Vapour lock in 2000 SC

ocarros

ocarros

Member
I've read a lot about vapour lock happening in V8s but don't think I've seen a post about it happening on a 2000 SC. I had a new stainless steel exhaust and manifold fitted to mine end of last year and she is not running right at all. The heat in the engine bay has increased significantly due to s/s manifold and all the symptoms I've seen of vapour lock are what's happening to mine.

Might this be possible? If so, what is the fix?
 
When I first bought Sparky, he was fitted with stainless exhaust manifolds. The heat under the bonnet was causing some serious issues, including some of the rubbers actually melting, including an engine mount.

I tried wrapping them and although it helped, it got tatty very quickly and didn't solve it fully, so I took them off and sent them away to have them ceramic coated inside and out. I did have to have the Y piece remade as well, as the one fitted wasn't very good, so I had that ceramic coated externally only.

Heat problems - gone. Bit pricey though :confused:

ceramic.JPG
 
Oh it happens on 4-pots too, especially when the heat gets up. It's mostly a thing in warmer climates, but I can see how fitting a stainless manifold would do the same.

Why did you fit a stainless manifold? I've never even seen one for a single carb car..
 
chrisw said:
Oh it happens on 4-pots too, especially when the heat gets up. It's mostly a thing in warmer climates, but I can see how fitting a stainless manifold would do the same.

Why did you fit a stainless manifold? I've never even seen one for a single carb car..
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I had the exhaust replaced with s/s system as it was blowing and the front box was original up in the engine bay. That needed to come out and when the bolts were loosened the manifold cracked. Had no choice but to get a s/s manifold fabricated. Seemed a sound idea at the time...!
 
I checked with Wadhams at the time and they didn't have this in then. I also live in Ireland so options available were very limited
 
Improving the heat shield seems like a good solution, and easy, basically. Having done LOTS of miles in 2 TCs in a warmer Oz (than the UK) and never experiencing vapour lock, I am a bit surprised. I would check that the pump valves are good, and that there are no restrictions in the supply piping or the tank.
 
jp928 said:
Improving the heat shield seems like a good solution, and easy, basically. Having done LOTS of miles in 2 TCs in a warmer Oz (than the UK) and never experiencing vapour lock, I am a bit surprised. I would check that the pump valves are good, and that there are no restrictions in the supply piping or the tank.
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All is good in fuel supply issues. She's running a touch rich which I've to sort but from eliminating all other possibilities I'm left with vapour lock as the cause
 
Are you running your fuel line about the top radiator hose or below it? If you run about the hose you will preheat your fuel as it passes by. I had trouble starting on a hot days years ago. I had just fitted a new radiator hose, and the fuel line was sitting above the hose. Then shut down for 10 or 15 minutes on a hot day and then the car would barely start afterwards!
 
It's running at the same height I guess but physically, it goes under the top hose. There were no issues at all with vapour lock symptoms though prior to getting the s/s exhaust.
 
Try fudging a second heat shield under the std one, with a gap between them - as big as possible. When you say new SS manifold and exhaust pipe, do you know have more pipes under the carbs? Pic would help a lot.
 
jp928 said:
Try fudging a second heat shield under the std one, with a gap between them - as big as possible. When you say new SS manifold and exhaust pipe, do you know have more pipes under the carbs? Pic would help a lot.
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Same set up as before. The original exhaust system had a front box up in the engine bay which I got rid of. I've ordered some titanium exhaust wrap which I'll try out

The 2 pics where you can see the heat shield - that's how it looks now. The pics with no heat shield (one from the top and one from underneath) they were taken when exhaust was being fitted.

I've ordered a temperature gun so I can record the temps. The part of the manifold that's not covered by heat shield - the throttle linkage above that gets so hot you can't touch it
 

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Well...nice black fuel hose there, directly above a nice new heat source. I suggest you put something like Firesleeve over the pipe from the pump to the carb, that will reduce its heat uptake. Have to ask - was the original manifold no longer fit for purpose? Hard to believe....
 
jp928 said:
Well...nice black fuel hose there, directly above a nice new heat source. I suggest you put something like Firesleeve over the pipe from the pump to the carb, that will reduce its heat uptake. Have to ask - was the original manifold no longer fit for purpose? Hard to believe....
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I just took a look back at photos I took of the car before I bought her and that fuel line is in the same place now as it was then. Thanks for that suggestion though, I'll get some Firesleeve. Car has been running fine over the winter with the colder temperatures. This has only happened in last few weeks with the warmer weather.

Attached are some photos of the original manifold. As the bolts were loosened on the flange, the bit you see cracked and fell off. The more he touched that area the more kept crumbling away so I had to get a new manifold fabricated
 

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