What a difference a day makes!

[SCguy]

I currently have been struggling with a number of minor problems on my TR6. 1) As you might remember after adding Goodparts springs I noticed that my car seemed to have excessive negative camber in the front. 2) I also had concerns about my recently rebuilt overdive not working. 3) Finally... my car had just begun running horribly and infact would not start.

So today... I walked out into the garage and and decided a new distributor cap and rotor were in order. Sure enough, my rotor had broken. Next I decided to have a good look at my front end. It clearly looks as if my mechanic has put my fulcrum brackets in backwards as the pivots are closest to the inside of the car. Finally, I decided to test drive the overdrive again a little more carefully. Good news! The car clearly goes into overdrive, but does not come out until the ignition is turned off. Turning the switch to the off postion has no effect once the car has gone into overdrive. Any thoughts on the overdrive? Is it the switch? /ubbthreads/images/graemlins/confused.gif

 

[jerrybny]

We all could use a day like yours once in a while.

 

[Alan_Myers]

Hi Larry,

Regarding the upper fulcrums, an "incorrect" orientation *might* be off-setting the increased camber from the springs you have noted. In other words, it could be a good thing *if* they are installed backward on a car with lowered suspension. Using the early car's fulcrum orientation on a later car should move the pivot point outward, i.e. move the ball joint outward and create more positive camber (or less neg camber). This would not be a good thing on an original TR4-TR6 front end that might have overly positive camber already, but might be just the ticket on a modified/lowered front end where too much negative camber is happening.

To clarify about the fulcrum position, the same part is used on all TRs, but the deeper U-shaped side of the fulcrum was originally faced outward on TR4 and later cars (i.e., toward the ball joint), inward on TR3A and earlier cars(i.e., toward the engine).

FYI, TR2 thru 4 were set up for bias ply tires and originally have 2 degrees positive camber designed into the non-adjustable front suspension. Using modern radial tires on these cars, it's a good idea to find a way to adjust camber to be more like the later models, and perhaps even a little more into negative camber territory.

Beginning with TR4A, there was some adjustablity (shims at the lower a-arms, as you know) and less positive camber in the set up right from the factory. The manuals for TR4A, 250 and 6 all call for 0 camber, +/- 1/2 degree. Personally, I'd err a little on the negative side for better handling.

So, I'd suggest having an alignment shop measure camber accurately before deciding on *any* changes. 1/2 to around 1 degree of neg. camber is probably a good thing in terms of modern tires and optimal handling, although more neg camber will mean more wear on the inner edge of the tire and you might experience some increased steering sensitivity with more neg camber. More than 1 degree neg camber is likely getting into "racing" setup, where tire wear isn't a big consideration, although some cars have had as much as 2 degrees negative and more, right from the factory.

P.S., out of curiousity I went out to the garage and used the same, crude "framing square" method you showed in your earlier posting, on my car... yours had approx. 3/8" negative camber if I recall... my TR4 has double that, 3/4", using that measuring technique. My car is definitely going to an alignment shop before finalizing the setup (adjustable uper fulcrums from Revington TR). However, I've got a long list of other things to do before that will happen!

Regarding the overdrive, a little more info please.

Which overdrive: A-type or J-type? Are you using the original style, column mounted lever switch? Are you driving the car, or is it sitting and idling, or is the engine off but the ignition turned to "on" when you are testing the OD switch?

A couple things come immediately to mind...

Too heavy oil in the gearbox/OD can cause too high hydraulic pressure and the OD to stick "on". John Esposito at Quantum Mechanics recommends 30W <u>non-detergent</u> or "racing" motor oil. Personally I think John is talking about freshly rebuilt units, since that's what he does for a living, and IMHO up to 40W might be used in an OD that has some years and miles on it, or a mix of some 30W and some 40W. 20W50 "racing" motor oil or 90W GL4 gear oil are most likely too heavy in an OD gearbox and can cause problems (although they work fine in a non-OD box). I personally wouldn't use synthetic or semi-synthetic oils in the TR gearboxes, but that's likely not related to your problem (usually causes gearbox to pop out of gear).

The original style lever switch can get grounded accidentally and cause the OD to stay engaged. I know this is a distinct possibiliy on TR4/4A, but am not sure if it occurs on the later models.

Hope this helps.

/ubbthreads/images/graemlins/cheers.gif

 

[Guest]

Larry, I hate to tell you this but those are EXACTLY the symptoms that my J-type overdrive did. I did everything in the world to correct the problem, many,many phone calls to John Esposito, had a local tranny shop keep it overnite, blew out every orafice, changed oil, screen filters, etc. All to no avail. (After you turn the engine off and let it sit awhile, the pressure bleeds down and the overdrive will disengage.) (Or, you can bleed it a bit and drop the pressure, same result.) Don't make the terrible mistake of jamming it into reverse while it is stuck in overdrive. Major, major damage will result! I pulled the whole thing, sent it back to Quantum, he stuck another one on and I never looked back. A total enigma. Man, your problem sounds so much like mine. (you think it is because I bought your Amco bars? BTW, I love 'em)

Bill