Tracking/alignment question
Discussion
Long-time lurker on this forum, but only just decided to join so I may discuss an issue (and hopefully contribute in the future)...
I have used the search facility, but all the alignment questions I have seen are more on the lines of "Where to get it done" rather than the technicalities.
Since it is my first post, and just for reference, my background is in engineering, but not automotive. I have built vehicles from Westfield, through a LandRover S2A rebuild and now on with Jag Mk2 and looking for Mk1 Mini. I have a 'classic' (at 20 years+) Japanese too, with one of those devilish rotory things. My interests are mostly classic based, our 'fleet' being between 56 and 8 years old.
I am really after some opinion on 4 wheel alignment and what is 'correct'. Short version of the story is having had a vehicle setup/checked on a Hunter machine, it is really down to what is the expectation of the result. I had the resulting print out from the Hunter machine, which as you all probably know is simplified to be green if the measurement is within the manufacturer's tollerance, red otherwise. It appears that the operator considers things to be 'right' if it is all green. This resulted in a bit of a discussion with the guy operating the machine who swore blind that the steering wheel centre position was nothing to do with tracking - which was a bad start. (Okay for pedants - I understand that the tracking can be correct with the steering wheel offset - but clearly adjusting the tracking settings equally from that point will centre the wheel).
However, let us for argument say that a setting tollerance is +/-1 degree. Is it acceptable when correctly setup for one measurement one side to be +1 whereas the other side is -1? I understand that each measurement is 'in spec' but it can't be a good setup. If I was doing this myself I would match each side (actually they haven't done it too badly in this respect). I understand that it is also possible for being 'at one end' of the tollerance may be better for certain situations eg. high speed stability. Again, if this setup was chosen, I would expect equal values. Also, I believe that a quality setup, may take account of the road camber and therefore have different values for each side.
If it helps the discussion I could share the measurements... it does however show I need to do something with the whole rear subframe in order to adjust a non-adjustable angle.
Does anyone have access to the 'proper' figures for a Jag SV8?
Am I just whinging about nothing?
I have used the search facility, but all the alignment questions I have seen are more on the lines of "Where to get it done" rather than the technicalities.
Since it is my first post, and just for reference, my background is in engineering, but not automotive. I have built vehicles from Westfield, through a LandRover S2A rebuild and now on with Jag Mk2 and looking for Mk1 Mini. I have a 'classic' (at 20 years+) Japanese too, with one of those devilish rotory things. My interests are mostly classic based, our 'fleet' being between 56 and 8 years old.
I am really after some opinion on 4 wheel alignment and what is 'correct'. Short version of the story is having had a vehicle setup/checked on a Hunter machine, it is really down to what is the expectation of the result. I had the resulting print out from the Hunter machine, which as you all probably know is simplified to be green if the measurement is within the manufacturer's tollerance, red otherwise. It appears that the operator considers things to be 'right' if it is all green. This resulted in a bit of a discussion with the guy operating the machine who swore blind that the steering wheel centre position was nothing to do with tracking - which was a bad start. (Okay for pedants - I understand that the tracking can be correct with the steering wheel offset - but clearly adjusting the tracking settings equally from that point will centre the wheel).
However, let us for argument say that a setting tollerance is +/-1 degree. Is it acceptable when correctly setup for one measurement one side to be +1 whereas the other side is -1? I understand that each measurement is 'in spec' but it can't be a good setup. If I was doing this myself I would match each side (actually they haven't done it too badly in this respect). I understand that it is also possible for being 'at one end' of the tollerance may be better for certain situations eg. high speed stability. Again, if this setup was chosen, I would expect equal values. Also, I believe that a quality setup, may take account of the road camber and therefore have different values for each side.
If it helps the discussion I could share the measurements... it does however show I need to do something with the whole rear subframe in order to adjust a non-adjustable angle.
Does anyone have access to the 'proper' figures for a Jag SV8?
Am I just whinging about nothing?
There are other threads...same deal.
Your concerns are valid....if they cannot even set the steering wheel straight, how on earth could they be trusted with any other aspect ?
And within spec....who's spec ? You're quire right, sitting at either end of tolerances would not be how I would leave something and be happy, unless there was some physical limitation preventing me from improving it. Either way the customer would be informed why this is the case and possible remedies
Of course you could say it is all subjective anyway, as who's to say their equipment is calibrated correctly and in most cases the biggest issue....used correctly, the operator being the biggest grey area.
Your concerns are valid....if they cannot even set the steering wheel straight, how on earth could they be trusted with any other aspect ?
And within spec....who's spec ? You're quire right, sitting at either end of tolerances would not be how I would leave something and be happy, unless there was some physical limitation preventing me from improving it. Either way the customer would be informed why this is the case and possible remedies
Of course you could say it is all subjective anyway, as who's to say their equipment is calibrated correctly and in most cases the biggest issue....used correctly, the operator being the biggest grey area.
No ideas for a name said:
I have used the search facility..
You've not tried very hard as this topic was covered in detail recently.http://www.pistonheads.com/gassing/topic.asp?h=0&a...
We've had many dealings with alignment, being an accident repair shop who have to make sure a car is right before it's given back to a customer, however been in this area of work you hear many stories and one that seems to crop up more often than not is the ones regarding the systems that have these 'green=good, red=bad' set ups, we've found that most technicians who operate them know how the system works but not a clue how to adapt that over to the vehicle there working on, and more often than not they will get your car as close as there ability can and then cheat, by either adjusting the guage or applying pressure to points of the car to get a false GREEN reading.
Anyway, to your other point, the steering wheel should be set to centre before doing a check/adjustment, this gives you the best starting point for a vehicle, although a rack could be out its far more likely to be something else so setting the steering wheel is the best start, although setting all the corners/axels to the same settings to ensure a more true set up in reality this isn't always the case, sometimes you will have to adjust cornes different to each other the make the vehicle drive better, for instance if you had a 10yr old car that had only ever been driven by a 20stone person then there would be significantly more wear on the drivers front corner so allowing an 'uneven set up' would allow the vehicle to drive better, hope that makes sense. It would also be down to what the vehicle is being used for, if its general road driving then a close to true set up would be needed, however if the vehicle were a track/race car then uneven set ups are more common depending on circuits it's been driven around( e.g.. if a track had 8left turns and 2right then more camber would be adjusted to one side and then toe ajusted accordingly to that setting)
Anyway, to your other point, the steering wheel should be set to centre before doing a check/adjustment, this gives you the best starting point for a vehicle, although a rack could be out its far more likely to be something else so setting the steering wheel is the best start, although setting all the corners/axels to the same settings to ensure a more true set up in reality this isn't always the case, sometimes you will have to adjust cornes different to each other the make the vehicle drive better, for instance if you had a 10yr old car that had only ever been driven by a 20stone person then there would be significantly more wear on the drivers front corner so allowing an 'uneven set up' would allow the vehicle to drive better, hope that makes sense. It would also be down to what the vehicle is being used for, if its general road driving then a close to true set up would be needed, however if the vehicle were a track/race car then uneven set ups are more common depending on circuits it's been driven around( e.g.. if a track had 8left turns and 2right then more camber would be adjusted to one side and then toe ajusted accordingly to that setting)
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