My rearend is permanently mounted at 3* up. I can mount my motor/trans at 3* up or level. 3* down really isn't an option. Is it possible to mount the motor/trans at 3* up or level and not totally screw up the harmonics of the driveshaft?
The crankshaft and the pinion need to be parallel in both planes but not concentric. A 1 -3 degree angle on the DRIVESHAFT is ideal.So to answer your question in simple terms,no.
Very very few ever mount the engine level, but I've never ever heard of anyone mounting it so the tailshaft of the trans is pointing up! Is that what you're saying? And you can't mount the engine/trans with the trans pointing down 3*? Can you explain why?
Pardon my ignorance. Is that 'no' I can't mount the motor/trans in that configuration or 'no' it won't screw up the driveshaft harmonics?
No I really can't mount the trans pointing down. Ideally, I'd like to have it pointing up. If I mount it pointing down, combining that with the rake of the ch***is the car is gonna look like it's bent in the middle!
Sorry...I was asking a question. Is it that you just can't mount the engine/trans nose-up tailshaft down? And why is that? Crossmember and/or trans tunnel in the way?
I see. But most guys mount the engine 3* tailshaft down regardless of the angle of the ch***is, 'cause most intake manifolds are milled so that when you do that, the carb ends up level. If you mount the engine with the tailshaft up at 3*, the carb is going to be sitting 6* forward. Just realized...you may be saying that you're building a g***er with a nose high stance? Regardless, the angle of the engine trans is always measured in relation to the ground, not the ch***is. And it's almost always 3* down at the tailshaft.
Still curious why you can't mount it normally. Anyway, you might get away with a couple degrees off, but it's best to get it parallel with the pinion shaft.
I believe this is what you are asking for? http://www.roddingroundtable.com/tech/articles/driveline.html
Don't confuse ( add, subtract, mismeasure) the rake angle and driveline angles. Draw the **** up on graph paper
I mount my engine so the carb base is level or close to it. Then I set the rear to match the rear to suit.
So, according to the above it is possible to mount the motor/trans with the tailshaft 3* up and still have the rear mounted 3* up. Am I seeing this correctly?
Yes I think so. Not sure about having the engine/trans pointing down in front as far as oil pressure and stuff.
No. I don't know why they label that image "correct examples"...'cause only the bottom pic is correct. Top pic is totally wrong. You'd have vibration/binding, maybe worse. The engine/trans and the pinion have to be at least real close to being parallel to each other. Not on the same plane, but parallel. Like this ----- ____
why don't you just turn your pinion down if your engine is stuck being up? .... they gotta be parallel.
If you read the text of the link I posted: The angle of both U-Joints must be equal. This is generally achieved by making the engine and pinion parallel. For example the gearbox and pinion may both be horizontal but at different heights. A really thorough investigation also shows that if the angles are equal but opposite, phase correction still exists, but this is generally only of interest in shaft-driven machinery, or trucks with extremely high lift. In such an exmple the engine could be horizontal, the drive sloping down at 5 degrees, and the pinion pointing up at 10 degrees. It is not necessary to have the yokes parallel, they can be equal but opposite and they will cancel the speed variation in the drive shaft the same way as parallel yokes. I have seen trucks like this.
Ok, what's the rake of the car? Lets say the rake is 3* nose down *** up. Now set your engine square to the ch***is for firewall aesthetics - the CL of trans should be parallel to the rake or 3* tail up. Should work well with your 3* pinion. Ignore the rake for a second and Set your frame to level. Set your engine at 3* down at the tail. Add the rake back in and you'll be at zero on the Trans. This would be your best bet but you'll have to move the pinion to Zero . As long as your drive shaft is either off set up and down or off center front to back. Take your raked ch***is and set your engine at 3* down at Trans. That's gonna be 7* kink look at the cowl. And what you are trying to avoid. Draw it up and you'll see. Having angles equal is correct, they can be parallel or intersecting.
OK y'all. Here is how we look at and build or make corrections. First off, always look at the car from one side, the side we know in the USA as the common driver's side, left side steering. Then view the centerlines through the crankshaft/transmission, the driveshaft, and the pinion as up or down from the same aspect. If the front is higher, it's up. If you're going to build your ch***is correctly, you'll have the engine set with approx. 3 to 5 degrees up as vehicle manufacturers do this, with your vehicle setting on the ground with intended rake and tire sizes. Then, if with a one piece and two u-joint driveshaft, the pinion is parallel or within 1 degree of parallel to the crankshaft. Parallel or within 1 degree. If so, the u-joint angles will take care of themselves if everything else isn't built so extreme to make one of the u-joint angles extreme. That's when you have the engine at normal angle and the pinion pointed down toward the driveshaft. This is where it gets more critical. If you do this, you need to have a good built or dummy driveshaft to take angle measurements. You need to know how to compare angle measurements to get them correct. Correct comparison if a two u-joint driveshaft? The angle through both u-joints are within one degree of angle of each other. Engine nose up 3 degrees, driveshaft 0 flat, pinion 2 degrees nose down=will work just fine. Engine nose up 3 degrees, driveshaft nose down 3 degrees, pinion nose up 3 degrees=should work just fine. Simple? Keep pinion angle and engine angle at the same at***ude and within one degree of each other. Don't use the bottom of an auto transmission pan as where to find angle. Don't use a rough casting for a reference point either. Use known machined surfaces parallel or perpendicular to the crank or pinion centerline.
Rake or tire size shouldn't matter to your driveline angle. Start first by leveling the frame the tail shaft should be pointing down 3* and your pinion should point up 3* with no more than 7* total between the two. According to you have 3* up on your pinion which is correct. That is how production cars are set from the factory according to Street and Performance. Check out their website and look at their engine tech under driveline angles they explain in great detail with pics.
Ch***is rake dictates how the engine sets. Tire size affects ch***is rake. Ch***is design dictates everything else, be it a custom, a hotrod, a ratrod, or a big *** 4x4. Been building driveshafts and correcting ch***is problems since 1989 for a living, and still today. Built my first hotrod ch***is starting in 2002.
Screw it! I'm gonna mount the motor/trans 2* down. That should make it 1* off but it sounds like that'll work. I can make adjustments to the body to make the car look 'not so bent'! The frame has a 5* rake but all angles are relative to the level garage floor.
A picture is worth a thousand words and a video is worth a million: http://www.youtube.com/watch?v=gmV4qwLfOMY
tail shaft angle maximum 3* DOWN..pinion angle maximum angle 3*UP ...STANDARD RULE... ..less chance of vibration, binding and u joint longevity.At engine end carb plenum rake on intake manifold make up difference ,and at driveline pinion end, spring torque is also taken into consideration.. End of story..common sense always prevails.. draw a picture..
It seems like this comes up every week - Maybe this link should be a sticky - Permanently! This should answer all questions http://www.iedls.com/asp/admin/getFile.asp?RID=5&TID=28&FN=PDF
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