Historic Forest Stage Rally 124 Spider

Non-engine, eg: aerodynamics, gearboxes, brakes, suspension
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Rallyroller
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Historic Forest Stage Rally 124 Spider

Post by Rallyroller » Tue Sep 27, 2011 1:05 pm

Following my thread in “competition cars” section (viewtopic.php?f=14&t=2538#p14007)

I have now got the shell back from the welders. As usual with these things, it did not all go to plan, and there is still some work to do.

As it is being used as a stage rally car, and not a track or show car, the project has to meet certain criteria. The application the car is being used for ( forest stage rally) , the MSA historic Rally rules and my wallet impose limitations on what will be done to the car.

I have found this web site fascinating and extremely informative. I certainly have taken inspiration from all of the content and really admire everything presented here. Also I must mention the threads from Miro and Simon on their car preparation. Fantastic discussions, informative views and logical conclusions. I must also pick up on a comment from Miro that highlights the whole ethos of this site. Discussions are made and logic and theories are discussed. From this information and deliberations decisions are made for the application in hand. We can all decide from the information provided what is the ultimate solution, but in the real world, time and usually money come into the equation. The benefit of this web site is that all options are discussed, the goals are understood and then the solutions are arrived at knowing all of the limitations that could be involved.

Anyway, back to the car.

The shot blasting of the shell did not take place for a number of reasons. The solution was to remove under seal /paint etc where required. The welding chappie rebuilds Rover P6 cars so he knows a thing or two about “hidden rot” . He gave it a good inspection and overall it was not too bad. The front engine bay was seam welded, the chassis rails strengthened, front turrets were plated and supported. The main part of the interior was seam welded. The passenger floor was repaired/replaced, and the rear “foot wells” on the floor were removed. ( These actually wore through on my old rally spider due to rough stages.). Rear lower arm mounting points were plated.

The boxes to locate the extended top links were installed, and the hole left by the fuel tank removal was plated. The Sparco Cage was also welded in position. It still requires the door bars, but they will go in after I have chosen the seats.

Some repairs were completed on the body (filling in fuel filler flap and US side indicators) but this will be completed at the next visit when the remaining seam welding will be done and the shell painted.

The car is being made as light as possible. The doors from the USA shell weigh in at 25kg each! The doors from my original spider may be fitted. The hardtop, bonnet and boot are fiberglass from Morenhout. ( I don’t have the time , patience or more importantly the skill of Simon to make my own.- Respect to simon!) . Aluminium will be used as much as possible for brackets etc.

The next stage will be for me to carry out some “first fit” of items ( fuel lines, brake pipes, electrics etc. ) Quickly said but not so quickly achieved, but at least I am cheaper than the garage. I have a number of harnesses that I will disassemble to make part of the new electrical harness. The rest will be new. ( No joining of wires or anything like that.)

I have finally decided to go to right hand drive. There are a few reasons for this. The main thing is brakes. I want to fit a brake balance system. Having right hand drive makes it easier (and it is within the rules). I can fit a balance system onto the back of the servo. ( Is a 131 servo bigger than a 124? will it bolt straight in?). I ran a balance system, hydraulic hand brake and twin remote servos on my last Spider and the ST. Nightmare to bleed!

The one thing that I have noticed is the problem with bulkhead flexing. You will see in the picture how the bulkhead on this road going left hand drive shell has split. Obviously the conversion to RH drive will mean a plated bulkhead to give more strength.

I am going for an aluminium radiator (for weight and efficiency). The fuel tank is also going to be alloy (foam filled) Those should be on order in the next week or so.

The gearbox will probably be a 131 unit. To get the fit right, I put a bare block in the engine bay and test fitted the box. I could easily see where the big hammer was needed to “ease” out the transmission tunnel. The 2 131 boxes I have do not have any remote linkage. Until I get the seats installed, I am not sure if this will be ok without the remote.( I suspect not). You will see from the photos that the car is on a “spit”. You would not believe how easy this makes things. I had the gearbox in and out 4 times, the trans tunnel cut and hammered into shape and the mountings measured for the gearbox mount and measured up the prop shaft in under 1 hour- on my own. If you have a major build, it is well worth constructing one.

I have started looking at the brakes etc. Apart from brake balance, I am fitting 257mm dia discs all round (vented front) with Porshce 911 calipers. I just need to work out how to get the rear calipers on plus the original calipers for the mechanical hand brake.(rules are rules!)

I am assembling the suspension components. The front will be to original works spec ( early) complete with sump guard cross member, single slipper skid springs under the wishbones and front tension rods. The wishbones will be strengthened and plated. 125 front hubs will be used. The front suspension bushes are new- but rubber not polyflex.

The rear will be standard 5 link. Lengthened upper links. rose joints, harder bushes, etc where required. An early 124 r anti roll bar will be fitted. (20mm dia to start with. If I do more tarmac events I may consider upgrading this.) My original rally Spider had Aeon rubber bump stops fitted. ( 2 on the axle and also to protect the diff nose.) I am still looking at other alternatives. I remember this set up gave very good control after “jumps”. Slightly softer suspension that gave a nice progression to full bump making the car very controllable.

I have read the post by Urbancamo with great interest, especially regarding LSD’s. I will look more into this, as while there may be a method of putting an Ford English diff and LSD into the Fiat casing (as the Lada rally guys did) , and the parts are easily available (from a rally prep business in my local town) I need to understand the full implications. It is always good to remember that the strongest part of a chain is the weakest link.

I will try and post some more pictures as I progress. Certainly there will be more questions.
Attachments
spit1.jpg
Car on Spit in Carport
spit1.jpg (100.66 KiB) Viewed 4429 times
spit 2.jpg
It makes it so easy
spit 2.jpg (145.21 KiB) Viewed 4429 times
upper link boxes 1.jpg
Upper link boxes fitted
upper link boxes 1.jpg (134.78 KiB) Viewed 4429 times
rear link- from below.jpg
and from below, showing floor mods and link attatchemnt strengthening
rear link- from below.jpg (107.81 KiB) Viewed 4429 times
fuel tank hole.jpg
Hole where fuel tank used to be
fuel tank hole.jpg (126.36 KiB) Viewed 4429 times
box in situ.jpg
Trial fitting of box.
box in situ.jpg (180.66 KiB) Viewed 4429 times
loom- it will work again  (Famous last words!).jpg
wiring loom - it will work again ( Famous last words!)
loom- it will work again (Famous last words!).jpg (270.94 KiB) Viewed 4429 times
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Guy Croft
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Re: Historic Forest Stage Rally 124 Spider

Post by Guy Croft » Tue Sep 27, 2011 1:27 pm

MODEL POST!

This is a very worthwhile & interesting project being executed in style and the article is very well crafted indeed. Taking such care requires a considerable amount of time and thought, so thanks and well done for investing those things and especially for your kind words about the site and its members.

G

Parkspeed
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Re: Historic Forest Stage Rally 124 Spider

Post by Parkspeed » Tue Sep 27, 2011 2:06 pm

GREAT POST

Enjoyed the read, very interesting as a Fiat lover myself i'll be following your progress.

thank you Simon

TR-Spider
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Re: Historic Forest Stage Rally 124 Spider

Post by TR-Spider » Tue Sep 27, 2011 9:19 pm

Nice!

Up to now that looks great.
The only thing I would reconsider is the use of rubber bushes in the front suspension.
I lost count on how many times I replaced the new rubber ones with newer rubber ones...
also the ability of holding a geomtry setting is poor from my experience.
I measured significant geometry deviations after a few 100's hard driven km's.
Switching to poly (and some more iterations...) finally solved it.

Thomas
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Biancorally
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Re: Historic Forest Stage Rally 124 Spider

Post by Biancorally » Wed Sep 28, 2011 11:46 am

Hi Thomas,

great job, very interesting, i'll be following your progress.

Good luck.

Daniel
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mickwood
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Re: Historic Forest Stage Rally 124 Spider

Post by mickwood » Wed Sep 28, 2011 1:10 pm

interesting - dont know where you are based but if you ever want to have any inspection of my G4 Abarth, then give me a call (guy has my contact details)

Some initial thoughts however.
1) you say you are prepping this for MSA (presumably post Historic) rallying. MSA/HRCR are quite tough on proving spec and have got tougher over the years. Hence you may have a problem with the 131 gearbox - yes it is much more robust than 124 but wasnt made until after the 31/12/74 cut off. I did get an exemption to run with one about 10yrs ago, but that was because you could not easily get the correct Colotti dog box at that time. Of course you may get away with it simply because nobody knows about these cars in the uk, and no one will care unless your car starts winning
2) Similar comments apply to alloy radiator. In fact, depending on your engine spec, you should find the standard one is sufficient. I ran my car for many years in 8v form with the standard unit and never had a problem with overheating. It would be a shame to spend that money and then find you cannot use it. I have only gone for the alloy rad now as i am running 16 valve engines where the cooling is more marginal and i prefer to be safe. I am also not planning on doing historic competition any more so dont need to worry about eligibility. If you do decide to go this route, you might want to call Pace as they made mine (and made a good job of it).
3) Not sure what you mean by "extended top link on suspension" - same would apply - you would need to prove this mod was used in international events in period (but - again, you may get away with it in UK)
4) Brakes - i would suggest keeping as LHD and eliminating the Servo - I can show you how works fitted the brake balance bar. Use 911 RS Porsche front calipers if you cand find them (homologated on Abarth). Not sure what you are using as front discs as MSA are very picky about this and works ones are not cheap at all. Rear calipers are steel from a period Alfa (ask Tony at Middle Barton Garage). I did have some rear discs made up to correct works pattern (with the bells for the mechanical handbrake inside) and can tell you where to get these relatively cheap
5) If you stay with LHD you have the advantage that you can fit the quick steering box if you can find one. Achy and I have been trying to remake these for a number of years and are getting closer, but not there yet
6) Doors - go with alloy door skin and replace all glass with plexy (Plastics4performance remade these for my car in modern materials as my old perspex stuff is too dangerous). Lifters are from (i think) 127 - thats what the works did

Guy Croft
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Re: Historic Forest Stage Rally 124 Spider

Post by Guy Croft » Wed Sep 28, 2011 1:49 pm

Nice work Mick - as I know - you definitely an authority on these.

Y'all got a picture of your 124CSA to show us yet?

G

mickwood
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Re: Historic Forest Stage Rally 124 Spider

Post by mickwood » Wed Sep 28, 2011 2:02 pm

Ps - if you stick with 131 gearbox, i think i have a short front propshaft section on the shelf which will suit. Free to you if you need it. You will obviously need to balance this with your existing rear section. I may also have other old competition bits which i dont use any more and which you may find useful.

I have found some nice photos of the car at goodwood on the web - just negotiating copyright issues

Rallyroller
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Re: Historic Forest Stage Rally 124 Spider

Post by Rallyroller » Wed Sep 28, 2011 7:55 pm

Wow

Thanks to all the encouraging replies. I’ll start with a few comments.
Re rubber bushes- in front suspension- thanks for the comments by TR-spider. I do understand the situation, and would be interested to know what you used the car for and what tyre/wheel combination you were using. I still have not fully decided but still have the option for poly bushes. My one concern is the front suspension on these cars was always a problem. Strengthening one part leads to problems in other parts. (I know poly bushes are not really a strengthening but you get my meaning) Also the car is being used on forest special stages, and not tarmac stages or a race track. The main problem on the works rally cars was bending things. Having “flex” may protect the car in the long run, even though handling is not perfect. However, I would also agree that perhaps my driving wont be as demanding on the car as the works drivers, so again there may not be a problem with stiffening everything. Another fact is that in the UK the MSA only allows 6 inch rims and 70 series tyres, so again grip is not at a maximum. I will make the decision later in the build.
Mick- many thanks for your comments. I have followed your Spider for years. I really appreciate your comments. You are right about the MSA and legalities. I have already had a run in regarding the cage. ( Now sorted by using a Sparco item that meets the regs. )
We were in contact a few years ago when I was looking for parts and you had 2x 8 valve engines for sale (one minus crank) after you changed to 16v. ( You don’t still have them do you? ) I still have your e-mail- but I will ask Guy to confirm so I can contact you.
Regarding the spec of the car, you are right regarding the 131 gearbox. I do think in some of these cases that it is how you present it but we will see. 131’s were made in 1973 – ok perhaps not with this gearbox but as you say who would know. Certainly if you got dispensation I will use that as a lever as well. (Who was it Paul Lawrence? ) . I also note that the MSA is looking at allowing FIA spec cars to run. In Europe some spiders run BMW period rear diffs as the original Fiat items are like hens teeth. Mine will be live rear axle (for cost and simplicity). The “extended top links” can easily be removed and the original ones replace if required. I do know that the mod was done on my original rally Spider in 1976, and I have articles to prove it, so I could always go into class D3 which would then bring the 131 gearbox into play. (Also a 2 litre engine! They rallied 2 litre injected spiders in 1978. )
Regarding the brakes, I have the correct Porsche front callipers. However, as the rear discs were homologated on the Abarth ( independent rear end) this could be an issue. The early works cars had Girling 3 pot rear callipers from a Fiat 2300. These are extremely rare and probably not that good. There is also pictures on the homologation form showing 2 callipers on each disc at the back. (I assume 1 for handbrake.)
I hope that the MSA are a bit more sympathetic regarding the Fiat- something a bit different. As you say if I start winning then perhaps they may look a bit closer. Certainly the mods I am doing are not giving a performance advantage over what was available in the period. As you say works pattern discs would be expensive, but if modern discs of the same thickness and diameter are easily available now, I can’t see how they could object. ( well perhaps I could). Again any mods I do will be easily removed.
The radiator was down to it needing a new one and the alloy is lighter. Again I will check the regs but Escorts use alloy radiators. The main sticking point for me will be the diff. Getting an LSD may be slightly difficult. The English Escort diff assembly will fit into the axle but anybody worth his pay will spot that under the car! Again I will have to check with the regs etc. I note that Ford Avengers can run Ford 2000e gearboxes.
I also appreciate the fact that with your car you have to keep it period. Your car is a piece of history, and great respect to you in keeping it up to scratch and showing it to the public in the environment it should be in, not just sitting on a stand.
I am just getting some of the other bits sorted. Fuel tank is causing some head scratching. To get a 50 litre tank, battery , pumps 2 spare wheels into the boot, with the tank against the bulkhead has got the fabricators thinking ( and adding up the cost!).
A MkII Escort BDA rally exhaust is a good fit (only slight mods required.) Handbrake is a small problem as you now have to have cable operation. Having looked at some of the “examples” currently used on historic rally cars ( which did not have cable handbrakes in period) I think they have “ friendly” MOT inspectors! I am still looking at using the Porsche rear callipers for the hydraulic brakes and hydraulic handbrake but try and fix the original rear calliper on to act as the mechanical hand brake. The standard handbrake mechanism is being removed ( it would only get ripped off on a stage) and I will construct a new cable system linked in some way to the lever. Trailer brake cables seem to be the simple and cost effective method to attach to the calliper.
Doors are going to be blasted this week. Depending on their condition will depend on if I have them re skinned. If I do they will be in alloy. I have the 4mm plastic for windows, just need to cut and fit it. I will investigate the Fiat 127 link- is it lighter?
I’ll up date you in a week or so or when I have more questions.
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mickwood
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Re: Historic Forest Stage Rally 124 Spider

Post by mickwood » Thu Sep 29, 2011 9:57 am

You are right that the greatest limitation on making these cars work in the forest, is the lack of ground clearance and lack of front suspension travel. Running flat chat through the long downhill sections through Pantperthog, with the car sitting on the sumpguard so no steering, tends to focus the mind! In That situation it doesnt matter if your bushes are rubber, poly or steel - it is a bit academic (was it Colin Chapman who said "Any suspension system, however badly designed, can be made to work after a fashion, if you just stop it moving!")
You also need to stop things bending. You have obviulsly seam welded the tub, but the factory doubly reinforced turrets, as well as plating wishbones, and reinforcing steering drop arm and idler arm. (I can post photos if you wish) For a "working, non original" car like yours i would go further and reinforce steering arms as well. Even then you will need to thoroughly check the quality of the tie rod, (because they are quite long and not straight they bend under shock loads -something akin to "Euler critical loads" if i remember right, but they only apply to straight components - it is the bend that creates the problem). also the steel quality of track rod ends and suspension pivots can vary considerably.
There are some tricks you can do with the roll cage to increase strength which are all MSA legal. For example, full cross bracing in "C" post area, with a lateral tie tube (used for mounting seat belts). I can post photos if you wish (having rolled my car i like a strong cage, even if not "period". Mine is a welded cage, but actually only bolted to the tub (it comes out in one piece - about the only advantage i can think of of an open top rally car). Welding in (as you have done) is obviously better
incidentally, i do still have those engines, but a) the "non works" one has been fully rebuilt by Guy and is now in the car whilst he finishes the 16v engines. It could be for sale when the !6v are done, but I am afraid it wont be cheap, b) the works engine is also at Guys being redone at this moment - I will not want to sell that as it is part of the cars history.

mickwood
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Re: Historic Forest Stage Rally 124 Spider

Post by mickwood » Thu Sep 29, 2011 12:31 pm

My car in the air at goodwood - note the lack of front suspension movement, even on full droop. Rear is better
Note also the sump guard - this is full length covering the front lip of the gearbox (which is otherwise prone to damage and scooping up crud).
Attachments
124 at goodwood 2011.jpg
124 at goodwood 2011.jpg (339.4 KiB) Viewed 4216 times

Rallyroller
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Re: Historic Forest Stage Rally 124 Spider

Post by Rallyroller » Thu Sep 29, 2011 5:11 pm

Thanks for the comments Mick. I know what you mean regarding running on the sump guard. When I first rallied the ST in the forests somebody approached me at service and said I was one of the nosiest cars on the rally- you could always here me coming. I questioned him as I said the exhaust was not that noisy although a Fiat Twin cam does sound a bit different. He said it was neither of them he could just hear the sump guard dragging along the floor for miles!! The guard on the ST covered the gearbox as well. It was huge- however I certainly think that this caused cooling problem in the engine compartment ( lack of air flow out of the engine compartment ) and with the gearbox as well. When I make my new one it will be similar to yours- covering the front edge of the gearbox. The ST ground clearance was cured by fitting Lada Challenge spec springs. What a difference. They transformed the handling of the car.
As you say strengthening the steering is crucial. I’m looking at similar mods as you describe. Problem is how far do you go? It is relatively easy to change the track rod ends and centre bar but changing the steering arm/box on a rally is not so easy. I bent the main steering arm from the box one on my old rally spider.

Regarding the cage, I still have not made the final decision yet. One interesting point, I asked the MSA if I could fit a cross tube in the roof of the cage on safety grounds as it has a fibre glass top and rolling into a forest onto cut tree stumps or across a stone wall could hurt a bit. They said no. The reason – it would set a president for other cars, and it would not be possible for Escorts or 911 to retrofit them correctly. They cannot take the roof off to weld the tubes in correctly.
I am away on business for a week, but I will contact you on my return. It would be great to come and see your collection and discuss a few things. Pictures of the car at Goodwood are great. I see that you have reverted back to the large arches. ( which I think were the original spec on your car? ) I only have the early arches. As the tyre and wheel sizes are limited, I thought I would use the smaller ones. Looking at the body work it might have been easier to fit the larger ones and remove more of the bodywork.
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mickwood
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Re: Historic Forest Stage Rally 124 Spider

Post by mickwood » Thu Sep 29, 2011 5:33 pm

Ok - thats fine - call me on return - i can show you the reinforced idler arm and steering arm - easy to replicate if you are good with a welder.
For UK Gravel and MSA spec tyres, i would suggest to avoid the full "scoops and vents" bodywork. The rear scoops will only fill with gravel and you are not going to overheat the brakes or dampers on a UK forest event. RH Front vent is only necessary on 16v (to increase cooling from engine bay) - LH front vent is for oil cooler ducting, but positions the oil cooler in the wheel arch - I would be worried going through Margam with that set up. If you can get away with 50mm arch extensions it would be best. you need 100m for 8" rims, but if you run 6" and 7" all you will do by using 100m is increase the overall width of the car meaning you increase the frequency that you wipe the extensions off as you clip chicanes (I have moulds for 100m if you need them however - best to mould them in flexible resin).

WhizzMan
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Re: Historic Forest Stage Rally 124 Spider

Post by WhizzMan » Fri Sep 30, 2011 6:06 am

mickwood wrote:i can show you the reinforced idler arm and steering arm - easy to replicate if you are good with a welder.
I think I will be speaking for most of us, if I asked you to please post pictures on the forum.
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TR-Spider
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Re: Historic Forest Stage Rally 124 Spider

Post by TR-Spider » Sat Oct 01, 2011 12:08 pm

Re rubber bushes- in front suspension- thanks for the comments by TR-spider. I do understand the situation, and would be interested to know what you used the car for and what tyre/wheel combination you were using.
Most of the experience I had was on 13" rims with 185 road tires and fast-road-driving. I started running sticky semislicks later, when I went for the track.
I understand your concearn about breaking things...as I also exceeded the material strength in many areas, particularily the front crossmember and the lower wishbones. I significantly strenghtend these, see pics here:
viewtopic.php?f=5&t=2141&p=11183#p11183
With that "final" evolution in strenthening I ran quite a number of km's with Yokohamas A48 on tracks without further signs of missalignment or cracks.
One has to see that the stress on crossmember and lower wishbone of the stock 124 will be even higher compared to the 124 Abarth design, as there the backwards bending forces are opposed by the pushrod.

Ground clearance - Oh jes, I learned the hard way, that on a 2 l Spider the oil pan clearance at full suspension drop after a jump is something like minus 15mm...

Thomas
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