0* Engine Angle

[Ivygreen65]

I have set my differential (97 TBird 8.8 IRS) and it has 0 degrees of angle - the pinion flange is square to the frame rails. To get 0* of pinion angle, I have my engine / transmission centerline parallel to the frame rails. Am I going to have any issues with not having any down angle with the engine / transmission centerline? I’m used to 2-3 degrees of down angle on other cars, but they were solid axle cars production cars. The one concern that comes to mind is the intake manifold having +/- 3* angle at the carb flange. Is this a concern or non-concern?

[mthrockmorton]

Do you have a handle on the rear axle angles at this point? May also be worth checking the angle (if any) that may be present at the mounting surface for the carb. (Some mfg compensate for engine angle here to level the carb. I consider 3 degrees a bit steep for u-joints...I strive to keep driveshaft angles at 1 to 2. 3 at the carb is ok ish...and should it become problematic, a tapered spacer under the carb is an option...

[olddog]

If you have a perfectly straight drive shaft with no angle in any plane, the U-joint caps will never move. Therefore the needle bearings will never roll, and they will wear flat spots. I think 2* or 3* is the minimum angle recommended by the joint manufacturers.

[bkozlow]

The manifold problem is solved in one of two ways, first thing you should do is determine how much hood clearance your carb is going to have. Clearance determined, you can add a tapered spacer, like 1/4" to 1/16th in or what ever combination to give you a level carb. The other alternative is to have the manifold milled, so as to give the same results, a level carb. I would suggest you add some angle to the engine, if hood clearance is available because one thing you have not mentioned is OIL DRAIN BACK. The level head will give you, even with front and rear drain backs puddling in the head.

Bill K

[Ivygreen65]

I have not gotten to measuring axle angles yet. I decided to switch from a toploader to a T5, so I'm fabricating a new transmission mount and I want to make sure driveline angles are on parallel planes. The transmission centerline is about 1" higher than the differential pinion center-line, so there will be a driveshaft angle in the horizontal plane - I just haven't measured it yet. There will be very little angle on the vertical plane. My main question is - are there any engine related issues that arise from a zero degree (horizontal) mounting?

[Ivygreen65]

Originally Posted by bkozlow

I would suggest you add some angle to the engine, if hood clearance is available because one thing you have not mentioned is OIL DRAIN BACK. The level head will give you, even with front and rear drain backs puddling in the head.

Bill K

Thanks, Bill. That's the sort of info that I was curious about. I'm assuming that if puddling were to be an issue, it would be when the car was at rest?

[olddog]

Whatever the depth of the puddle in one end the puddle will get deeper with a running engine and the more rpm the deeper the puddle. I would guess about 3 GPM is pumping up there at high rpm, but that is a long story.

[Gaz64]

And another reason for the angle is to help air bleed out of the cooling system, which is generally done on a flat workshop floor. Some cars need to face up hill to help the air bleed out.
Gary