[Healeys] Heat management

[Bob Spidell]

On my latest 4K mile road trip through the Southwest I was having apparent vapor lock problems when the engine and fuel lines were heat-soaked; i.e. after driving in hot weather, shutting down then restarting after 30min or so. At startup, the engine would stumble a bit until I got moving and got some air circulating. I'm thinking maybe a ceramic coating of the manifold and downpipes might alleviate this problem. Also wondering--this is mostly a pipe dream--what coating the entire exhaust system would do. I would think at least it would lessen the heat under the driver. 

I haven't had this problem until the last few years, which coincides with the greater prevalence of alcohol-laced gasoline. I can't prove a correlation, but if the vapor pressure of gasahol is lower than 'real' gas then it could be the cause. We tried to find a station that pumped pure gas for comparison, but east of CA--and in most of CA--the pumps all read 'Contains Ethanol.' 


bs 

-------------------------------- 
Bob Spidell - San Jose, CA 



I just wrapped my downpipes with a high tech wrap in hopes of cutting down on rough idle (vapor lock or gas getting to hot???) at high outside temps and in stop & go traffic. 

Did you notice any difference in this area? 

I'm driving the BJ8 to AZ next month and will update. 

Randy 


On Aug 26, 2010, at 12:05 PM, Bob Spidell <bspidell at comcast.net> wrote: 

> As long as we're on the (neverending) topic of heat management--thermostats, etc.--has anyone done a before/after analysis of manifold/downpipe ceramic coatings (JetHoat, etc.) and the effect on engine temps? I know we've discussed it before--and there seems to be some anecdotal, positive results--but does anybody have any definitive info to add? 
> 
> I wrapped my downpipes, and the net result was seemingly hotter gases at the exhaust exits--I didn't actually measure the temps, but the exhaust went from hot to pistol hot--circumstantial evidence that more heat is being moved away from the engine compartment. I can't say I saw a measurable decrease in coolant temp, but unless you do before/after testing under identical ambient conditions it's going to be subjective at best. 
> 
> 
> bs 
> 
> -------------------------------- 
> Bob Spidell - San Jose, CA