Steering "return to center" is ill-defined - returning to alignment shop

[Helirich]

I’ve heard people say “Return to center” can be effected by camber, tire pressure, shocks and all sorts of stuff. But the only things that I have ever experienced do it are caster and too tight steering components. (Usually the sector shaft adjustment) Of course a rack and pinion doesn’t have the sector adjustment. Not sure if the Delorean rack has some kind in that regards, but most likely it’s caster. I read where Dave said there is no caster adjustment, but something could be bent. I don’t recall if you build is mostly stock, but I think you could effect caster with the sway bar. If you have the Delorean industry lower control arm braces, you could definitely effect it. Some other brands may also do this. I hate to sound like a commercial, but that is one upgrade I really believe in.

If you want to do some caster adjustment, remember the bottom of the wheel should go forward or the top back to give more caster. (And return to center) You don’t want to get that backwards.

[82DMC12]

I do have the DPI Caster arms. I'm thinking I might loosen my sway bar to front frame extension bolts and take all the tension off of the caster arm, if there is any. Then roll the car back and forth a bit and then tighten down the sway bar wherever the LCAs end up. Then tighten the caster arms just enough so that they keep the LCA from going backward and they're not influencing the position of the LCA. Then when I get to the alignment shop they have a neutral position to start with.

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[dmcman73]

I do have the DPI Caster arms. I'm thinking I might loosen my sway bar to front frame extension bolts and take all the tension off of the caster arm, if there is any. Then roll the car back and forth a bit and then tighten down the sway bar wherever the LCAs end up. Then tighten the caster arms just enough so that they keep the LCA from going backward and they're not influencing the position of the LCA. Then when I get to the alignment shop they have a neutral position to start with.

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Curious, did you torque all suspension bolts under pre-load when you reassembled everything?

[82DMC12]

Curious, did you torque all suspension bolts under pre-load when you reassembled everything?

Yes, absolutely. I know that's not it. Gonna "reset" the DPI caster arms, and if these guys are still struggling with it all tomorrow, I'm bringing it someplace else. This is a fairly large shop but they admitted they basically give all alignments to one guy, he did my initial alignment after the frame off was done and he also found I had something funky going on with the inner tie rods. That guy was good and a pleasure to work with. I got the inner tie rods tuned up and tensioned but then when I went back to get the toe set properly I found out the good tech is out for back surgery and it sounds like the guy who tried to do it was struggling. I'll be back there tomorrow on the shop floor watching and helping whoever is doing it and hopefully we get it sorted.

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[82DMC12]

Yesterday I went back to the alignment shop and, thankfully, I was on the floor working with the tech. I did raise the car up 1/2" so that threw off all the old measurements which meant the alignment had to start from square one again.

As I was walking around the car as he was working, I saw the passenger side front alignment reflector thing that slipped and was no longer centered on the axle. Since the wheel is concave it was also pointing inward a bit too. I pointed this out to the tech "hey not sure if this makes a difference, but looks like this one isn't straight?". He was "surprised", said it "probably doesn't make a difference" but I insisted that he center it again. And of course once he rechecked everything with the computer it was all fucked up.

Anyway now everything was straightened out and we got caster on 3.8 deg each side and toe at 0.25 deg per side. This also got my camber back to within 0.5 degrees equal. Not perfect but without camber adjustment it isn't bad. The rear is pretty good with -0.5 deg camber and toe is within 0.10 deg equal with total toe at 0.44 deg. Could have got the rear toe "perfect" if I had more some half-thick shims but I'm not going to stress it.

End result? Return-to-center is lot better than before. Maybe not as good as my daily driver (power steering too though) but certainly better than it was.

[David T]

Yesterday I went back to the alignment shop and, thankfully, I was on the floor working with the tech. I did raise the car up 1/2" so that threw off all the old measurements which meant the alignment had to start from square one again.

As I was walking around the car as he was working, I saw the passenger side front alignment reflector thing that slipped and was no longer centered on the axle. Since the wheel is concave it was also pointing inward a bit too. I pointed this out to the tech "hey not sure if this makes a difference, but looks like this one isn't straight?". He was "surprised", said it "probably doesn't make a difference" but I insisted that he center it again. And of course once he rechecked everything with the computer it was all fucked up.

Anyway now everything was straightened out and we got caster on 3.8 deg each side and toe at 0.25 deg per side. This also got my camber back to within 0.5 degrees equal. Not perfect but without camber adjustment it isn't bad. The rear is pretty good with -0.5 deg camber and toe is within 0.10 deg equal with total toe at 0.44 deg. Could have got the rear toe "perfect" if I had more some half-thick shims but I'm not going to stress it.

End result? Return-to-center is lot better than before. Maybe not as good as my daily driver (power steering too though) but certainly better than it was.

When the Tech says "probably doesn't make a difference", that would not have instilled any confidence that he knew what he was doing. Too many techs really don't understand alignments, they count on the computer to do it all and tell them what to do. By getting the castor right you corrected your centering problem. Is the steering wheel straight when you are going straight on a flat road? Make sure your tire pressures are all correct, 23 front and 30 rear. Does the car want to go off to the left or right or will it go pretty straight if you take your hands off the wheel? Finally, it should not pull to either side when you apply the brakes. This final one has to do more with the brakes than the alignment.

[Josh]

Like Mark said, the two biggest items you are fighting against is the lack of caster and a stiff steering rack.

Not much you can do about the steering rack. You have adjustable upper control arms, so you can get more caster. You need to ask for this because the guy at the alignment shop will just adjust it to stock specs.
Most modern cars have 5+ deg of caster. A delorean has half of that stock.

Comparing a 40+ year old car to a much newer one will always leave you disappointed. I am not saying to settle, however there is only so much you can do in certain circumstances.

[David T]

Like Mark said, the two biggest items you are fighting against is the lack of caster and a stiff steering rack.

Not much you can do about the steering rack. You have adjustable upper control arms, so you can get more caster. You need to ask for this because the guy at the alignment shop will just adjust it to stock specs.
Most modern cars have 5+ deg of caster. A delorean has half of that stock.

Comparing a 40+ year old car to a much newer one will always leave you disappointed. I am not saying to settle, however there is only so much you can do in certain circumstances.

Be careful adding too much castor. It will increase steering effort and as you know, the Delorean doesn't have power steering to handle a lot of castor. There IS the possibility of adding power steering and if you do then you could consider modifying your alignment specs. All alignment specs are a balance and compromise with a lot of factors. Remember, the suspension was designed and optimized by Lotus Engineering and they did the best they could at the time. They were considered among the very best in suspension technology (and still are!).

[Josh]

Be careful adding too much castor. It will increase steering effort and as you know, the Delorean doesn't have power steering to handle a lot of castor. There IS the possibility of adding power steering and if you do then you could consider modifying your alignment specs. All alignment specs are a balance and compromise with a lot of factors. Remember, the suspension was designed and optimized by Lotus Engineering and they did the best they could at the time. They were considered among the very best in suspension technology (and still are!).

I have about 6deg of caster on my car, as well as some other owners on their cars.
I think you are giving lotus far too much credit for their work on these cars.
The stock suspension on these cars is a compromise to put it nicely, certainly not "optimized" or "the best"

[82DMC12]

All good thoughts guys, thanks. I probably won't find the need to get the alignment looked at again but if I did I would first get adjustable front upper arms so I can get the camber perfect at the same time. It would be interesting to experiment with different levels of caster but I wouldn't let this shop I was at do it!