cabrio steering heavy.

[norman ball192]

My 3.9 Cabrio has alwayshad VERY heavy steering, after being built it went to marlin for setting up, TWICE, and it was still very heavy. Whilst visiting Procomp with my sons Westfield they looked at my Cabrio. And although Mark had given me every assurance that all was well with my car & set up, it now appears that this was not so.
Procomp checked caster & camber tec and thought shims would help, but calculations showed that 44mm would be required, obviously too much. Further investigation showed that when Marlin had welded the blocks for the anti roll bar, that they had marked the location of the block front, but then fixed the BACK to this point, thus meaning that the anti roll bar is 1.5 inches too far forward. No wonder fittin the thick V8 bar was such a struggle, and why the front roll bar bushes dont last.

It is going to be sorted in the near future, and I will report on what difference this makes. I report this in case there is any other member with excessively heavy handling.

Thanks Mark, as with the unsuitable drive shafts fitten on his advise, another Marlinism!!!

[Mike]

Re: cabrio steering heavy.

Norman

Marlin are not too fussy how they "solve" problems. I am building a Cabrio with the 6 cylinder BMW M50 engine. On the original demonstrator and the one other factory prepared Cabrio with the M50 engine Marlin shortened the forward legs of the Anti roll bar by around 40-50mm and moved the mounting blocks forward to prevent the cross bar fouling the sump: probably in a similar position to where your mounts are now.
When I sent my ARB away to Marlin for modification, this is what they sent back..................two stub arms, and a b****dy gap in the middle! ie no longer a Anti Roll Bar, and a very questionable mounting arrangement with big penny washers to hold them in place in the mounting bushes.
After crawling under several other Cabrios at Stoneleigh I found a V8 fitted with a different shape ARB - from a P100 Sierra truck which allowed me to fit a proper ARB, and the different crank shape on this version does not foul my sump.

[Mike]

Re: cabrio steering heavy.

I can't get my photo showing the difference between ARBs back from my flickr site, but if you have a look here you can see the very different shapes and how it alters the way it does/does not foul with the sump.
http://www.flickr.com/photos/mikes_bmw_marlin_cabrio/4594901407/#/photos/mikes_bmw_marlin_cabrio/4594901407/in/set-72157603853056410/
I believe this has properly solved my ARB problem.
Mike

[Mike]

Re: cabrio steering heavy.

Norman - this shows Chris Cunliffe's Cabrio with the forward arms cut, shortened, and collared. You may be able to do the same to bring your suspension back in to alignment.
One other solution is to fit adjustable track control arms and do away with the ARB all together. These used to be fitted to the Sierra Coswoth to improve the precision of the handling.Have a look at Simon Gregory's set up here.
http://www.flickr.com/photos/marlin_bmw_cabrio/2640165352/in/set-72157605993210128/

[Mike]

Re: cabrio steering heavy.

Hope this works?

[Mike]

Re: cabrio steering heavy.

Hope this works?

[greyV8pete]

Re: cabrio steering heavy.

Mike. I am also trying to change the anti roll bar on my Hunter and the lower one in the photo above looks right for me. Is it 24mm diameter? Can you please contact me on plicence (at) eclipse.co.uk to discuss this. If you email me your phone number I will call you. Many thanks . Peter. PS. Apoligies to Norman for hijacking your thread. Peter.

[Mike]

Re: cabrio steering heavy.

Hi Peter
Yes my current ARB is 24mm. I think I first saw this shape of ARB under a V8 engine - probably Dave Kitson's Cabrio? The crank angle across the centre is ideal for more clearance away from the sump under heavy suspension compression.
I have emailed you as requested.
Regards
Mike
Mike

[cabrioman]

Re: cabrio steering heavy.

Not sure I fully understand this Norman.

Whilst I know only too well the Marlinisem which equates to "engineering", can it really be as far out as you say. If the ARB is standard I cannot beleive you would be able to phisically make the ARB go on. If its 1.5" too far forward on the chassis mount it would mean the track controls arms would have to move forward a similar amount which I can't see would be possible. What does the Castor actually read in its current configuration

[dogoncrazy]

Re: cabrio steering heavy.

Mike
where did you source the anti roll bar. I also have the Marlin set-up of a 'shortened ' bar which i've never been totally happy with.

[Mike]

Re: cabrio steering heavy.

Alan
I found mine at a 'specialist' Sierra breaker's yard about 15 miles from home. I do not know whether my ARB is particular to early P100 Sierra's or were fitted on other Sierra's.
Peter Licence would like a 24mm one as he feels his 28mm ARB is too stiff, but is not bother about the crank angle. When I have some time I'll take a ride out to the local yard and see if he has anything suitable for each of you.
It is interestinmg you say you are not happy with having just arms. I was not happy, but I've not even driven mine, so it was simply the idea it had no ARB, AND that the method of location seemed pretty poor from an engineering point of view. Simon Gregory has done the jopb properly by fitting rose jointed compression struts (from Burton Power ~£200)to his M20 BMW Cabrio, and says the handling is good, and does not feel his car requires an ARB.
Do you feel yours needs an ARB, or are you just not happy with Marlin's engineering?
regards
Mike

[dogoncrazy]

Re: cabrio steering heavy.

Mike
In answer to your question on am I happy with the set up. It does the job! but as you rightly state it in no way acts as a ARB. I have only my previous Cabrio to compare with and that was a SWB pinto engined car and I cannot honestly say that they feel any different. the 'Burton power' set up is in my opinion better engineered but apart from being able to adjust the castor offers similair location to Marlins answer to the problem.
My difficulty is in whether or not the P100/early type bar would clear the sump .On Peter's car his engine was slightly further back than mine and only just cleared and i believe his had the early Sierra bar.
In summary I don't personally think that an ARB is required, I just think that from an aesthetic point a complete unit or Burton torsion bar would look better.

[copperleaves11]

Re: cabrio steering heavy.

Hi all.I have a Cortina 22mm anti-roll bar,complete with new rubbers which might suit. Anyone interested can contact me through the number in Pitstop. I use a Metro 18mm bar on my Sportster which seems fine in view of the difference in weight between donor vehicle and Marlin.Regards

[danny_nelson]

Re: cabrio steering heavy.

Hi Alan,
If it clears Mikes, then it will clear yours. Peter done some work on the bulkhead, and made his own mounts to be able to get the engine back and retain the bar off the Sierra.It is interesting to see that Ykc done something similar with the front of their Sierra based model. They used a short strut with the Sierra upright, cut the ends of the ARB and changed them to opposite sides to locate the track control arms. I dont think that the ARB is reqd, but I do think that it could look better.
Danny.

[cabrioman]

Re: cabrio steering heavy.

Alan

I think there is a fundimental difference between your car and Mike's. Mike has fitted an M50 which I believe, unless I am mistaken has the deep part of the sump to the rear of the engine, yours is an M20 with the deep part of the sump to the front. Very different engine and very different clearence considerations.

From the discussion I had with Pete Morris, with an ARB fitted, he ended up with 5mm clearence front and rear even after cutting the bulkhead . Simon indicated to me even after cutting his bulkhead he couldn't squeeze it in with an ARB, hence the reason he went with compression struts.

I am sure the best solution is to fit struts as it allows the castor to be setup very exactly and if anything gives better handling than an ARB as the caster is locked and doesn't float araound under braking and cornering as it does with an ARB.

The only concern I had with using compression struts was an over harsh ride (or worse than standard) but Simon states he has had no problems in that respect.

John