Carb level or eng.

[Dano51]

I'm putting in new motor mounts. Do you level the carb intake or the motor? If you level carb intake the motor isn't level. Dan

[dwcsr]

The top of the manifold where the carb bolts to should be level front to back side to side.

[mknittle]

The engine doesn't care about the angle ,But if the carb is at an angle the float level will be off then add a hill and flooding could occur.

[Root2812]

I was thinking about this the other day. I have never swapped an engine.

So why is it that some shows on tv tell you to tilt the motor back 3 degrees to line up the tranny to the rear end but you guys say it needs to be level?

I thought about this for a while. Is it just that 3 degrees is hardly anything?

[dwcsr]

When the manifold is level at the base the crank is at 3 - 5 degrees. Almost all GM manifold are built that way.

[DransportGarage]

Originally Posted by Root2812

I was thinking about this the other day. I have never swapped an engine.

So why is it that some shows on tv tell you to tilt the motor back 3 degrees to line up the tranny to the rear end but you guys say it needs to be level?

I thought about this for a while. Is it just that 3 degrees is hardly anything?

Focus on that 3-degree orientation of the tranny tailshaft, driveshaft and pinion. No hot rodder in the 60s ever had an engine problem beyond a carb float adjustment because he flipped his leaf spring shackles to get that "stinkbug stance" (or heaven forbid, put in some 15" shackles!); however, a ton of people have had vibration problems (and u-joint ear problems) because of driveshaft orientation. We probably have control of maybe +/- 5 degrees without digging holes through the firewall or dragging the drivetrain on the ground, and we drive up and down hills all the time that are +/- 30 degrees.

[mknittle]

Originally Posted by DransportGarage

Focus on that 3-degree orientation of the tranny tailshaft, driveshaft and pinion. No hot rodder in the 60s ever had an engine problem beyond a carb float adjustment because he flipped his leaf spring shackles to get that "stinkbug stance" (or heaven forbid, put in some 15" shackles!); however, a ton of people have had vibration problems (and u-joint ear problems) because of driveshaft orientation. We probably have control of maybe +/- 5 degrees without digging holes through the firewall or dragging the drivetrain on the ground, and we drive up and down hills all the time that are +/- 30 degrees.

That is why I mount the engine/trans before the rear end. this has worked for me for the last 35 35 35 years.

[booger1949]

i installed my motor level an i have no problums with vibrations at all, go pop your hood on your new truck an c if your motor is runnin up hill

[JumboAMONGus]

i always heard put the motor in and put angle finder on top of intake and tilt it back about 2-3 degrees and thats it ,,no more then 5 degrees then you get driveline problems but that was on 4x4s ,,2 wheel drive i read and had friend he says just shoot for 2 degrees so sounds same ,,ive done a fj40 conversion to v8 and same on that most go for 3 degrees ,

[mknittle]

Don't forget with leaf springs the pinion will rotate upwards 1 to 2 degrees at cruise speeds.

[paintman]

Originally Posted by mknittle

Don't forget with leaf springs the pinion will rotate upwards 1 to 2 degrees at cruise speeds.

I thought the pinion raises upwards upon accleration and then returns to the preset angle upon reaching cruise speed.

[cajundragger]

Originally Posted by paintman

I thought the pinion raises upwards upon accleration and then returns to the preset angle upon reaching cruise speed.

when the torque input is constant it still lifts the pinion a bit. 1-2° is usually rule of thumb.

Originally Posted by booger1949

i installed my motor level an i have no problums with vibrations at all, go pop your hood on your new truck an c if your motor is runnin up hill

it is. they all are at 3° back relative to the frame. the kicker is most to all the stock trucks have a good rake to them. just about in the neighborhood of 3°.

[paintman]

Originally Posted by cajundragger

when the torque input is constant it still lifts the pinion a bit. 1-2° is usually rule of thumb.



it is. they all are at 3° back relative to the frame. the kicker is most to all the stock trucks have a good rake to them. just about in the neighborhood of 3°.

Not to split hairs or anything....I'm just a simple minded painter, But if its true that your pinion is always at a 1-2 degree incline (beyond the 3 set 3 degrees), even at cruise speeds, wouldn't it then make more sense to set the pinion at only a 1 degree incline on the initial mock up?
Reason being....if the tail shaft and the pinion are already at a 3 degree set alignment, say 3 degrees, that means at cruising speed your pinion would raise the 1-2 degrees additionally and then it would be at a constant 4-5 degrees? So your tail shaft and pinion never really are matched perfectly?
I'm sure this topic has been covered at length all over the net, but hey what the hell else do us gear heads have to talk about in the dead of winter?