Viscous Coupling with Mk 2 Fan on Mk 1 Car

[JeffW]

Hi

My Mk I had the engine replaced with a much later Mk 2 engine 6 years ago or so. It appears whomever did it reused some of the Mk 1 parts like the radiator, power steering pump and, as it turns out, the Mk1 fan blades and viscous coupling. The coupling was spinning freely so I bought a new Mk 11 one, a new set of Mk II fan blades, the screws, pulley, spigot etc.

However today trying to install it, I cannot get the crank bolt to bite and I realised that I had the fan reversed according to the diagram in the parts catalogue / Rimmers site. If I put the fan the correct way around (where the geometric pattern is facing away from the engine), it hits the lower valance so obviously won't spin at all. If I install it so the fan leans towards the engine, it will spin but the crank bolt won't bite this way either.

Does anyone know what I have done wrong? The main pulley appears to be home as it is very close to the timing marker and the alternator belt lines up. It seems like the spigot from the pulley to the coupling (159153 in the diagram) pushes the fan blades out far too much and therefore they won't spin and either way the crank bolt will not bite. If I remove the large washer on the bolt and have the blades leaning in then will will tighten up.

I did notice the Mk 1 blades have the edges cut off at an angle, presumably so as to not hit the valance?

Thanks
Jeff

[NeilR]

The pulley outer part is different for MK2, i.e shorter projection. So your fan is too far forward.

You could just machine some off, if you had a lathe.

[JeffW]

The pulley outer part is different for MK2, i.e shorter projection. So your fan is too far forward.

That is a new Mk II pulley from the brothers, https://rimmerbros.com/Item--i-159151

I just watched this video on a Mk II engine and he didn't have the spigot in place. If this is correct, I wonder what the spigot it for as it is not listed as being for a Mk I or Mk II.

https://www.youtube.com/watch?v=vCuYFiLYKjo

[trunt]

Not sure but can you get the viscous coupling the wrong way round? Maybe that would cause the fan to be a bit to far forward?

Or could the engine mounts be sagging? I know that they can cause issues when a shroud is fitted.

[trunt]

The pulley outer part is different for MK2, i.e shorter projection. So your fan is too far forward.

You could just machine some off, if you had a lathe.

It’s the mk2 pulley that has the longer nose, it looks like a mk2 in the OP’s picture. Indeed, Maybe that spigot is not needed? Or it was needed to make the mk1 pulley work?

[JeffW]

Not sure but can you get the viscous coupling the wrong way round? Maybe that would cause the fan to be a bit to far forward?

Or could the engine mounts be sagging? I know that they can cause issues when a shroud is fitted.

Not that I could tell. I installed it as per the ROM with the fins the correct way. I looked at flipping it but it doesn't seem like it would make a big difference.

Thanks anyways - I still think it's the mysterious spigot.

EDIT - just saw your second post. Perhaps the Brother's site has mislabelled the spigot as being used for a Mk 2 when in fact is it is only for a Mk 1?

Further edit - found this image in the parts catalogue. Looks like the spigot is only used on Federal USA cars.

J

IMG_1173.jpeg

[trunt]

I had a mk1 and the shorter nose was needed for the mk1 viscous, maybe that spigot was used on early mk2 while they used up the stock of old mk1 pulleys.. wouldn’t surprise me!

Also in the boot of my “engine-less” mk2 there was a Mk2 complete harmonic balancer with a third version of pulley which was flat nosed, i.e. had no smaller diameter turned into it.. explain that one! On the right a Mk1 Pulley

*edit. Mines a federal.. maybe that’s why? But I don’t remember a spigot.

engine9.JPG

[JeffW]

I had a mk1 and the shorter nose was needed for the mk1 viscous, maybe that spigot was used on early mk2 while they used up the stock of old mk1 pulleys.. wouldn’t surprise me!

Also in the boot of my “engine-less” mk2 there was a Mk2 complete harmonic balancer with a third version of pulley which was flat nosed, i.e. had no smaller diameter turned into it.. explain that one! On the right a Mk1 Pulley

*edit. Mines a federal.. maybe that’s why? But I don’t remember a spigot.

engine9.JPG

Must be as it's a Federal - but why? What is on a Federal that would need the fan pushing forward? Some form of anti-pollution part?

J

[trunt]

Nothing I can see.. Federal had a shroud but I don’t think that’s the reason.. as you found out it would probably foul the crossmember.

[MandM]

I think that part number 159153 is not required it make the fan etc to close to the rad, have a search on here it may pop up, or someone will know

This is my MK2 fan and coupling in place

P1100001.JPG P1090996.JPG P1090994.JPG P1100003.JPG
The coupling only had about 5mm location on the pulley, but if i fit the spacer 159153 the fan will kill the rad, I think the spigot bush is a mistake of some kind but correct me if my memory is wrong.

[JeffW]

I think that part number 159153 is not required it make the fan etc to close to the rad, have a search on here it may pop up, or someone will know

Actually you knew! Missed this from April, and Mike Lingen pointed out it was likely wrong on the Rimmer's site showing the spigot being used on a Mk II setup.

https://www.socforum.com/forum/forum/stag-owners-club/soc-forum/816995-viscous-coupling-change-mk1-to-mk2

Thanks all, will remove it and this should bring the fan into the right position.

Jeff

[sujitroy]

Im aware from the ROM there are 3 coupling used on Stags. I have samples of all three. Some federal mk2 Stag have metal fans the coupling with this fan uses a spigot bush.

[JeffW]

Im aware from the ROM there are 3 coupling used on Stags. I have samples of all three. Some federal mk2 Stag have metal fans the coupling with this fan uses a spigot bush.

Ahh right thanks Sujit!

Jeff

[NeilR]

My initial comment was entirely from memory of 15 years ago.
Been electric fan only ever since, machined the boss on the pully casting off & used a shorter bolt.
Gave more room to allow the 16" fan to fit engine side of the rad (more efficient way than in front of the rad).

[sujitroy]

Here is a photo of the US viscous coupling with the bush(top) used on Fed Mk2 Stags. Below it, is the Mk2 viscous coupling used or UK stags. The second photo shows a side view of the US Fed. coupling with bush. I have two Mk1 Fed. Stags and don't recall needing this bush.

Sujit