Okay, this should be an easy one. When mounting an engine in a car to be run on the street, the rule of thumb has been to mount the engine such that the carb(s) would be level. In the case with the Hemi I'm building I'll be running a 6x2 log type manifold that is parallel to the engine, with no angle. In my mind this tells me the engine will also sit level and in-turn the output angle of the transmission will also be level. Now, from what I read on here and other places (although argued frequently) the pinion angle of the third member should be parallel which is going to put the axle level as well. I should have enough of a difference in height to give the drive shaft the angle it needs, but just want to make sure that under normal street driving conditions that zero angle at the rear is going to be substantial. Should I ***ume level carbs and mount that Hemi level? If so, will I be okay with zero pinion angle at my third member? Any reason a Hemi can't be mounted level (fluid flow, etc.)? Thanks guys!
Scooter,, When We Mounted Mine In The Sport Coupe I Used A Stock Manifold To Get The Stock Engine Angle. With All The "correctness" Aside .... If You Mount The Engine Level In The Frame Not Only Will It Look Funny, But Once The Car Is Done, If You Have Any Rake, The Engine Will Be On A Down Hill Tilt Towards The Front Of The Car. Get A Stock Intake And Set It Up With The Stock Manifold Being The Plane. Level The Carb Base Will Give You The Engine Angle You Want.
I'm not sure what you mean about ZERO pinion angle. Somewhere you'll need about a degree and a half. That'll be the difference between the driveshaft tube and the output shaft of the trans, and the driveshaft tube and the pinion gear. Any less, and your u-joints don't get to work, and keep the grease circulated. And as you approach 4 degrees, you'll experience vibration in your driveline
They say to keep the trans/crankshaft centerline parallel to the pinion (top of my drawing), which is OK in a perfect world (normal cars). When we "Z" the rear frame 8-10 sometimes 15 inches all bets are off (lower part of my drawing), as this radically kinks the u-joints way beyond their intended range. So the parallel thing no longer applies. This, something often gets overlooked. Hope this helps your end result.
This is the argument I hear all the time. I fully agree those u-joints need to move and work in order to keep themselves lubricated. I worked in an industry for awhile with 6" driveshafts that had u-joints on them and several of them were installed incorrectly not allowing the grease to work itself into the rollers and cups... the result was catastrophic failure and ultimately destroyed very expensive components not to mention could have killed someone... This is why I asked though.... I was thinking that rear end would need a little bit of an angle at least to account for suspension travel. 1.5 degrees came to mind. Would that be 1.5-degrees point up, I ***ume? I will be running a 4-bar rear. DE SOTO brotha'.... I agree might look sorta' funny. That's why I bothered to put this thread up. I was concerned for that very reason. I haven't seen too many engines sitting level... but if I don't, the carbs will not be sitting level. They will be leaning back. I will not have any rake to the car (***uming I've done my homework and I'm not screwing up my ch***is and suspension setup as I build). How much can a Holley 94 be sitting at an angle before I have float and flow problems? Thanks for the replies guys! keep 'em coming.
No matter how you point the engine, up or down, the angle of the front and rear joints needs to be the same and within the design parameters of the joint. Extra down (not up) pinion angle is for leaf springs to account for axle wrap under power - it's more a race thing to make the joint angles the same under power. Not needed with your 4 link. One other thing, if your rear has the pinion off center, that may give you all the angle you need to "work" the joints.
Check out this thread - mostly good information. http://www.jalopyjournal.com/forum/showthread.php?t=166826&highlight=pinion+angle
DE SOTO brotha'.... I agree might look sorta' funny. That's why I bothered to put this thread up. I was concerned for that very reason. I haven't seen too many engines sitting level... but if I don't, the carbs will not be sitting level. They will be leaning back. I will not have any rake to the car (***uming I've done my homework and I'm not screwing up my ch***is and suspension setup as I build). How much can a Holley 94 be sitting at an angle before I have float and flow problems? SCOOTER, ILL TELL YA WHAT I DO WHEN INSTALLING AN ENGINE, BUT I WILL NOT GET IN A ******* MATCH WITH ALL THE MATHEMATICION'S ON HERE. I SET THE 389 PONTIAC IN MY TRUCK, THE DeSoto IN MY SPORT COUPE, & THE FLATTY IN MY KIDS '27 ROADSTER ALL THE SAME WAY.... I PUT ON A STOCK MANIFOLD, AND SET THE ENGINE PLANE TO THAT, AS IT CAME FROM THE ORIGINAL CAR, THE WAY IT IS MENT TO SIT IN THE FRAME............... THEN SET THE REAR END TO THE COMPLIMENTERY PINION ANGLE. ALOT OF THESE CARS THESE ANGLE GO OUT THE WINDOW WITH LOWERING OF THE CAHSSIS & SUCH.. REAR GETS HIGHER THAN TRANS CENTER LINE, ETC. YES, WHEN YOU SET THE HEMI AT STOCK ANGLE (level at the carb surface) AND RUN THE LOG MANIFOLD THE CARBS DO LEAN BACK, BUT NOT ENOUGH TO HURT THEM, THE MANIFOLD WAS DESIGNED TO BOLT ON AN ENGINE IN A STOCK CH***IS, ALSO WHEN THE CARB IS LEANED BACK A LIL ITS COVERING THE JETS ANYWAYS SO NO PROB. MY DeSoto IS THAT WAY & I HAVE NO PROBLEM IN THAT AREA. I KNOW ALL THE GENIUS'S ON HERE ARE GOING TO **** ME ALL UP .... BUT DONT OVERTHINK THIS. YOU KNOW THE BASICS AND IF YOU SET THE ENGINE AT STOCK ENGINE ANGLE AS THE ORIGINAL CAR, & SET PINION ANGLE TO CORROSPONDE.. YOU WILL BE FINE
blown49, Yep! Seen that! Very informative! Groucho, yeah, sorry! I posted right when you were posting that picture. I'm running a 48 ford banjo rear that's been converted with a Winters Quick Change, so the yoke is offset down I think 3 or 4 inches. The frame and everything attached to is being designed from scratch, so everything is being designed as a system to work together. I can do whatever I want since I have a clean slate. Not modifying something that's already existing. 4-bar can be at any location I want on the frame and/or axle, panhard, pinion angle, engine mounts and angle etc. I want to get the optimum for a street driven car with a moderate amount of HP and a very light overall weight. So.... we've covered pinion pretty well and I think the diagram above sorta' says it all, so what about the angle of the Hemi? What should I do? Stock it was mounted at an angle as suggested by DE SOTO above. Do I say screw it and just let the carbs lay back a little? DE SOTO... can you put an angle finder on your block or something to give me the angle that you found? I believe it should be the same for a Chrysler. BTTT
LOL! Funny how people get worked up... Dude, that all sound completely acceptable to me! I'm definitely one to try and stay with OEM specs on certain things. Engineers designed motors to sit a certain way (for oil flow, water flow, whatever it may be) and I don't want to interrupt that. Your method of installment seems very reasonable. This is great info guys! I like how this is coming together! BTW... here's a picture of someone's Chrysler in a Model A. It's definitely obvious it's not sitting level and it's also running a 6x2.
PUT A STOCK MANIFOLD ON YER ENGINE WHEN YA GET READY TO PUT IT IN THE CAR. ANGLE FINDER ON THE CARB MOUNTING SURFACE, SET THE ENGINE IN WITH THE ANGLE FINDER (or a common level) ON THE CARB MOUNTING PAD AND SET IT LEVEL. THIS WILL PUT THE ENGINE AT FACTORY SPECS ANGLE LEANING BACK, THE WAY THE ENGINE WAS INTENDED FOR USE. IS THAT CLEAR ? MY ENGINE IS OUT ... AGAIN ... SO I CANT TELL YOU WHAT MINE IS, BUT IT DONT MATTER IF YOU SET YERS IN A ZERO or LEVEL AT THE STOCK CARB PAD
Don't know about the hemi in question but most american motors range from about 3 to about 7. 3 or within a few minutes of 3 is pretty common for mopar motors.
Yes the parallel thing no longer applies in certain applications, but what does apply is keeping the working angles the same from the trans to driveshaft and rear axle to driveshaft. The theory goes that so long as you keep the angles complimentary - you will effectively cancle out the speed variations in the driveshaft. So what that's saying is you could have the trans angled 2 degrees up and the rear angled 2 degrees up (motor out by 4 degrees in relation to rear) and you'd STILL be following all the rules because the "parallel rule" is a poor way to say "complimentary" angles.
Just to make it easy think about a 9" Ford rearend where the pumpkin is offset in the rear end. Looking from the top the driveshaft is not straight in the car but the angles on the front and rear universals are complimetry.
Scoot, If your running parallel leaf springs and no traction bars normally you droop the pinion just a touch, that allows for your springs to wrap a bit when you're plowing with it. If you can keep your pinion angle from changeing make your pinion parallel with your crank center. Done deal. Where a lot of guys run into trouble is when they get extreme kick ups and the pinion center line is way above the crank center line. If you put your u joints in a major bind you will be changeing them on a regular basis, it gets magnigied a ton if your running a short drive shaft. it that case you will actually be better off to fudge it a bit and droop your pinion angle to allow your u joints not to bind.
Will be parallel 4-bars with a transverse model A spring, so there will be no change in pinion angle through the suspension travel. Also, the engine and trans sit with only about a 3 or 4 inch differential in height with about a 32 inch long drive shaft. I think things will be reasonable and the geometry should be pretty nice. Unfortunately my tunnel has to be a little tall with a 6-speed in there, but who said hot rods are practical!!? Thanks guys.... Now, if anyone knows the stock angle of the engine, p*** it on!
New day.... I still need that angle for the stock mounting position. Does anyone have a stock manifold they could just sit on a table level and measure the angle of the carb mounting surface?
Don't you have to consider the differences in heights between the yoke on the transmission and the rearend? They may be parallel, but if they're at different heights the angle of the driveshaft would effect how much the u joints are angled right? I don't see what it matters if the engine is level or not, if the centerline of the transmission line and the pinion line is parellel it still may not be lined up on the z axis, or offset left to right, giving you the angle you need?
Damn Scooter, drop that hemi in there already! Seriously, I'd set the motor up and see where it looks good, if you're anywhere from 0 to 5 degrees (maybe a couple more) when it looks right it won't be an issue. I dont have a hemi to measure but like I posted earlier, my memory says 3 degrees. Checked the S/B mopar I'm setting up right now, it's 3 degrees.
I've been thinking 3-degrees is a nice number. I will probably just set everything up at three degrees and be done with it.
I think that is what Scooter is saying these old Hemi engines dont have an angle built into them. If you put the engine into the ch***is with the carb mounting pad level and the ch***is is sitting at ride height, then the angle of the ****** output shaft will also be level to the world. This is the same exact issue I am trying to find out about right now. My ch***is is sitting in the jig at ride height about 2 1/2 degrees down in front. I plan on mocking up the engine with the carb plate level so the ****** will also be level. Should I weld my spring hangars on to the rear end now so that the pinion angle is also level.
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