Hi Dick, I have set up one of my Mangusta's this way. You can set it up yourself as most alignment shops will not wish to spend the time and effort to get it right. Set up a laser pointer off the hub to allow tracking of the wheel as it goes up and down. There are a number of setups to do this on various websites to setup alignment. The adjustments are done with rear shocks removed and upper limit and lower limit of wheel movement are used as total movement datum. Check this with the original top T link setup. You will find as the wheel moves up to full compression the toe out will be displayed. As the lower trailing arm is shortened and top trailing arm is lengthened this toe out will be reduced. Should be able to get zero toe change or some small toe in improvement. These changes cannot be done with the fixed top link as the hub cannot get any caster change. I think this Mangusta problem has mostly been seen as an issue when changing throttle position while cornering or a change in gear under constant cornering. Hope this makes sense, Mike
Johnny,
Thanks for doing this. I assume this is all done with the original trailing link Heims attachments and the offset links at the hub carrier end .
I also have looked at the Ford GT and deduced that the Mangusta and the Ford were the same basic architecture but that the Ford was a much more detailed execution especially in the area of the bridge which is much more sophisticated, trapped to eliminate side movement.
I made a drawing last night and I understand completely now what happens.
1.
Upper link has to get longer to get castor.
2.
Lower link gets shorter to pull the upright back into the proper toe in, in relation to the front wheels.
Why could I not just firmly set up a laser on my hub with a board in front of the hub to track it as the hub moves up and down, in and out? I could then adjust the upper rod with the new joint while tracking it. That would get me the desired rear wheel movement, eliminating the toe out.
Since my rear wheels are now well aligned with my fronts I can do the rear wheel adjustment on both sides to the same values and then test the car.
I know that normally the rear wheels are aligned first then the fronts to that set up.
I may need some fine adjustment to the front wheels.
How does that sound?
Dick Ruzzin
Thanks for doing this. I assume this is all done with the original trailing link Heims attachments and the offset links at the hub carrier end .
I also have looked at the Ford GT and deduced that the Mangusta and the Ford were the same basic architecture but that the Ford was a much more detailed execution especially in the area of the bridge which is much more sophisticated, trapped to eliminate side movement.
I made a drawing last night and I understand completely now what happens.
1.
Upper link has to get longer to get castor.
2.
Lower link gets shorter to pull the upright back into the proper toe in, in relation to the front wheels.
Why could I not just firmly set up a laser on my hub with a board in front of the hub to track it as the hub moves up and down, in and out? I could then adjust the upper rod with the new joint while tracking it. That would get me the desired rear wheel movement, eliminating the toe out.
Since my rear wheels are now well aligned with my fronts I can do the rear wheel adjustment on both sides to the same values and then test the car.
I know that normally the rear wheels are aligned first then the fronts to that set up.
I may need some fine adjustment to the front wheels.
How does that sound?
Dick Ruzzin
Johnny,
In relation to your comment about the Mangusta and Ford GT taking a long time to align.
My car has new large diameterrear trailing links with right and left hand thread Heims joints on the ends so that they can be made shorter or longer in place without removing the end attachment bolts.
This makes wheel alignment easier.
I would make the upper link that way also.
Dick Ruzzin
In relation to your comment about the Mangusta and Ford GT taking a long time to align.
My car has new large diameterrear trailing links with right and left hand thread Heims joints on the ends so that they can be made shorter or longer in place without removing the end attachment bolts.
This makes wheel alignment easier.
I would make the upper link that way also.
Dick Ruzzin
Hi Dick,
Sorry I am so long responding. I am working on my barn and a Mangusta and dont have much time for anything else!
If you have changed your trailing links to L/H thread on one end this will make it much quicker to adjust. The only down side to this is you cant stop the bar/link from turning while you are tightening up the nuts without gouging the paint as you try to hold it with Vise-grips or pipe wrench!
You do understand me correctly, the top trailing link will get shorter and the bottom longer. The bottom link is only just long enough so make sure you have enough rod end in the tube when you have finished.
Mounting a laser on the hub and pointing it forward onto a wall will not work because the ark you see on the wall will include the ark of your A arms. This is why you have to shine it into a mirror and then back onto a piece of board that is attached to the laser it's self. Then you only record toe change as the in and out movement of the A arm ark is not recorded because of the mirror.
Please send me an email Johnnyrwoods@aol.com and I can send you pics of the laser jig I made and how I did the top link Rose joint mod. Resizing and posting pics on this forum takes too long. If I could upload any size picture and the forum automatically resize it to 200KB it would be SO much better (like uploading pics to ebay).
Also call me anytime, it would be good to talk. +44 781 718 7333
Johnny
Sorry I am so long responding. I am working on my barn and a Mangusta and dont have much time for anything else!
If you have changed your trailing links to L/H thread on one end this will make it much quicker to adjust. The only down side to this is you cant stop the bar/link from turning while you are tightening up the nuts without gouging the paint as you try to hold it with Vise-grips or pipe wrench!
You do understand me correctly, the top trailing link will get shorter and the bottom longer. The bottom link is only just long enough so make sure you have enough rod end in the tube when you have finished.
Mounting a laser on the hub and pointing it forward onto a wall will not work because the ark you see on the wall will include the ark of your A arms. This is why you have to shine it into a mirror and then back onto a piece of board that is attached to the laser it's self. Then you only record toe change as the in and out movement of the A arm ark is not recorded because of the mirror.
Please send me an email Johnnyrwoods@aol.com and I can send you pics of the laser jig I made and how I did the top link Rose joint mod. Resizing and posting pics on this forum takes too long. If I could upload any size picture and the forum automatically resize it to 200KB it would be SO much better (like uploading pics to ebay).
Also call me anytime, it would be good to talk. +44 781 718 7333
Johnny
Johnny,
I will email you.
My new trailing links have a threaded bung welded in each end that is configured with a six sided nut on it so you can turn the rod with a wrench. Works very well.
I look forward to doing this. I will then have a very solid rear subframe with my modified rear bridges and a corrected rear wheel travel with no toe out with the modified upper link.
Can you give me some kind of description of the resultant improvement in handling? Does having
weak and soft rubber bushings in the bridge make the problem worse?
I hope that those reading all of this realize how profound your modifications to the Mangusta rear suspension is.
Johnny,
Have you read my account of the modifications I have made to my car regarding the two rear bridges? With soft old bridge bushings my bridge would move 1/2 inch from side to side when shifting from 1st to reverse.
I will email you.
Thanks, Dick Ruzzin
I will email you.
My new trailing links have a threaded bung welded in each end that is configured with a six sided nut on it so you can turn the rod with a wrench. Works very well.
I look forward to doing this. I will then have a very solid rear subframe with my modified rear bridges and a corrected rear wheel travel with no toe out with the modified upper link.
Can you give me some kind of description of the resultant improvement in handling? Does having
weak and soft rubber bushings in the bridge make the problem worse?
I hope that those reading all of this realize how profound your modifications to the Mangusta rear suspension is.
Johnny,
Have you read my account of the modifications I have made to my car regarding the two rear bridges? With soft old bridge bushings my bridge would move 1/2 inch from side to side when shifting from 1st to reverse.
I will email you.
Thanks, Dick Ruzzin
Johnny,
My hub carriers, with the trailing links adjusted for good alignment, are sitting horizontal at the bottom. In other words the big bolt running through the bottom of the upright is horizontal.
Is that attitude changed with the new upper link after adjustment?
Dick Ruzzin
My hub carriers, with the trailing links adjusted for good alignment, are sitting horizontal at the bottom. In other words the big bolt running through the bottom of the upright is horizontal.
Is that attitude changed with the new upper link after adjustment?
Dick Ruzzin
Johnny,
Your quote below:
My crude drawing shows the opposite. Please comment.
Dick Ruzzin
Your quote below:
quote:You do understand me correctly, the top trailing link will get shorter and the bottom longer.
My crude drawing shows the opposite. Please comment.
Dick Ruzzin
Dick, I had the trailing arms reversed re lengthen and shorten. I originally made my top link with one left and one right thread and yes made for quick and easy adjustment and had I built in a way to stop it turning while tightening I would have kept it, however with the possibility of these coming loose I opted for right hand joints on all ends. This way if the ends do come loose the geometry will not change. With your relationship (toe) between front wheels and rears OK, before you replace the rear top links take a laser and get a datum to set up the rears once the adjustments are made. All the attachment points are as original, you only need some spacers to centre the top heim in between the top "EARS" of the hub. Your bottom long bolt will be inclined when adjustments are finished. Sorry I have no photos to show as my car is getting some bodywork done at present... Mike
Thanks Mike for your input.
Johnny,
Since I have always worked with drawings and I enjoy doing it I might make a three view full size drawing of the rear suspension since the pick-up points are few and simply organized. I can then, as it is currently adjusted, run it through the motions with the shocks off on the drawing twice, with the original T bar and also with a double joint bar, I will record that motion on paper. I will measure both sides and compare them as they may be slightly different.
Then I can create the required change and adjust the trailing links on the drawing accordingly. I will measure the Heims threads so I can make the required movement of the trailing links on the drawing and then translate them on the car, preserving the alignment.
With a drawing I can also move the bridge and inboard pick-up point for the upper bar toward the center of the car to see how that effects the upper hub carrier and trailing links. Maybe about five millimeters. That will also show
what happens when cornering. My theory is that camber diminishes on the left wheel if the right wheel is loaded, causing camber to increase there.
That will be an interesting study, I might engage Werner Meier who is a GM chassis engineer to review my "papers", even help me define the study plan. He is the one who spotted my bridge moving when shifting from first to reverse and he made the new bridge for my car.
After that I would drive the car and then have the suspension alignment checked and adjusted if required.
The only fly in the ointment is the fact that the Mangusta, as other low volume cars of the era, is not dimensionally perfect. When my car was aligned on a computer driven machine the technician found it to be .04% off front to rear so he compensated for that. He said that was the best he could do because the chassis was not geometrically perfect. He did a great job.
Dick Ruzzin
Johnny,
Since I have always worked with drawings and I enjoy doing it I might make a three view full size drawing of the rear suspension since the pick-up points are few and simply organized. I can then, as it is currently adjusted, run it through the motions with the shocks off on the drawing twice, with the original T bar and also with a double joint bar, I will record that motion on paper. I will measure both sides and compare them as they may be slightly different.
Then I can create the required change and adjust the trailing links on the drawing accordingly. I will measure the Heims threads so I can make the required movement of the trailing links on the drawing and then translate them on the car, preserving the alignment.
With a drawing I can also move the bridge and inboard pick-up point for the upper bar toward the center of the car to see how that effects the upper hub carrier and trailing links. Maybe about five millimeters. That will also show
what happens when cornering. My theory is that camber diminishes on the left wheel if the right wheel is loaded, causing camber to increase there.
That will be an interesting study, I might engage Werner Meier who is a GM chassis engineer to review my "papers", even help me define the study plan. He is the one who spotted my bridge moving when shifting from first to reverse and he made the new bridge for my car.
After that I would drive the car and then have the suspension alignment checked and adjusted if required.
The only fly in the ointment is the fact that the Mangusta, as other low volume cars of the era, is not dimensionally perfect. When my car was aligned on a computer driven machine the technician found it to be .04% off front to rear so he compensated for that. He said that was the best he could do because the chassis was not geometrically perfect. He did a great job.
Dick Ruzzin
DENIS,
No, my car does not have those. Can you send me a shot that shows the end that attaches to the wheelhouse?
Thanks.
Dick Ruzzin
No, my car does not have those. Can you send me a shot that shows the end that attaches to the wheelhouse?
Thanks.
Dick Ruzzin
Johnny,
You know more abut the rear suspension than any one.
Can you tell me what the offset clevices at the hub carrier end of the trailing links do?
Are they some kind of anti-dive mechanism? Or do they simply move the attachment point to the hub carrier outboard?
Do you recall what they did when you ran the suspension through its paces without the shocks attached?
DICK RUZZIN
You know more abut the rear suspension than any one.
Can you tell me what the offset clevices at the hub carrier end of the trailing links do?
Are they some kind of anti-dive mechanism? Or do they simply move the attachment point to the hub carrier outboard?
Do you recall what they did when you ran the suspension through its paces without the shocks attached?
DICK RUZZIN
Hi Dick,
I dont know why they have offset clevices. I know they have to point side ways because if you have them pointing up the Rose joint cant be attached because it exceeds it's misalignment. They do offer a little sideways adjustment to help the trailing arm clear the chassis and the exhaust. When I had my laser jigs set up I could not see any change to the bump steer by moving them within the limited travel available.
I will be interested to hear how you get on with your drawings. I too found the car to need more adjustment one side to the other. This is all part of the charm of a hand made car!
Johnny
I dont know why they have offset clevices. I know they have to point side ways because if you have them pointing up the Rose joint cant be attached because it exceeds it's misalignment. They do offer a little sideways adjustment to help the trailing arm clear the chassis and the exhaust. When I had my laser jigs set up I could not see any change to the bump steer by moving them within the limited travel available.
I will be interested to hear how you get on with your drawings. I too found the car to need more adjustment one side to the other. This is all part of the charm of a hand made car!
Johnny
Is the new format not working?
I have not seen a single post since it went into effect.
Dick Ruzzin
I have not seen a single post since it went into effect.
Dick Ruzzin