<VV> Engine Bay Air temperature experiment

[Joel McGregor]

Good info but it's about what I would have assumed.  I have always been under the impression that heat in the engine compartment while running was only a problem with turbos on boost for an extended time.  Otherwise you have so much fresh air from the fan that it's pretty much ambient.
My '65 (non turbo) with a Megasquirt system has what appears to be a hot soak problem.  It runs ok from a cold start and runs fine hot.  If I shut it off hot and try to restart after 15 minutes it either won't start at all or barely runs for about 5 minutes until (I'm assuming) everything cools back down.  It seems like it's running super rich but it doesn't blow any black smoke.  I can manually run the fuel pump for a while before I start it with no change in behavior.  It broke a cam gear and I had to move and don't have my shop setup yet so I can't work on it but I'm wondering if your symptoms are anything like mine.
Joel McGregor

-----Original Message-----
From: VirtualVairs [mailto:virtualvairs-bounces at corvair.org] On Behalf Of kevin nash via VirtualVairs
Subject: Re: <VV> Engine Bay Air temperature experiment

The reason I became curious about all of this had to do with strange running under certain conditions, usually after it had been started and run a short while and then shut off again- I began to think that not having that rear seal installed might be causing or making worse a hot soak problem- which it most definitely was, particularly when the damper doors just start to open! The other reason for the test was that I had noticed that the manifold air temp sensor (located in the cross over tube between the heads and turbo) was reporting considerably higher than ambient temperatures at the end of the same ten mile drive, and it always seemed to coincide with the engine running leaner than I was after, so I needed to figure out exactly why that was happening and what to do about it. Part of the "why" was to make darn sure as to what engine compartment "ambient" really was after driving a while.
To make a long story short, I fixed those issues!
Kevin Nash
63 Turbo EFI Daily driver