[DB]

Having scooped the Chevron B21 in the post race auction of the  IROC Race of Champions, the challenge raised was to describe the differences between a B21 and B19.

The B19 car had closed cockpit over the passenger seat and roll hoops where not full width.  The B21 had to be open cockpit over the passenger seat, full cockpit width and full windscreen due to new rules which stated in 1972 the cars had to be 2 seaters.

In 72, a change in tire type occurred.  Slicks came along and some cars ran the treaded tire  and some tried slicks which had a different side wall height.   As such, this could result in a modification for B21s rear wishbone lengths / camber castor ride height.

The differences between B19 and B21 chassis is that the B19 has a narrower central member between the “seats” about 3″ wide. The B21 was made wider (due to new rules) about 5″. The side pods on the B21 are narrower than the B19 to accomodate the wider centre section without increasing the overall width.

Happy New Year.  :yahoo:

Dave

 

Topic

[MiA]

Thanks Dave. No wonder that I can never tell them apart just looking!! Great summation of the little details of the Chevron ‘evolution within the B19/21/23 series of cars.

The car you have I think (and Art may correct me if I’m mistaken) was a B23 that ran at LeMans in 1973. Chevron B23 chassis #73-09  that had a Ford Cosworth FVC in line 4 cylinder, 4v DOHC 1930 cc motor. It was entered by Escuderia Montjuich and driven by José Juncadella (E) & Jorge de Bagration (E) It was a DNF due to gearbox issues.

The B23 was the last of the ‘space frame’ Chevrons before going to a Monocoque chassis because Chevron’s were being beaten by the Lola’s of the era. As I understand it, the B23 was basically a B21 with minor modifications some of which Dave may have found as he was researching the B19/21 info. Perhaps he will share those with us. As I understand it, it was limited to a bolt on piece that closed in the tail section behind the rear wheels.

Many cars of this type are being raced around the country at vintage events. They are indecently fast little devils!!!

 

[Arthur]

I have seen many Fly Chevrons and the only noticeable difference between their models is the cockpit opening/windscreen/mirror configuration – and although they modeled the B23 there is no difference from the B21 body… thanks for posting the topic and the addition! :good:

The Happy Canadian Scale Modeler!

[f1nutz]

Great info! thanks for elaborating.

[DB]

Yes, probably a B23 albeit without the rear bolt on arch valance.

The B19s, 21s and 23 were somewhat fluid in that the were tweaked each season.  The 19, 21, 23s were all fundamentally the same except for the tweaks.  The 21s evolved into the 23 due to front suspension changes  (badged as B21/23s intially) and the rear bolt on arch valance and headlights (B23s).

There is some variation in the cars seen on the track – some cars used  both a rear air spoiler and rear arch valance.   A quick google on Chevron B23 will show this.

 

 

That’s all folks …… Happy New Year

 

 

[Author]

Replies