Rastrahouse Posted August 2, 2012 Share Posted August 2, 2012 I just finished a complete overhaul (rings, bearings, valve job, grind crank, surface heads and block) on my 99 legacy GT (2.5L DOHC E25D) because it has spun the #3 rod bearing. I also upgraded the oil pump to the STI pump, thinking that more flow would help prevent the problem in the future. I was very happy with the results (stronger and smoother than it has been for a long time) until last weekend when it started ticking again with about 500 miles the on engine. It sounds like the original failure, not as loud, but getting worse quickly. On a cold start the ticking is very loud and quickly quiets down as the oil pressure comes up. After that the sound is quiet at idle, but get louder at higher revs. Is it possible for a rod bearing to fail that quickly? I thought about valve adjustments, but I wouldn't expect them to change that quickly, And I wouldn't expect them to quiet much as the oil pressure comes up (mechanical cam follower, no hydraulics). One interesting note, on the same trip that I noticed the ticking noise, I also found an oil leak. It is just enough to wet the heat shield at the junction of the two header pipes at the rear of the motor, and make a little smoke and smell. It's only intermittent. I'm guessing that it is the rear main seal, and that I tore it putting it in. All this really put a damper on what started out a very fun drive. This was the first time I was willing to open it up for any amount of time; I got to pass a few times on a clear road and was able to accelerate hard through the top three gears. 4500 in 5th gear is starting to be real fun, with the engine still pulling hard. Any suggestions would be appreciated; I'm back to driving the Suburban until I figure this out.. Quote Link to comment Share on other sites More sharing options...
Crazyeights Posted August 2, 2012 Share Posted August 2, 2012 Did you replace the #3 rod with a good used one or have them checked/re-sized? Was plastic-gauge used to check the rods before final assembly for clearance problems? Was the inside of the block hospital clean of any metal debris before re-assembly? Just some ideas to think about. Good Luck and please keep the thread updated with new info as you find it. Quote Link to comment Share on other sites More sharing options...
Rastrahouse Posted August 3, 2012 Author Share Posted August 3, 2012 I had all 4 rods reconditioned. I did verify the clearance of all 4 with plastigage; they were at the high end of the spec, which is what I asked for (better oil flow). The block was cleaned by the machine shop, and I rinsed it again with brakeclean before assembling it. I changed the oil after I noticed the problem (I planned to at 500 miles anyway) and it came out mostly clean, with a bit of of brown residue on a rag. The first 500 were with a straight 30wt oil. Quote Link to comment Share on other sites More sharing options...
Ricearu Posted August 3, 2012 Share Posted August 3, 2012 did you have the crank polished/machined? Quote Link to comment Share on other sites More sharing options...
Crazyeights Posted August 3, 2012 Share Posted August 3, 2012 He says he had it ground in the first post. Well if you are sure it's internal again and not something fooling you then I am not sure what else to say. You will probably end up pulling it out again and doing some forensics on it to find out what exactly went wrong. Perhaps then you will find out what caused it. Probably better to do it before it gets any more serious. Bummer though, for sure. Quote Link to comment Share on other sites More sharing options...
Ricearu Posted August 3, 2012 Share Posted August 3, 2012 (edited) whoops. on the high side of the tolerance being what exactly? high tolerance is .0018 That is less than 2 thou. if the shop ground/polished the crank in the wrong direction, it could cause premature bearing wear also. also, did you use assembly lube when you assembled that engine, or at least straight lucas additive on them? Edited August 3, 2012 by Ricearu Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted August 3, 2012 Share Posted August 3, 2012 What brand of bearings did you use? Did you prime the oil system before the first start? Whats the temperature been like there since you got it running? Straight 30wt oil doesn't flow well when it's cold. That can cause it to take longer to get full flow to the bearings on cold starts. Quote Link to comment Share on other sites More sharing options...
Crazyeights Posted August 3, 2012 Share Posted August 3, 2012 In addition to using a good assembly lube I usually pre-fill the oil filter and the oil pump through the screen. Then I crank it over with the plugs out (for higher cranking speed) until I am sure the oil pump is primed. Perhaps a dry start the first time could have caused some damage? Quote Link to comment Share on other sites More sharing options...
Ricearu Posted August 3, 2012 Share Posted August 3, 2012 In addition to using a good assembly lube I usually pre-fill the oil filter and the oil pump through the screen. Then I crank it over with the plugs out (for higher cranking speed) until I am sure the oil pump is primed. Perhaps a dry start the first time could have caused some damage? that is what i am thinking as he said he sprayed the bearings and parts down with brake cleaner prior to assembly. Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted August 3, 2012 Share Posted August 3, 2012 OWCH! A completely bone dry start? Would it even turn over? At all? :-p Quote Link to comment Share on other sites More sharing options...
john40iowa Posted August 3, 2012 Share Posted August 3, 2012 My '99 SOHC did the same thing after being rebuilt. This was '04 and I can't really remember all the specifics, but I had rebuilt due to the dreaded "Rod knock." My head gaskets were still fine with 135K, replaced anyhow. The warranty for the rebuild covered yet another rebuild and with a lot arguing of course. The solution for mine as determined by the shop was to have the cylinders slightly over bored and with larger Pistons to compensate. This did solve my engines problem and so far eight years and tens of thousands of miles later it still runs super strong with no major problems. Don't know if any of this applies to yours, and I know ccr recommends against boring a Subaru. Mine was minimal and has caused no problems whatsoever. Quote Link to comment Share on other sites More sharing options...
Rastrahouse Posted August 3, 2012 Author Share Posted August 3, 2012 A completely dry start would have been incredibly stupid. I hose it down with breaklean since my shop space doubles as a wood shop and is impossible to get absolutely clean. I coated each bearing with hyperlube (similar to lucas). The pistons were left dry, as recommended by the machine shop and the factory manual. I did not prime the pump and oil filter but had to spin it quite a bit before running it much; I forgot to connect a large vacuum hose, so there was plenty of oil in it by the time I got it running much. The bearing clearances were between .0016 and .0018. I have read a few articles about Subaru bearing tolerances being tighter than industry norms with recommendations to open them up to as much as .003 to improve oil flow and cooling. Apparently Subaru has done that on later engines. Quote Link to comment Share on other sites More sharing options...
Rastrahouse Posted September 3, 2012 Author Share Posted September 3, 2012 I got the engine stripped down and found what I thought I would; the #3 rod bearing fell out of the rod and looks as if it was running with no oil on it, even though it came out soaked in oil. The surface looks like it had melted and flowed sideways. This is the same bearing that failed originally. The baring caps were torqued properly; I was worried that it might have come loose. What could cause this? Could the oil passage in the crank be blocked? How would I check or fix this? Quote Link to comment Share on other sites More sharing options...
WoodsWagon Posted September 3, 2012 Share Posted September 3, 2012 Yup, could be clogged or it might not be getting fed enough through the main bearing the rod is lubed from. Check the passages in the block leading to that main. Quote Link to comment Share on other sites More sharing options...
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