the prop.