Sideways Mustang
I enjoy your column in HMM, Ray—I always learn something!
Here’s one for you: I have a 1968 Mustang coupe that has a 1970 302 (bored to 306-cu.in.) making about 375 hp, a TCI Street Fighter C4 automatic with a TCI 3,000-rpm stall converter, and a 9-inch axle out of a ’78 Lincoln Versailles. The 9-inch is equipped with factory disc brakes, a 31-spline “Detroit Locker,” and Moser axles. It had a spool before the locker. The driveshaft is stock with stock U-joints. The axle sits on stock leaf springs (it bolted right in) and I use South Side Machine lift bars to control wheel hop. I run a 26-inch-tall drag radial on factory steel wheels for the track and the same size Cooper Cobra tires on Torq-Thrust wheels for the street.
The issue is that when I do a burnout (track or street), the car drifts to the driver’s side so severely that I have to stop the burnout after one or two seconds. On street tires, it’s almost as bad. It happens immediately and severely when the wheels start to spin. It’s much worse at the track. It did this with the spool and the locker. The engine doesn’t make a ton of torque, so the light burnouts haven’t made the launch an issue. It launches straight and it drives fine, and doesn’t pull to either side. It makes the expected clicking sound from the locker when going around turns but handles and drives fine. I should mention that the 8-inch axle with the limited-slip differential that the 9-inch replaced did not do this.
Why did I go to the 9-inch? I got a great deal on it, along with the Moser axle shafts, plus I got the factory rear discs to boot. Please let me know what you think.
– Mark Frazier Sr., via email
For full disclosure, I am not an expert on Detroit Lockers, but there may very well be someone in the audience who is. If so, please reach out to me so that I can forward your wisdom to Mark.
Now, I will offer some thoughts that may have no credence at all. I would think that the differential is unlocking during the burnout or partially unlocking. You state that it does the same thing at the track and on the street. I have heard of this before if, for example, the driver makes a turn into the water box before doing a burnout. In this scenario, during the turn, the differential unlocked and the car did not go straight for enough distance for it to lock again.
The other question that I can’t answer (because I’ve never given it any thought previously) is, if one tire is spinning faster than the other, will the car drift toward the faster spinning or slower tire? Did you ever try stopping, then pulling forward straight, and then doing a burnout? I do not know if this proves anything, but it is worth a try.
I would also be curious to know (and again, this may be of no value) if the ride height of your car is not even at the rear, so that it is leaning, even slightly, on one side; I’d also like to know if one side is heavier than the other. If you rent a set of scales, you can quickly find out what each corner of the car weighs.
My uneducated guess is that something is “tricking” the locker into believing the left and right side are different enough to not want to function properly. Is it that the differential has something going on inside or is it being fooled? I tend to think that it is being fooled. I wish that I could be of more help. Please let me know what you find.
Knowing or Guessing?
Ray, from time to time, you mention the word “dyno” in your column, as you did in the May ’23 issue. This brings up an interesting question. Over the years I have known hundreds of muscle car owners driving everything from T-buckets to C-8 Corvettes. The vast majority are quite willing to part with thousands of dollars to improve the performance of their rides when something catches their eye. Yet I can count on one hand the number of these folks who have ever parted with a few hundred dollars to put their cars on a dyno, even just for a baseline, let alone for any tuning. Why is that?
That’s okay, of course, but I’m just surprised more folks don’t take advantage of finding some relatively “free” horsepower that can usually be obtained with some dyno work and adjustments.
Any thoughts on the subject?
– Karl Oesch, Mesa, Arizona
I am just as confused as you are! I laugh when I read a horsepower figure in a car feature that is listed as “estimated”. I could never figure this out, so once again, I will use your letter to maybe move the needle on this thought, and this is geared toward the readers of HMM.
As part of a rebuilding/restomod project, every engine should be run on an engine dyno before being installed in the car. Not only would this enable the tuning of the engine, but a dyno session also provides the opportunity to find potential problems before the engine is installed in the vehicle. So many people write to me about issues with an engine, such as oil leaks and coolant leaks, blow-by, poor running, and so on, and almost all of them are learning of these issues after the engine is mounted in the chassis. Then they lament about what to do. For example, a rear main seal issue is much easier to correct on an engine stand than in the frame of the vehicle. Even if you are not concerned about maximum performance, concerns stemming from exposing the body of the car to possible scratches and other damage that can occur during wrenching on the engine is worth the cost of a dyno session alone.
If you are just doing bolt-on modifications and the engine was never removed from the frame, then once you are done, the chassis dyno is where you need to go. Why bother to buy speed parts and leave the majority of power on the table? If you think that you can guess total ignition timing, carburetor jetting, or EFI calibration on the street, then you are fooling yourself. You may get the engine to 70 percent, but not much more. And if you get it to 70 percent, you are pretty good. Most tunes are so far off it is not funny.
I am not being a wise guy here. If it is just a show car and you do not care how it runs, then good for you. No worries. But if your desires are loftier than that, please heed my long-time advice: go to a dyno.
So now I will respectfully send it back to those who shun the dyno. Please reach out to me and tell me why. I may be missing something, but I want to hear it from you, rather than making assumptions. Let the emails and letters come! Please enlighten me.
Canadian Cruiser
Ray, you may already have received my question, and I may have missed your reply, or I am still in the queue. Sorry if I am impatient or missed your help.
So, I have a Canadian 1963 Pontiac, which is basically a Chevrolet in every mechanical aspect. I have a small-block Chevy 350 and a Muncie M22 four-speed in the car now. I am running a 3.73:1 rear gear with a Posi unit and 29-inch-tall BFG T/A tires.
I want to move to an overdrive transmission, which could be either five-speed manual or a 700-R4-type automatic.
This leads to the question of whether or not I would have to re-address driveshaft length and/or the transmission slip yolk in either case. My clutch pedal linkage has all been strengthened, and I am comfortable with a manual transmission, but would you suggest a hydraulic slave? I am not racing the car, but I want to do more touring. Right now, it is a 60-mph cruiser, and I believe the overdrive is a better option than a differential change due to the M22 ratio setup.
Can you provide your wisdom, which I have found to be so good over the years?
– Dale B., via email
There is a very strong possibility that you will have to change something with the driveshaft if you make a transmission swap. Until you perform the swamp, you will not know. As with almost everything in hot rodding, do it and then do what you need to so that it works!
Now I will play devil’s advocate with you. I look at car modifications through a very practical lens, often to the dismay of many readers (I have the letters to prove it.). You state that you want to do more touring. That is great! I love that. But back in 1963, people drove faster than 60 mph and often with only a two-speed transmission. Also, be realistic about how much you are going to tour and the miles you will be putting on. Let’s say that you want to put on 12,000 highway miles a year on the Pontiac and you want to run 75 mph for all of those miles. What rpm will the engine be running? I will guess, and I may be wrong, but based on your tire size and gear ratio, probably around 3,500 rpm. Yes, the fuel consumption would go up a little and it would be noisier in the car, but the engine is not going to care. With most collector cars, having the engine run at a higher speed is a blessing since they often loaf around town while just going to a cruise-in or car show.
So, my question to you is, how much time, effort, and money are you willing to invest to get the engine speed down on the highway? There is no right or wrong answer, it is your decision. Or you may find instead of running 75 mph you drive 70 and drop the engine speed down a little.
My concern is that you may spend a good deal of time and resources to reduce the engine speed and, when all is said and done, it may not be worth it. This is a hobby of desires and emotions. I will not tell you what you want, but from my experience, unless you plan on driving 20,000 miles a year, it would be hard to justify making the change.
I would do a test run and see how it is. Take a trip that you want to in the car as is and drive at the speed that you want. You are not going to hurt anything, but it will confirm or challenge your desire to swap out the transmission. This way you will have no regrets either way.
Regarding the hydraulic slave cylinder, you may want to consider it. I do not know how old you are, and if you want to keep the car for 30 more years, it may become an asset down the road.
I will just share a little story with you. In 1970 a friend of my family purchased a new Plymouth Fury with a 383 two-barrel. It was brand new and there was something wrong with the shift linkage—it would not go into drive, so it would not shift past second gear. The owner did not know that and drove from New Jersey to Minnesota and back at 75 to 80 mph in second gear. When he came home, he figured out that the engine was loud and brought it to the dealership to find out why. Granted, that car had a 2.76:1 rear axle ratio, but he ran second gear for over 4,000 miles at 80 mph. Nothing happened to the engine or transmission and the car lived on with no problems at all for more than 20 years until it succumbed to rust.
Commercials Cooperation Advertisements:
(1) IT Teacher IT Freelance
立刻註冊及報名電腦補習課程吧!
电子计算机 -教育 -IT 電腦班” ( IT電腦補習 ) 提供一個方便的电子计算机 教育平台, 為大家配對信息技术, 電腦 老師, IT freelance 和 programming expert. 讓大家方便地就能找到合適的電腦補習, 電腦班, 家教, 私人老師.
We are a education and information platform which you can find a IT private tutorial teacher or freelance.
Also we provide different information about information technology, Computer, programming, mobile, Android, apple, game, movie, anime, animation…
(2) ITSec
www.ITSeceu.uk
Secure Your Computers from Cyber Threats and mitigate risks with professional services to defend Hackers.
ITSec provide IT Security and Compliance Services, including IT Compliance Services, Risk Assessment, IT Audit, Security Assessment and Audit, ISO 27001 Consulting and Certification, GDPR Compliance Services, Privacy Impact Assessment (PIA), Penetration test, Ethical Hacking, Vulnerabilities scan, IT Consulting, Data Privacy Consulting, Data Protection Services, Information Security Consulting, Cyber Security Consulting, Network Security Audit, Security Awareness Training.
Contact us right away.
Email (Prefer using email to contact us):
SalesExecutive@ITSec.vip