I just recently set mine at "or Less". seems to work fine even when I am hitting it hard full throttle.
I put 2 degrees up in mine today...that makes mine 3 down and .70 up. I am going to add 2 more tomorrow giving me...3 down and 2.70 up... I don't feel a viberation but I can hear a slight pulsing sound.... I also may bring the transmission tailshaft up .30... (that will make mine "Or less" )... C4/ 3:55s at 75 MPH/3200 RPM ......
That pulsing sound is why I did mine. It was at about 4 degrees on the rear and 2 on the engine. ("about" because of my poor measuring device). I put in 2 degree shims on the rear, so I am about 2/2. I lost the pulsing sound. And it was BAD before. Vibrated stuff loose, and likely even vibrated those 3 rocker arms loose a couple months back.
I don`t know what mine is...Never been a problem for me.If I ever build a race car I guess I`d look into it though.... .
i rechecked the pinion angle after the 2 degree shim install...it is 1.2 up... i put the driveshaft back in and took off to Summit...got down the road a short ways and it sounded like the driveshaft was comming out... i took it back home and put it on my lift. when i removed the driveshaft and checked the U-joint...the rear U joint was shot... (300 miles).. being that my C-4 has been doing better i thought it was time to reinstall my Gearvendor...i have a new driveshaft for it... Jeff w/mav and Earl w/mav were down today and gave me a hand...:Handshake after the test drive i noticed a vibration... drove it to Harolds shop and pulled the driveshaft...the rear U-joint was shot...(150 miles)... Harold had a new one so we installed it and 2 degrees more angle... 3 down/3.2 up i will check/test drive it tomorrow... ...... ...
Watching this thread closely.. How shot are you talking? Like play in the caps and everything, or just darkened grease?
I`m not a racer so I may be totally wrong on this,but shouldn`t you have the straightest possible line between the trans and rear end shafts? I was told way back,to set it up so the trans and rear align as though one shaft went though both of them,with the car loaded as you normally drive it. Mine is factory setup and it looks like it`s almost straight when I look at it on a lift where the car sits on it`s wheels. Hey I might learn something today!
That's the first time I've ever seen a recommended pinion up angle. Normally they tell you to put the pinion down 3* since it will rotate up when you accelerate. I'm no driveshaft expert, but the pinion up angle doesn't pass my common sense test.
who are they... this is...Currie According to Currie, a street driven vehicle should strive for between 1 and 3 degrees between the transmission and driveshaft, and 1 to 3 degrees between the driveshaft and pinion. Furthermore, the two angles should be nearly equal (between 1 and 3 degrees), but always opposite. Otherwise stated, ideally, the angles between the transmission output shaft and driveshaft, and between the driveshaft and the pinion will be equal and opposite and 3 degrees or less. See the example below. this is...Inland Empire Driveline
True race cars are designed with pinion angle down. My stock cars had the transmission fairly level and I put a mininum of 4 degrees downward pinion angle in the rear. With 10 inch slicks and 620 gears, anything less would tear up the rear. Now as far as street cars go- I'm just paying attention to what is talked about here and hoping to learn sumtin' :Handshake
