Lowering blocks/Pinion angle

[cbodybob]

Any of you guys ever angle cut your lowering blocks to improve pinion angle ? It's a 69 B body 8 3/4 rear Super Stock springs.

 

[dvw]

Yup, Measure the current angle and angle mill the block. Works fine.
Doug

 

[747mopar]

Never had to but no reason it won't work. The only warning I'd have to others is to never cut the axle pads off and re-weld them to correct pinion angles unless you have a jig for keeping the axle tubes straight (you wouldn't believe how much that weld pulls the tubes).

 

[cbodybob]

Yea I know relocating the spring pads is the proper way. I just want to try this to make sure my hunch is correct. The car is running well, but my 60ft are varying about 1500's That's much improved over what it was when I first installed the SS springs. Still it cost me a round Saturday night. My pinion is 1 degree up. I have dialed in the shocks, air psi, front T bars. Just need to tighten that 60 ft up a little more. I'm thinking pinion angle.

 

[dvw]

Pinion angle won't affect 60 ft. If the shocks are dialed in, it'll be deadly. Read my shock post above. If mine can run 9 teens and run 60 fts with-in .01 on a 10.5 tire you can also. But it takes decent shocks and willingness to test and take good data. The end results are worth the effort.
Doug

 

[cbodybob]

dvw read your shock post. Nice car by the way. Love those candy stripes. I have been chasing my tail for a year. Made many changes. Some defied logic , but my car liked them. My car is more of a stocker & does not have a lot of power. Last year it was all I could do to get a 1.90 60 ft. And they varied between 1.91-1.93 on darn near every pass. This season i have seen regular 1.89 60 fts. To 1.90. So I'm close. The 60 fts have been more consistant too. In the 3rd round Saturday night I got the points leader. So I knew I had my work cut out for me. My previous 4 passes the 60's where 1.88 1.89 1.89 1.89. So I dialed honest as the car had 3 8.69 passees. Thinking all I need to do is tree him. Which is going to be tough, but my only chance to win. I did just that. .012 to his .020. Hit my shifts dead on. He ran 7.045 on a 7.04 dial & my car slowed to a 8.72 on a 8.69 dial. My 60 ft fell to 1.905 and that's what made me a spectator the rest of the night. If the car had of run the # I would have won. So you don't think getting my pinion angle correct will help this? Cause I don't know what else to try. I don't want to go backwards.

 

[dvw]

No pinion angle is for U-joint life. Adding to much angle can bind the housing up and sometimes band aid another issue. I'd love to see the both time slips. You may have been in a little deep. Better R/T, slower 60 and ET. Post em up. To be honest a 8.70 car should hook pretty easy.
Doug

 

[cbodybob]

I'm pretty sure I was in shallow. I'll get pics tomorrow of both tickets. I know I hit my shifts good. I bump in very carefull. Now I did add 1 pound of air psi to the front tire. Rear tires at 15 all day. That's seems to work. I've tried 14 & 16. I did a good burn out. Count to 3 & release line line lock. Made sure I was in grove. Maybe it was just one of those things. I do appreciate your help

 

[cbodybob]

Time tickets

Ok here are the last 2 runs. Looks like it was my 330 that was off. Apparently I didn't hit that shift as good as I thought. Ticket on left I'm against #2 in points & missed the tree. Car ran the #. Ticket on right I'm against the points leader & nailed the tree. So maybe it was a quick shift. Sucks cause this guy is hard to beat & I had him in my gun sights. Runs where 50 minutes apart. 8 pm vs 9 pm. Temps the same. They did hold us in the water box a bit while they reset the tree. Don't think that affected it though. Car temp was the same.

 

[dvw]

This is what I do. Subtract your incrementals. This will show if it was down on power, traction, or missed shift.
8.723-5.599=3.124
8.683-5.563=3.120
only .004 difference, not power related
5.599-1.891=3.708
5.563-1.881=3.682
.026 difference, highly probable the shift point was missed. Add the .004 and we now have 75% of the .04 ET loss. Far more drastic than the .01 loss in 60 ft which I believe was probably a result of being in a little deeper. Which R/T is closer to your ave R/T? A .077 spread in R/T is huge.
Doug

 

[cbodybob]

That's pretty clever. It does look like a missed 1-2 shift. My R/t is typically high 20's to low 40's. So let's say average is .035. Funny thing is I knew who I was running & got up on the wheel. As I hit each shift I thought to myself that I nailed that one. Kept the car straight. The data as you pointed out doesn't back that up though. I run muffs for two reasons. It gives me a bit more lower end & I can hear the fast cars comming. This opponent runs muffs too & I was surprised when he came up on me & I could see he was ahead at the stripe. Oh well. Thst is a useful way to read the tickets. Thank you for sharing that