OK next things next on the list of things to be done on my M20B20 With L Jetronic. Since I got the car it has been running roughly and making a slight tapping (pinging?) noise towards the rear of the engine. It runs loudly and sounds like a tractor. I've changed the timing belt and played with the ignition timing in addition to putting in brand new spark plugs and spark plug leads, changing the fuel filter and oil. I fixed one leak I found in the vacuum lines. I haven't gone to the point of doing a smoke test. Is there anything I'm missing? Here is a video. What does it sound like? https://youtu.be/W8TRDyZoAyc And when messing with the distributor timing https://youtu.be/I7gQc_Dk_CM
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Stock M20 runs like a tractor
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Originally posted by ForcedFirebird View PostPinging on the distributor m20's is more than likely too much timing from a faulty distributor advance (which is vacuum and centrifugal advance). Add that to the higher compression and lack-luster fuel and they are quite unhappy.
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You don't have a location, so unsure if you are in the US. Fuel ratings are different from EU to US, so yes, 89 octane or better (91+ preferred). There is no "adjustment" for vac advance, there's mechanical vac canisters, check valves etc. Then there's also a weight inside the distributor that advances timing as RPM goes up. If either system is faulty, the timing will be all over the place.
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Originally posted by ForcedFirebird View PostYou don't have a location, so unsure if you are in the US. Fuel ratings are different from EU to US, so yes, 89 octane or better (91+ preferred). There is no "adjustment" for vac advance, there's mechanical vac canisters, check valves etc. Then there's also a weight inside the distributor that advances timing as RPM goes up. If either system is faulty, the timing will be all over the place.Sent from my Mars pro using Tapatalk
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If it looks like a tractor, it's probably a tractor.
In all seriousness, a smoke test is your best bet to accurately highlight any vacuum leaks.
Yes it's a bit of messing about (and may require a DIY smoke tester if you don't have one) but it takes the guess work out.
From the video, does sound like the valve clearances need a check.
My M20 has 197k km on it and even with correctly adjusted valves it sounds a bit like a sewing machine.
As you're also in AUS, I'd stick to 95 RON fuel.
Our old leaded super petrol was 94-96 RON.
You can cheap-out with E10 which is circa 95 RON - but keep in mind the energy density of E10 is lower than regular fuel.
E30 320i vert
But daily drive is Volvo V60 Polestar
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