What width is stock for the rearend and front axle? I have seen a number of different front axles and even tube axles. The rear end width is How wide? Every rearend is different and many rearends do not have the pinion centered in the rearend meaning one axle would be longer than the other---NOT SAFE!! So can you cut down the long axle tube to make the car safe???? What width Kingpin to King pin does the front axle have to be?
The axle lengths must not be altered from as manufactured. If you find a narrow axle or a wide axle, that's how wide it is. some axles have the pinion offset far to one side like early jeep, you can not cut down the long side to make it fit. The basic concept is the axle housing isn't cut down. If you want the rear narrow find the narrowest "stock" axle you can and go for it. Front axles vary by width also. My Lincoln Zephyr axle is wider than a stock Ford by a couple of inches. Just adds character. If you want the front end narrower, run an Anglia or English ford axle. As I interpret the rules, tube axles are ok as long as the basic width relates to a "production" axle. If you can't figure out what "the Spirit of the Bug" means, go back over the HA/GR postings and do some research and ask for help from the other car builders. This isn't designed to be AA/Fuel cl***, no slingshots, etc. It's supposed to be how it used to be, before the cars were built in big shops, and racing was fun. If you look at the posted pictures of cars that are running and the vintage pictures of the Bug and its contemporaries, it's pretty self explanatory.
From previous posts it appears that Ryan has been open to taking Tech questions of the nature of yours. I would suggest that if you feel you need to modify some part from how it was originally made that you get it cleared by Ryan first...otherwise you may have to change it later. Also keep up with the rules...if there are others building a car in your area PM them and ask their advice/interpretation of the rules. Again, might keep you from spending time and energy to change something later. Good luck with your build. Ron.
I guess I'm misunderstanding the intent of your question, If so my apologies, and the answer is that for offset pinion rears we mount'em with the pinions offset just as they were designed to be mounted. Thus the wheels are equally distant from the centerline of the car. From that point you may use the driveshaft's u & slip joints to deal with the offset (as the factories usually did) or mount the engine with the same offset as the pinion. This latter choice also tends to counter the engine's torque reaction as well as simplifying the alignment process. Chrysler was one company that dabbled in this a bit later. Stock width is pretty much that width at which the unit was manufactured. Aftermarket units of the period pretty much reflected factory manufactured unit dimensions.
Why is an offset pinion unsafe? I'm not following you. Almost every production rear wheel drive car built is this way.
I'm wondering this too- For my HA/GR I picked a Dana 44 out of a Jeep CJ for a whole bunch of reasons that appealed to me, and the pinion is not centered to the wheel flanges. I've been planning on running the pinion in the middle and the wheels off of center, figuring that with a spool the thing would launch straight pretty much no matter what. Am I in big trouble?
When I ran my old Front engined rail we put a new 9" in it. The rearend was setup so the pinion was centered and both axles had to be the same from the center of the Pinion. I was told by NHRA safty guys that if there was a longer axle it would tend to leverage the car, say the rt. axle is longer it would tend to push the car to the left. Were if both axles are = then the torque is =. Thats what I was told by NHRA many years ago and as far as I know it's still inforced on all NHRA Rails.
OK, got it ......... Roothawg, Dutchtreat (like Moparsled) is ***uming that placing the pinion on the cars centerline is a desirable objective. This would of course, leave the wheels of an UNALTERED rear at unequal distances from the cars centerline. Definately a bad idea and one ANY sanctioning body would frown on. The relationship of the pinion itself is actually cir***stantial, it's the relationship of the wheels to the car's centerline that must be maintained. The cir***stance for centerlining the pinion (and going to the trouble of modifying the rear end) would be to be able to centerline the engine that's directly inline with it, something VERY desirable in a short-coupled, narrow wheelbased situation such as a slingshot. And in that you're already severely narrowing the rear for a modern designed rail the added cost and work of centerlining the pinion is negligible. For a car with a normal width rear the "mis-alignment" is handled by the u-joints. Close-coupling to an unmodified normal width rear is best done by accepting and matching the offset in the engine's mounts. Moparsled, what you're doing will produce what's called "cat-tracking", where the rear track is offset from the front. Many cars operate on the street with this defect with no real problems beyond uneven tire wear, but they're not racing'em (and they're funny to follow). You'll get little (if any) disagreement from anyone who's raced nearly anything that you want to build your car as straight and as squarely as you can. That said, I'm certain someone will sooner or later point out that some circle trackers have and do build cat-tracking into their set-ups. Few drag strips however, go in circles. I do tend to over explain things so I've tried to keep this as basic as I might and still get it across. Hope some of you are still awake .........
I was asleep then, but I'm awake now. On the topic of offset pinions, I recall a Ford Four powered car back in the early '60s that had the pinion offset to the right and the engine offset to match with the driver to the left. Believe the name was "Midnight Oil", and the car looked like a smaller version of the old Indy roadsters. Maybe someone here remembers the car. Saw it run at the old San Gabriel strip.
I am running an 8inch ford rear end. The pinion is centered in the car. Both axles are different lengths......but here is the shocker.....The wheels are the same distance from center line! How is this possible? Well, it should be obvious. The pinion is centered, but the carrier isn't. This is why one axle is longer than the other. I have a friend with a 6 second slingshot top fuel car. He is running a 9inch ford rear end. His pinion is centered, carrier is offset and each axle is a different length. I would suspect that if this was really a safety issue he would not be allowed to run his car. It p***es tech on both ihra and nhra tracks. Another shocker? This is how production cars are made!!! The pinion is centered, the ring carrier is offset, which requires a slightly longer axle on one side. NOT a safety issue!!!!
MoparSled, I ran that very axle under my old altered. It was a Jeep cj-5 I think. It had a factory 5.38 Ring and pinion with a posi carrier. It was offset and everyone that looked at it just shook their head. Misalignment just made the ujoints work. Car went 10.10 all day long.
Gentlemen, First, HA/GR rules clearly require the use of an un-narrowed rear end. While some rears have indeed been made with unequal length axles and centered pinions most are designed with equal length axles and slightly offset pinions for manufacturing cost reasons. These latter units are obviously the ones in question, as observed and posted. Second, if you wish to go fast in reasonable safety the first consideration has to be to build a straight running car. For drag racing purposes this requires that the wheels be arranged evenly about the centerline of the car. Thus third, if you've chosen to centerline mount your engine and chosen to run an offset pinion rear then you allow the driveshaft and u-joints to handle the obvious diference in alignment, it's what they're designed for. Framed correctly, the question answers itself.
ok, maybe I miss read the question. I thought the question of safety was being address in regards to rear ends that had different length axles, which most (all rear ends that have a centered pinion) do. My mistake. I'll go back to sleep.
Bottom line is.......the drive shaft and universal joints don't know if they are going on a downward slant, sideways, or all of the above. Thats why they are there, to allow for misalignment and keep all of the turning parts turning.
Nah Sarge, your overall point was dead on anyway. A centered pinion axle would solve both their problems by not having to be either altered or compensated for, and they're certainly available.
my solution will likely be to set the engine off center with the pinion, and run the wheels even to the centerline. U-joints, driveshafts, and all that don't apply- I'm running a shortened Lasalle trans coupled pretty much directly to the rear. However, let me pose a different question- The rules say stock width rear, and the question was asked - "what about taking two inches off one side to center a rear?" the answer was no. So, what about taking an inch off one side and adding it to the other? The axles and housing have been modified, but the overall width remains unchanged. The result is a centered pinion in relation to the wheel flanges, and technically, a rear that falls within the current rule.
You can probably make it as complicated as you want to.......but why? That's like saying an 8" Ford rear axle is 46" when used under a Bronco II, so why can't you cut a 52" housing from a 9" axle to 46". Why not just find a rear axle that fits what you want to use without modification, or using different offset on the wheels? The idea is to keep the cost down by limiting parts to something from production vehicles. Sure you could have a custom made axle housing built to whatever specifications you wanted, but why? The whole idea of the cl*** is to build and race cars like they used to make for FUN. If you want to go to all that work, build a nostalgia top fuel car.
Yeah, That's the answer we came up with for the Barn Job, just pushed the engine over a tad (we're close coupled too). It'll help slightly with torque reaction and makes a bit more room inside the frame for the gearbox and clutch linkages on the other side as well. That's an intriguing idea. Reworking an axle to center the pinion without changing the track. Shouldn't be a rules problem, a bucket of work for nearly no advantage in this cl*** but looks to be legit. Now if say, you were also running it as a belly tanker at LSR meets it would make a bit more sense. But of course an already centered unit would make even more sense then. "Just to have done it." is possible too, but would likely only be an appealing reason to the hardest core of fabricators. Still, could be a fun cobble ........ Same thing with cutting one down to a legit smaller track. Not enough cl*** advantage to make it worthwhile. How 'bout running a 52" wide rear with 12" negative offset rims to yield a 28" track? OK, sorry, I'll quit now.
Why not just build to the spirit of the cl*** and have fun. For all the work being discussed here, how much advantage will be gained when all the power is still going to end up at the pavement through the same 6" tire?
Why do you think they used the old Ford bango units. Pinion was in the center.. As was the Lincoln HyPoid unit. up untill 48.. There are cars today that the pinion is NOT centered in the frame.. The drive shaft just goes where it has to to hook up. But the wheels are centered to the ch***is, You should look up in a book the angle and geometry of a drive shaft. they are not in a straight line.
Awwwww, You had to go and get realistic. And just as I was starting to have some fun with it too (aside from honestly trying to talk Mr. Sled out of building a cat-tracker). ......... pout ............
um... ok... now I'm all defensive about my questions and my choice of rear end. first of all, I chose the Dana 44 because it is WELL within the spirit of the cl***- 44's as far as I can tell, were intro'd in 1941. They're light, strong enough, EXTREMELY plentiful in a BUCH of configurations, and parts are dirt friggin' cheap. Just because my pinion is off center and your 8" Ford's isn't doesn't make my choice wrong. I chose the CJ rear because it is quite narrow- 51 inches out to out- specifically because it fits the style of my build. I studied a bunch before I started gathering parts, and, centered or not, the width works for me. BTW, from some of the reading I was doing, narrowed rears started popping up BEFORE '54. The rules I read said "stock width front axles and rear ends only" overthinking or not, if I haven't changed the overall width, it's within the current rule. The rule doesn't say you CANT REARRANGE EVERYTHING to put it where you want, it says it must remain STOCK WIDTH. I take that to mean its own stock width, not some other rear's stock width. I have no intention of doing what I asked about- cutting one side and adding to the other, I can't afford to, and Ryan has handed down his decision on the matter, so I guess it all doesn't matter,however, Ryan, I think you're wrong. To add- I overthink EVERY SINGLE PIECE of my rail as I go. As far as I'm concerned, that's a part of the spirit. Looking for something someone else didn't think of, or maybe have the stones to try.
Moparsled, I don't think Ryan is saying you can't use a Dana rear, you just can't narrow it. Don't worry about the offset pinion, the ujoints will never know the difference. Just build it......
Don't know what this obsession with "centered" is all about. It really don't matter and won't actually make much difference other than visual symmetry. Sort of one of those "fly poop and pepper"things.
There's nothing wrong with your choice at all, nor your "blue skying" (kicking around ideas). Hell, the 44 Dana's been our own planned next step (if we can't get what we want out of the 7 1/4") from the outset. And I typically indulge even the most radical kibitzing, it's fun and sometimes (OK, often) I learn things. But of course I conclude with my own decisions. And should someone get all worked up over'em, , well, God knows that's fun too. I do try to have fun.
Amen to that, and as my flight instructor used to say, "if ya ain't havin fun......what in the hell are you doing it for? Life is too short to take seriously anyway.
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