[Healeys] Bonnet louvers

[Freese, Ken]

The production 100S had no need for louvres as a carburetors air source.
They have their own cold air box with trunking down to the grill. I
would think they were for hot air escape.
Ken Freese
100S Registrar

-----Original Message-----
From: healeys-bounces at autox.team.net
[mailto:healeys-bounces at autox.team.net] On Behalf Of John Harper
Sent: Monday, April 20, 2009 12:37 PM
To: Editorgary at aol.com
Cc: healeys at autox.team.net
Subject: Re: [Healeys] Bonnet louvers

May I add more detail. As you say the Le Mans cars were not fitted with
louvers. However in the photographs Gary refers to the bonnets look up
at the back. When I ask Roger Menadue about this he said that they
slipped a piece of wood about 2" high under the back of the bonnet and
then relied on the safety catch to keep the bonnet closed. This he said
helped a great deal with the under bonnet temperature.

I have tried this myself and it does appear to help with fuel starvation

I have a BN1 100 Le Mans , modified at the Cape and this has no louvers.

In fact if you look at sales literature put out by the Donald Healey
Motor Company, no louvered bonnet was available on their price list.

A louvered bonnet does however appear in the later issues of the 100 BMC
Parts List but not in the first, pink paged, issue dated March 1954 so
it appears that BMC themselves did not recognise louvered bonnets on a
100 until after that date but I am sure that if you approached the
DHMoCo with enough cash they would sell or fit you one.

Regards
>
>
>The louvers were NOT originally to deal with thermal problems. Roger
>Moment, Tom Kovacs, and i spent some time looking at original pictures
>in Donald and Geoffrey Healey's books, and have determined that the
>evolution was: No louvers on the original 100s that raised at Le Mans
>(the original 100Ms), louvers on ONE side of the bonnet on the 100S
>that raced at Sebring, clearly cut there while on site, and pretty
>definitely to increase cool air going to the carburetors. Then, when
>the 100S was put into production, louvers were cut on both sides
>(because it looked better?) and fairly soon afterward, the "100M"
>bonnets were produced with louvers cut in the same places.
>Ergo: louvers were originally cut to increase air to the carbs, and
>maintained because they looked "cool" whether or not they had any
>cooling effect on the engine.
>Gary
>
--
John Harper
_