HRBrat Posted November 8, 2019 Share Posted November 8, 2019 Hi all. Im the owner of an 87 BRAT that’s in really excellent shape. Minimal rust. Everything works. Almost all original. It had been running great, but after my most recent drive which involved some big highway climbs with a load in the back I started hearing a new noise that i suspect is rod knock. It’s louder and lower than lifter tapping, and it changes speed with the engine. Never had it before. Checked the oil and it was down about half a quart, but topping it up didn’t make a difference. I suspect that i need the engine rebuilt or replaced. I do all of my own regular maintenance and do bolt on stuff like CVs, brakes, struts, and Weber swap, but I think a full rebuild is probably beyond my skills. I’ve got an 84 rusted out field BRAT that runs well and could be a donor for a swap. Ive contacted local Subaru Specific Garages that have expertise in older models, but I haven’t found one willing to do either a rebuild or a swap. So now I’m most interested in finding out if there’s a guru or garage somewhere in the northwest who could take it on. This is definitely one of the nicest BRATs still on the road, and I don’t want it to just be a pretty lawn ornament. It’s been my daily driver and orchard vehicle for market for the last few years. I would also consider an EJ-22 swap depending on help i could get. I’m not a fan of sorting out wiring harnesses! I’d love to find a garage or mechanic in the Columbia Gorge or Portland area but could trailer it farther if need be. Anyone know now any good resources or have other good ideas for keeping this on the road? Thanks! Quote Link to comment Share on other sites More sharing options...
el_freddo Posted November 8, 2019 Share Posted November 8, 2019 Do a cold start and see if you can hear any knocking. I would say there isn’t any. What I think you might be hearing is actually pre-detonation. This can be due to lowered compression, poor timing, worn plugs, oil mist (from blow by pressurising the crank case), worn rings. If you do hear constant knocking at cold start up, even after oil pressure is built up, you’ve got rod knock. Unlikely in these engines unless constantly over-revved, and/or starved of oil. Cheers Bennie 1 Quote Link to comment Share on other sites More sharing options...
HRBrat Posted November 8, 2019 Author Share Posted November 8, 2019 I’m out of town at the moment and won’t be able to try a cold start until the 14th unfortunately. I checked the timing when it happened and it was still at 12btdc. I advanced it last year when putting the Weber on it. Not sure if that would have contributed. The car has never had a problem with blowing smoke but does consume and leak some oil. I’m good at keeping it topped up though. The plugs are less than a year old and are the recommended NGK. I’ve never checked the compression. The noise came out of nowhere to be very noticeable. Would a ring fail that rapidly? I had a problem with frequent backfiring in this car prior to switching from the hitachi to a Weber, but it hasn’t happened since. With the more advanced timing and the Weber it initially pinged badly under acceleration, but I’ve been running premium, and that seemed to take care of it. The current noise happens even at idle and seems very different from the prior pinging... Quote Link to comment Share on other sites More sharing options...
HRBrat Posted November 15, 2019 Author Share Posted November 15, 2019 Back in town and tried a cold start after it sat for a few weeks. Started right up, and the noise is gone. Good call el_freddo! I'm very glad to find that it's not rod knock, but i still have some concerns that the noise happened. Any thoughts on next diagnostic steps or if i should be worried? I've been meaning to check the compression for a while, and it seems like that might be a good place to start. 1 Quote Link to comment Share on other sites More sharing options...
el_freddo Posted November 15, 2019 Share Posted November 15, 2019 Yep, start at the compression check. I’m still yet to do mine. Also check the shaft play on the throttle body of the carb. I reckon this can easily mean out the mixture by sucking in air after the Venturi, leading to predetonation. Cheers Bennie Quote Link to comment Share on other sites More sharing options...
HRBrat Posted November 15, 2019 Author Share Posted November 15, 2019 I’m still a bit confused on what actually happened. I’m familiar with predetonation in the setting of pinging, but I’ve only experienced it under hard acceleration presumably while the vacuum advance is fully engaged. This sound happened at idle as well as throughout the throttle range. Any idea what might have been going on and how letting it sit for a few weeks would make it go away? Quote Link to comment Share on other sites More sharing options...
el_freddo Posted November 15, 2019 Share Posted November 15, 2019 Can’t happen at idle. Are your valve clearances correctly adjusted? Cheers Bennie Quote Link to comment Share on other sites More sharing options...
HRBrat Posted November 15, 2019 Author Share Posted November 15, 2019 It's an 87, and i'm pretty sure it has the hydraulic valves that you aren't supposed to adjust. I haven't taken the covers off to look at them though. The day the noise happened i first noticed it while getting off the highway and it continued whether i was driving slowly, going up a steep hill, or just idling. I restarted it later that day (maybe about 45 minutes after shutting it down) and the noise was still there. That was after topping off the oil. I also checked the timing at that point and found that it had not changed. Yesterday i started it up, did not notice the noise, and took it on a ten mile test drive encompassing easy 40mph driving, some in town driving, and a 55mph run up a moderate hill on the way home without hearing anything amiss. I'm going to drive it to work this morning and see how that goes. Quote Link to comment Share on other sites More sharing options...
skishop69 Posted November 15, 2019 Share Posted November 15, 2019 Good post Freddo except one thing..... Pre detonation is caused by too MUCH compression, over advanced timing or roo much blow-by bring oil into the combustion chamber. Quote Link to comment Share on other sites More sharing options...
el_freddo Posted November 15, 2019 Share Posted November 15, 2019 7 hours ago, skishop69 said: Good post Freddo except one thing..... Pre detonation is caused by too MUCH compression, over advanced timing or roo much blow-by bring oil into the combustion chamber. You’re right, I should’ve been more specific with the low compression and that it’s related to blow by and pushing oil mist into the intake system. @HRBrat - you’ll have to work out if you have hydro lifters or not. We only have solid over here. Also check for a bent push rod. Cheers Bennie Quote Link to comment Share on other sites More sharing options...
skishop69 Posted November 17, 2019 Share Posted November 17, 2019 I do it all the time, especially in the morning before I'm fully awake with copious amounts of coffee on board. I've posted stuff way more wrong than that. lol Quote Link to comment Share on other sites More sharing options...
HRBrat Posted November 20, 2019 Author Share Posted November 20, 2019 Got around to checking the lifters. They're hydraulic. I think the 86 and later EA-81s have them over here. My 89 that i had back in high school definitely did. I've been driving it all week and it appears to be running just fine. Not sure what happened, but definitely glad that the engine rebuild appears to be off the table for now! Quote Link to comment Share on other sites More sharing options...
HeyZeus Posted November 22, 2019 Share Posted November 22, 2019 HRBrat Get ahold of General Disorder. He’s in Milwaukie and owns ‘Superior Soobie and Import’. He’s leading the way in EJ swaps into second gens. He’ll be doing my swap in the next couple of months. Quote Link to comment Share on other sites More sharing options...
HRBrat Posted November 23, 2019 Author Share Posted November 23, 2019 Thanks HeyZeus! That’s great to know about. For now it seems to be running fine, but if problems come back I’ll give him a call. Quote Link to comment Share on other sites More sharing options...
el_freddo Posted November 24, 2019 Share Posted November 24, 2019 GD will say scrap the EA platform for daily duties or start stock piling spare parts that are or will be NLA. Just saying! Cheers Bennie Quote Link to comment Share on other sites More sharing options...
Checkerboard Comet Posted November 24, 2019 Share Posted November 24, 2019 (edited) Mathewson's Automotive (Renton, Washington) kept my old 86 Subaru GL running for the past 20+ years......until engine finally gave out at over 340,000 miles. They typically work mostly on vintage hot rod and collector cars, but I used them because they knew their s.... If they are within striking distance of you and your 87 Brat, I'd consider using them for your engine rebuild needs. Edited November 24, 2019 by Checkerboard Comet Quote Link to comment Share on other sites More sharing options...
GeneralDisorder Posted November 24, 2019 Share Posted November 24, 2019 You can't rebuild an EA81. You can't buy oil pumps for them. Who is going to do a rebuild without a new pump? Not to mention *I* won't rebuild one without doing a mainline hone and no one is setup to do that to an EA. Best thing to do is just find a 90-94 Legacy and do a swap. We can easily put a LINK on it and it will have parts available well into the future. GD Quote Link to comment Share on other sites More sharing options...
HRBrat Posted November 25, 2019 Author Share Posted November 25, 2019 Thanks all! As the noise has not returned I’m back to using it as a daily driver without issue so far. I’m definitely glad to know about the resources above in case I have more trouble though. Quote Link to comment Share on other sites More sharing options...
Subarule Posted November 25, 2019 Share Posted November 25, 2019 Pacific Import Auto in Tacoma is kind of a Subaru repair specialist shop. There are good and bad reviews but who knows what actually transpired to earn a bad review? The shop has been there for decades. Quote Link to comment Share on other sites More sharing options...
Teamemdor Posted November 27, 2019 Share Posted November 27, 2019 Try bringing the timing down to 10 and keep running premium. See if you can get ethanol free. I have a new ea81 oil pump btw. It's rare I know lol Quote Link to comment Share on other sites More sharing options...
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