Engine Placement in Altered/Funny Car Chassis

[captndiet]

How far out and what crankshaft angle/ground clearance are typical for the average altered chassis.

I know many Alky cars have the engine out 67"+ but not sure what crank centerline is, up, zero or down.

The Mark Williams F/C print has the engine out 63" and the centerline at the front of the crank is 10 1/4" from the ground, which would be down in the front. Chassis ground clearance is 3 1/2".

The S&W altered print has the engine out 62 1/4" and centerline at the front of the crank is 13 5/16" from the ground which would be zero. Frame ground clearance is 4 1/2".

Any input is appreciated.

Jeff

[rooman]

Jeff,
     what you are planning to run for power and what will transfer that power to the rear end has a lot of influence on the motor location.

Roo

[captndiet]

Roo

Initially just a small cubic inch injected alky/auto trans deal.

500-600 hp.

1700 lb.

Solid front & rear suspension.

125" w.b.

1/8 mile car.

Jeff

[rooman]

Jeff,
     I would put the motor 65 out and slightly nose down.  The M-W blueprint is very old as evidenced by the fact that 67 out is the norm for a current funny car. I presume that you are planning about a 31" tire from you comment on the S & W print. The S & W print also sounds a little suspect in light of current track preparation standards. Unless your local track is dirt I can't see that you would want the motor that far back and up.

Roo

[captndiet]

Roo

Thanks for the input.

I will probably follow your advice.

Jeff

[captndiet]

O.K. Roo, one more.....

Lets use the Mark Williams print as a referance...

The rear axle centerline is called out as 15" above ground level with a 33" tire with 3 1/2" ground clearance on the frame.

If you run a 33" M/T tire or equivalant all is good.

If you run a Goodyear D2585, 31x12x15 tire, they actually grow more than a 33" M/T, but setting there are about 31".

What would you set the rear axle centerline at?

Thanks!

Jeff

[rooman]

Jeff,
     put it at 15" (even if you end up running the Goodyear). If you run a rigid front front end the 3.5" dimension will work for ground clearance but 4" may help a little, especially when loading the car into the trailer. If you run a regular wet sump the oil pan generally ends up being the low point on the car anyway.

Roo

[captndiet]

Roo

Thanks agin for your advice.

Jeff