living here in arizona where the summer temps are always over 100 F i’m looking for ways to keep the bay cool. i’ve also got period AC. i’ll put in a high cfm pusher fan to replace the hinkey four blade desk top fan from the '60s that’s in there, fab up a valance scoop to pump more air into the bay and vent the rear sides as this build did:
the vents are visible above the brake disc at about 1:11 into the video -
I cut out the whole triangle instead of louvers on my car. Also made a chin scoop to drive air up in front of the crossmember (is this what you mean by valence scoop?). With both of those, made a huge difference. I’ve also heat shielded under the hood and the whole firewall, plus put a heat blanket over the headers. All of that also made a huge difference for heat soak and almost no heat enters the cabin.
Another thing that made a massive difference is building a cold air intake box, so instead of breathing in hot air from under the hood my car takes in cool air from under the fender. Makes the engine run consistently in all temps and conditions since it’s always taking in ambient air.
I seriously considered cutting the backs off my foglight openings (It’s illegal to use foglights in that location here in CH), and making the right one a cold air feed for the intake, and routing the other towards the exhaust manifolds.
I debated this too but the challenge is the chrome grills mount in the center, so I couldn’t think of a clean way to open those areas while keeping the center mount intact. Could be possible to sort of drill a bunch of holes and then put a collector behind?
With a plasma cutter, an angle grinder, and a sufficiently large hammer… anything is possible.
a sufficiently large hammer… anything is possible.
Quite.
The 420G setup is great, pulling from the eyebrow, with u beaut trunking and padding
one thing I did find however, on an entirely different vehicle, with a bad rep for air intake position
I put a thermo gauge on the air intake mouth, and found that at rest, yes underbonnet air temp is much higher than ambient, but once moving at above ~20mph, there was not much difference at all !
Using the very rough rule of thumb 10F = 1HP, I can recall it was between 1-2 extra HP max, at over 20mph
on the other forum, this member did just that. he has put a LS motor into the bay and added therefore, massive amounts of heat. with that and a custom fabricated under valance scoop plus cooling upgrades it’s a daily driver.
link:
https://www.jaguarforums.com/forum/mki-mkii-s-type-240-340-daimler-61/3-8-s-sleeper-bodywork-almost-done-73952/page2/
alot of work but well worth it i’m sure.
george miller would be proud!
watch out for those hills!
theo - did you consider wrapping the headers in heat shield tape? I might try that as well.
I’ve read that wrapping the headers can destroy the finish and the material burns onto them. Not that the finish is that great, but figured I’d rather just use a blanket, it’s easier to attach and take off. Plus, because they aren’t “headers” they are manifolds it’s not as clean to wrap the pipes with heat strips.
Hi Robin,. Do you wrap them in situ, or is it done prior to installation? I can see it would be easier off the car, but then there may be difficulty getting the nuts etc on…
You know, dry ice is very cold and would do the job. It has the added special effect of white fog at the stop light which will surely draw attention to the car. 
Or to take it a step further, use a CO2 extinguisher plumbed into the intake manifold. Then using a long string to the handle, you could bring it on as needed… Think of it as “Nitrous on a budget”
I think I did them on the engine, it’s a slow build 
currently prepping a replacement r/h wing section to replace the one on the car, damage to the side light pod
I used this stuff to wrap both rear resonators and over axle exhaust pipes that were in the vicinity of the fuel pump and fuel lines on my XJ40 to hopefully prevent summer vapor lock and fuel pump cavitation in high ambient temperatures. Awaiting summer for a full test.
