Pinion Angle? Do I have this right before I cut it up?

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Suggestion, use the pinion snubber mounting surface to measure the pinion angle. Going off the end of the pinion itself may not provide a true vertical surface.

Trans 2 done, if you want overall pinion angle at 5 down, the pinion itself needs to be at -3
 
crackedback said:
Suggestion, use the pinion snubber mounting surface to measure the pinion angle. Going off the end of the pinion itself may not provide a true vertical surface.

Trans 2 done, if you want overall pinion angle at 5 down, the pinion itself needs to be at -3
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I measured off of crank face, pinion snubber location, output shaft end and also a linear cast molding line in the side of the tail shaft. All have almost exact measurements of 2* to 2.25* down. But thanks for the idea anyway.

Thanks for double checking my math, thats what I figured, -3* to -5* if I want to accomplish -5* to -7* static. With stiff SS springs I figured static -5* was a good aiming point.

Going to be pulling it first thing in the week, sure wish I had bought that plasma cutter, would make nice clean work of those perches.

Looks like they cancelled the races on Wednesday anyhow, track temp was still too cold to run on. I still have snow in my yard... Anyway, that gives me two weeks to get all this squared away before the next track day.
 
I made my engine/trans level with jack under diff,and set pinion 2 degrees down. Done. That is for daily driver. I then used the tremec app and it was good.
 
Tooljunkie said:
I made my engine/trans level with jack under diff,and set pinion 2 degrees down. Done. That is for daily driver. I then used the tremec app and it was good.
Click to expand...

Even though that app didn't work for me first time, I'll definitely try it again once the modifications are made and see what it says.
 
You can measure all this with the car upside down if you want. It really doesn't matter. However, "I" prefer to level the frame rails to the ground front to back and side to side.
 
66fyssh said:
Just messin',, it will make you loopy thinking too hard about it....and maybe having a "number" of Dark Rum and Cokes on Saturday night. :D
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Oh absolutely. It's like everything else in the hobby. There's always more than one way to do it. I prefer adding a couple extra degrees pinion DOWN because I like the extra spring wrap. It's not much, and no it's not a matching angle to the transmission output shaft but it's not enough to cause a vibration either. I like my angles closer to even while under power going down the road and a couple extra degrees down at the pinion does it.
 
For what it's worth, and my opinion only..... I would try the pinion angle shims before I went to the trouble of cutting the perches off. Summit sells up to eight degrees. As I understand it, you haven't driven it yet. I would at least give the shims a shot.
I run four degree shims with my super stock springs. I'm about five degrees down. Bracket car, with a 440.
 
If you are going to level the car or raise the car up to check the angles remember that the suspension needs to be loaded in the position it is at ride height ( weight of car on the tires). Like on a "drive on" type hoist, car ramps, blocks under the wheels or jack stands under the rear axle. Ideally the weight of the car would be on the front tires also. If you use jackstands under the frame in front place them as close (front to rear ) to the front tires as possible. This will keep the rear suspension close to ride height. Be safe. If you position the car so that the engine/ transmission centerline is level the math is easier as your actual pinion angle reading will be relative to the crankshaft. Hope this is helpful in confusing people even more and if you weren't confused before hopefully you are now. lol
 
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[/quote] If you position the car so that the engine/ transmission centerline is level the math is easier as your actual pinion angle reading will be relative to the crankshaft.[/QUOTE] so if you leveled the transmission CL you would then level the pinion plus/then moving the pinion down a few degrees (from level) depending on the type of driving/racing you will be doing. Am I on the right track here?
 
If you position the car so that the engine/ transmission centerline is level the math is easier as your actual pinion angle reading will be relative to the crankshaft.[/QUOTE] so if you leveled the transmission CL you would then level the pinion plus/then moving the pinion down a few degrees (from level) depending on the type of driving/racing you will be doing. Am I on the right track here?[/QUOTE]
Yes. With the weight of the vehicle on the suspension. Keep in mind there are two planes that you are working with. As viewed from the side and as viewed from the top. You will want the angles as viewed from the top to cancel each other or nearly cancel. I only mention this because in a race car where you are mounting the engine from scratch it is possible to get the motor in pretty crooked. Same for the rear end. If you have ever pulled a pto driven mower, baler, or manure spreader with a tractor you would get a working example of what happens when the angles get off in the view from the top.
 
YwhSRMB.jpg


:rofl:
 
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