B-210 GX Posted January 30, 2018 Report Share Posted January 30, 2018 After completely replacing the wiring harness and having the engine rebuilt at a reputable local machine shop, I still have a miss in cylinder 3. Plugs 1, 2, and 4 are fouled normally, 3 is clean as a whistle. Have replaced plugs and plug wires, to no avail. Also swapped in a Pertronix electronic ignition setup. Anything stupid I'm overlooking? Been working on this car for a year and a half now and I'm convinced it'll do anything to stay in the garage. Quote Link to comment
Crashtd420 Posted January 30, 2018 Report Share Posted January 30, 2018 First thing that come to mind is ignition timing... Have you checked or replaced the distributor cap... could be something wrong with it.. even if new... maybe try an old one.... look and see if anything looks burnt up.... Quote Link to comment
datzenmike Posted January 30, 2018 Report Share Posted January 30, 2018 Check the valve lash. Check the compression. 1 Quote Link to comment
banzai510(hainz) Posted January 30, 2018 Report Share Posted January 30, 2018 engine rebuilt? that's should have found a crack valve or a valve not set right if constant. wire harness? Now I don't know how or why that would be only of cylinder 3 bad as ythat dnt make sense trouble shooting wise. now if 3 is not fireing you can tell buy grabbing it with yur hand with the plug wire . If you get shocked then the dist is routing the crrent to the spark plug. so its either cracked valve , bad plug ,severly blown ring or maybe the guy forgot to put the piston in , cause your not compressing the mixture to explode as it going ut some where or you got a massive intake leak on that runner if its a sideraft set up. If just a normal downdraft carb the other cly would see this also. Quote Link to comment
racerx Posted January 30, 2018 Report Share Posted January 30, 2018 I don't think it's timing. I'm with Mike and do a compression check or bad spark plug wires or connection. 1 Quote Link to comment
Crashtd420 Posted January 30, 2018 Report Share Posted January 30, 2018 I don't think it's timing. I'm with Mike and do a compression check or bad spark plug wires or connection. If his timing is way off it could be a problem.... Pull all 4 plugs and make sure they are all sparking... then go from there... If #3 isn't firing then switch the plug and wire and see if the error follows or not... If the error stays with #3 then check the cap and rotor... If that tells you nothing then start at the beginning... As Mike said compression check Valve lash.... then start at tdc... Make sure the dizzy is installed correctly... then reset your timing... Quote Link to comment
banzai510(hainz) Posted January 30, 2018 Report Share Posted January 30, 2018 timming way off? a timming light would catch this. not a motor rebuild. before or after. we assume he swapped the rotor and cap already as it cheaper than engine rebuild. but one can grab end of wire and get shocked and that would be the ezeist or place near ground to get spark. I don't know A motors if this Hydralic valve set up or not. My 510 when it runs on 3 cly I pull the plug wire and runs (if I get shocked I know wire is good) Ithe valve lash fell out of retainer. or valve too tight. Quote Link to comment
Doctor510 Posted January 30, 2018 Report Share Posted January 30, 2018 After completely replacing the wiring harness and having the engine rebuilt at a reputable local machine shop, I still have a miss in cylinder 3. Plugs 1, 2, and 4 are fouled normally, 3 is clean as a whistle. Have replaced plugs and plug wires, to no avail. Also swapped in a Pertronix electronic ignition setup. Anything stupid I'm overlooking? Been working on this car for a year and a half now and I'm convinced it'll do anything to stay in the garage. Firing order: 1-3-4-2 COUNTER CLOCKWISE 1 Quote Link to comment
datzenmike Posted January 31, 2018 Report Share Posted January 31, 2018 After completely replacing the wiring harness and having the engine rebuilt at a reputable local machine shop, I still have a miss in cylinder 3. Plugs 1, 2, and 4 are fouled normally, 3 is clean as a whistle. Have replaced plugs and plug wires, to no avail. Also swapped in a Pertronix electronic ignition setup. Anything stupid I'm overlooking? Been working on this car for a year and a half now and I'm convinced it'll do anything to stay in the garage. How do you know it's #3??? If idling and you pull the #3 wire off and there's no change in the idle then yeah something not right. Try pulling the other three off one at a time and observe the results. Quote Link to comment
distributorguy Posted January 31, 2018 Report Share Posted January 31, 2018 It can be simply too much fuel as well, but look at it from a scientific perspective: loss of compression? Check valve lash and test compression Then check for spark - timing light on each plug wire to verify, try 8-10 BTDC at idle. Ohm your plug wires and verify under 5000. Adjust fuel mixture to get a good plug color. Quote Link to comment
banzai510(hainz) Posted February 1, 2018 Report Share Posted February 1, 2018 maybe cam lobe for #3 cyl is worn down Quote Link to comment
B-210 GX Posted February 3, 2018 Author Report Share Posted February 3, 2018 After replacing the dizzy cap and spending some time with a feeler gauge, car runs like a dream. Greatly appreciate all the help and advice, don't know where I'd be without this forum. Quote Link to comment
racerx Posted February 3, 2018 Report Share Posted February 3, 2018 The contact on dizzy cap was corroded? Quote Link to comment
datzenmike Posted February 3, 2018 Report Share Posted February 3, 2018 Yes it sure would be nice to know what cured the problem so others can try it. Quote Link to comment
B-210 GX Posted February 3, 2018 Author Report Share Posted February 3, 2018 Im fairly certain the valves were just adjusted poorly, the valves for cylinder 3 were very loose. Quote Link to comment
datzenmike Posted February 4, 2018 Report Share Posted February 4, 2018 Loose is OK. When the lifter is off the bump on the cam the valve should be closed and there can be clearance. A too tight valve, one with no clearance between rocker and valve tip, can hold the valve open. Quote Link to comment
distributorguy Posted February 6, 2018 Report Share Posted February 6, 2018 Its not uncommon to have a new cap with a terminal that's not machined correctly. A significantly smaller air gap between the terminal and the rotor will result in a cylinder with a weaker or stronger spark. A rotor with almost no clearance or scraping a terminal will have very poor spark. Typically the gap is about the same size as your plug gap, and that helps boost coil output voltage. Without that gap, that cylinder will have a weaker spark. Quote Link to comment
banzai510(hainz) Posted February 6, 2018 Report Share Posted February 6, 2018 was doing it before the rebuilt and after and a wire harness comes down to a dist cap? Quote Link to comment
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