Cadillac

[markss327]

Yeaaaaa.
When's she gona hit TRP?

[Basement Paul]

Today 32V and I took the Caddy on a little trip to Summit. I bought some B&M trans fluid and a new helmet on the closeout table. I put over 100 miles on the car today without incident and it was lots of fun to tool around on a nice day.

I changed out the trans fluid this afternoon and as far as I'm concerned, I'm ready to race. This weeks forecast looks pretty bad for Wed, and I have to work next Saturday for the Rainbow's race at TRP, but I'll get it out at least once before the year is out.

I can't wait!

-BP

[Basement Paul]

With wheel hop fresh in my mind, I took a trip to pull a part after work yesterday in search of a rear sway bar for the Caddy. I found one in a '79 Caddy that seemed to be a little too narrow, according to my measurements, but decided to give it a try. It's now in the car, and the seems to be OK. I haven't driving it yet though.

This sway bar size seems to be in LOTS of GM cars from '77 and up. The one I bought is the skinnier of the two I've seen, but if I decide to go with the fat one, I won't have to change the mounts inside the lower control arms, just the bar itself so it should be pretty easy.

I've also jacked up the air bags in the rear to add more weight to the rearend. As it turns out, the car was not sitting level, but lower in the rear (according to my level), so I put about 25psi in the rear bags which (in my mind) should help plant the rear a little more. I won't know until I drive it, so hopefully I can get some good weather to give it a try. I'll post pics later.

-BP

[Basement Paul]

The rear sway bar trick didn't really fix the wheel hop problem so I had to get more serious. I was able to pedal the launch to a 13.73 at 99.5 mph in 78 degree heat with the new 9" and 3.50 gear.

Since I had a pair of new traction bars laying around from my old Trans Am, I got the idea that I should put some bars on the Caddy to control the hop.

Sooo... I found a piece of scrap diamond plate at work and went to work...

Step 1-



Step 2, I went to my brother in law Matt's place, and used all his HGR bought cool saws & stuff to make these pieces of that would turn into the brackets that would be welded to the rear axle.



Step 3, I had to trim some shock mount and leaf spring stuff off the traction bars.

Step 4, weld up brackets & stuff





Step 5, weld to rearend, & adjust...








I have the traction bars set up to where when I run the airbags in the rear coils at normal cruising level (13psi), they sit about 3/8" away from the stops for better ride quality, but when I put them down to 6psi, they sit right on the stops. I've only tested them at ride height, but the hop seems to be a little better, but not perfect. I haven't messed with it at the lowered pressure, but I can only hope and assume it will be better. I will be testing it this Saturday afternoon after work at TRP.

With the temperatures being about 25 degrees cooler, and the traction bars, I'm hoping to be around 13.50 or maybe a little better.

-BP

[TireSmoker]

Well done! I'm jealous.. you've gotten to that next stage of hotrodding where I want to get to..

"I happen to have some steel plate laying around so I cut it out to some pieces and welded up XYZ..."

-Dave

[Racin'Jacin]

Nice Paul! Looks awesome with those bars hangin' down there - love it!

[oldvettedad]

Looks real good! A couple of questions though.
1. Are there any links from the rear end/axle to the frame? The old Stock and Super Stock full size chevys, and 66 and up chevelles (I think) had a link from the rear to the frame, making a 3 link. We would weld another from the other side of rear to the frame effetively creating a four link. The links don't specifically affect wheel hop but they did help due to general stiffening.
2. Your bar goes from the rear husing to the front of the lower control arm. It effectively "mimics" the lower control arm.I'm not sure it will affect wheel hop as much as it will affect tire plant and body lift. Not sure, I'm not a suspension genius, but you should know soon.
3. When we put bars on the old big chevy's we went from the rear housing to the frame.Thus isolating it from the lower control arm, I'll be interested to see how this works.
4. Since the bar is a slapper bar it is short. Usually designed to from the lower spring perh to the front of hthe leaf spring, to keep the spring from "wrapping". Just from looking at your setup i woild feel you need a longer bar. This all has to do with suspension geometry of 3 an 4 links, and ladder bar suspensions. How well you plant the tire depends on the "instant center". This is found by logically extending the links until they intersect, However with a ladder bar ( non adjustable link), which is what yours mimics, the instant center is where the ladder bar meets the frame. It just looks short to me.

Anyway, I don't think it can have any negative effect, i'll be interested to see how it works.
I like the innovative approach!

[Basement Paul]

The traction bars seemed to have helped tame the bad wheel hop, but as it turned out, the regular BFG Radial TAs weren't sticky enough to get me consistant launches, and would chatter and spin enough to have to pedal it. SOOOo, I went to my tire shelf and pulled my old, mostly bald Mickey Thompson drag radials off and mounted them up Friday night before racing to see how they would react.

I had very consistant 1.93-1.94 60' times, and the car became consistant enough to win the street tire portion of the gambler's race on Sunday (four rounds). There isn't even a hint of hopping anywhere now. I'm calling the mission a success.

Next thing to do is try to figure out the carburetor. It seems that it won't take a fast mashing to the floor without giving me a small bog. If I push it to the floor quickly, but not as fast as possible, it seems OK. This is a mostly race carburetor with a center squirting, single accelerator pump on it. ALso the throttle blade open with very little progressive-ness, so basically the secondaries start to open at about 1/8th throttle.

When I launch on the converter (about 3100 rpms), I'm already in the secondaries. I think the 50cc accelerator pump is too much since it's already pulling fuel from the secondaries at this point. I'm going to try to put a 30cc pump on it to cut back some fuel at the pump of the throttle, and if that works, I might try to fatten up the jetting to get me more top end down the track.

This last week I pulled the intake manifold because the front rubber seal was cracked and leaking all over the front of the motor. Apparently the rubber gasket is too thick for the Performer manifold as the new one seems to have pushed out again and oil is slowly coming out again. Next time I'm just putting RTV on there and eliminating the rubber seal altogether. I used to do this on my small block Chevy and it worked fine.


So I think I'm going to get a new set of drag radials for next year. I haven't decided if I'm going to get another set of rims or not and just switch from street tires to drag radials, or just drive on drag radials all the time. I don't really take this car on trips at all, so the drag radials would probably be fine all the time.

-BP

[Basement Paul]

About two weeks after this last post, I was driving the Caddy to Thanksgiving dinner when I looked in the rearview only to find lots of smoke coming from my car. I pulled over and stuck my head under the car only to find it COVERED in dripping tranny fluid. As I was close to home, I quickly wheeled around and was able to get back home. I blamed the leak on a bad rear tranny seal and put a new one in the next day.
I then drove it only a few miles to find the same problem happening again... hmmm. At that point, I basically just parked the car until Spring broke. It seems the problem only occurs when the car is driving down the road. I tried to diagnose the problem up on jack stands and in gear, but after about 15 minutes of screwing around (I did replace the seal again BTW) the new rear seal didn't leak a drop. hmmm... So then I took it for a little spin around the block, and within a mile, the rear seal was leaking again. WTF?

So basically, it only leaks while driving. And it leaks alot.

Part of my repairs before the on the jackstand test was to get a new driveshaft yoke that had splines that go all the way to the end as opposed to the one I got with the new driveshaft where the splines started about 1" inside the yoke. My concern is that I may have bent the rear tailshaft as it seems there's a little vibration when driving too.

Life has been pretty busy, but hopefully in the next week or so, I can pull this trans out and see if I can find a real problem. Keep in mind, this is the TCI trans that has just over 600 miles on it... Ugh. Not a good tranny year for the Cossicks.

-BP

[Maverick]

Any chance the new yoke is longer and is punching the rear seal when you're driving? With jack stands under the rear axle, there should be about an inch of clearance to allow the yoke to move forward.

Maybe the drive shaft needed to be shortened when you installed the 9"? I know the drive shaft needs to be shortened a little when going from an 8" Ford rear end to 9".

Can you pull the drive shaft and run the engine in gear and check for tali shaft run out?

[ttamrettus]

You can probably put it up in the air, put in neutral, put a magnetic base dial indicator on it and check it for runout as Maverick suggested.

My concern would also be as stated earlier by Maverick that when the suspension compresses the yoke tries to move to far into the trans and causes a leak.

[Basement Paul]

I did show the pictures of the yoke in the trans to the guy who made the driveshaft and he said the yoke spacing looks good. If I didn't mention it before, it's a custom driveshaft that seems to fit perfectly. What's perplexing is that I raced it and drove it and put more than 600 miles on this combination before I had any problems. And when it finally started leaking, I was not abusing it... go figure, just like when the original rearend let loose.

The problem happens with the old yoke and the new yoke installed, so that's not the problem.

When I did the testing on the stands, I did have the jackstands in the rear under the rear axle so it would simulate driving conditions. At this point I think the only way to check it correctly is to pull it out and give it a good once over. Worst case I'll take it to a tranny guy or just put my old trans back in and see what happens.

I guess this is just another hurdle. I'll figure it out eventually.

-BP

[Maverick]

Could the old spline have prevented the yoke from entering the transmission too far but the new one, with the splines cut further, allow the yoke to go in and damage the seal? When the weight is on the rear axle, how much smooth surface is outside the seal? When the weight is not on the rear axle, how much smooth surface is outside the seal?

You might also check the tail shaft bushing. If the bushing has a lot of play, maybe when the car is sitting still with no load on the drive train the yoke doesn't get too far out of position but when your driveing the torque and bumps move the yoke around enough to wipe out the seal?

Don't know your rear suspension set up but I'd also check all the bushings and mounts to see if under load your rear axle might be moving forward or backward.

I've never seen any of those things happen but, since its easy to check them, you might want to look at those things before you pull the transmission. Just some thougts. Its an interesting puzzle. I'll shut up now.

[Basement Paul]

The only thing that it might be is the tailshaft bushing. I know from just having the rearend out of the car that those bushings are all in great shape. I may try to pull the tailshaft off before I pull the whole trans, but that will be a gametime decision. There's only about an inch sticking out when the suspension is in ride height, and that doesn't change much at all when it's hanging down.

Looks like I may have a chance this weekend to mess with it afterall.

Time will tell.

-BP

[Maverick]

The only thing that it might be is the tailshaft bushing. I know from just having the rearend out of the car that those bushings are all in great shape. I may try to pull the tailshaft off before I pull the whole trans, but that will be a gametime decision. There's only about an inch sticking out when the suspension is in ride height, and that doesn't change much at all when it's hanging down.

Looks like I may have a chance this weekend to mess with it afterall.

Time will tell.

-BP

Sounds perfect. Let us know when you sort it out.