oliproctor Posted June 26, 2018 Report Share Posted June 26, 2018 Hello all, I need your help please! My 1965 Mk2 Spitfire has begun spluttering and backfiring under acceleration after around 15-20 mins of driving to the point where it has cut out once or twice. It did this last summer before it was taken off the road for winter for some TLC and bodywork restoration however the problem was foxed after I noticed the vacuum advance tube had split in the middle after adding heat-shields to the carbs as I thought I may have been due to overheating and vapour lock. After turning the advance all the way in it ran like a dream and was smooth and a delight, something it still does until it reaches 20 mins of running. I have checked the spark plugs and cleaned them, all were in good condition bar number 3 which had carbon fouled (maybe due to the timing being out??), drained and cleaned the fuel tank and replaced with fresh petrol, new fuel filter and tubes and I even added lead additive to see if that may help but to no avail. The only resulting possible problems I can see now are the fuel vapourising after 20 mins of running and the timing being out. My brother and I thought to maybe add an electric fuel pump to the boot of the car so heat radiation from the engine won't be an issue anymore and keep the original as a 'dummy'. The carb dashpots do not get hot due to the heat-shields but the fuel pump has done over the past few days and I can only touch the pump for about 3 seconds before having to take my hand off it. I did a test today in the midday sun (around 30 degrees, barmy for North Yorkshire I know) and one at 22:00 to see if it was heat related. The dashpot were cool tonight and fuel pump cooler than midday with me able to hold onto it for 8 seconds or so before it being too hot to hold onto but it still started spluttering uncomfortably after 20 mins again. Surely if the timing was out it would splutter straight away? Anyone have any words of wisdom please? Here are a few pics of 'Lockie'. Thanks Oli Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 27, 2018 Report Share Posted June 27, 2018 Back fires sounds like a typical condenser failure there are some awful condensers about . It wont be vapourisation , might have fuel blockage with rubber slivers floating and jam behind the float needle valve Is very common Check th e brush in the dizzy cap actually contacts the rotor arm sweep plate Read the post about manifold leaks , amd fitting heat shields , can alsomhave air leaks Squirt some brake cleaner or even petrol along the gaskets , does it suck it in ? Timimg will affect all plugs the same and wont be erratic the vac pipe only helps economy it wont affect how it runs and any air leak is so small and enters after the throttle plates wont cause much problem. Do check the small braided wire in the dizzy is intact Are the dizzy contact terminals secure , also check the coil is wired for correct polarity if its negative earth at the batery then the coil neg goes to dizzy and pos+ has the ign feed Do you have std or pancake air filters? Check the HT coil wire terminal is clean in side no green corrosion under the plastic seal inside the coil head I guess this is a delco dizzy they generally dont suffer from rotor arm problems Let us knowmwhat you find Link to comment Share on other sites More sharing options...
oliproctor Posted June 27, 2018 Author Report Share Posted June 27, 2018 3 hours ago, Pete Lewis said: Back fires sounds like a typical condenser failure there are some awful condensers about . It wont be vapourisation , might have fuel blockage with rubber slivers floating and jam behind the float needle valve Is very common Check th e brush in the dizzy cap actually contacts the rotor arm sweep plate Read the post about manifold leaks , amd fitting heat shields , can alsomhave air leaks Squirt some brake cleaner or even petrol along the gaskets , does it suck it in ? Timimg will affect all plugs the same and wont be erratic the vac pipe only helps economy it wont affect how it runs and any air leak is so small and enters after the throttle plates wont cause much problem. Do check the small braided wire in the dizzy is intact Are the dizzy contact terminals secure , also check the coil is wired for correct polarity if its negative earth at the batery then the coil neg goes to dizzy and pos+ has the ign feed Do you have std or pancake air filters? Check the HT coil wire terminal is clean in side no green corrosion under the plastic seal inside the coil head I guess this is a delco dizzy they generally dont suffer from rotor arm problems Let us knowmwhat you find Thanks for this, I'll have a look today. I'm not sure of the make of the distributor and they are pancake air filters not standard. Why would that make a difference? Thanks Oli Link to comment Share on other sites More sharing options...
Clive Posted June 27, 2018 Report Share Posted June 27, 2018 Like Pete I reckon ignition related. My first checks would be rotor arm, condenser and possibly cap. Also the coil... New ones don't seem to be very good, Lucas are not what they were. If you have locals, borrow known good bits off their cars.... If it is the coil, I would buy a bosch one 1 Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 27, 2018 Report Share Posted June 27, 2018 pancakes offer less resistance to the incoming air and as such this lowered depression in air vacuum cant suck as much fuel from around the needle and its jet so they often require a needle change away from std. f it also has a 4-2-1- tubular extractor manifold the problem gets bigger and even more of a needle change and damper springs can be needed to richen the running mixture thats why its often best to stick with what triumph designed ....it worked unless you are into much twiddling Pete Link to comment Share on other sites More sharing options...
oliproctor Posted June 27, 2018 Author Report Share Posted June 27, 2018 Hi Pete and Clive, I'm pretty new to ignition systems so you'll have to bare with me! Distributor was changed last year by the last owner and looks clean and all in working order inside (see first pics) and seems to be a Delco dizzy like you said. All connections seem secure and rotor arm seems to be contacting the contacts nicely as they're all marked, does this answer your comment below? (see pic 2). If so where is the brush you mention? 4 hours ago, oliproctor said: Check th e brush in the dizzy cap actually contacts the rotor arm sweep plate 3 hours ago, oliproctor said: also check the coil is wired for correct polarity if its negative earth at the batery then the coil neg goes to dizzy and pos+ has the ign feed With regard to this sentence above, my car is positively earthed at the battery (not negatively as you said) with the coil positive going to dizzy and negative going to the ignition feed back through the bulkhead, is this correct? (see pics 3 and 4) All terminals are clean with no green corrosion. What is the best way to make sure the condenser is working too, just double checking to make sure its the silver small cylinder (like a AA battery) in the dizzy (see first pic). Thanks and sorry for asking so many questions, very keen to learn! Oli Link to comment Share on other sites More sharing options...
DerekS Posted June 27, 2018 Report Share Posted June 27, 2018 Just a thought here. The other problem with pancakes is that they tend to draw hot air from the engine and exhaust manifold rather than cooler air from the front of the car. I had problems with this a few years ago using K+N filters, going back to standard sorted it. Link to comment Share on other sites More sharing options...
oliproctor Posted June 27, 2018 Author Report Share Posted June 27, 2018 17 minutes ago, derekskill said: Just a thought here. The other problem with pancakes is that they tend to draw hot air from the engine and exhaust manifold rather than cooler air from the front of the car. I had problems with this a few years ago using K+N filters, going back to standard sorted it. By going 'back to standard' do you mean the pancake filters within an air filter box? I didn't think that was standard on a Mk2? Thanks Oli Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 27, 2018 Report Share Posted June 27, 2018 that all looks ok there is no diy easy test for a condenser, if the contacts get burnt badly then expect a condenser fault there are some terrible ones on sale with little inside the can. brush contact with the sweep plate is shown on top of the rotor arm the springy contact must touch the carbon brush in the top of the cap , you cant see this , but a nice light rub mark on the springy bit shows its in contact, if there is a etched burnt mark then theres a gap and the spark is having to jump this and the cap contacts and the plugs . do have squirt test on the carb heat shields and manifold gaskets , dont use brake fluid it burst into flames staright oil works but will smoke on the exhaust, then if its all sound have you ever re set the mixtures it may just be set very lean , pete Link to comment Share on other sites More sharing options...
oliproctor Posted June 27, 2018 Author Report Share Posted June 27, 2018 33 minutes ago, Pete Lewis said: that all looks ok there is no diy easy test for a condenser, if the contacts get burnt badly then expect a condenser fault there are some terrible ones on sale with little inside the can. brush contact with the sweep plate is shown on top of the rotor arm the springy contact must touch the carbon brush in the top of the cap , you cant see this , but a nice light rub mark on the springy bit shows its in contact, if there is a etched burnt mark then theres a gap and the spark is having to jump this and the cap contacts and the plugs . do have squirt test on the carb heat shields and manifold gaskets , dont use brake fluid it burst into flames staright oil works but will smoke on the exhaust, then if its all sound have you ever re set the mixtures it may just be set very lean , pete Hi Pete, Video attached shows the Easy Start spray noticeably increasing revs under idle when sprayed onto the heat shield/manifold gasket. Maybe not completely noticeable from the video but is this the source of all my problems? If so, why is it not spluttering straight away and only after 15-20 mins? Thanks Oli IMG_2214.TRIM.MOV Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 27, 2018 Report Share Posted June 27, 2018 i would think heat is opening the gaps and helping loose sealing and clamping is probably defective air leaks will cause backfires Link to comment Share on other sites More sharing options...
oliproctor Posted June 27, 2018 Author Report Share Posted June 27, 2018 So would you suggest taking the carbs off with the heatshields, clean up the gasket areas and make sure each surface is smooth, replace gaskets???, add gasket sealant and new gaskets and then do up the bolts nice and tight to see if that makes a difference? Is it worth changing the fuel line that runs around the carbs whilst I'm at it? Thanks Oli Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 27, 2018 Report Share Posted June 27, 2018 have you had a read of the troubles we had on twiddle day and the post i made about manifold studs all to do with air leaks Pete Link to comment Share on other sites More sharing options...
Colin Lindsay Posted June 27, 2018 Report Share Posted June 27, 2018 1 hour ago, oliproctor said: By going 'back to standard' do you mean the pancake filters within an air filter box? I didn't think that was standard on a Mk2? Thanks Oli Mk2 had the very nifty black pancake filters, no box. However: Fitting a box may help, if you can find one with the correct spacing for the carbs, or else make one. Link to comment Share on other sites More sharing options...
Ben Caswell Posted June 27, 2018 Report Share Posted June 27, 2018 In the close up pic of the coil it looks like a yellow wire is chafing against the neg terminal worth moving anyway. Ben 1 Link to comment Share on other sites More sharing options...
Casper Posted June 27, 2018 Report Share Posted June 27, 2018 51 minutes ago, Colin Lindsay said: Mk2 had the very nifty black pancake filters, no box. However: Fitting a box may help, if you can find one with the correct spacing for the carbs, or else make one. I'm not sure you are right, Colin. My Herald has a Mk 2 Spit manifold/carbs and airbox. Mk 1, however - I think that originally had open pancakes, and perhaps changed to airbox. The spacing is different on a Mk 3. Con Link to comment Share on other sites More sharing options...
oliproctor Posted June 27, 2018 Author Report Share Posted June 27, 2018 1 hour ago, Pete Lewis said: have you had a read of the troubles we had on twiddle day and the post i made about manifold studs all to do with air leaks Pete Yes I've had a read, luckily my threads and nuts are all okay. But is what I said the correct thing to do as below? Thanks 1 hour ago, oliproctor said: So would you suggest taking the carbs off with the heatshields, clean up the gasket areas and make sure each surface is smooth, replace gaskets???, add gasket sealant and new gaskets and then do up the bolts nice and tight to see if that makes a difference? Is it worth changing the fuel line that runs around the carbs whilst I'm at it? Link to comment Share on other sites More sharing options...
oliproctor Posted June 27, 2018 Author Report Share Posted June 27, 2018 1 hour ago, Colin Lindsay said: Mk2 had the very nifty black pancake filters, no box. However: Fitting a box may help, if you can find one with the correct spacing for the carbs, or else make one. ANyone have one of these spare or willing to sell? Thanks Oli Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 27, 2018 Report Share Posted June 27, 2018 its not good to use sealer on manifolds there's a lot of panting where heat and vibrations in the engine make faces shift about more than you imagine many sealers have a long term hate with petrol and it can get dissolved in time however with the multiple faces to seal with gaskets manifolds heat shields and carbs the use of a non setting high viscous sealer may solve some of your problems , needs must rules apply. once all is airtight you can readjust the needles to get the mixture and idle speeds under control and see how she runs pete Link to comment Share on other sites More sharing options...
oliproctor Posted June 27, 2018 Author Report Share Posted June 27, 2018 13 minutes ago, Pete Lewis said: its not good to use sealer on manifolds there's a lot of panting where heat and vibrations in the engine make faces shift about more than you imagine many sealers have a long term hate with petrol and it can get dissolved in time however with the multiple faces to seal with gaskets manifolds heat shields and carbs the use of a non setting high viscous sealer may solve some of your problems , needs must rules apply. once all is airtight you can readjust the needles to get the mixture and idle speeds under control and see how she runs pete Is there a sealant you would recommend? And what about new gaskets? Thanks Oli Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 27, 2018 Report Share Posted June 27, 2018 always best to use new gaskets , as for sealer blue hylomar or similar i use loctite 574 but thats a setting sealer ok on carbs faces but not manifold to head ...really that needs to remain dry fit Pete Link to comment Share on other sites More sharing options...
Anglefire Posted June 27, 2018 Report Share Posted June 27, 2018 RTV is the other type of sealant that is often used - has a very high temperature tolerance - 300'C is some cases. Link to comment Share on other sites More sharing options...
Colin Lindsay Posted June 29, 2018 Report Share Posted June 29, 2018 On 6/27/2018 at 5:43 PM, Casper said: I'm not sure you are right, Colin. My Herald has a Mk 2 Spit manifold/carbs and airbox. Mk 1, however - I think that originally had open pancakes, and perhaps changed to airbox. The spacing is different on a Mk 3. Con You're right! It was the MK1 with two filters and the Mk2 with the black-painted airbox. Well, it was a long time ago Link to comment Share on other sites More sharing options...
daverclasper Posted June 29, 2018 Report Share Posted June 29, 2018 Hi. According to a experienced member. If you remove the condenser, as suspect, then car will run ok, though will burn our points if left like this. Dave Link to comment Share on other sites More sharing options...
Pete Lewis Posted June 29, 2018 Report Share Posted June 29, 2018 if it runs it wont be very happy condensers also buffer the coil to aid it discharge cleanly, a failing condenser can cause backfires if it discharges when you dont want it i found a local last week where the heel had worn down so far there was no adjustment left and the points were all but closed without a spare, remedy was to grind the end which now fouled the condenser mount and slot the adj screw hole the points faces were as flat as new so it had a brilliant condenser fitted , we need more like that . if you get a duff one cut it open should have around 9ft of waxed insulated foil wound up inside . Pete Link to comment Share on other sites More sharing options...
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