Hi,
Is there any problems with making the chassis 14" or 15" instead of 13" as in the book to give more engine clearance

Thanks

Paul Ludlow

Hi Paul,

I added 2 inches to the height in my 442 chassis (ergo, the "2" in 442)... for a total height of 15 inches. Drawings are available at http://mcsorley.net/locost . The custom chassis that I'm currently building is 14" tall.

For even more engine clearance, you might consider making a taller nosecone. The chaps at ChampionMotorCars.com in Alabama,USA produce what they call a "newer" nosecone that is 8.5" tall (instead of the original 7.5) and it goes down in the front a full 13" (compared to only 10" originally). The 13" perfectly covers the front of a book chassis, and the added height provides more engine clearance.

This whole idea of covering the front end height is something you might consider when buying/creating a nosecone. An original nosecone goes down only 10" and the gap is usually filled with a piece of bent sheetmetal... so with each inch that you add to the height, the gap at the bottom increases accordingly.

The other thing to consider when increasing the height of the chassis is the compound angles on the front end (LA/LB, etc). These angles are a initially a function of how far back LC sits from LD (from a side view). What I found is that the book's offset of LC/LD is about 3", a 14" tall chassis would use an offset of about 3.25", and a 15" tall chassis has an offset of about 3.5". These offsets allow LA/LB to sit at generally the same angle from a side view thereby accomodating the same nosecones (again, from a side view).

Then you get into issues with the angle of LA/LB from a front view... as you increase the height of the chassis, the width of LC should increase (if you're trying to keep the book angles from a front view). Keeping the book angles on LA/LB is something you really want to consider if you are also relying on the front suspension geometry from the book; The front view angle on LA/LB directly impacts the alignment of the upper wishbone brackets against FU1/2.

Anyway... that's probably more detail than you were looking for, so the short answer is, no... there aren't any serious problems with making the chassis taller... just a bunch of geometry to consider along the way.

Cheers,
-Jim M.