wheel alignment

[lew]

Does anyone know what the correct rear wheel camber should be on an Ace or Aceca.Mine measure 1 1/2 deg neg on one side and 3 neg on the other!!!. clearly not correct
   I will need to make up a suitable length main leaf or new wishbones however I need to know the correct spec in order to calc the lengths. even a consensus measurement of existing cars would steer me in the right direction.
   Thanks
   
   Lew

[lew]

Hi Guys
   
   40 of you have read this post but no reply!!!!!!!!!!!
   Please someone measure your car to give me a start point
   Surely one of you that races an Ace etc MUST know what suspension settings you run!
   
   HELP  HELP
   Lew

[nikbj68]

Lew, just wondering if you could reset the spring to even them up at 21/4° for a start, unless you plan on oval racing? [;)]
   Sorry I can`t be of more help than that. [:)]

[lew]

I had thought of making an eccentric centre bolt and doing just that but it would still give far too much negative camber for normal road use
   thks for the suggestion
   Lew

[nikbj68]

Lew, the leafspring Cobras had 2° of negative camber, and although an inch wider on track used the same leaf spring, albeit with an extra leaf added.
   Not knowing how an Ace rear hub/upright differs to a Cobra one(but for now assuming they were the same), if they both used the 41" centres leafspring but the Ace is a 50" track & the Cobra 51", that would suggest more than 2° neg for the Ace.
   Do you think your spring is sagging unevenly, or is it possible it was always like that? Maybe just re-tempering would resolve the disparity?

[lew]

Guys,
    Got it for those that are interested. I eventually foned the specialists that advertise in ACtion + a few others.
   The general consensus of opinion is that my existing specs of -3 and -1 1/2 are not unusual.
   I am informed that this is a result of the poor build quality at AC and I was told by one that he has never ever measured two cars having the same or symmetrical cambers!!!!
   The consensus is that for road use they should be set at between 1 and 1 1/2 deg negative
   
   Cheers
   Lew

[nikbj68]

Glad you have your result, I suspected that may have been the case! Probably best to just even them out rather than go to greater expense of new parts, unless you need them for other reasons. I believe the front is 1° to 11/2° positive... do you dare check that too!?

[lew]

what I am going to try is to get another main leaf made and  about 3/8" longer.Then I will drill a centre bolt hole asymmetrically in it to give the extended lengths I need. If this works it should get me close and fine tune with off set Vesconite bushes.
   Strangely enough I have checked the front end and its fine.
    This all started off by trying to eliminate"clunks" from the back end and to replace the bronze bushes with Vesconite to eliminate having to grease every 1000 miles.
   I opened a can of worms but there was no point in putting the lid back on without getting the worms back in order.
   At the front end I will then find out how to do the "stiffening device" and fit the "trick" plate to the steering box to hopefully get it to steer better.Will report back to the forum on progress or the lack thereof !!
   Cheers
   Lew

[nikbj68]

Lew, wouldn`t the spring need to be shorter to reduce negative camber?

[AC Ace Bristol]

Nik
   
   Climb out from under the Ace,  The Transverse Spring is above the diff housing and attaches level with the top of the Alfin Drums.
   Whilst  thr Rear wish bones are situated towards the bottom of the alfin Drums.
   
   By reducing the length of the spring you pull the top of the wheels inward thus producing negative camber.
   
   Front Spring for Ace....37 1/4 inches (8 leaves, free camber of spring 3 1/4 inches)
   
   Rear Spring for Ace.....   41 inches   (7 leaves, free camber of spring 5 5/16 inches
   
   Nik get those overalls off, wash your mits, go to pub and have a pint of Guinness.
   
   Keith

[nikbj68]

Cheers Keith... I think I`d confused me positives with me negatives.... I do that with the ol` bank account too, explains a lot!
   Lew... I`ll shut up now that an expert has entered the room!!!

[AC Ace Bristol]

Lew.
   
   I'm no expert but can list a few areas worth investigating, subject to how you wish to use your Ace and exploit full potential.
   
   Many Aces and Acecas Left Thames Ditton with various odd permutations of camber, even with differing camber from one side to the other.
   
   Rear suspension really c an wear quickly and requires regular greasing of all,,, ALL  grease points every 500 to 1000 miles.
   
   All bushes need regular attention along with checking that the transverse leaf spring is correctly seating / located.  sometimes one can release and retorque other times turning through 180 degrees can help.
   
   Springs do loose the shape and proporties.
   
   Hopefully the figures given earlier give you a starting poin t.
   
   The front camber & Caster settings are :-
   
   Caster Angle             5 degrees
   Wheel Camber             1  degree to 2 degrees
   King Pin Inclination     9 degrees
   Wheel Toe in on Rim      1/16th inch
   
   TR6  front anti roll bar kit also improves handling for fast road and track use.  Adjustable shockers  also help.
   
   For serious track work it's trial and error, single transverse leaf springs different offset wheels etc etc ..... all pending rules and regulations for the race series you may wish to partricipate in..[?]
   
   Hopefully some one with a lot more knowledge than I can elaborate and give you some additional starter points....[;)]
   
   Keith

[pls01]

Lew
   Do know if you have taken it apart yet and may have already found this.
   
   The spring has a locating pin in the center.  This pin engages in a hole in the top of the differential to center it.  The spring is held in place with a clamp and four studs with nuts.
   
   The original clamp was less than rigid.  When the nuts were tightened, the clamp would just bend at the corners. It didn't hold the spring very well.  Could the center locating pin have become disengaged from the hole allowing the spring to slide off center?  The clamps are usually modified by welding ribs across to stiffen them up.
   
   Another place to look is the lower control arm mounts at the chassis.  I found cracks in the welds of the rear inner mount on my Ace.  If a rear inner mount come loose, you will get more negative camber, more toe in and maybe some knocking noise.
   
   Yes, Aces are not perfectly accurate but things have to be out over 3/8" to the camber you measured.  Something is wrong.
   
   Are you measuring the camber yourself or having a shop do it?  I made a camber gauge with a digital level.  The digital level must be "zeroed" because the shop floor is not level.  I zero it at each wheel.
   
   Peter

[lew]

Thanks guys,now the info is rolling in!!
   1)the back end is completely out of the car and left with the bare chassis tubes(Aceca diff housing comes out)
   2) have stripped the nose from the diff and checked pinion back lash .003" ,good enough
   3)checked pre load on carrier bearings.OK so thats not the source of my clunks,the diff that is.
   4)all bronze bushes had been replaced by previous owner about 2000 miles ago when he "rebuilt?" so they were ok
   5)did find however that that there was some "end float" at the wishbone to chassis mounts and wishbone to upright including the spring.the bronze thrust washers were not set up correctly.
   6)the above hopefully is the source of my clunks as drive is taken up. replaced all bushes and thrusts with Vesconite reamed to size
   7) no cracks to wishbone mounts and no signs of previous accident damage
   8)mount plate of spring very substantial and not bent. locating hole still correct diam to centre bolt and still spherical.
   9)As i have built and raced many cars over the past 50 years I do all my own work(dont trust others where I live!)car set up on a specially cast flat floor on adjustable pads and measured myself on my own gauges.
   10) I agree 3/8" on overall spring is a lot but its about 1/16" on one side and 5/16' on the other. calculated from simple trig knowing the angle required
   11) I am told by the "experts i foned that its extremely difficult to make the eyes of a leaf spring accurately and thats why there is this vast variation in cars. note the spec given by AC for the front,the variation they allow is 2deg!
   
   Getting the slowly and will continue reporting if anyone is interested.Perhaps i am boring everyone?
   
   By the way its not a fun job taking the diff housing out for a 68 year old grumpy old man, dont do it unless you have to!!
   
   cheers
   Lew

[Jim A]

Probably way sophomoric, but in the 30 plus years I had my Ace, it would routinely develop the very "clunks" you mention.
   They turned out to be loosening of some of the four bolts on some or all of the half-shaft flanges (16 possible altogether).
   I finally got aircraft quality locking bolts and nuts from my FBO mechanic and solved the problem.