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Topic Review (Newest First)
05-08-2019 07:42 PM
chasracer
Quote:
Originally Posted by ericnova72 View Post
Engine angle in the chassis means nothing really....all that has to jive together is the trans output and the pinion input.

That's within reason...can't have the engine/trans centerline down 10° and pinion up 10° and have it live for long...to much working angle on the u-joints.

Another good place to check engine/trans angle is the face of the harmonic balancer.

Fuel injection makes it even lees important what the intake top angle is, carbs with floats are the only thing affected there by too much angle.

Exactly ^^^ But you also cannot have a zero angle at both ends of the driveshaft either. U-Joints need a slight angle to work correctly.
05-08-2019 05:59 PM
ericnova72 You don't want me to say it...but adjustable upper arms or 1/8" longer lower arms for the rear suspension.

The reference of pinion angle and horsepower is a valid one.
05-08-2019 03:47 PM
greenmonster1970 Howdy everyone. Ive still been playing with the angles and reading more articles on pinion and driveline angles. Found this cool tool at spicer.com. You enter the degree and direction (up/down) of the engine, the driveshaft and the pinion. You hit calculate and it shows you the working angles for trans -> driveshaft, and pinion -> driveshaft. If youre under 3 degrees for both of them, you're all set.

On my car, I shimmed the trans/mount up. I now have 5 degrees at the engine, 5 at the back of the trans and 5 at the pinion. That gives me 0 degrees working angles (according to the tool at spicer.com. From what Ive read, you must have at least a half degree. The problem I think I have now is that with the trans shimmed all the way up, and basically a straight line, I have no room to compensate for the pinion tipping up under acceleration. I can try to fit another shim up there but the trans is pretty close to the floor (tunnel). Any ideas? (please dont say adjustable upper rear control arms.... lol).

I even read one article where one guy based pinion angle based on horse power. The more horse, the more negative angle at the pinion.
05-06-2019 04:40 PM
55 Tony That's good to know Eric. I see he has a Holley Dominator, the picture on summit appears as if it's angled but that's just a guess. The blown up pic looks angled, but the 360* view makes it look flat so ???
05-06-2019 02:11 PM
ericnova72
Quote:
Originally Posted by 55 Tony View Post
If your intake manifold is showing 8 degrees, that's WAY off. The intake is normally made at an angle 3° to 5° so when the engine is tilted down in the rear, the intake (and carb) are level. Try leveling the intake and re measuring the transmission with a yoke in it to see what angle you end up with.
This is not completely true...factory manifolds, and many aftermarket manifolds are angled to account for engine tilt in the chassis so as to allow a carb to sit level....but a lot of the racier single plane and air gap manifolds often are not . They figure the engine is being set low and flat in a race chassis and doesn't need any angle compensation for carb mounting /float bowl level.
A lot of those "race" intakes end up on stock location engines.

Quote:
Originally Posted by greenmonster1970 View Post
Thanks Tony.... Im going to do a little testing with the shims tonight and see what I get. Are you saying the intake by itself isnt level across the carb opening?
Depends on the intake.

With a flat cut intake, showing 8° at the carb pad means that if the engine is tilted back up 3° you would end up with the crankshaft centerline near the factory 5° angle.
05-06-2019 11:26 AM
greenmonster1970
Quote:
Originally Posted by 55 Tony View Post
If your intake manifold is showing 8 degrees, that's WAY off. The intake is normally made at an angle 3° to 5° so when the engine is tilted down in the rear, the intake (and carb) are level. Try leveling the intake and re measuring the transmission with a yoke in it to see what angle you end up with.


If you plan on some type of traction bars on the rear, then you want to get close to the opposite of the transmission angle and just allow a degree or so for spring wrap up. CalTracs actually work by using a little spring wrap up, so they can have a couple degrees to allow for. Ladder bars allow very little so you don't really have to allow for any spring wrap up.
Thanks Tony.... Im going to do a little testing with the shims tonight and see what I get. Are you saying the intake by itself isnt level across the carb opening?
05-06-2019 11:24 AM
greenmonster1970
Quote:
Originally Posted by RWENUTS View Post
What’s the angle on your driveshaft?
I didnt check the angle of the drive shaft. I will when I get home. I will post here when I do that. Thanks!
05-06-2019 10:02 AM
55 Tony If your intake manifold is showing 8 degrees, that's WAY off. The intake is normally made at an angle 3° to 5° so when the engine is tilted down in the rear, the intake (and carb) are level. Try leveling the intake and re measuring the transmission with a yoke in it to see what angle you end up with.


If you plan on some type of traction bars on the rear, then you want to get close to the opposite of the transmission angle and just allow a degree or so for spring wrap up. CalTracs actually work by using a little spring wrap up, so they can have a couple degrees to allow for. Ladder bars allow very little so you don't really have to allow for any spring wrap up.
05-06-2019 09:32 AM
RWENUTS What’s the angle on your driveshaft?
05-06-2019 09:04 AM
greenmonster1970 Thanks guys....
05-05-2019 07:06 PM
ericnova72 Sure, shimming up the tail would give to the same effect as tipping the pinion down for allowance of axle wind-up and pinion climb.
With the big engine you've got I'd definitely want some 2-3° pinion down relative to the trans to allow this....so shimming the trans tail up 2-3° gives you exactly what you want to have.
05-05-2019 06:56 PM
greenmonster1970 Eric...this is only an issue for me cuz the engine is visibly tilted. If it didn’t look that way I wouldn’t care. That’s when I put the gauge up on top of the intake and saw 8 degrees. I was hoping the pinion angle would be off too but both the trans and the rear pinion are at zero. So I’m assuming that’s a straight line between the 2. So I think if I can shim up the tailshaft and bring the engine more level while keeping within tolerance on the pinion angle, I’d be ok?
05-05-2019 06:33 PM
ericnova72 Engine angle in the chassis means nothing really....all that has to jive together is the trans output and the pinion input.

That's within reason...can't have the engine/trans centerline down 10° and pinion up 10° and have it live for long...to much working angle on the u-joints.

Another good place to check engine/trans angle is the face of the harmonic balancer.

Fuel injection makes it even lees important what the intake top angle is, carbs with floats are the only thing affected there by too much angle.
05-05-2019 06:24 PM
greenmonster1970 Eric... yes I was too wondering if the pan was a safe place to check the angle. That’s why I checked the angle across the opening of the tail shaft where the yoke slips in.
05-05-2019 06:22 PM
greenmonster1970 Holley Dominator. Like I was saying, I could shim the tail of the trans up. The crossmember came with shims. This should bring the angle closer to level on the engine.
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