No float on propshaft

[richardl46]

I've just refitted the engine and gearbox in my car, a 1972 +2 S 130 with Spyder chassis. After tightening all mountings I find there is no fore and aft float on the propshaft. In fact the rear flange cannot be moved sideways from where it locates into the diff input flange. All turns ok and I'm 99% sure all went back together as it was before stripping down. It's possible the car has been running like this for years before I bought it, but I know its not correct and the photo shows how close the front UJ is to the tailshaft.

The chassis crossmember, on to which the gearbox rubber mount is attached, has slots for the bolts that would allow the gearbox to move forward up to 15mm. Where the engine brackets attach to the rubber engine mounts they could be moved in front of the engine mounts to gain about 12mm of forward movement of the engine (see photo).
This action would leave only about 5/7mm clearance between the front of the sump and large tubular cross member.
Can anyone tell me if the engine brackets are correctly fitted to the rubber mounts? Any ideas how the situation may have arisen?

Thanks, Richard

[Donels]

Are you sure you have the mountings correct? On my S130 the rubber mountings bolt to the engine first and then to the chassis. You have your mountings bolted to the chassis. See attached photo. Mine is a Lotus chassis so may be different.

[SENC]

I don't have a spyder chassis so can't help from that perspective, but the worry I'd have with that fit is the risk of the gearbox driveshaft popping the welch plug out of the propshaft yoke and allowing a gearbox leak. The photos below show mine before and after the yoke was inserted.

It is hard for me to tell from the pictures, but it looks like your yoke is original - if the yoke is new, that could be the problem as all of the reproduction yokes I've found are not the same dimensionally as the originals. See my previous gearbox rebuild thread for details.

[mbell]

My memory is in the original lotus chassis the engine mounts bolt to the front of the chassis ears. As you say you could swap them to the front to get some clearance and that would be more in line with a lotus chassis.

Do you have the chassis installation instructions from Spyder? If you find I think they have been posted here and would be worth checking.

[elj221c]

Are you sure you have the mountings correct? [/attachment]

Correct for a Spyder frame.

[JonB]

S130/5 with Spyder chassis here and recently been pulling the engine and gearbox out / in / out / and shake it all about.

You definitely have the mounts the right way round. They bolt to the chassis. When I first refitted my engine I tried to get the Spyder bits bolted to the chassis but the holes don't quite align and there wasn't enough clearance for the plate to sit squarely on the chassis. Good job too!

Exhaust side mount

The only thing you might try that I can think of would be to move the engine forward by bolting the lugs on the mounts to the rear facing side of the Spyder mount arms. If you look closely at the picture, this is how I did mine (more by luck than judgement). This would give you an additional 2.5mm of space.

[Mazzini]

I recently worked on a friends Lotus 7 S2, it too had a similar problem, the yoke was hard up against the gearbox. My local propshaft shop took half an inch or an inch (can't remember) off the prop and all was well after that.

[nmauduit]

The chassis crossmember, on to which the gearbox rubber mount is attached, has slots for the bolts that would allow the gearbox to move forward up to 15mm. Where the engine brackets attach to the rubber engine mounts they could be moved in front of the engine mounts to gain about 12mm of forward movement of the engine (see photo).
This action would leave only about 5/7mm clearance between the front of the sump and large tubular cross member.

it seems to me that having the red engine mounts in front rather would give 6-8mm extra clearance at the shaft which should be enough if it is just touching, and would leave enough at the cross member (6-8mm less than the present situation)... Some extra may be gained via the play in the holes, but should not be necessary if there is 4-5mm of play at the shaft.

[AussieJohn]

Both my +2 130'S had the same problem, I tried a different propshaft and still had the same problem. I guessed that both cars had been running like that for years so I just left it as it was, so 10 years on no problems yet.

[Donels]

Have you replaced the reaction bushes at the diff? If not you could replace with new. When these are tightened it pulls the bottom of the diff forwards, rotating the diff around the mounting bolts, moving the flange forwards. New bushes may give you another 5 mm or so.

[richardl46]

My thanks to those who responded. I can confirm that moving the red engine brackets in front of the rubber mounts gained about 10mm of float on the propshaft and reduced the gap in front of the sump to a similar distance. All very acceptable and quite a relief.

Photos taken by the previous owner in 2008 showed the brackets behind the mounts. From the markings on the parts I would guess they were in that position when the Spyder chassis was first installed in 1987.

A great result that allows me to move on to the next problem.

Thanks again and best wishes to all for 2020.