Previous owner of my 79 Devon moonraker running a 1600 stock engine said it would overheat after around 3 hours driving and he’d stop her for a good hour and she’d be fine again. Recent trip and it did the same to me around 3 hours in on a drive cruising at average 50mph she started to splutter and cut out on me. Smelt hot but no oil was leaking out of anything. Left it for half hour and was fine again for me to continue. I’m wondering if the issue isn’t overheating but my carb causing the issue!?. Or could a carb heat up and cause issues. (Stock solex). What are the symptoms of overheating, how would I know? It cut out as if fuel cutting out like, i coasted into a lay-by and it shut itself down. Sent from my iPhone using Tapatalk
She runs around ok on short trips it’s the longer ones it’s an issue Sent from my iPhone using Tapatalk
Could be heat soak affecting the coil - as they get hot they loose spark and its like a fuel cutoff with some spluttering If it runs fine for 3 hours I wouldnt think its the carbs - although you can get phenolic spacers to prevent heat soak through the manifolds to prevent fuel evap and assist in hot starting
Check the engine timing. I have been told if its slightly out the engine will overheat. Then of course the tin wear and foam seal must all be correct.
It does sound like the coil, was the engine hot?ie. could you touch things in the engine bay liked dip stick? Electronic ignition can also fail when hot
Its set up very badly. Overheating at 65mph plus is easy even stock. At 50mph, no there are many things to check. If it has points check points gap. A narrowing points gap advances the timing and can cause ovweheating and simply stopping Check timing. Adjust valve clearances. Check for split rubber boots on inlet manifold, and other air leaks around the inlet manifold. Is the ignition switch worn out .. do all the dash lights go out when it stops ? Bad electrical connection to coil ? Bad fuel feed ? How long does it take to restart, and how long does it last after dying?
It has electronic ignition now and did it before that was fitted also, ignition lights stay on, tinware fine also none of the cheap chrome effect stuff on the engine. Foam seal all there, it can take anything from half hour to hour and a half to start up again and runs fine for another 3 ish hours. Puts me off going far . Sent from my iPhone using Tapatalk
By start up again do you mean it turns and wont catch or just wont turn over for the half an hour to an hour period?
Do you know if it has a thermostat fitted? It is possible that it is not set up properely. There are lots of things to check. Go through Mikejames post first. but also check the thermostat. The rod needs to be properly adjusted to allow the cooling flaps to open fully.
Ok what you are describing is quite likely the effect of it being very rich when hot, and the normal hot start procedure of putting your pedal to the metal in a single move, no pumping, and cranking for about 30 seconds is not working. Check that the choke heater is powered as this might fill it up with rich mixture as you stop.
Put points In see if happens then. I had an ignition module fail as it got warmed by conducted heat from the block. Replaced with points issue solved. Make sure to try one thing at a time to pin down the cause.
This ^^ It`s a process of elimination but try the simple things first - replace the module with points is a good start . If the problem still persists then it`s NOT the module . Check for air leaks as mentioned . Remove the thermostat if you have any doubts about it functioning as it should . Others will shoot me down but never had one on mine = one less thing to go wrong !! Invest in an oil temp guage and see what`s happening , shouldn`t really be above 125 degrees .. Etc etc .... There`s lots to check but eliminate the simple things first
Please don't remove thermostat . A simple way to check overheating is wether you van hold the dipstick .if it's so hot you can't hold it then there is a chance it is overheating . Does sound like a coil ,ignition ,fuel issue
Old style thermostats fail safe - they stretch out as though hot if they leak so your engine will still be cooled properly. It is harder to start a hot VW as every pump of the accelerator gives it fuel it doesnt need. Which is why cranking with pedal to the metal for a while sucks out the petrol as the air is not flowing fast enough through the carburettor to suck in more petrol than comes through the idle circuit. If the carburettor has dirt in the fuel metering inlet needle valve, this can make it dribble too much petrol straight into the manifold and make it hard to start and very reluctant to run when hot. As others say, electronic ignitions have their own special characters when they die - one I had acted up when hot and caused random misfires, and then died acting as a rev limiter by suddenly cutting out at about 3000 rpm, great fun to drive in stop start rush hour traffic, spectacular backfiring !! I have changed a coil because the old one got burnt by sparks tracking across the insulator. . Another possible source of misfiring. But mainly as others suggest try one thing at a time, start with inspection, adjustment and work progressively up the price range . Its likely to be something simple.
Holding the dipstick theory - I can hold mine but it's a tad uncomfortably hot. does this mean: a) I'm super human and mere mortals would be losing their skin and my van is actually overheating...or b) I'm a pansy and there is nothing wrong with it?
