M&W 550 Overhaul...

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alfacat
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M&W 550 Overhaul...

Post by alfacat »

Hi Guys
So I thought I'd put down my ideas, intentions, triels and tribulations as I (and people far more skilled than me) try and get my Spyder Rep back to the car it should be...
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and a few old Lotus.

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Re: M&W 550 Overhaul...

Post by alfacat »

Image
A pic to get things moving along...

Right let's start with a little background...
The car is a 1989 Martin & Walker 550 rep with a 1700cc Alfasud engine and gearbox fitted. She was originally purchased by Mr Philip Needham who was apparently Registrar of 'The Replica Spyder Register' (any further info appreciated).
Originally painted red it was resprayed Silver with red details about five years ago.
The car drives and stops, has a current MOT and feels pretty quick but during its life it's picked up a few unwanted mods (some downright dangerous)!
As she arrived with a lot of history and photos I'll post more details as they become relevant.

Next up a list of things that need doing...


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________________

Gone but not forgotten
72 2.4 T in Sepia (Charlie)
60s, 70s, 80s, 90s & 00s Alfas
Caterhams (one fast & one very Fast!)
and a few old Lotus.

Still with us
997 C2S (Alice) & M&W 550 Spyder (Lil Caesar)
neilbardsley
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Re: M&W 550 Overhaul...

Post by neilbardsley »

That looks like a good rep

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Re: M&W 550 Overhaul...

Post by alfacat »

Major Problems list
There are three main big issues

1. The brakes are a complete liability, there are no flexible pipes at the rear of the car, its all hard copper line so if the suspension moves the pipes could and one day will fracture. Unsurprisingly this is top of the list to fix!

2. Someone has installed (badly) what appears to be costly Willwood pedal box, strangely this places the master cylinders directly under my heels and reduces footwell height.
It’s a mess (it probably doesn’t help the brake issues)and it’s coming out to be replaced by an ‘Outlaw718’ 550 replica pedal set (thank for your help and advice Paul).

3. Although the Alfa 5 speed box has recently had an overhaul the linkage is awful, 1st gear is only selectable if the car is stationary and then its hit & miss (mainly miss), 2nd gear I still haven’t found. Hopefully this is just a case of adjustment.

All the above issues will be farmed out to people who know what they’re doing, rebuilding a brake system is not a thing I feel comfortable with and there is an excellent Porsche transmission guy local to me.
Last edited by alfacat on Wed Sep 09, 2020 2:52 pm, edited 1 time in total.
________________

Gone but not forgotten
72 2.4 T in Sepia (Charlie)
60s, 70s, 80s, 90s & 00s Alfas
Caterhams (one fast & one very Fast!)
and a few old Lotus.

Still with us
997 C2S (Alice) & M&W 550 Spyder (Lil Caesar)
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Re: M&W 550 Overhaul...

Post by alfacat »

neilbardsley wrote:That looks like a good rep

Hi Neil
Yes, despite all the mecheninical problems it's a good car thats been messed with by the wrong people.
Barrie from M&W has been a great source of help and advice, Paul Foreman (Outlaw 718 on here) has also helped out with advice and some parts supply.
I brought with my heart not my head (and was unable to test drive the car) but I hope it will end up the car it once was and should be!

All the best
Ian F.

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________________

Gone but not forgotten
72 2.4 T in Sepia (Charlie)
60s, 70s, 80s, 90s & 00s Alfas
Caterhams (one fast & one very Fast!)
and a few old Lotus.

Still with us
997 C2S (Alice) & M&W 550 Spyder (Lil Caesar)
rhd racer
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Re: M&W 550 Overhaul...

Post by rhd racer »

Hi Ian

Luckily those issues (assuming they are the major ones) should be easy to sort. The brake pipes on the rear can be cut short and flared, and flexi pipes fitted to them (suspect will be m10 x 1.0mm) which is standard for VWs and Porsches. I am sure Barrie has told you which rears he uses as standard, the length will be critical to ensure you can fix the joint to the suspension arm so it doesn’t pull as it travels. If not serviceable, a new pair of rear hard lines can be made up for a few £s in copper nickel.

The front might take a little more work. Wilwood uses imperial fittings, and as you have already worked out the master cylinder is not in the location Barrie intended. This means possible a new line up the centre tunnel, and both front pipes too. The existing fronts might be reusable if adaptors have been used from imperial to metric, but I doubt it. Still not a big job, just re-routing, plumbing job.

The reason people usually fit Wilwood pedal boxes (and it will have a value when removed) is to allow you to change front to rear bias by adjusting a pushrod. This mod may have been done for show, but maybe because the prev owner was not happy with the brakes snatching at either end. Whilst doing the mods to the lines, you could fit a brake bias (sometimes called a compensator) to allow you to fine tune. They are made by Wilwood amongst others and fit before, in the middle of, or after the central line. You can position to adjust it from your seat, or underneath so you set up once and leave. These are made in m10x 1.0. I would have thought that the weight distribution of the car should not warrant one (Barrie again will advise if he uses them or not), unless of course someone has updated just the front brakes for example, and tried to dial out the over-performance. If you have a pic of the brakes we can try and identify them and confirm the threads.

None of that is a great deal of work, and hopefully the pedal mounts weren’t ruined in the process of the previous changes.

Hope none of the above is teaching you to suck eggs! Keep us posted, it looks great

All the best
Wayne
93 964 C2
99 Boxster 2.5 > 2.7 hill climber

71 914/6 3.0 - gone

'You see Paul, hill climbing is like making love to a beautiful woman. You get your motor running, check your fluids, hang on tight and WHOA..30 seconds later it's all over!' Swiss Tony
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Re: M&W 550 Overhaul...

Post by neilbardsley »

Isn't being able to change the front rear brake balance useful? I see the F1 drivers playing with this setting all the time

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Re: M&W 550 Overhaul...

Post by smallspeed »

rhd racer wrote:The reason people usually fit Wilwood pedal boxes (and it will have a value when removed) is to allow you to change front to rear bias by adjusting a pushrod
This is for adjusting brake balance not bias - correct brake balance can be achieved through correct sizing of master cylinder(s) and is important to get right
Brake balance affects the front vs rear brake line pressure for any given pedal travel and is usually calculated using a max braking potential for the car. Its worked back from the max brake effect at the front vs rear tyre contact patches, to give you the correct pressure ratio front vs rear at the master cylinder(s)
Think of it as a graph with two straight lines at different angles - pedal travel on the X Axis, brake pressure on the Y Axis. The balance is the difference in gradient of the lines

if the rear brake graph is steeper than the front = more power to the rear brakes than the front
single line = same power front and rear
if the front brake graph is steeper than the rear = more power to the front brakes than the rear

Almost always you have more braking force on the front axle, which (assuming brake discs and pads are similar F-R) requires a higher line pressure
Whilst doing the mods to the lines, you could fit a brake bias (sometimes called a compensator) to allow you to fine tune
This is for adjusting brake bias
Consider the above graph again, this time with a dog-leg in the rear line, so initially a reasonably steep gradient, then at a certain point it changes to a flatter one
The intention of a brake bias valve is to prevent the rear from locking up as weight shifts forwards under heavy breaking. So up to a certain braking force or brake pressure the front and rear brake pressures increase in a straight line, above a certain pressure the front pressure will continue to increase in a straight line, the rear will increase less quickly

Brake bias valves come in two common flavours

1) adjust bias % with a fixed point - this type of valve adjusts the angle change between the two areas of gradient
2) adjust both - you can adjust the amount of bias and the position where it occurs

the third is less common

3) adjust bias point with a fixed % - this type of valve adjusts where the dogleg occurs along the line but the angle is fixed

Here's a graph from pelican forum which does a reasonable job of explaining it
They refer to it as a proportioning valve, and use the term "change over pressure" for the point where the bias takes place
They have mislabled the axis - the X should be pedal travel and the Y should be brake line pressure - the axis as they have it would be for a single line (the red one) and not two lines (front and rear) like they've shown

You can see here the red line is the rear brake line pressure, the blue is the front - there is a difference in angle initially which is due to the difference in sizes between the front and rear master cylinder. At the "change over pressure" point, the bias valve starts to reduce the pressure gradient on the rear line, preventing the rear wheels from locking up as the weight on them reduces under heavy braking

Image

if you're not happy with the brake pedal box you have then remove and sell it on ebay, they're £600 ish new, master cylinders are £75 each, they hold their value pretty well. Just be aware if you're changing for cosmetic reasons i doubt you'll get anything better performing for under £2k, the 600 series are a really nicely made piece of kit, although it sounds like you maybe have some headroom issues and that's the reason for change?
I have the same pedal box in one of my cars and its served me really well

There are plenty of online calculators for brake MC sizing - you want one that takes into account axle weight, centre of gravity, caliper piston size, brake disc effective diameters, pad height, etc. The more of a pain in the arse it looks the better it probably is. All of the info is googleable or measurable so its not a big deal to do. Get your MC size right, and then starting with a bias valve set to "off" (or equivalent) you can experiment somewhere safe to bring the rear line pressures down a bit

Re: lines - I'd say its not worth the potential headache with modifying the rear lines, if they've been flexing they could be damaged or work hardened up and down their length, so better to just replace them. Then you know they're from kunifer not copper, clipped properly, etc., etc.. the materials are cheap, if you get someone else to do it for you and they have the right tools its not going to take them that much longer than modifying whats already there. Depending on how accessible it all is, probably worth doing the whole lot so they fit the new pedals correctly too. Might also be worth doing the clutch line as well (assuming its hydraulic?) and bleed the whole lot with some fresh fluids so its as good as it can be

HTH
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Re: M&W 550 Overhaul...

Post by smallspeed »

neilbardsley wrote:Isn't being able to change the front rear brake balance useful? I see the F1 drivers playing with this setting all the time

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F1 Drivers are threshold braking most of the time and in a lot of cases trail braking too, they're adjusting the balance to assist rotating the car into the corners or to compensate for different speeds/braking conditions from corner to corner
Application for mere mortals would be wet vs dry to avoid locking the rears, different track conditions from circuit to circuit, or potentially when using different tyres. I believe quite a few club level championships do not allow cockpit adjustment
For the most part this adjustment has been done away with through modern 4 line ABS systems anyway - a decent system can now achieve threshold braking independently, wheel to wheel
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Re: M&W 550 Overhaul...

Post by rhd racer »

You say balance, I say bias! Yes, Bad terminology on my part but meant the same thing, good right up Ben. Or to use the car stereo term, I meant fader!

I don’t see the point in adjusting on the go either, other than initial set up is easier. On my old race car I simply went out on a very slippery day on old tyres and started at 20mph doing emergency stops, adjusted to dial out locking, repeated slightly faster, and repeat. Once I got to no locking (or all 4 depending on speed) it felt right. I then competed in the car for 15 years in all conditions without adjusting again unless I did a brake mod which would change it. I am very hard on the brakes due to the discipline, and do once well and leave worked well. I am not a fan of cocking around with things and then realising you went one nadger too far with the adjustment as you head towards a guard rail or tree!

Cheers
Wayne
93 964 C2
99 Boxster 2.5 > 2.7 hill climber

71 914/6 3.0 - gone

'You see Paul, hill climbing is like making love to a beautiful woman. You get your motor running, check your fluids, hang on tight and WHOA..30 seconds later it's all over!' Swiss Tony
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Re: M&W 550 Overhaul...

Post by smallspeed »

Exactly - i did the same with my e36 in the dry on track day tyres to get the balance set somewhere around the middle (road/trackday/slick tyres) and only really adjust a couple of clicks when its cold and damp, and a couple more in the wet, but that's on track - hill climbing i imagine is very different! On the road i put it back to the normal baseline setting everytime
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Re: M&W 550 Overhaul...

Post by alfacat »

Hi Gents
Thanks for your advice, it helps a lot. The Willwood has to go as it’s construction (cylinders on the driver side of the pedals) raise my heels to a point where even without shoes my toes drag on the top of the footwell. Also the way the pedal box has been piped seems to have caused the clutch to drag (Barrie explained what’s likely to have caused this), so repiping the rear of the car seems the most sensible way to progress, happily the front brakes seem to be in a better state (they at least have flexable pipes where appropriate) and as the master cylinders are moving closer to the front, hopefully they can be ‘spliced’ in without to much trouble!

To be continued...
________________

Gone but not forgotten
72 2.4 T in Sepia (Charlie)
60s, 70s, 80s, 90s & 00s Alfas
Caterhams (one fast & one very Fast!)
and a few old Lotus.

Still with us
997 C2S (Alice) & M&W 550 Spyder (Lil Caesar)
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Re: M&W 550 Overhaul...

Post by neilbardsley »

Thank you for the detailed write up Ben

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Re: M&W 550 Overhaul...

Post by alfacat »

Sorry if sounded 'damded by faint praise' there Gents, It helps a lot to get input from folks that know more than me (and that's just about anyone really)
Ben, thats makes total sence to me. Wayne, not in the slightest are you 'teaching me to such eggs' quit the opposite in fact...

Thanks again Gents

Next up some thoughts on wheel and tyres (and I spend some money)!
Last edited by alfacat on Wed Dec 02, 2020 12:58 pm, edited 1 time in total.
________________

Gone but not forgotten
72 2.4 T in Sepia (Charlie)
60s, 70s, 80s, 90s & 00s Alfas
Caterhams (one fast & one very Fast!)
and a few old Lotus.

Still with us
997 C2S (Alice) & M&W 550 Spyder (Lil Caesar)
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Re: M&W 550 Overhaul...

Post by alfacat »

So a bit of an up date...
The Spyder is still fitted with it's orignal set of Michelin MXL and while they're not that worn they are around thirty years old so they have to go...
So one of the first things I brought for the car was a set of 165HR 15 (80 ish profile) tyres, however I have held off fitting them as I rather fancy a set of 'Wide 5' wheels and it seemed a little silly to fit them only to remove them at a later date!

The plan was to go from this...
Image

Via this...
Image

And this (parts are missing here)...
Image

To this (well sort of)!
Image

I'm currently waiting on some CPS M12/M14 stud (adaptors) before I test fit the 'tyreless' wheels & spacers. I'll be buying the last few bits to complete the job once I know it all fits.

NB. I am well ware of the 'arse about face' nature of sorting out wheels and tyres on a car that can't be driven... :-(

Coming in the next instalment, a bit of tiding up and fault finding in the wiring loom, I'll need a drink before reporting on that!

All the best
Ian F.


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________________

Gone but not forgotten
72 2.4 T in Sepia (Charlie)
60s, 70s, 80s, 90s & 00s Alfas
Caterhams (one fast & one very Fast!)
and a few old Lotus.

Still with us
997 C2S (Alice) & M&W 550 Spyder (Lil Caesar)
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