Technical Flathead Engine Angle

I'm building a Av8 with a 52 Flatty / Trans and have a technical question. I just got the wheels and tires on and can finally see the stance of the car. I mocked everything so that the engine is parallel with the rails. Given the rake, is this fine or should the rear be pulled down slightly. I used a 52 cross member. I figure the body will pull the rear down some... What angle should the engine be at? Should the rear cross member be lower?
Photos are here:

http://www.flickr.com/photos/98354829@N03/sets/72157636626438393/

 

The rear does look a little high.

Regardless of rake, the carb mounting surface of the intake should be close to level, thus putting the engine at a slight tilt to the rear.

F1 crossmember? It looks a little high.

My crossmember is mounted quite a bit lower.

Rich

 

we always went with 3 degrees of angle with the car sitting perfectly level. that mad a good slope for oil to run after the car was shut down and sitting.. non was left sitting in the front of the pan....
i like your build so far. i have many photos in my AV8 build in my sig if you need any help

 

I've always heard the 3-degree off the frame rule. Also, get a bunch of weight on the rear end of that car before you start really worrying. With the engine mounted, the front isn't gonna come down much more, but when you get a body mounted, the back should come down quite a bit. The final-angle would be more to be concerned with...

 

That frame looks like the twin to the one under my A-V8 project, same frame z in the rear and same f-1 crossmember. I think you'll be fine.

 

Thanks everyone. I was thinking that keeping the engine as close to level as possible would be good... but then when I put the meat on last night... the angle was pretty steep (followed the tardel book). Just hope the rear sits down some with the body weight.

 

A couple of things.
First, late 8BA intakes angle the carbs 3 degrees forward, like yours, because the open drive cars/trucks have the engine angled down 3 degrees. Early intakes locate the carb level with the crankshaft, because the torque tube cars/truck's engines sat level in the chassis. Using an early style intake will minimize the forward carb angle on your setup.

Second, the only way to know for sure the true stance of the car, along with engine and drive line angles, is to establish a target chassis ride height, IMO.

 

This is my first ground up build... so I've followed the Tardel book... hoping that their recommendations will result in a nice stance overall. I guess I should get the body on the car and then make some decisions... Looking for a little rake to give it that "1950's 18 year old kid built from spare parts" look...

Thanks V8 Bob

 

I found the Tardel book set up to be pretty bang-on. Rear frame height kickup, engine mount height etc all by the book in my build. I set the trans mount to keep the tube drive basically straight to the rear axle. The engine in mine has a slight angle down to the rear as a result. I fine-tuned the final ride height by changing spring leaves etc. Rear spring is a T with eyes reversed; front spring is A with eyes reversed too and a 3" axle drop. Looks like a cool build underway!

 

I too used the Tardel book for the front engine mounts, although i found the engine mount hole dimension to be a little bit off, i center punched where it said to put them.. got it mocked up and found they needed to be moved back about 4 - 5mm towards the chassis.

I had my chassis rails already boxed before i put the v8 into it, but still made the mounts the same 4" like the book says but ended up wacking off the part that would of gone into the rails, so my mount effectively sits probably 7 - 8mm higher than if you had it inside the chassis rails, as i've mounted it sort of over the top of the rails like so:



When working out the angle, I let my mate whos built a few rods before me use his experience and trusted in what he thought was a good angle. After getting the mounts done and tacked in, i've put a degree finder on the chassis rail and the carb mounting base and they both are the same degree.

This is the rear mount i've made to utilize the rubber donut mounts. I was going to fabricate an F1 style crossmember but found this to be easier.

When i look at the chassis side on, the engine block is sloping downwards only a flyshit, so say i can eye off the sump pan mounting edge at the front in line with the top of the chassis, its slightly just below at the rear of the block.

I am using a '40 24 stud engine block as mock up, with a '37 21 stud as the actual engine it will run.

I'm not familiar enough with the late 8BA engines to give you sort of any reference points to go off in relation to mine to help you. So i'm sure someone else will be able to chime in.

Hope this helps somewhat.

 

Well I cut and dropped the rear cross member down 1". This already looks much better and once the body is on, the engine should be in a much nicer line towards the rear and a slight tilt down back from level. I'll post up some more pics as progress happens... maybe I should get the ball rolling on a build thread... Thanks everyone!

 

How many leaves you got in that rear spring? Looks like a full pack. Which is a lot more than you need. That is some of your problem.

 

yeah, full pack. Posies 46" spring.

 

I always level the carb which (as previously mentioned) is about 3 degrees...

 

You need to angle the engine about 3 degrees down from the yoke on the rear end. Depending on the wheel size and the heigth of the engine, the engine may be angled up,down or flat.