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  #1  
Old 01-18-2003, 01:15 AM
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440cj 440cj is offline
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Unhappy Ok, who has actually checked their pinion angle...and on what combo?

My '74 Dart is in need of a proper driveline alignment. What pinion angle should a 290 rr wheel 360/727 go with? HD rear springs, 240 x 60 x 14's in rear, front torsion bars cranked up to make car level. New motor mounts, tranny mount, front end bushings and re=arched rear springs with new bushings. I have a thrumming problem that I am convinced is due to wrong pinion angle. HELP! 440cj
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Old 01-18-2003, 02:37 AM
Mopar_Maniac Mopar_Maniac is offline
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440cj...

I set my '66 Coronet up with 5 degrees down angle.

Automatic tranny cars are recommended to run at 5 degrees down.
Manual tranny cars are recommended to run at 7 degrees down.

I set mine up on a shops drive on hoist (alignment rack) to make sure the suspension was at ride height. You need to verify that the suspension is at its normal level to get accurate numbers.
If the suspension is unloaded at all you will NOT get a true reading.

Good luck,
Mopar_Maniac
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Old 01-18-2003, 02:55 AM
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Default Pinion

Hi 440cj,

The combo does'nt really matter when it comes to pinion angle. I will try to make this as easy as possible.

Pinion angle is the DIFFERENCE between the center line of the pinion and the center line of the driveshaft.

You need an accurate angle finder to do this. Not the $10 plastic one at the local Ace.

Leaf spring cars 5 - 7 degrees
Ladder bar cars 2 - 3 degrees
Four link cars 1 - 2 degrees

As an example: On a leaf car, if you had say 3* on the shaft and 8* on the pinion you would be ok. 8*- 3* =5*
The whole idea is to get your car as close to zero angle under load as you can. You can use wedges to change the angle on the pinion. Mopar sells em.

Thrumming??? Your d'shaft is balanced...right?

For more help go to: http://www.moparts.com/~carl/captain/dsa.htm

I hope this helps.
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  #4  
Old 01-18-2003, 03:13 AM
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Mopar Maniac,

It seems you may want to check out the link I have provided.
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Old 01-18-2003, 12:26 PM
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:shock: Uhhhhhhh

Yup, driveshaft was balanced at 3,000 rpm. Will check out the link and see what's there (am at work and don't have a lot of time, will reply later ) 440cj
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Old 01-18-2003, 02:01 PM
Mopar_Maniac Mopar_Maniac is offline
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thecudaguy...

That is the site I used for setting mine up.

I answered the question assuming that he understood the basics. You know what they say about the word ASS-U-ME?

Your answer was much better thought out than mine.


Thanks for following up with the link. I lost that link when my old computer crashed...now I have it again.

Later,
Mopar_Maniac
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  #7  
Old 01-18-2003, 02:24 PM
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I hope I did'nt come off as a know it all. I figured you knew what you were talking about when you mentioned your tranny angle. That is the simplified version.

At least with pics he will know exactly what to do.

Take a look at one of my posts and give me your opinion on it. It is in the drag race forum under "can't get no satis-traction".
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Old 01-18-2003, 11:47 PM
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Wink Well alrightythen...

Thanks, guys, Tuesday Lord willing I will visit a chassis shop that will look her over and let me know what I really have regards current angles, etc. I will post results then. 440cj
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Old 01-18-2003, 11:53 PM
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Don't have access to an angle gauge?.....
you'd save a heap o' cash, boy!! :baby0:
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  #10  
Old 01-19-2003, 03:01 AM
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Gripe Nope..

No guage and what's worse...no TIME. I will have to entrust the chassis guys that set up my engine builders' cars to find/fix her. At least they have tons of experience and are fair on the pricing. I hope. Maybe. Hmmmmmmmmm.... 440cj
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  #11  
Old 01-19-2003, 07:36 AM
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Blah..... Well good luck. Let me know how you make out.
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Old 01-19-2003, 11:50 PM
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Default more

I just want to say there is more to this subject than is covered in the link. The 5-7 (nose down) deg recommendation mentioned is for drag race apps. Alot of the members here may be dealing with non oem drivetrain combos and/or swap installations. The main thing to keep in mind, is the centerline of the driveshaft and the C/L of the pinion should be parallel to start with, then you can adjust the nose down position to suit your app.
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  #13  
Old 01-20-2003, 12:00 AM
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Yessssss. If you had read the article that's pretty much what it says. But I believe he also wanted to know what he had for angle now.
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  #14  
Old 01-20-2003, 02:28 PM
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OK, then just say it's impossible to predict what angle you have just spouting out a hundred variables. My point is that dialing in 5-7 deg nose down nor reading your article a hundred times, does absolutely nothing to address the issue of parallel centerlines in plan view. The article only looks at things from an elevation perspective. If somebody has swapped in components and fabbed tranny mounts, or engine mounts, there exists a strong possibility the centerlines are not parallel in plan view anymore.

We haven't even touched on the proper length of driveshaft and checking the d/s for straight, let alone dynamic balance.
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  #15  
Old 01-20-2003, 07:11 PM
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The two angles you are reading, are drive shaft and pinion. You subtract these two angles to come up with what is favorable.. which is 5-7 degrees, in 440cj's case. You do not put your pinion angle @ 5-7 degrees down. These angles that we are talking about are in relationship to the ground. That is the PARALLEL.
Which is what I think you are trying to say?

This, by the way, should never be done on anything but a perfectly flat surface. If you have ever been to a national track you may have seen a concrete pad down in the pits. This is exclusively for chasis tuning not for a quick oil change. There is a reason for this...Parallel.

Anyone who has not taken into consideration the angles of relationship relative to the trans. and the rear end when doing a swap like that should probably stay away from chassis tuning.

To quote you......
"We haven't even touched on the proper length of driveshaft and checking the d/s for straight, let alone dynamic balance."

How does this relate to drive shaft/pinion angle? An angle of 3 degrees will still be 3 degrees even with a 10 ft. bent driveshaft that is not balanced.

If I have come across as not knowing what you are talking about....you're right.

To 440 cj, it's not that complicated. It is a methodical process that must been done step by step.

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Old 01-21-2003, 06:08 PM
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Once you have eliminated the bells, whistles, smoke and mirrors it is the difference, expressed in degrees, between the centerline of the pinion and the centerline of the driveshaft. The ground plane does not enter into the equation, just the pinion and driveshaft.
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  #17  
Old 01-21-2003, 06:28 PM
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jelsr,
Thank You!
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  #18  
Old 01-21-2003, 07:19 PM
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leaf spring pinion angle is 5-7 degrees. the tranmission angle should also be with half a degree of whatever the pinion angle is.this creates the working angle . if not withing half a degree,driveline vibration can occur.
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  #19  
Old 01-22-2003, 12:40 AM
mauve66 mauve66 is offline
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now this is something that i've been trying to decide which way to go on.....

stock mountings...
383, 727, 8 3/4

changes.....
GV O/D
5 spring leafs on left
7 spring leafs on right
driveshaft - 38 1/2 inches
with the car on a level surface (torsion bars still need to be cranked up a little bit though) the end of the O/D seems to be 0* and the front of the pinion seems to be 1* down. Will the torsion bars change these?? the only semi-flat area to do the measurements were the flat sides of the u-joints where the
u-bolts go through the yoke. Is this flat enough? I'm using the angle finder from Lakewood Engineering for their suspension set-ups. Is there a better area to do this measurement from??
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Old 01-22-2003, 12:45 AM
rustycowl rustycowl is offline
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Default last time

when I said 'plan view', imagine you are floating 50' above the car looking down, the car body is almost invisible and you see only the drivetrain. The centerlines still must be parallel when viewed in this way. Life is 3-d. If you can't see it now, I 've done all I can, you'll need to read some service manuals.
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Old 01-22-2003, 01:01 AM
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Quote:
Originally posted by mauve66
now this is something that i've been trying to decide which way to go on.....

stock mountings...
383, 727, 8 3/4

changes.....
GV O/D
5 spring leafs on left
7 spring leafs on right
driveshaft - 38 1/2 inches
with the car on a level surface (torsion bars still need to be cranked up a little bit though) the end of the O/D seems to be 0* and the front of the pinion seems to be 1* down. Will the torsion bars change these?? the only semi-flat area to do the measurements were the flat sides of the u-joints where the
u-bolts go through the yoke. Is this flat enough? I'm using the angle finder from Lakewood Engineering for their suspension set-ups. Is there a better area to do this measurement from??
Thats a good spot. Put a socket in the u bolt on the joint if you cant get at it . This will still be the same angle. It's just an extension. Know what I mean? I welded a tiny flat bar to the side of the carrier parallel to the pinion. It's easy to get at, the guage fits perfectly, and it's my car! Crank your bars, you raise the front, which raises the tranny....Yup.
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Old 01-22-2003, 01:09 AM
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Default

.
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  #23  
Old 01-22-2003, 01:12 AM
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Default Re: last time

Quote:
Originally posted by rustycowl
when I said 'plan view', imagine you are floating 50' above the car looking down, the car body is almost invisible and you see only the drivetrain. The centerlines still must be parallel when viewed in this way. Life is 3-d. If you can't see it now, I 've done all I can, you'll need to read some service manuals.
Yes I do understand. Your drivetrain must have a common centerline. If you have messed that up......drop the wrenches and buy a boat.
This does not affect angle relationship when setting pinion angle. It is of coarse, very important. It just does'nt have anything to do with what we are talking about.
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Old 01-22-2003, 01:49 AM
rustycowl rustycowl is offline
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Default excuse me?

I believe the original post mentioned a problem with a 'thrumming sound', that sound can eminate from a host of problem sources which I mentioned. I believe you have concentrated on just one of them.
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Old 01-22-2003, 11:31 AM
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In regard to the front angle, the book says it can be any angle, but not zero. On my circle burner the rear is 4-5 deg. nose down and the front is only about 1 deg. up.
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  #26  
Old 01-22-2003, 07:57 PM
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Default Re: Ok, who has actually checked their pinion angle...and on what combo?

Quote:
Originally posted by 440cj
My '74 Dart is in need of a proper driveline alignment. What pinion angle should a 290 rr wheel 360/727 go with? HD rear springs, 240 x 60 x 14's in rear, front torsion bars cranked up to make car level. New motor mounts, tranny mount, front end bushings and re=arched rear springs with new bushings. I have a thrumming problem that I am convinced is due to wrong pinion angle. HELP! 440cj
He asked what his pinion angle should be. I think I answered him honestly.
As for the thrumming, if he thinks it's from an incorrect pinion angle he may well be right or not. I have not driven his car. He would have more of a diagnostic advantage than any of us.
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  #27  
Old 01-22-2003, 08:06 PM
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440cj 440cj is offline
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Biggrin "HE" is back...

So far I have discovered a "wobble" in da harmonic balancer's outer ring, have the new "stock" balancer in hand and will hopefully get it installed sometime this next week. Hopefully that solves the problem as the engine angle and driveshaft angle see ok... Hmmmmmmmm 440cj
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Old 01-22-2003, 08:09 PM
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Beautiful....hope that solves the prob!
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Old 01-22-2003, 08:31 PM
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rolleyes2 Ya, me too...

So far I have spent $900.00 and haven't fixed the original problem YET! 440cj
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Old 01-22-2003, 08:40 PM
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OUch! I Know you said the shaft has been balanced....but check and see if the shaft pooped the weight.? You never know. Is this
noise rpm related, the faster you go the worse it gets?
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