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MGB Insulating MGB fuel lines

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wkilleffer

wkilleffer

Jedi Knight
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Ok, we had a pretty balmy day here today, with a high temperature around 65deg and blue skies all around. I decided to use the B as a work car, and am glad I was able.

The problem is that in the heat of the day, it seemed to be having issues with boiling fuel.

The engine's an 18GK and the carbs are HS4s. A little over a year ago, I replaced the long-gone asbestos insulation on the back of the heat shield with some mylar-fronted underhood insulation fabric. It made a good difference in the heat level around the carbs.

Maybe that's not perfect, but I'm inclined to think the fuel line that runs at the back of the engine compartment could be the culprit now.

Thanks to tips received in a recent post, I seem to have the car running more or less the way it should, or at least acceptably.

The issue would sometimes crop up when stopped at a light. The idle speed would slowly drop down and idle would start to feel rough. Once we were moving, everything seemed just fine. The worst of it would come after the engine had been stopped for a short time, like five or 10 minutes. Then, the car would be hard to start. Once started, it was hard to keep running. If we came to a stop and I wasn't quick about it, the engine would end up stalling.

Is there a way to insulate that fuel line to make this less of an issue? I use 93 octane if that matters.

Thank you,
-Bill
 
I doubt the problem is the fuel pipes. The carbs are directly over the exhaust manifold, and the fuel in the bowls can boil when the car is stopped on a very hot day. If your heat shield is good then I would consider ceramic coating the exhaust manifold. That will reduce under-bonnet temps a great deal.
 
Ok, so it's pretty much something I'll just have to live with? Is it normal?

I know the current heat shield is better than nothing, though it's probably hard to top the original asbestos shields. Before I made the foil/cloth shield, it used to feel like the carbs were getting cooked. Now, it's still hot under there, but it's a more "moderate" heat.

Today's temps were pretty balmy and pleasant. It can and often does get up into the high 90s around here during the summer months, so I wonder just how bad things will get.
 
I've suffered vapor lock in my B a few times, but it usually takes sitting in traffic in 100+ temps. In a pinch, pull the choke out a little. It shouldn't be a chronic problem, and not a problem at all if the car is moving forward.
 
Bill, I had that problem once when we were at MG 2006 in Gatlinburg. We were in heavy stop and go traffic in Pigeon Forge on a very hot day. I solved the problem by insulating the fuel line that crosses over behind the engine with a racing type fuel line insulation, bought from a speed shop. Arrows show line. It comes in various colors, I chose black. You just slide it on and forget it. I've never had a vapor lock situation again. PJ

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