heralddolly Posted March 5, 2011 Share Posted March 5, 2011 Hi.Cannot be 100% but I think my carbs / fuel delivery is being affected by fuel vapourisation.Carbs are brand new and with the correct needles. Fuel delivery is spot on as is the timing with the electronic ignition.Currently running Tesco 99 RON fuel, so tip-top.After sitting at traffic lights for a couple of minutes I need to blip and give the revs a boost to get it running smoothly again. After about a 100 yards or so, or seems back to normal.Switching the engine off for five minutes and then restarting is very problematic as it would appear there is MASSIVE fuel vapourisation. Leave it for twenty minutes and it fires up okay and runs 95% spot on (still fine tuning at the moment !!).Coolant system is spot on as well and runs a normal temperature.Having spent the last few months overhauling everything, I'm certain that I'm on top of any of the usual suspect problems.So, is it a case or re-routing the fuel pipes (still in original position) AND is it worth getting a carb heat shield ??Any thoughts would be welcome.Many thanks.Richard. Link to comment Share on other sites More sharing options...
Nick Jones Posted March 5, 2011 Share Posted March 5, 2011 Yes, Strombergs do suffer from fuel vapourisation. I can remember a particularly severe example driving back up from Grenoble to Caen and passing through Macon on Saturday (market day!). We were in stop-start traffic for 45mins in 35ºC ambient...... kangaroo petrol - pop, spit, fart, pop, spit, die. Constant blipping the throttle to keep it going and some very long winds on the starter when I failed - Not funny.Heatshield were never were fitted as standard but no reason why you can't make something up. I fitted SU HIF 4s on that car not long after the Macon incident, as stolen from a 1500 Allegro ( :B) and they came with some strange heat shields made of a very thick fibrous gasket material - see pic. Certainly seemed to help. A sheet of alu cut and shaped would do fine.Nick Link to comment Share on other sites More sharing options...
heralddolly Posted March 5, 2011 Author Share Posted March 5, 2011 Thanks Nick.What made you change to SU's ??Regards.Richard. Link to comment Share on other sites More sharing options...
Nick Jones Posted March 5, 2011 Share Posted March 5, 2011 The Stroms were knackered..... and this was late 80s/early 90s when Strom parts were really not available. The SUs (note HIF not HS) cost me £ 10 and were in good shape. Had to spend another £10 on needles but they worked much better for hot starting, idle and low speed running with much improved mpg as well. Never felt it went quite as well as it did with the Stroms though. EFI is waaay better than either :)Nick Link to comment Share on other sites More sharing options...
TR7th Heaven Posted March 5, 2011 Share Posted March 5, 2011 I too suffer from vaporisation on my Vitesse. I already have a shiny pair of heat shields but have never fitted them as I'm worried that the bolts that hold the carbs to the induction manifold seem a bit too short to accomodate the thickness of the ali heatshields. I've wondered whether it's possible to remove the spacers to accodate them but was going to seek advice on this before trying it.I've read that as the ethanol content of modern fuel increases over the next few years (currently 5% I believe) it'll make vapourisation problems more common.The other thing I thought of trying was wrapping the exhaust manifold and downpipe to reduce heat in the engine bay. However, as I've already got the heatshields I should try that first, right?Rich ;) Link to comment Share on other sites More sharing options...
ResinRocket Posted March 5, 2011 Share Posted March 5, 2011 I suspected fuel vapourisation problems too, but my concerns was with the routing of the fuel pipe which goes all the way around the cylinder head from the fuel pump, over the red hot exhaust manifold and to the carbs.I re-routed the piping around the back of the engine so that it isn't sitting over hot engine parts.As it was part of a big effort to get to the bottom of an array of running problems, I can't say for sure if vapourisation was a problem, but I felt more comfortable with the new route of the pipes just in case. Link to comment Share on other sites More sharing options...
TR7th Heaven Posted March 6, 2011 Share Posted March 6, 2011 1504 wrote:I re-routed the piping around the back of the engine so that it isn't sitting over hot engine parts.So, did the re-routing work?Rich ;) Link to comment Share on other sites More sharing options...
ResinRocket Posted March 6, 2011 Share Posted March 6, 2011 TR7th_Heaven wrote: So, did the re-routing work?Rich ;)Difficult to say for sure! I've had no trouble with it, however I had a lot of different problems - I was getting water in the fuel, the ignition timing was way out and other niggling faults. I attacked it all at the same time sorting out the carbs, ignition etc, so I'm not really sure if it needed re-routing!However, it is less likely to suffer from vapour lock now as there are less hot engine parts near it. :) Link to comment Share on other sites More sharing options...
Steve P Posted March 6, 2011 Share Posted March 6, 2011 Not sure about the Stroms but on my 2.5 Vitesse with HS6 carbs i was suffering badly when stationary for any time,i wrapped the manifold,fitted stainless heat shields and routed the fuel pipe(braided)round the back of the engine.Seems ok now,just need a clean air feed to the filters.Steve Link to comment Share on other sites More sharing options...
TR7th Heaven Posted March 6, 2011 Share Posted March 6, 2011 Ooo, that underbonnet pic is very, very nice.You've spent some money there Steve.Is there a link to more info/photos of your car? I don't want to hijack this thread.Rich ;) Link to comment Share on other sites More sharing options...
dazzer Posted March 6, 2011 Share Posted March 6, 2011 You definitely need heat shields. I've just fitted and tested a pair of 175 strombergs to replace the original 150s and the problem as you describe persisted.This is on an early 2000 narrow head fitted in a triumph 2000 rally car with a extractor manifold. It would would be OK on the move but anytime stood ticking over or stop for fuel and trying to get the hesitation to clear was a pain.Completely cured and tested this weekend on a rally, left ticking over for well over ten minutes at a time, after all day hard driving and its transformed not a hint of anything.I used seperate alloy heat shields (smallish) and to stop them acting as heat sinks (which they can do from the manifold) I got hold of a couple of plumbers pads about £10 each I cut the top edge off and took out the padding which left the heat proof outers (same material as exhaust wrap) I then pulled them around and up the heat shields so both sides of the heat shields are insulated. Bit fiddly on the car but with a bit of patience and some stainless lock wire they were fastened into place. I also have exhaust wrap on the manifold as well.To lengthen the studs. Just wind them out the manifold a couple of turns or so with a stud remover as there's plenty of thread in the manifold, you can also loctite all the threads for piece of mind. Do not remove the spacers as they are heat insulators.CheersDarren Link to comment Share on other sites More sharing options...
TR7th Heaven Posted March 7, 2011 Share Posted March 7, 2011 Thanks Darren,Rich ;) Link to comment Share on other sites More sharing options...
Pete Lewis Posted March 10, 2011 Share Posted March 10, 2011 we run with a non isulated 631, mechanical engine fan, twin stroms,+ ally heat shield, it will idle for and hour sit in traffic, snort here there and everywhere without missing abeat , have used good quality rubber fuel hose throughout the engine bay as it is less conductive to the heat, (except the carb tee off pipe,)with 50mm waste pipe for filter intake of cold air never ever a problem, Peter Link to comment Share on other sites More sharing options...
heralddolly Posted March 13, 2011 Author Share Posted March 13, 2011 Folks.Thanks, for those updates - very useful and encouraging.Peter - when you say good quality fuel hose is there a specific make or product type ?? Also, have you re-routed your fuel pipes to keep them away from as much heat as possible ??Dazzer - With the heat shields, am I right in thinking that 1x heat shield (protecting both carbs) is less efficient than 2x separate shields with regard to heat dissipation ??Thank you.Richard. Link to comment Share on other sites More sharing options...
Pete Lewis Posted March 14, 2011 Share Posted March 14, 2011 richard, not that special just used fuel injection supply hose from a local factors,has a bit better reinforcement in it ,kept the run as original around the front of the stat housing , its cooler at the front than the back of the headbut its rubber from the pump to the carb tee.the fan is a 7 bladed plastic , quieter than the original old steel 6 blade , same fittings there is no side shield fitted on the drives side to help air escape, Pete Link to comment Share on other sites More sharing options...
Lord Sorbington Posted March 17, 2011 Share Posted March 17, 2011 My 2000 was becoming increasingly hard to re-start on hot days and suffered from a poor idle when the engine bay got warm.I suspected fuel vapourisation and was getting ready to fit heat shields and stuff but on a whim I changed the ignition coil: problem solved! Link to comment Share on other sites More sharing options...
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