GeneralDisorder Posted August 17, 2006 Share Posted August 17, 2006 Tearing down the EA81 out of my Brat. Approximately 175,000 on the engine. Previous owners were none too kind to it, and I've flogged it pretty hard for the last 40k. Anyway, it's never idled right, and while it did have a lot of power, it also had a rough idle that I couldn't get rid of, and a knocking noise that you can feel in the shifter, and hear very clearly and distinctly when the oil fill cap was removed. I always assumed this was probably a main bearing knock. The knock was not like a rod knock, and persisted for many thousands of miles. The oil pressure wasn't great when I got the car, and I promptly changed the pump - after which it was 25psi hot idle, and over 50 cruise. Although I think it was too late. After doing a lot of work to put on the SPFI and comming up with an idle quality that was too poor for my needs, I decided it best to tear the engine down for a full rebuild. The mains are scored, and pretty far out of spec. I haven't removed the rods as it doesn't really matter at this point - I already have a turned crank and full bearing set ready to go. My quandry is I can't find any place that sells plastiguage that measures down to the tollerance of the EA81. It's extremely close - acceptable being .010mm - .025mm. The smallest I can find online measures *down* to .025mm but no smaller.... and the stuff I had on hand (red) seems to indicate the old bearings were somewhere around .075mm or more - anyone think that could confirm my analysis of the noise and poor idle quality? The cam - well the cam lobes look just aweful. I imagine lack of oil delivery was probably the cause here, but wow - I've taken out a few EA82 cams with far more mileage and probably just as bad or worse treatment that don't look anything like this.... Looks like some severe oil deprivation caused heating and spalling of the surface - maybe just for a short time it was run without oil or something? GD Quote Link to comment Share on other sites More sharing options...
jeffast Posted August 17, 2006 Share Posted August 17, 2006 checker sells plastigauge i forget what we call it but i have seen it edit that looks awful Quote Link to comment Share on other sites More sharing options...
Phizinza Posted August 17, 2006 Share Posted August 17, 2006 That looks nasty! Quote Link to comment Share on other sites More sharing options...
4x4_Welder Posted August 17, 2006 Share Posted August 17, 2006 The lifters weren't spinning. It looks also like it's not really a question of whether or not it was run without oil, but how many times. As far as clearance, that has to be a typo. There is no way less than one one-thousandth of an inch can allow sufficient oil flow to prevent contact. If you drop the zero out of the metric version, it makes a good deal more sense, and puts the range at roughly .004-.009". I wouldn't run an engine with less than .002", you're just asking for a burnt bearing that way. I mean, I understand that these engines are very precisely machined, but an oil film can only go into so tight of a spot. Quote Link to comment Share on other sites More sharing options...
NorthWet Posted August 17, 2006 Share Posted August 17, 2006 ...As far as clearance, that has to be a typo. There is no way less than one one-thousandth of an inch can allow sufficient oil flow to prevent contact... Ummm... If you look in the FSM that I loaned you, it probably says what the clearance should be. :-p Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted August 17, 2006 Author Share Posted August 17, 2006 Hhhmmm - don't think it's a typo - both the FSM and the Haynes manual I have list that spec. GD Quote Link to comment Share on other sites More sharing options...
NorthWet Posted August 17, 2006 Share Posted August 17, 2006 For the EA82, clearances are listed as 0.0004-0.0021inch, so similar for the EA81 sounds reasonable. Gosh, that is tight. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted August 17, 2006 Author Share Posted August 17, 2006 So..... where do I get the plastiguage that the FSM calls for? GD Quote Link to comment Share on other sites More sharing options...
4x4_Welder Posted August 17, 2006 Share Posted August 17, 2006 Oh, I did look it up, cause I remembered that I forgot to give that back to you, and it does say the same spec. Haynes and Chiltons books are just poor copies of FSMs, so I would expect any misinformation to be the same. I'm not saying that the manual is wrong, but that has got to be wrong, the minimum spec is .0003", the max is .0007", just way too little. Also listed in the manual, the range of main journal size is .0006", more than the accepted range of the bearing. Quote Link to comment Share on other sites More sharing options...
NorthWet Posted August 17, 2006 Share Posted August 17, 2006 "Borrowed" the following from another website: Plastigauge: Green- 0.001-0.003, Red-0.002-0.006, Blue-0.004-0.009, Yellow-0.009-0.020. Looks like Green for you/us. IIRC, this (green) was the stuff that I used to use all of the time; should be fairly common. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted August 17, 2006 Author Share Posted August 17, 2006 "Borrowed" the following from another website:Plastigauge: Green- 0.001-0.003, Red-0.002-0.006, Blue-0.004-0.009, Yellow-0.009-0.020. Looks like Green for you/us. IIRC, this (green) was the stuff that I used to use all of the time; should be fairly common. But you are missing a zero..... the range is .0004 - .0012.... even the green doesn't go low enough to measure the limit of the tollerance, although it would at least tell me it's within spec I suppose. Jeez, that's close. GD Quote Link to comment Share on other sites More sharing options...
NorthWet Posted August 17, 2006 Share Posted August 17, 2006 But you are missing a zero..... the range is .0004 - .0012.... even the green doesn't go low enough to measure the limit of the tollerance, although it would at least tell me it's within spec I suppose. Jeez, that's close. GD Yup... and yup. Green comes "close": Within .0006 of minimum. I can't recall having ever seen specs smaller than 0.001inch, not even on my motorcycles. Most I have heard of were 0.002-0.003 range. This is the best argument I have seen against using thicker oil. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted August 17, 2006 Author Share Posted August 17, 2006 No wonder they last so long - when they hit 100k miles, they are mearly broken in to the specs that GM started with Seriously tho - I'll be running 30 weight in all of mine now Any thoughts on the cam? Anyone? GD Quote Link to comment Share on other sites More sharing options...
NorthWet Posted August 17, 2006 Share Posted August 17, 2006 I would check out what 4x4_Welder said about lifters not rotating; I am not sure if Subarus are designed to or not (probably are). What does the wear on the lifter bottoms look like? Were they sticking in their bores? Those pictures look odd, almost like the lobe edges were crumbling. Were all of the damaged edges towards an "end" of the engine (i.e. - all were on the rearward edge of their lobes)? That might make a case for the non-rotating lifter. Quote Link to comment Share on other sites More sharing options...
bgd73 Posted August 17, 2006 Share Posted August 17, 2006 No wonder they last so long - when they hit 100k miles, they are mearly broken in to the specs that GM started with GD Cheers to that one-- no doubt about it Can't you just get bearings, ignore plastiguage if you know what your putting it into? Manufacturing original didn't use it. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted August 17, 2006 Author Share Posted August 17, 2006 They are supposed to rotate, and while the bottom of the lifters is not pristine, they don't look like the cam either. They are dished, and the cam lobes are set off at a 4 degree grind to fascilitate the rotation. They did not tick at all, were not stuck in their bores, and do rotate freely. Looked alright really.... I can't explain it. GD Quote Link to comment Share on other sites More sharing options...
GL-10 Turbo Posted August 17, 2006 Share Posted August 17, 2006 Cheers to that one-- no doubt about it Can't you just get bearings, ignore plastiguage if you know what your putting it into? Manufacturing original didn't use it. That's what Crawford Performance does... ...and they have the "bobblehead" design pistons. http://forums.nasioc.com/forums/showpost.php?p=12512810&postcount=13 Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted August 17, 2006 Author Share Posted August 17, 2006 Cheers to that one-- no doubt about it Can't you just get bearings, ignore plastiguage if you know what your putting it into? Manufacturing original didn't use it. In this case I'm using oversized bearings, and I need to double check the machinists turning work. I'll not be putting it together to find the machinist undersized my crank by .050mm, and my bearings are .025mm over Would much rather spend the few $$ on some plastiguage and find out before I try to start it.... GD Quote Link to comment Share on other sites More sharing options...
SuBrat84 Posted August 17, 2006 Share Posted August 17, 2006 I'm really curious about your cam shaft there... I just pulled an ea81 out of a brat that has nearly 1/4 million on the ticker... and the cam looks almost exactly like yours... deteriorating on the edges of the lobes like that. It wouldn't idle right or make power over 3k and it would start to overheat. I tore her apart to try to find the problem... I'm not done cleaning parts but it looks to me like the cam shaft is the only "bad" part. Is it possible that damage like that is causing our problems? Is it possible other stuff is/was getting damaged by have a cam shaft that looks like that? Looks like I need to buy micrometers and plastigauges and crap, eh? Quote Link to comment Share on other sites More sharing options...
idosubaru Posted August 17, 2006 Share Posted August 17, 2006 ive never seen any cams like that on XT6's or EA82's and i've pulled a few that had blown head gaskets and were run for awhile with water leaking badly inside the head gaskets. cams always looked good. the one i pulled apart that was run without oil had metal scarring and flakes, nothing looked like it was deteriorating like that. interesting pictures. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted August 17, 2006 Author Share Posted August 17, 2006 I am not of the opinion that the cam was causing your problems (or mine). I had excelent power, and it's never had overheating problems (new radiator). I think the rough idle could be related, but I think it more likely that it was bad main bearings that caused that as well. The cam wear looks ugly, and the flaking surface metal probably contaminated our oil, but it doesn't appear to have worn out the lobes. I never had any valve train noises, but I have hydrualic lifters and unless your 84 is an automatic, it would be solid. I haven't checked the cam journals, but that may also be the culprit of my knocking noise. I'm curious - did your engine make any noticeable noises? GD Quote Link to comment Share on other sites More sharing options...
SuBrat84 Posted August 18, 2006 Share Posted August 18, 2006 Yeah very noticable noises. at idle it clacked pretty badly.. between 1200-3000 rpms it sounded quite like it was supposed to and anything beyond 3k the clacking came back with a vengence. I had assumed it was the rod bearings.. because it still clacked when I had it down to the block.. #3 did it the worst.. and #1 did it too. Now I'm leaning more towards bent rods or something warped or I don't know. The rod bearings seem to be very smooth and okay.. but that may because they are detached from the pistons? Maybe the main bearing was bad? This is the very first block I've ever split. So.. I'm totally lost! Edit: Yeah it is Solid lifters.. and they all were just fine, really clean still and smooth and moved around flawlessly. Like I said I haven't seen anything look odd except that cam.. and didn't really think that a little deteriorating would cause my problems.. but had to ask. Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted August 18, 2006 Author Share Posted August 18, 2006 Did you ever adjust your valves? On solid lifter engines it's required every 15,000 miles.... GD Quote Link to comment Share on other sites More sharing options...
SuBrat84 Posted August 18, 2006 Share Posted August 18, 2006 I never knew if it was solid or hydro.. Would that cause over heating too? Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted August 18, 2006 Author Share Posted August 18, 2006 Not by itself - just really noisy valves. Overheating is usually the 20 year old radiator, and crappy aftermarket thermostat's. Possible you had a leaking head gasket. It's not uncommon. GD Quote Link to comment Share on other sites More sharing options...
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