ok im building my first mdl a, and am learning lots from here as i go along. im trying to do everything safe,reliable,proper. im pretty sure i have the right answers to these questions but just want to make sure. im ready to mount the split wisbones up front and i know they have to be around 6 degrees, but should they be mounted at 6 degrees with the weight of the motor sitting on the frame? i already have the proper tires im running so i know how the frame is going to sit. i placed the motor on the frame tonight and it dropped the front end about 1 1/2 inches. the same question/thought goes about the front shocks..i know i need to mount them 1/4 compressed, and im guessing they should be compressed with the motor weight on frame.. and then another thing i was unclear about was. the angle on which the motor sat.. a couple degrees back? measured from where.. and i have a rear 4 bar from speedway. is there tips or anything else i should know when installing it? i thank you for ur time and any feedback. lenny edit** here's some pics of my car..that i took tonight.
If you mount the axle with 6 degrees with no weight on it you may get another degree with the weight on it. No big deal. I like more caster. It helps keep the car going straight at higher speeds. Easy way to set up your motor. Take the carb off of the intake. Put a level on the intake where the carb bolts on. When it reads level that's where you want your motor. Shocks...if you have the weight on the car sure 1/4 compressed will be Ok. the car should settle an inch or two after driving it some. Clark
What clark said but watch the level carb pad,i know thats ideal but alot of aftermarket intakev carb pads are different angle when engine is set in at 3degrees down.i dont take the reading off the carb pad ill usually take it off the starter and point it 3 down and with certain intakes it makes the pad level,but on others its not.just my .02
I typically place a level across the top of the block (with intake removed.) What you need to do is place the car at ride height. Two: mock the motor and trans. up at the height they will be sitting in the car. Three: Have your rearend sitting at ride height with pinion down about 2/10ths of a degree (rearend pointing down.) Four: Now measure from ground up to center of input on rearend. Five: Measure to crank centerline of the motor. What I like to do here is measure the distance from measurement to measurement (rearend to crankcenterline measurements) and cut me a piece of tubing the same distance and mock it up on the floor. One end at 0 and the other end at the height that is the difference of your two measurements. Once that is done find the angle of the tube and that will be what angle you need to place your motor in the car. Shock ? I would set your suspension up at ride height. Now measure to where your suspension will be bottomed out at. I would set my shocks up where it was almost compressed half way at ride height so that it would not bottom out in the shock when it does. That is what kills the valving in shocks. With the 4bar I would make sure that the rearend is in there square and I would leave a 1/4" of thread on my bushings showing past my jam nuts so that you can have adjustment either way with your bars. This will allow you to adjust front to rear and pinion. I think that is it Good Luck. Heath P.S. I like to run 6 degrees of caster and about 1 degree of camber.
The info that comes with the Pete and Jake's ladder bars says to point the rear pinion up at 4 degrees. then your rear trans tailshaft points down at 4 degrees. Which you'll see is pretty close to the info on placing a degree finder on the intake at 3 degrees... if you can keep every thing pretty close, whether at 3 degrees or 4 degrees will get you pretty much right on. Front Caster at 5, 6 or 7 degrees will result in good front end staability. Unless you want to go into the 200 mph club at Bonneville, where even more front castor is dialed in. The more caster you run, the more stability at high speeds. Preloading your shocks at 25% will work fine also. I put tube shocks on the back of my Model A woodie and set them up so they'd almost be compressed 100% when the rear end bottommed out. Which probably won't happen as I'm running 10 leafs out back from a Tudor Sedan.
Remember, if you are going to be running big & little tires, ie: 26" up front and 30" out back, you will add approximately 2 degrees of rake into the car with this tire set up... What I'm trying to explain, set your frame on build up, with a 2 degree rake to take into account the tires. 7 degrees of front axle caster is good, however; if you have slightly more, the car will track better, however; maybe a little harder turning.... Some straight axle g***ers which double as drag cars, are running 10 to 13 degrees of front axle caster....
Your carb question. My advise is to take the level from INTAKE YOU WILL BE RUNNING. Different intakes have slightly different rakes, you don't want your carbs running uphill as you changed intakes part way through your build... Carbs. should sit as close to level as possible....
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