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Old 07-04-2006, 02:04 PM
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Rear Coil Over Shock placement

Hi Everyone!!
I am starting to assemble the rear suspension on a 23T Bucket. I am looking at "All American"or "Carrera" Coil over shocks.. Because the wheel base is so short on this ride 103"
I am considering installing the rear shocks in FRONT of the rear axle.. It will move the axle back about 3 inches..With a pan hard bar holding the centerline, the low mounted radius rods maintaining 90 degree axle to frame and the pinion parallel to the floor..What I want to know is does it make any diference on which side of the axle you mount the coil overs??? Can the pinion parallel be maintained???
Thanx for any suggestions or advice..
Bob "Slohand" Mosher

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Old 07-04-2006, 03:58 PM
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Bob,
The rear axle doesn't care where the shocks are located, tho conventional location is behind the axle to allow for 4 bars, hair pins or triangulated linkage or whatever holds the housing in place. As far as setting pinion angle, the adjustment is by way of a screw threaded clevis or joint of some sort. With a t bucket, you may have a problem with +/-3 degrees as I did on one I had years ago. I just factored a set of $15 U-joints in my yearly maintenance and carried a spare "just-in-case". I still have that spare joint, ten years after parting with the car.Remember, the engine slopes down 3 degrees, therefore the pinion has to point up 3 degrees

My vote would be for Carrera, Speedway, Pro or some other coil overs. All Americans are a TCI product and not easily obtainable at a reasonable cost over the internet. I currently have All Americans on my current car, but the entire chassis and suspension is TCI !!!

As a note, ALL Model A's had a 103" wheelbase and ALL '32's, a 106". So you are not building an unconventional short wheel base car
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Old 07-04-2006, 05:29 PM
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Coil Over Shocks

Hi Ireland's Child !!!
Thanx for the information..I was aware I was not building an
unusual wheelbase..I just didn't want to make it any shorter than it is..I know that the ride is not going to be "Caddy-Like" either..With a buggy spring front and stiff coil over rear it has to be close to "Buckboard" I wasn't sure about mounting those coils in front of the axles, but I couldn't think of or even find any reason other than room that they needed to be on the back side of the axle..The only other mount on the rear axle are the hairpin radius rods and I have a Speedway lower than axle mount for them..I think they will fit if I mount the shocks at about 20 degrees.. I think I can purchase a pair of All-American from a TCI Shop here in Oregon about 170 miles away for about $270 a pair..The Carrera's have a strange top mount on them they use a 7/16 bolt..most others use 5/8 standard shock mount studs... I noted you indicated the engine and pinion angles.. engine down 3* and pinion up3* I was going to install the engine with the crank and output shaft ...and the pinion parallel with the floor maintaining the 180* between the two locations..with everything centered and parallel..The down slope of the drive shaft between the two attachments shouldn't be out of phase causing a vibration or the bearings to prematurely fail due to brinelling of the bearings.. I haven't checked the angle of the U joints..I do know that 2* to 3* angle is optimal..Am I missing something??? I haven't installed the rear or the engine and tranny mounts..As indicated I was going to try to level ... (Parallel) both ends and allow the shaft to slope..I can make the tranny mount and make it parallel.. I can "Tweak" The radius rods and raise or lower the pinion ... Do I got it wrong??? Let me know..Thanx for the great info...
Oh.. By the way.. I am from the upstate area too. Ft. Edward, Lake George..Glad to see some of us stayed home..and have the hot rod bug too
Bob "slohand"Mosher
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Old 07-04-2006, 09:57 PM
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Rear coil over shocks allow an adjustment for ride height. Changing ride height will change the angle of the trans output shaft without changing the corresponding pinion angle a corresponding amount. For instance, let's say you have your pinion and trans output shaft set up properly after installing the coil overs and setting the initial ride height. Now, later you decide you want to increase the ride height an inch. This will raise the back end of the frame, and correspondingly the trans output shaft, but not the axle (the rear axle will pivot a very small amount because the front of the radius rod pivots up a bit, but it will be pivoting the wrong way anyway, compounding the error). This ride height adjustment will require you to reset the pinion angle. As an aside, the ride height adjustment may be slightly easier if the coilovers are mounted behind the axle.

In actuality, every time your car goes over a bump causing the shock to compress, the pinion angle / trans angle relationship changes momentarily. The best you can hope for is to set it up for the condition you most often drive in. I used coilovers on my T, and because weight in the car will change ride height, I set the ride height with my weight in the front seat, about half my weight in the passenger seat, and the equivalent weight of half a tank a gas resting on top of my installed fuel tank. Then set the rear panhard bar to center the axle, and set the radius rods so the rear axle is exactly parallel to the front axle. I've found I can't set it up correctly with the vehicle empty.
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Old 07-04-2006, 11:23 PM
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Coil Over Shock Mounting

Hi Cucumber1949 !!
Thanx for the great and practical information..I have been wanting to build this "23 T" for 45 years and finally have the time..Setting the ride height and weights sounds like a very practical solution to a thorny problem.. My initial thoughts indicate all vehicles have the same load and bump misalignments between pinion and outputshaft as they go down the road with diferent weights and road conditions..When building the initial frame and suspension set-up logic seems to be that if I set everything parallel to the shop floor the angles are going to change as I add engine tranny and body etc..because the weight distribution is not even on each wheel..with the front axle I should be able to re-set the castor and toe with the radius rods and tie rod adjustments on the clevises and rod ends..I am assuming the engine would remain close to the initial parallel set-up because of the addition of about 600+ lbs when it is installed..The output shaft could be shimmed up..down would be more difficult..unless provisions were built into the trans mount tubing..Moving the pinion shaft up or down on it's axis could be accomplished by re-setting the clevises on the rasdius rods.. but may cause a bind on the shocks..The panhard bar can recenter the rear with minimal problems..I am kinda thinking out loud here.. So now I feel kinda lost..cause everything you say will effect the geometry of the drive shaft and U joint angles..Can I ask How you usually set up the shaft and U joint angles as you are building the chassis and working toward a completed ride...?? Any additional information you can provide will be used and be very helpful.. Thanx!!
Bob"slohand"Mosher
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Old 07-05-2006, 06:51 AM
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T Buckets

Sorry about your move to the left coast from the frozen tundra of the great North East - I'm in Ballston Lake, about 2 miles from I-87.

Comment about pinion angles - and the 3 degrees I stated.
Assume your engine is sitting on a cradle, and on the floor and is levelfront to back as looking at the manifold flange to carb . Lay a bubble angle finder on one of the valve covers or better, the starter and you will see that the engine (and transmission, etc) are at an ~3 degree angle. Rule of thumb is that the pinion will be a reciprocal of that angle. That is, engine/trans pointing down 3 degrees, then the pinion angle should point up 3 degrees.

Cucumber1949 brought up some excellant points as well.
Might be an idea to look at this web site as well. I used to lurk there occasionally, but haven't for a long time.
http://www.nationaltbucketalliance.com/

Also, Total Performance has an assembly manual as well that has a lot of very good information tho it reads like it was written by a 12 year old. The manual that I had was given to the new owner.

This was mine
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Old 07-05-2006, 07:14 AM
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Pinion angle disc

Here you are a good discussion of pinion angle Pinion Angles and Driveline Setup for the Street

As far as the spring location setting the coil overs behind the axle gives a longer spring base for handling reasons..Study Carroll Smith and what he wrote in Engineer to Win about this..Course on T-buckets most of those get built "this way" because that is the way T-buckets are done..

Sam
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Old 07-05-2006, 08:32 PM
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Pinion Angle discussion

Hi One More Time and Ireland's Child...
I am a Member of the National T-Bucket alliance..They do have some good advice and forums..I will check the tech sections out again.. So far the reasons for mounting coil overs behind the axle tube are.."That is the way T-Buckets are Made.." "It is easier to make ride hight adjustments..and " It makes a longer spring base for handling and ride." All pretty good reasons...I think I am going to look at it both ways..I am leaning towards ahead of the axle tube because it will move the rear wheels/axle back about 3" and the mounts on the frame are within less than a 1/2" of mounting it behind the axle tube..They may look strange there and I may not like it when I mock it up, but if that is the case I can always move the axle a couple inches and final mount em behind the tubes..Thanx for the hyperlink to the forum I will go/save and learn ..Thanx Again Sam

I think Ireland's Child and I are on the same page and don't know it.. If the engine has a negative 3* tilt to the output shaft and the rear end has a positive 3* up tilt to the pinion ..The 180 degree balance between the two points is maintained or..87 *for the engine and 93* for the pinion the total is 180degrees.. I do believe that installing the pinion with an up angle of 3 degrees and the engine with a down angle of 3 degrees will be easier than trying to make them both 90 degrees to the floor.. I am convinced that it will be easier to install making the carb top and manifold level therefore allowing the tranny output shaft to have a negative 3 degree angle to match the up 3 degree angle of the pinion..

Cucumber 1949 did have some great observations and points and I know I am going to pre-load my buggy before I finalize the ride hight ..I will double check pinion angles and make sure the pan hard bar has that pumpkin input shaft centered to the frame and the rear wheels are in line with the front and frame.. The photo of your T-bucket came thru and all I can say is I hope mine turns out as well as yours looks..I am impressed and saved the photo..I am curious about your steering set-up..I am using a speedway 4" dropped front axle with Chevy spindles, Mustang rotors and a 5 on 4 1/2 Ford wheel bolt pattern with GM Metric calipers..I tried to put the tie rod in front of the axle as you had yours installed..but I checked the Ackerman angles and It was going to be inboard of a good intersection on each side by about 1.5 inches..so I refit the flat tie rod arms and installed em behind the axle and thru the hairpins.. I have a reversed corvair steering box and pitman as well as a Ford Mazda Courier steering column which will cut down to fit and has a 5/8 matching steering shaft..What did you use on yours?? It is a very cool T-bucket..I can imagine you had a lot of fun times driving it around the north country..

My wife and I lived there until we were 19 years old..I migrated to the left coast and a year later we got married and moved out here in 1960 and been on the wrong coast since!! She has a brother living in Malta..a Mom and two sisters living in Gansevoort..We just got back from there, a brother in law passed away..We fly back and spend a couple weeks there about every year.. Next time maybe we can get together for lunch or a cup of coffee at Sonny's Truck Stop on I-87 just north of Saratoga or at The Point Diner south of Saratoga.. here is my regular e-mail address..www.slohand58@aol.com drop me a line sometime and we will see.. Thank you for the great advice and information I really appreciate it..
Bob Mosher
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