Dirk Posted November 7, 2009 Share Posted November 7, 2009 (edited) My No3 cylinder pings at idle. It does this mostly when its warm but if I remove the plug lead the ping dissapears. The symptom is not present under load. Its an early EA71 engine. no mods. I re-built the engine two years ago so bearings are all good and all else in there seems to be fine. Cylinders honed, new rings, valves re-seated, new oil seals, new bearings, heads skimmed etc. Timing is correct spark plugs are correct valve clearances are near enough carburetor is fine too although a little worn. Ignition system is new Oil pump in good nick recent compression check perfect. I have searched through the threads but not yet found my particular problem. Pretty sure this is not the Tick of Death since my valves are mechanicly lifted. I was wondering if I am getting pre-ignition for some strange reason. Compression check was spot on but I just get the feeling that this cylinder may just be getting to hot. Or perhaps a burning carbon deposit. It also occured to be that the master vac hose connects to the mannifold on this side. Could it be leaking extra air into the cylinder running it leaner and hotter? Does any one have ideas or a specific thread to look at? THanks in advance Edited November 7, 2009 by Dirk additional info Link to comment Share on other sites More sharing options...
Dirk Posted November 7, 2009 Author Share Posted November 7, 2009 I checked my valve clearances this morning and they are perfect. Had a look at the spark plug and it seems healthy. The valve lifting rods were in good order when I last saw them and in any case the noise dissapears when I remove the plug lead. This suggests to me that it is not a mechanical problem. I thought pinging only occurs under engine load but the engine is fine under load and at speed. It only pings like this at idle and under very light load and only when the engine is warm. Link to comment Share on other sites More sharing options...
ihscout54 Posted November 8, 2009 Share Posted November 8, 2009 Sounds a little like a bad wrist pin. Perhapse the noise is too faint to notice under load. Could be an issue with the piston as well. You will need a laser thermometer to test your theory. I would think youde have a lousy idle befor youde have a ping at idle. Are you sure this is a ping, and not some other rattle? Does your car have an egr valve? Link to comment Share on other sites More sharing options...
Dirk Posted November 8, 2009 Author Share Posted November 8, 2009 wrist pin is the one holding the piston on its rod, right? Can't garantee that its a text book ping but it at least sounds very similar. You are quite right about me not being able to hear the noise at higher revs. It is possible that it is still there. No erg valves. My rocker vent hoses are currently venting in to Red Bull cans. Im still suspicious that the sound dissapears when there is no spark. Looking into octane ratings and timing at the moment. Its a 1979 EA71 so I guess it was origionaly designed for leaded fuel. Currently using premium fuel which here in New Zealand is between 95 and 97 RON. I wonder if this is also a factor? Link to comment Share on other sites More sharing options...
Numbchux Posted November 8, 2009 Share Posted November 8, 2009 Currently using premium fuel which here in New Zealand is between 95 and 97 RON. I wonder if this is also a factor? could be. higher-octane fuel burns slower. although, I don't remember which octane tends to be higher. Our fuel is rated as an average of the 2, so your octane rating isn't necessarily comparable to ours. Link to comment Share on other sites More sharing options...
Dirk Posted November 8, 2009 Author Share Posted November 8, 2009 Ive just been fiddling with the timing. Whether I advance or retard, it makes no difference. I guess this rules out the octane theory? The noise deffinately gets worse as the engine gets hotter. At this stage the wrist pin looks likely although I would still like to explore the possibility of pre-ignition. Not sure if I can get hold of a laser thermometer. What about using a colder spark plug? Which would be a higher number right? Currently using 6bps. Link to comment Share on other sites More sharing options...
ihscout54 Posted November 8, 2009 Share Posted November 8, 2009 wrist pin is the one holding the piston on its rod, right? Correct, they usually make a clink clink tick sound and can sometimes be heard through the exhaust. I have never heard one on a flat 4 though. Im still suspicious that the sound dissapears when there is no spark Since there is zero load on the piston when its not firing, wrist pin and rod noises dissapear when the cyl isnt firing, unless they are really bad. Link to comment Share on other sites More sharing options...
ihscout54 Posted November 8, 2009 Share Posted November 8, 2009 Does this sound have any mech. rythm to it, or is it just kinda sporadic and random? Link to comment Share on other sites More sharing options...
Dirk Posted November 8, 2009 Author Share Posted November 8, 2009 The sound is a consistent mechanical noise. I guess the answer here is the wrist pin then. Shame, I was hoping for a quicker fix. The sound was present before I re-built the engine and when I did I inspected all parts pretty thoroughly. I guess not thoroughly enough. That said, any play in that pin must be fairly nominal for me to miss it and the engine doesn't seem to suffer much for it. Think ill just live with it until the next re-build. Thanks so much for all your help. It is at least nice to know what the problem is. Link to comment Share on other sites More sharing options...
ihscout54 Posted November 8, 2009 Share Posted November 8, 2009 Its probably not the pin its self, but one of its connecting points or the bushing is out of spec. Did you replace the rod bushings? Start tracking down another piston, pin, and rod from a j/yard, so you have them ready when you are going to do the next rebuild. Its better to get stuff while you are driving then loose a month during a rebuild hunting parts. IMO you have time, just keep an ear on it. One of my ex-scouts had a wrist pin noise for 2 years (daily driver) and I sold it that way. It never got any worse, but just hearing it kinda took some of the fun out of my drives. Good luck! Link to comment Share on other sites More sharing options...
Dirk Posted November 8, 2009 Author Share Posted November 8, 2009 Sound advice. Cheers Link to comment Share on other sites More sharing options...
GeneralDisorder Posted November 9, 2009 Share Posted November 9, 2009 I have experienced rod bearing failure, and on the EA engines it doesn't sounds like a rod knock. It's a very gentle metallic noise - much like a ping. Only does it when warm and usually only under throttle. At the time I didn't know what it was. It never got worse as far as I could tell - till one day I was doing 65 MPH on the freeway and it got REAL loud for about 1/2 mile. Then the rod smashed through the top of the block. Guess which cylinder it was No. 3 is farthest from the oil pump and in my years here I've asked most of the people that have experienced rod bearing failure which cylinder it was - always No. 3 My vote is for a rod bearing. Wrist pins experience almost no actual rotation and they are VERY strong. I strongly doubt it's a wrist pin. GD Link to comment Share on other sites More sharing options...
Dirk Posted November 10, 2009 Author Share Posted November 10, 2009 Thankyou GD Sadly I do not have the time or money to re-build at this stage. So I guess I will have to wait a while before I am able to truely satisfy my curiousity. The sadist in me is quietly hoping for a spectacular result. Time will tell. Many thanks for your time. By the way, When do you sleep??? Link to comment Share on other sites More sharing options...
GeneralDisorder Posted November 10, 2009 Share Posted November 10, 2009 Well - it's 7:30 PM here in the great state of Oregon. Although it's true that I only sleep about 7 hours a night for some strange reason. I visit the board on breaks from the garage and from the laptop while watching the TV. GD Link to comment Share on other sites More sharing options...
ihscout54 Posted November 10, 2009 Share Posted November 10, 2009 Well - it's 7:30 PM here in the great state of Oregon. Although it's true that I only sleep about 7 hours a night for some strange reason. I visit the board on breaks from the garage and from the laptop while watching the TV. GD If you dont have TIVO its one way of getting through the redonculous amount of prime time commercials. Link to comment Share on other sites More sharing options...
GeneralDisorder Posted November 10, 2009 Share Posted November 10, 2009 If you dont have TIVO its one way of getting through the redonculous amount of prime time commercials. Yeah - and it's how I drown out the rediculous shows the woman has to watch :-\. Why do we have to watch people looking at houses to buy (House Hunter's)..... I'm not in the market for a house and I really don't care what these strange people want or are looking at 3000 miles from me..... WTF is the fascination with the drivel of other people's lives? GD Link to comment Share on other sites More sharing options...
Dirk Posted November 10, 2009 Author Share Posted November 10, 2009 How I laugh! All becomes clear. We threw out our TV years ago for the same reason. so many channels and all the same crap. By the way, how old were you when you got your first subaru? I'm guessing from the quantity of knowledge and experience you have it must have been pretty early. Plus I also guess you were educated the real way i.e. as an apprentice? Link to comment Share on other sites More sharing options...
GeneralDisorder Posted November 10, 2009 Share Posted November 10, 2009 (edited) By the way, how old were you when you got your first subaru? I guess I was about 21 or 22 at the time. Got an EA81 wagon for $400 at a dealer auction. I'm guessing from the quantity of knowledge and experience you have it must have been pretty early. Plus I also guess you were educated the real way i.e. as an apprentice? Not exactly. No one in my family owned a Subaru prior to me. And my father never worked on a car that I can recall. He worked 35 years for a lumber yard though so I grew up no stranger to tools. He was a C-130 mechanic in the Air Force and I later joined the Army as a generator tech. I took everything apart that I could get my hands on as a kid. Used to fix lawn mowers and tillers as a young boy. Bought them for a few $$ each from the city dump. My education history is long and varied. Everything from Software Engineering to Industrial Machinery.... I get bored with stuff fast. I soak up information like a sponge but don't ask me to remember anyone's name. . It's got to be some kind of disease or brain damage - or maybe I just don't find "people" or their problems very interesting. ZatAoMM...... yeah. GD Edited November 10, 2009 by GeneralDisorder Link to comment Share on other sites More sharing options...
Dirk Posted October 1, 2011 Author Share Posted October 1, 2011 UPDATE: Well there was indeed a little pinging/knock going on which I have resovled with a combination of tuning and cooling. The major noise however was infact the rocker assembly! Most of the oil passages needed a good clean. One in particular was totally blocked. Have totally reconditioned the rocker assemblies and cleaned out the push rods properly. Also I have reamed out the oil passages in the rocker adjusting screws since these were the smallest holes. After this and the tuning the engine sounds beautifully smooth and quiet with just the satisfying sound of my happy little tappy tappets. ALL GOOD! Thanks to all for input. Dirk Link to comment Share on other sites More sharing options...
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