dickruzzindesign@aol.com

Hi Dick
Just wondered if you could help. Do you know of any supplier in the US who has made a stronger steering rack for a Mangusta. I race my Mangusta and the Renault Four rack, A is not up to the job with sticky race tyres and B the ratio is so bad that if the car brakes away in a corner it takes forever to wind the steering back to correct. Let me know if you can help.
Kink regards
Mike Eagles email mike.fairmont@gmail.com

MIKE,
No-one would make aftermarket parts for a market of 401 cars. The Mustang rack is available easily in racing catalogs. I would check there.
DICK RUZZIN

Hi Dick, a previous owner of 1302 was a highly respected race chassis/ exhaust engineer. He calculated swept ratios etc and came up with replacing the front callipers with Volvo 246Gt callipers. These originally were a 2 hose connection in Volvos, however they were drilled through for a single connection hose setup. Only other change is mounting plate and kept original Girling callipers. Resulting difference from original is chalk and cheese with fronts just locking marginally before rears under heavy braking. Overall I feel it is a well balanced system and I am running EBC Red pads all around.
Thanks Mike

Whatever works. That was a lot of work and expense.
Adding an adjustable proportioning valve keeps the car original and allows you to fine tune the front brakes. It goes in at the front brake line junction that is bolted to the chassis.

Are RED pads soft street pads? What manufacturer?

Dick Ruzzin

Hi Dick, as all the hard work was done well and the system works much better than on my other original setup Goose I am happy to leave it as is. The pads are from EBC and Redstuff type. They are a top quality street pad and not sure how soft they are, but have little brake dust with them. Mike

While I am at it,
does anyone have a source for motor mounts?
They are called, ANTI VIBRATION SANDWICH MOUNTS.

They are 75mm Diameter and 25mm high, M-12 bolts on each end.

I find them in catalogs of different companies but they do not make them duet the size, the taller 40mm ones are available, they size will not work.

I was wondering if Johnny Wood might know.
All the best, Dick Ruzzin.

Steve has some on eBay right now !

http://pages.ebay.com/link/?na...=web&id=321361096149

I understand that Ford powered Mangustas have motor mount problems with heat and oil.

If so you can get some adhesive aluminum tape, 2 inches wide, at Home Depot for a very reasonable price. The same tape is called "Racer Tape" in the performance catalogs.

Just take one turn around each one to protect it from oil and fumes and reflect 60% of the heat.

DICK RUZZIN

Hi Dick, there should be a protective aluminium shield that helps keep the heat off the engine mounts. They seem to work pretty well as 1302's are 70,000 miles old and still OK. Even so I have some of Steve's sets for the future. Mike

If you have that many miles on them I would change them.

Mine look fine, the first replacement set I have put in. But I started to get a vibration through the shift linkage and a lot of forward and backward motion to the shift lever when I accelerate in gear, or back off of the throttle. Also I started to get the "feeling" that the whole power train was loose, hard for me to explain. I suspected a bent rod or bent pushrod somewhere because of the vibration. Wires and plugs were good. As I said they look like new.
Last week I loosened both and rotated them 180 degrees and went for a ride, I could feel a real difference but the car is not back to where it was when they were installed.

Another thing that happens can be felt on high speed curves, 70-80 mph, you can feel a lightness coming and going in the rear as the car jounces over slight surface imperfections. The engine is jumping up and down back there. That is a lot of weight to have moving around and not being tied down solidly.

That is what I deduced after putting in the new ones. Your car will drive much better and feel much safer.

Put some new ones on and also some new poly bridge bushings in and your car will be transformed.

Dick Ruzzin

Dick, I am presently doing work on the cosmetics of the car and after completing a bare metal respray will change mounts etc. The car is driving quite nicely at present, but still as you say worth changing mounts. Steve's mounts are top quality. Mike

Steve is sending me two sets.
I neglected to mention when I suggested new poly bushings that the two at the end of the large bridge at the rear are the ones to replace.

They are the culprits when experiencing camber change in the rear.
DICK RUZZIN

Hi Dick, yes I will replace these as well. Another issue with rear suspension on Mangusta's is the change in toe when the suspension moves through its full travel. On compression, if the toe is correct, as the wheel moves up the toe goes to toe out. I feel a lot of the poor articles re handling were having this effect acting on the rear suspension. Johnny Woods has written about this issue previously. Changing the top rear link to a double ended Heim joint allows this effect to be cancelled. Thanks Mike

Mike,
I saw Johnys article but do not see how it changes toe in. It seemed to me that the double ended Heims just aided in setting camber, allowing adjustment without removing one of the bolts at either end of the upper control rod.
Please explain.

Dick Ruzzin


Dick Ruzzin

It was my understanding that the benefit of replacing those end bushings with heim joints was to remove the binding and subsequent snap-release under load. The GT40 suspension design is similar in many aspects to the Mangusta but is fully heim jointed and works rather well. My old GT40 replica had some heims and some bushings and I replaced all the bushings with heim-joints. The difference was astonishing. Completely predictable and no snap response under extreme conditions.

Mark

Dick,

I agree with your thoughts on the rear bridge. The stronger you can make this area better. This flexing in the rear fame is only effecting camber however. Camber change through chassis flex is not desirable of course but the real problem on the back of the Mangusta is toe change as the rear suspension goes into bump. I spent a long time making laser jigs specifically for the Mangusta.

I also spent time studying the GT40 rear suspension and found the Mangusta to be identical in design except for one very important part - the top link on the Goose only has a Rose joint on the inside. On the outside (upright end) it has a "T" bar with bushings. This T bar means the top arm cant move side to side thus making it impossible to incline the rear upright in order to adjust the rear toe change under bump. It's hard to get your head round this until you have the spring and shock off the car, mount the laser jigs on the rear wheel and then wind it through it's travel so that you can see the toe change.

All Mangusta's I have worked on with the standard rear set up go from 1.0 degree tow in to 0.0 degree toe at full bump. In other words it toes out by 1.0 degree from ride height to full bump, very dangerous! I believe this is the main reason the Goose got such bad press in it's day. All they had to do was look at a GT40 like I did. If you read any chassis engineering book they all say to avoid rear toe out like the plague.
Having rear toe out is dangerous enough, but the Mangusta is even worse - it can bump into tow out in the middle of a corner!

Fortunately, this is very easy to fix with one simple modification. I remove the top arm and cut the "T" bar off and replace it with another Rose joint. This then makes the rear suspension the same as a GT40 - infinitely adjustable.

Then you can lean the rear upright back (effectively increasing the castor) until it bumps neutral or slightly into tow-in (a totally safe condition). Make sure you have enough Rose joint left in the rod of the top trailing arm. The rule of the thumb here is if it's and 18mm Rose joint you need a minimum of 18mm thread in the rod.

I did all this on Jonathan Roots car and spend hours and hours. I think it's way beyond the scope of the average alignment shop even if they have got 30K worth of Hunter equipment. Any owner would be better off doing it themselves at home because the alignment shop will get pissed off with it and not get it right.
Warning, aligning the rear of a Mangusta or GT40 takes a very long time!

Here is the principal I used to set the bump steer front and rear on the Mangusta
https://www.youtube.com/watch?v=LO07qmJ9zkk

In the above video I dont think the measurement from the wheel to the mirror is relevant.

There is another way of reducing (not fixing) this rear bump steer problem, by using much stiffer rear springs. This method helps by simply reducing rear suspension travel but also rips the top shock mounts out of the chassis on the early cars that have a two bolt crossmember rather than the later 4 bolt crossmember.

Johnny

JOHNNY,
I am going to send your description to Werner Meier the GM chassis engineer who changed the mounting of both my rear bridges. He reversed the engine-ZF suspension by hard mounting the rear bridge to the sub-frame with shoulder bolts and welded in tubes then he soft mounted the ZF to the bridge with three Corvette steering bushings. This resulted in an amazing change to the cars ride and handling and it nearly eliminated the feeling of weight bias front to rear even with a full tank of gas.

I like your approach as it addresses a different part of the rear suspension and seems an easy thing to do.
Thank you very much, I understand the principal now.

DICK RUZZIN

Johnny,
My car now is very well aligned, it feels neutral under hard acceleration and braking with absolutely no rear wheel steer. If I modify the upper link with the Rose joint and keep it the same length it is now what adjustment is then required to the upper trailing link?

Should the rear alignment be changed? If so to what?

Thanks,
Dick Ruzzin

Johnny,
My car now is very well aligned, no rear wheel steer at all under hard acceleration or braking. This with the original T end on the upper link

If I replace the T ends of the upper links with Rose joints, keep the upper link the same length as before modified, what alignment changes am I expected to have to make to achieve the desired castor?

It seems to do this I have to find a race shop that understands and can adjust bump steer, that is, zero toe out.

DICK RUZZIN

Your statement below. Am I interpreting it in the right way?

Then you can lean the rear upright back (effectively increasing the castor) until it bumps neutral or slightly into tow-in (a totally safe condition). Make sure you have enough Rose joint left in the rod of the top trailing arm. The rule of the thumb here is if it's and 18mm Rose joint you need a minimum of 18mm thread in the rod.