Hi Martin, I have a suggestion for Paul at least for the Vapor Lock. I installed a 3″ brushless (uses very little amps) bilge blower with a 2.5″ flex hose to my Weber 40 DCOE in my Sebring front left hole (Not sure of the Speedwell bonnets air holes). I have a switch with a relay so on very hot days in traffic here in Virginia I hit the blower switch. This is so good it cools the engine bay a tad too! I have a few pic’s. Thanks, Pete
A reply from Juergen Schaefer
“I’ve an Archers (Monza) bonnet with the extra front inlets and the following mods: Exhaust manifold (-flow) ceramically coated, plus heatshield under footwell. Side exit of ducting (provided for oilcooler) closed, oil cooled by water cooler as per Turbo Metro engine Fender outlets behind the inner wing and the firewall. No scoops, just cut outs with light alu screen glued w. mastics from the inside to prevent intrusion. Electric fan for aluminum cross flow rad. Extra bypass hose with shut off valve for cabin heater line I’m having the “standard” SU’s with KN filter elements inside the black pots, but shortened the long proboscises to allow the rear one to be turned down and forward for cooler air and less intake roar to the driver. A slightly turned down alu inlet stub from med fits nicely into that filter. I have still experienced high temps and irregularities of carburation in summer holiday traffic jams, but not all mods installed at same time, so the testing goes on. Latest try considered is, return to Sebring bonnet, offering bigger air inlet and saving quite some weight, which with my little 1080 cc short stroker is more important than high speed aerodynamics in view of growing limitations even on German autobahn. Unfortunately I have no proper engineers measurements of the effects of above Any other ideas on this matter ?
If more details wanted, don’t hesitate to contact me directly Regards, Juergen “.
Overheating with a Speedwell Monza bonnet
Paul Bos writes:
” This past summer and into the fall I was able to get out in the Sprite and do some driving. Our summer temps often hit near 40C and with our fuels in California often containing more alcohol I have had a few cases of vapor lock. I have sourced a Weber heat shield and am considering wrapping my header pipes, fuel lines and now that I have converted to an alternator an electric cooling radiator cooling fan will be installed. The Speedwell Monza bonnet seems to have issues with getting heat out and air in. The question I have for you and your readers is how have they cooled the engine compartment and provided cool/cooler air to the motor?
I observed fender vents were used as early as 1959 in the Alpine Rally standard bonnetted car using an Austin of England vent and in some period films I observed a NACA vent on some cars. That was not surprising as Frank Costin was the first to use a NACA duct in a car. I realize that you may not be dealing with the same ambient temperatures as we do, but possibly someone could provide their thoughts on getting heat out of these bonnets.
Regards, A. Paul Bos, Escalon, California”. Feedback please.
