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Post by JLantz on Mar 29, 2004 18:37:57 GMT -5
I have adjusted the valves on my 91 4wd according to the specs in my Clymers manual- .006 intake, .010 exhaust, engine cold, 1-3-2......but they are still noisy. I have adjusted valves on a few older VW's and Volvos before and am confident I am performing the procedure correctly. I've checked the valves when the engine is warmed up and they are .010 intake, .012 exhaust. So what's up? How do you experienced Justy mechanics do it?
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Post by Justy4x4 on Mar 29, 2004 19:51:45 GMT -5
It sounds like you have the correct clearance specs. All I do is check the clearance on the compression stroke with both intake and exhaust cam lobes evenly positioned so that neither one is trying to open a valve. I favor the tight end of the specs which is 0.0051" intake and 0.0091 exhaust. So far all is quiet! I have adjusted the valves on my 91 4wd according to the specs in my Clymers manual- .006 intake, .010 exhaust, engine cold, 1-3-2......but they are still noisy. I have adjusted valves on a few older VW's and Volvos before and am confident I am performing the procedure correctly. I've checked the valves when the engine is warmed up and they are .010 intake, .012 exhaust. So what's up? How do you experienced Justy mechanics do it?
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Post by JLantz on Mar 30, 2004 10:34:06 GMT -5
Did you have noise issues when using the stock .006, .010 specs? Using the tighter .005 and .009 clearances is the route I'm leaning toward, but am worried about valve burning.
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Post by Justy4x4 on Mar 30, 2004 11:01:57 GMT -5
I had previously set the valves to the specs from a Chilton manual (I think) and they were WAY noisy! After getting a genuine factory service manual I soon learned the specs from the Chilton were wrong (too loose). I reset them to the tight end of the correct specs and it's been quiet and trouble free for 7,000 miles. The valve clearance usually gets larger when an engine heats up, so valve burning shouldn't happen. Just don't go way tighter than recommended
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Post by JLantz on Mar 30, 2004 14:15:45 GMT -5
Great, I'll readjust to .005 and .009 and post the results. Thanks
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Post by JLantz on Mar 31, 2004 17:32:37 GMT -5
Ok, I adjusted to the tighter specs and it's still noisy. What about adjusting the valves when the engine is hot? I've been researching valve adjustment tips and tricks, and the 70's Datsun Z car guys adjust theirs when hot, though the manuals say to do it cold. They compensate for the expansion by adding .002" on each valve. They say they get less noise and more power due to it being a more accurate adjustment. Anyone here adjust the valves hot?
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Post by Justyracer on Apr 1, 2004 9:34:32 GMT -5
i have to say that im suprised that you have such a hard time to adjust those valves....i have done it many time and it was never a issue ? and i was far from knowing if i was doing it wrigt those litle engine can be prety noisy....wen the chain from the oil and water pump is getting loose it can make noise that "kind of " sound like the valves?....but it definatly dosent come from the same place
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Post by JLantz on Apr 1, 2004 13:09:55 GMT -5
I've used an automotive stethescope on the valve cover, the injectors, and other various points on the block, and it's definitely the valves. I'm researching how to determine what hot lash spec to experiment with now, and then will adjust intake and exhaust separately to see which ones are the noisiest.
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Post by justyfanatic on Apr 1, 2004 22:16:41 GMT -5
BTW have you checked the valve seals. Mine was making noise until I replace the seals because of excess oil blowby. The noise stopped right after.
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Post by JLantz on Apr 2, 2004 14:15:24 GMT -5
That's interesting, maybe your valve guides are worn causing stem vibration, and the new seals are helping to dampen the stem. How many miles since you installed the new seals?
Does anyone know of a source other than the Subaru dealer to purchase new lash adjustment screws?
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Post by Justyracer on Apr 2, 2004 15:02:02 GMT -5
most engine parts are only available from subaru...
but usualy these things are not so expensiv...its the labor if you dont do it your self...
i have like 2 or 3 heads that i dont need...the valves seals should be good on them... but i would not use used seals...for the trouble of changing them...get new ones....but if you need parst from the head...that i can help...i dont know what i should do whit all those heads...
maybe i can port and polish them and sell them ?
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Post by justyfanatic on Apr 2, 2004 15:40:46 GMT -5
;D Interesting!! That's the first time I've seen "Subaru" and "not so expensive" in the same sentence.
I think you may be right about the guides being worn. I changed the seals about a year ago. Not sure about the mileage. I've found the valves noisey as a rule though. I had to have them adjusted 3 TEXT after getting the car new in 1994. I didn't change the guides because of unavailability here in JA. The cost of special order wasn't worth it then. I'll do it if and when I rebuild the engine.
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Post by JLantz on Apr 2, 2004 19:00:48 GMT -5
Ok, so I pulled the lash studs out and the end were unevenly worn, so I couldn't get an accurate adjustment. I cleaned them up and readjusted to .006" and .010" specs and had less noise at start up. I did call Subaru and these studs are $2.22 each, so I'll probably get them. The valve stem ends were not worn unevenly, I think because they are able to spin. Anyways, I went for a spin and the clatter started up again. I got out my stethescope again to pinpoint the noise and it still seemed like it was coming from the valves. I started poking around the block, exhaust header, intake manifold, injectors, distributor- WHOA- lots of clatter. It seems it's the distributor. I'll pull it tonight to check for worn bearings and other gremlins. A remanufactured distributor is $230 from Napa, I'd rather rebuild it. Have any of you performed the task?
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Post by justyfanatic on Apr 3, 2004 9:56:52 GMT -5
Yes I did. What looked like a 2 hour job turned into an all day affair and 2 visits to the machine shop. The distributor in mine has a singe bearing on the shaft that has a really weird spec. I eventually matched and got one that comes from some kind of Honda application. The dealer sells the bearings but not the inner seal. The inner seal around the shaft was not listed in Subaru's parts manual at the dealer so I had to take it out and buy a replacement from matching at a bearing and seal specialist here. The parts were cheap but the machine shop and labour were not so. The bearing had to be pressed off and on to the shaft and the little pin at the end of the shaft had to be pressed out hence the machine shop visit.
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Post by JLantz on Apr 3, 2004 19:16:34 GMT -5
Was your distributor making noise before the overhaul, JustyFanatic? I pulled the distributor and the bearings have no play, but I did find something interesting. The pictures show the distributor to cam coupling, which is mounted on a pin (the one JustyFanatic had to have pressed out) and is free to wobble about that axis. That makes sense, but what is odd is the engagement tabs are off center. If you look at the bottom picture, you can see that for the tabs to be in the center, the coupling has to be loaded to one side. I assume this could create uneven centrifugal forces that would cause this to vibrate like crazy at the right RPM(My noise is most distinct around 3000-3500). I went to the local U-Pull-It to see if other Justy distributor couplings are like this but all of them in the yard had the distributors removed. When I wiggled the coupling it made the same noise as valve clatter. I used some thin plastic from a toothbrush package to temporarily limit the coupling play but it seemed to have no effect. I triple checked again with the stethescope and other than #2 intake valves making a little noise it still seems to be coming from the distributor-right where the body is in the cylinder head i.e., at the coupling. When the car cools down, I'm going to readjust the intake lash to the tighter .005" spec and see if that will help, but I'm stumped at the moment. Any thoughts?
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Post by Justy4x4 on Apr 3, 2004 21:23:29 GMT -5
The distributor drive tabs are suppose to be off center when the drive is centered on the shaft. If you look at the end of the camshaft you'll see that the slot in the end of the cam is also off center. The idea behind this is to prevent the distributor form being installed 180 degrees out of time. It'll only go in one way!
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Post by JLantz on Apr 3, 2004 22:37:31 GMT -5
Great, thanks for clearing that one up 4x4!
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Post by JLantz on Apr 9, 2004 17:29:17 GMT -5
Ok, I got a valve cover from the JY and cut out the middle so I could run the engine with access to the valve train without oil everywhere. The yellow dots in the picture indicate where the most noise was detected with my stethescope; right where the rocker arms pivot on the rocker shaft. I held the rocker arms at the ends and wiggled them, lots of play. It makes sense as this must be the worst lubricated pivot in the entire engine. To fix this: -The rocker arms can have new bushings pressed in and reamed, right? -What about the shaft? Its steel, so it shouldn't have worn as much as the rocker bushings, but if it has worn, can it be machined undersize and the new rocker bushings matched to the smaller dimension? Subaru wants $80 for a new one. I'm looking into rebuilding the cyl head anyway, so I'd have this done all at once.
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Post by JLantz on Apr 13, 2004 14:03:30 GMT -5
Will one of you that has the authentic Subaru Justy service manual post the dimensions and tolerances for the rocker arms and rocker shaft? These are not listed in my Chilton manual.
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Post by JLantz on Apr 26, 2004 0:11:14 GMT -5
I had a head rebuilt and I mounted it this weekend. The noise is still present. I didn't have the rockers reamed or bushings pressed in because the guy at the shop said he had good rockers to install. The shaft wasn't worn. I went with this because I needed to have the head done now and it was a good price. Anyways, the distributor coupling area is lubricated only by a pool of oil. The "wiggle" part of the coupling doesn't actually get oil directed at it. The oil that gets on the cam's portion of the coupling will get flung off by centrifugal force, so I think it is safe to say that the coulping is poorly lubricated. When the engine is cold there is no noise, I believe the cold residual oil that is in the "wiggle" part is thick and dampens the coupling. Tomorrow I will pack the coupling with grease when the engine is warm and see if that makes a difference. I'm hoping that the coulping and the pin it rides on is just worn.
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