SUBARU3 Posted March 14, 2005 Share Posted March 14, 2005 One of my gen 1s has been doing this knock on start up. (Knock always stops, EXACTLY when the oil pressure light goes out) Oil pressure light stays on longer now. Longer than any of my other gen 1s. I could understand if the vehicle had been sitting a week , but 2- 3 hours and it does it again. The knock lasts about 2-3 sec. No issues with the engine at all. Runs fine/plenty of oil, (mobil one for the last 30K) Is this the oil pump starting to fail? Is something leaking down and not primed on startup?? o-ring?? Should I just change the pump and see if that makes a difference? Ideas would be appreciated. Quote Link to comment Share on other sites More sharing options...
HattoriHanzo Posted March 14, 2005 Share Posted March 14, 2005 Worn mains??, might try hooking up a test gauge in the sender port so you can take a reading, and synthetic does flow much better than regular oil so you made a great point about leakdown, perhaps you'll need a filter with a valve, or it is siphoning out of the bearings back into the sump. Quote Link to comment Share on other sites More sharing options...
SUBARU3 Posted March 14, 2005 Author Share Posted March 14, 2005 Gosh, I hope it's not the mains! But in a 4 speed BRAT, it does rev higher/more wear. So could it be the oil pump being weak? Quote Link to comment Share on other sites More sharing options...
erik litchy Posted March 14, 2005 Share Posted March 14, 2005 are you using a real oil filter? Quote Link to comment Share on other sites More sharing options...
SUBARU3 Posted March 14, 2005 Author Share Posted March 14, 2005 Using the Purolater equivilent of the Subaru filter....NOT EVER A FRAM!! LOL Todd Quote Link to comment Share on other sites More sharing options...
swiftt Posted March 14, 2005 Share Posted March 14, 2005 The knock is most likely the con-rod bearings. They're making all that noise because no oil has reached them yet on the start-up. I think the oil pump would be a good place to start. I've read on this board that to reseal the oil pump is not too hard and makes a world of difference. I've never done this myself so I won't speak to it. New oil pumps are not that expensive so that's certainly an option too. Depending on what you use this car for, keep in mind that some damage has already been done to the bearings. If you only use it for groceries on Sundays, you'll probably get a lot more use out of it with only the work on the oil pump. On the other hand, if you count on this car to be reliable, you may want to start saving your pennies knowing that a bottom-end rebuild is in the future. Quote Link to comment Share on other sites More sharing options...
SUBARU3 Posted March 14, 2005 Author Share Posted March 14, 2005 Thanks for the feedback! I think I will start with the oil pump. I have 6 cars and it's not driven alot and it has, at the most, had 10- 15 starts this way. I think until I replace the pump.....I'll flood it a sec to prevent it from starting right away and let it crank the oil pump a bit first. (Heck, this might be an excuse to put in one of my 3 spare engines) Todd Quote Link to comment Share on other sites More sharing options...
hops Posted March 15, 2005 Share Posted March 15, 2005 Hey Todd, I used to have a similar problem with my '78. It always went away after I changed out the oil filter and oil. I also think that my oilpump was weak in that engine. Klaus Thanks for the feedback! I think I will start with the oil pump. I have 6 cars and it's not driven alot and it has, at the most, had 10- 15 starts this way. I think until I replace the pump.....I'll flood it a sec to prevent it from starting right away and let it crank the oil pump a bit first. (Heck, this might be an excuse to put in one of my 3 spare engines) Todd Quote Link to comment Share on other sites More sharing options...
tailgatewagon Posted March 15, 2005 Share Posted March 15, 2005 hi subaru3. i have this on my 73 if its at idle the light is on. i think it has to do with the idle being set to low in my case... in your case it sounds like people used cheep oil filters in the past. cheep filters dont have the little check valve or it leaks down and the oil filter is empty on startup... so the crank is empty at start up to... this is what caues the knock on ea81s most of the time and i bet its what has happend to your ea71. i dont know whay people dont just use oem filters there not that expenisve and they work grate. or at least i wish people wouldnt go to walmart and get the 1.88 dollar ones... oh well good luck... my ea81 has had this knock for 2 years its gotten worsh but not buy much.... Quote Link to comment Share on other sites More sharing options...
hops Posted March 15, 2005 Share Posted March 15, 2005 Don't jump to conclusions about whether people buy cheap oil filters. My '78 also had the "oil light is on" at idle syndrome, but only after getting off the freeway and coming to a stop at a light. It had nothing to do with the idle speed, naturally if you set the idle at 2000 rpm's the problem would not happen. So I am possitive that it was an oilpump problem. Klaus hi subaru3. i have this on my 73 if its at idle the light is on. i think it has to do with the idle being set to low in my case... in your case it sounds like people used cheep oil filters in the past. cheep filters dont have the little check valve or it leaks down and the oil filter is empty on startup... so the crank is empty at start up to... this is what caues the knock on ea81s most of the time and i bet its what has happend to your ea71. i dont know whay people dont just use oem filters there not that expenisve and they work grate. or at least i wish people wouldnt go to walmart and get the 1.88 dollar ones... oh well good luck... my ea81 has had this knock for 2 years its gotten worsh but not buy much.... Quote Link to comment Share on other sites More sharing options...
SUBARU3 Posted March 15, 2005 Author Share Posted March 15, 2005 I'm going to change the oil pump. I'll let you know the results. My oil light never comes on when running, it's just on for a few "extra seconds" at start up. That's when I have the knock. The knock stops and the light goes out at the same time. Quote Link to comment Share on other sites More sharing options...
moosens Posted March 16, 2005 Share Posted March 16, 2005 Doesn't the oil pump supply the heads primarily? and the crank,main bearings,and con.rods are lubed from the oil bath in the oil pan? You do get noise upon start up when your filter doesn't have the bladder valve but that's top end noise. Good luck Todd. Quote Link to comment Share on other sites More sharing options...
swiftt Posted March 16, 2005 Share Posted March 16, 2005 I've never pulled apart a Subaru engine but I have pulled apart a lot of various automotive engines. In every application I've experienced, the crank has oil galleys that pass through it. There are exit holes drilled on the journals for oil to pass and lubricate the mains and the con-rod bearing surfaces directly. I don't have a Subaru manual with me to confirm but I can't imagine it's lubed strictly by an oil bath in an automotive application. In my mind, it would be hard to get the 300,000 miles some report out of an engine with a primitive oil bath lubricating the bottom end. The crank's oil galleys are pressurized by the oil pump. On start-up, the oil is in the pan and needs to be circulated to the engine by the pump. Until this oil reaches the crank journals, the journals are dry (of course this varies depending on how long the engine sat since last start-up) and will have a tendency to make some noise. This would be why he hears the noise until the engine oil light extinguishes. This is because the oil system pressurizes, feeds the journals and quiets them, simultaneously triggering the oil sending unit to open the circuit and extinguish the dash light. Just like magic, the engine has oil pressure. The knocking quiets in roughly the same instant the light goes out. This sequence happens in all of our cars every day. A strong oil pump, clean quality filter, clean oil, clean oil galleys, and journal bearings that are in good shape make this routine virtually inperceptible. When the oil system starts to get tired, the bearings start to wear, the symptoms described will become more and more pronounced. Quote Link to comment Share on other sites More sharing options...
moosens Posted March 16, 2005 Share Posted March 16, 2005 Sounds good to me.Thanks Quote Link to comment Share on other sites More sharing options...
SUBARU3 Posted March 18, 2005 Author Share Posted March 18, 2005 Well, it was the oil pump! The screws on the back plate were loose, the oil ring was severely compressed and there was a crack in the back plate too. These pumps are a bit_ cH_ to get off, but the new one went right on! (Gosh I love using my new parts instead of just moving them around the workshop!) At any rate, it starts without a knock and the oil light goes out immediately! (Just like my other 3) Thanks for all the feedback!! Todd Quote Link to comment Share on other sites More sharing options...
HattoriHanzo Posted March 19, 2005 Share Posted March 19, 2005 Right on!! Glad it was nothing major. Quote Link to comment Share on other sites More sharing options...
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