Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) wishbone front suspension

Hi,

I'm toying with the idea of junking my sliding pillar front suspension (Morgan plus 4) and going for wishbones. Is it possible anyone can supply a full set of parts for the conversion? I have a feeling someone on here was involved with the (complex and time-consuming) fabrication and development of such a system but Librands are the only people I can find who seem to sell it. They only quote for fitting it themselves, are a long way from the end of Cornwall where I live, and appear to charge a small fortune for the job.

cheers

Wonder if Mulfab could be persuaded Griffo . This is what you are looking towards - a lot of welding I understand.

This is a query from an ignoramus. Wouldn’t you need to provide for much more suspension travel in order to make wishbones worthwhile? There doesn’t seem to be enough clearance under the wings.
SFG

Not sure... my Boxster has limited suspension travel, but very well designed and engineered suspension that works better than most, despite being "just" a McPherson strut at each corner. My Aero Plus 8 likewise. Double wishbones can be wonderful, nut need very careful development.

I still think that a double wishbone set up on such a flexible chassis will be compromised, even without limited travel. Like all suspension mods, it's almost impossible to try a Morgan out so fitted, and even then it's subjective.

For what it's worth, a friend of mine converted his 4.6 racer to wishbone front suspension (provenance of the set-up unknown to me) and it really wasn't very successful - the handling was unpredictable, even after having a detailed review and consultation with the chap who made Terrapin hillclimb/sprint single seaters (IIRCC Alan Staniforth). I drove the car in its wishbone form and it definitely didn't gel for me. The car was eventually sold, and was converted by the next owner back to sliding pillar.......

Dave

Exactly this.

For me the best thing that wishbone front suspension would bring is the elimination of bump steer. But that's part of the reason it's expensive cos it needs a new steering rack.
Cheers
John

The steering rack used on the Mulfab front wishbone conversion is a Mk1/2 Escort item so it's not expensive at all, it also readily available in a huge range of gearing options from 2.9, 2.7, 2.5, 2.4 to 2.2 turns LTL; for the record, the rack in my Mulfab wishbone conversion is 2.7 LTL.

Now, let's be honest with ourselves here, the Morgan sliding pillar suspension is very ‘vintage’ in its design, it's also extremely compromised in a number of ways and seems to be the source of much criticism on these pages with owners often complaining about crashy ride quality, bump steer, excessive maintenance requirements, high wear rates, and a short service life.

Being blunt, it's quite clear other car makers would have copied Morgan's sliding pillar front suspension if it was any good, they didn't, indeed from the 1950's on car makers tended to go in one of two directions.

1. McPherson strut - Ford lead the way here

2. Double unequal length wishbones with coil over damping - Triumph lead the way here, but in truth they took it from race cars of the period

If someone fitted a front wishbone setup to a Morgan and it didn't work very well, it wouldn't have been because front wishbones are a bad concept, it'll be because the setup was poorly designed. My Mulfab front wishbone setup works extremely well, tun-in is wonderful, ride quality and handling is impressive too. However, I think what any Trad Morgan owner would immediately notice is how well the Mulfab wishbone conversion soaks up rough surfaces and potholes compared with the sliding pillar setup, sadly the ability for a car to deal with potholes is becoming increasingly important given the current state of British roads!

There are however two issues with the Mulfab front wishbone conversion:

1. It was very expensive - I have a bill in Monty's file for over £6k

2. It's no longer available - I believe SiFab was looking at producing a second run, but I don't think there was enough interest/commitment for him to start the project before he sadly closed his doors.

As I understand it only six Morgans ever received the Mulfab front wishbone conversion, so finding a car with setup already fitted would be very challenging indeed, but if you can it's definitely a big improvement over Morgan's antiquated sliding pillar arrangement so should be viewed as a very desirable upgrade.

Of course Morgan themselves have been using twin unequal length wishbones for years, starting with the Aero 8 and continuing now with the new CX platform cars. The sliding pillar front suspension is almost as iconic as the wood frame construction, but when Morgan designed the CX platform cars they didn't fit the sliding pillar setup, and for good reason. They retained the ash frame because it’s so much part of the car’s unique identity, but for obvious reasons they went with the far superior wishbone arrangement both front and rear.

Maybe worth adding that unequal length (shorter at top) but parallel wishbones provide the geometry to increase negative camber under compression. This helps the outer tyre in a corner maintain a flat contact patch with road as body rolls.