The engine (350) in my 47 setting on an S-10 chassis is on more of an angle than I would like. The front of the engine is higher than the rear. I'm considering placing a rubber trans mount between the transmission and it's mount to raise the back of the engine. If I raise the back of the transmission This will increase the driveshaft angle. My question; what is the correct driveshaft angle between the transmission output and the rear end? Thanks Ron
This is a very good question and this is what you want to do.... First thing you want to do is level the truck using stands or blocks, whatever it takes to get the truck sitting level. Then the best thing to do is pull the carb off the manifold (assuming you have a V8). Put a level on the manifold and raise or lower the trans. tail shaft until the level shows that the engine is level. Of course the engine won't really be level but the carb mounting surface will be. Now take a degree finder and place it on the flat surface of the trans tail shaft and take a reading. This is the degree you should set your pinion angle. The pinion and trans center lines should be parallel to each other....Big Tim
This is a pretty good page on angles and harmonics... http://www.hotrodhotline.com/md/html/drive_shaft_harmonics.php
People agonize over this and it is a non-problem. To hell with the carburetor, just mount the engine in to where it looks to your satisfication and then importantly, have your pinion angle a degree down from the trans mainshaft angle. This is to rotate the needle bearings in the U-joint cups and prevent flat spots. On Vette, Jag, Kugel, or any other independent rear suspension (IRS) the carrier is mounted rigid to the frame and and just a 1/4 or 1/2 degree will do. The IRS and any rear with ladder bars or 4 link the pinion angle can be either above or below the trans shaft centerline angle since there is no rear end wind up on hard acceleration. The angled down without anything to control wind up means the slip joint gets pushed further into the trans under acceleration rather than pulled out as it would if angled up. The joint angle also gets straighter rather than increasing as when angled up. Back to the carb; I swear I have seen cars with carburetors in San Fransisco and the Rockies where the carb is almost NEVER on the level and they were running just fine.
They may work fine with the carb at an angle but they look stupid and like the builder didn't know what the F#$K he was doing. Also pinion angle is important because you can pick up vibrations if not done properly. As a Millwright and certified welder for the last 30 years my job as well as others in my trade requires doing quality and precision work other wise I make myself and others in my trade look bad. one of our logos is " We make engineers look good " Also as I stated before and Spika verified with his link,the pinion and trans center lines should run parallel to each other. The reason for this is so the bearings and seals in the trans and rear end and the u joints last longer and a smoother ride.....Big Tim
OK, you enticed me into this once again. I do think it is important to strive for correct alignment and offset. If you don't, it will primarily show up, as bigtim stated, in premature wear of the moving bearing parts. On a truck like I'm building, it's probably a pretty good idea to pay close attention, as I've been known to push the speed limit a wee bit, and hope to log at least 5-8K miles a year. If you don't expect to get more than a few hundred miles on your truck in a year, and aren't likely to get it above 55 mph very often, odds are you probaby won't ever notice if you are off a little. As for the engine angle, I side with both of the last posts...these carbs can operate quite well at a pretty good angle. The floats are set to be at optimum on a level plane, but they have the ability to work outside of that quite a bit. Sometimes just the fit requirements of cramming a different engine into a spot not designed for it forces you to drop the rear just a tad, and I don't think that will be the end of the world. But, to acknowledge bigtim, if it is very far out of level, it does show up that way to the observer/admirer, and leaves people wondering why the engine isn't fitted in level. Can be a bit of a distraction from an otherwise nice install. One final note...it is imperative that the ujoints are indexed correctly...if you are 90° out of sync, it will chatter til the cows come home. There. I've said more than I know. Now I'm happy.
Guess I got my come uppance here. 61 years of working on these junky projects and learned nothing. Almost ashamed to show pictures of my non-precision work and mud dobber welds. Here's just a few junky projects: Billet tractor block is fresh out of the Haas 5 axis mill, 11,000 HP tractor with everything crooked and looking f#*ked up and with the driveshaft in MY way. Welds ground smooth (no filler) for show finish and near zero loss of strength. Gave up my pipeline and high pressure vessel tickets years ago and must have forgot everything. I wish some really smart and skilled person would come by the shop and show how to do things right.
47 Chevy truck ( daily driver ) verses a high dollar tractor puller which is driven 30 seconds at a time.... Apples and oranges.... Nice work though Evan....Big Tim
Eh~hemm... Speaking of drive shaft angle... How does that work on a split shaft? My 3/4 has the carrier bearing, and it seems that once the shaft hits the bearing, the angle changes quite a bit. (It seems to drop by about twice the degree.) TIA
Sorry Even , I'd love to be of help but I'm really busy right now . . For me, the Farm ways will never die , I run my old beat up shop truck harder than most ever will and it doesn't leave me afoot so I follow your advice closely my friend . Those welds ~WOW .
Beautiful work there, Evan! I'd hate to even guess the value of that machined block. The things I could do with a 5 axis mill in the shop and enough smarts to run it. I've always enjoyed machining, but never pursued a job doing it. Everything we have here in the shop is manual, as we really don't machine much. You've actually got 4 engines linked together on that puller??? Do you have a link to a site with more pics of that? Would really like to see more. I can't imagine how you could get enough traction to utilize 11,000 hp. Tractor pulling used to be pretty popular around here back in the late 70's, but haven't seen any for several years.
Ac My 49 3100's factory AC still works perfectly..... 2/60 air , roll down both windows & go 60 MPH , yes I sweat like a dog in a Chinese restaraunt but I'm happy .
Spika, I think you do darn well with manual machines and better yet is you have imagination. Your a/c register vent dies that you milled out of aluminum is something I would have never tried. I would have used steel and probably heat treated but you got a neat finished product at a fraction of the price, good work. So many of the ones on this forum have abilities that keep me amazed.
