Subject: [TR] Hot Start of Will Daehler's TR4

From: Joe Alexander <[email-masked]>
Date: Mon, 1 Sep 2014 09:06:02 -0500

Will Daehler,

Maybe you already have a heat shield. I don't remember.

But Triumph needed heat shields like the other British cars with carbs sitting
on exhaust manifolds.

More so now, with new fuels. And cooler fuel is always good.

And street cars need heat shields more in stop and go heat soaking traffic
than race cars do when at full throttle.

Joe Alexander
645 1st Street
Jesup, IA 50648
The-vintage-racer.com
Gasketinnovations.com

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From: "Randall" <[email-masked]>
Date: Mon, 1 Sep 2014 11:31:08 -0700

> than race cars do when at full throttle.

I can certainly vouch that my TR3 starts much easier hot with one of Joe's heat shields installed.  Installation was relatively
painless, though I did have to open up the hole for the vacuum line just a bit, so the compression nut would pass through.  Here's a
photo, in case anyone is interested:
http://tinyurl.com/k9d3jgq

I was thinking that 10 minutes was not long enough for Will's problem to be a heat issue; but on second thought that may not be
true.

Another thing that seems to help is taking the factory advice of holding the throttle partway down while cranking.  Setting the
carbs a bit on the lean side (half a flat or so) seemed to help as well.

What I still don't really understand is why the problem seems to be worse with E10.  Gasoline of course is made up of many different
chemicals, so the refining process controls the initial boiling point.  But most sources give it as well under the boiling point of
either ethanol or water.

Furthermore, the EPA defines fairly tight standards for the permissible range of initial boiling point (aka Reid Vapor Pressure), in
order to balance easy starting (hard starting engines blow a lot of pollution during the cranking process) with fuel evaporation.
The limits even vary with area and season (so winter fuel boils easier than summer fuel).

My guess is that the changes in fuel standards have much more to do with the problem than just whether there is ethanol in the mix
or not; or how much water has been absorbed.  

Of course, if the fuel has separated, it would be very hard to start, but probably harder cold than hot.  And in my limited
experiments, you'd need heavy choke to keep it running smoothly even once it is warmed up.  Ethanol has to run much richer than
gasoline, or it won't run at all.  I tried burning a gallon of "white lightning" in a TR3A once, and had to keep the carb jets down
by roughly 3/16 inch for it run smoothly hot.

Randall