June 19, 201411 yr My 2002 H6 Outback with 220,000 miles. One intake valve is tight - can't get my smallest gauge in it.The other intake valve in that same cylinder is fine. All the exhaust valves are fine. If it were an exhaust valve I'd be concerned, but will intake valves cause any issues over time?
June 19, 201411 yr If it won't seal, it'll leak exhaust, but it won't get as hot as an exhaust valve (unless the valve or seat erodes). One tight valve out of all of 'em, are you sure you're not catching an unworn portion of the bucket?\ What is spec, and what is your smallest gauge?
June 19, 201411 yr What kind of valve setup does that thing have? Rocker arms or direct overhead cam? Does that engine have a shared rocker arm for the intake side like the phase 1 EJ has?
June 20, 201411 yr Author DOHC, shim over bucket fairtax. no rocker arms. lobes directly engage the buckets. .008 int and .010 ex like most subarus i think. definitely more than zero! .003 & .0015 gauges wouldnt fit. i checked them all a few times, rotated engine over.
June 20, 201411 yr Author wonder how many shims they normally have? could i simply remove a shim. i wont but sounds tempting.
June 20, 201411 yr I believe these are set up like the 25d, which has one shim placed in the bucket. Shims of vary in thicknesses and the bucket is a constant. You could calculate the thickness you need to get it back in spec and order the single shim from subaru.
June 20, 201411 yr Author Could you take some off the valve's stem? yes, but the engine is not disassembled. if i get to installing the engine tonight or tomorrow I might grind down the shim to a lesser thickness if it's holding me up from installing the engine. otherwise i'll get one from Subaru. i've never heard of a burnt intake valve though or intake valves causing issues...so i'm also tempted to leave it. wonder what Gloyale, GD, or Shawn would say to this one intake valve situation? well i guess they'd just say - adjust the valve!
June 20, 201411 yr Engine is out of the car? I would pull cam and swap shims around with another looser Intake valve and see if you can get your clearance right without havi g to buy shims. I used to do that on motorcycle engines. Find the loosest intake valve and swap with it and hopefully that will give both enough room to breathe
June 20, 201411 yr Something iffy is making that valve different, either the stem is stretching or the seat is receding or maybe the shim isn't seated properly under the bucket... when you adjust the clearance it will be interesting to see just how much lack-of-slack there is. For grins, do a leakdown on that cyl while you have the engine out?
June 20, 201411 yr Author I guess I should investigate - it's one thing if it's tight, another thing if there's zero clearance. Will do Monday when I get back in town.
June 20, 201411 yr Usually if unsure about valve clearance you can just tap the valve stem with a hammer to open and reseat the valve. Not sure if that's doable with the DAMB. Maybe you can cut a small block of wood to fit around either side of the cam lobe and have the ends sit on the bucket.
June 20, 201411 yr yes, but the engine is not disassembled. if i get to installing the engine tonight or tomorrow I might grind down the shim to a lesser thickness if it's holding me up from installing the engine. otherwise i'll get one from Subaru. i've never heard of a burnt intake valve though or intake valves causing issues...so i'm also tempted to leave it. wonder what Gloyale, GD, or Shawn would say to this one intake valve situation? well i guess they'd just say - adjust the valve! 3 options 1) Loosen cam caps slightly , slip a "J" shaped tool with an edge on it under the cam against the edge of the bucket.(Snap-on, Mac, Cornwell all sell this tool for shim replacement) to force the edge of the bucket down on the vavle......this will allow the shim to slip out. Measure it and buy a thinner shim.I think they are sold in .02mm increments....0.02~.04mm 2) remove cam entirely, remove bucket, grind tip of valve that protrudes above spring just a bit.....can't take too much or the stem tip will be below the spring retainer.....but you might get .005"(in) which should be enough to get in spec. this option really is best when the heads are off and the valve can be removed and ground...rather than on the engine. 3) leave it.......if you can get even any feeler in at all there is some space
June 23, 201411 yr So these are shim-over-bucket... So maybe you could take a bit off the bucket part that pushes against the valve stem- not sure how you'd do it though...
June 23, 201411 yr In that case I would use a prybar or screwdriver or whatever else to push the bucket down a little and pop the shim out with a magnet. Then get a new shim for it.
June 24, 201411 yr My 2002 H6 Outback with 220,000 miles. One intake valve is tight - can't get my smallest gauge in it. The other intake valve in that same cylinder is fine. All the exhaust valves are fine. If it were an exhaust valve I'd be concerned, but will intake valves cause any issues over time? Yes,you will get a rough idle once the clearance disappears. Page 23 may interest you. http://www.submariner.org/thepno95/Documents/Subaru%20H6%20Technician%20Reference%20Manual.pdf Edited June 24, 201411 yr by naru
June 24, 201411 yr So these are shim-over-bucket... So maybe you could take a bit off the bucket part that pushes against the valve stem- not sure how you'd do it though... The point isnide the bucket on this engine is not nearly so long. For Subies it's just barely a nub on the inside of the bucket. Gary, you need to determine if they are even truely shims on bucket........or various thickness of the Buckets themselves (like newer WRX). Shims are Cheap($3) Buckets are more expensive ($20) You could try what Zombieforce suggests......if you've got a valve with alot of clearance, swap the shim (or whole bucket) with the tight one and recheck clearance. No garauntee.......but you might get into spec this waay. I know when I do a whole 16v regrind on a head.....I ussually only need to buy a new shims because you can swap around alot to reuse ones you already have.
June 24, 201411 yr Yes,you will get a rough idle once the clearance disappears. Page 23 may interest you. http://www.submariner.org/thepno95/Documents/Subaru%20H6%20Technician%20Reference%20Manual.pdf Looks like it's a big disk shim, at least that's harder to lose. Hmmm, how rough? My idle isn't all that great. Actually there's a vacuum-gauge test for this, isn't there?
June 25, 201411 yr Author Why can't I just grind down the shim and make it thinner? That seems like the easiest solution. Engine goes in today if all goes well, i may try this first. Engine sat for a few months - is it possible the bucket or something is just stuck from sitting? I'm thinking of just running it and rechecking after it's run a bit.It's hard to imagine all the valves having plenty of clearance except for one.
June 25, 201411 yr Author Looks like one issue with grinding a shim - if they are case-hardened then you remove the hardness from them. If I have time to drop the engine in tonight I'll grind down the bucket side of the shim so the cam lobe only rides on the "case hardened" side, if that be the case.
June 25, 201411 yr The shims are designed to rotate, the cam doesn't hit them right in the middle. They may not be perfectly flat on both sides, and if you did grind down the 'flat' side you might not get it flat enough. You could sand down the low 'flat' part of the cam lobe... (forget I said that) If it is hardened, as you suggest if you ground down the bucket side the hardening is probably not important on that side. Edited June 25, 201411 yr by CNY_Dave
June 25, 201411 yr Author ha ha - thanks dave! of course i'd prefer just getting dealer shims but it's terribly inconvenient due to distance and other logistics. i would have just bought a bunch of different ones, but there's so many i wouldnt' even know where to start or what a "typical" shim thickness even is.
June 26, 201411 yr Author 220,000 miles - all valves had decent clearance except this one valve. The shim of the tight valve was 2.42 mm and another was 2.32. Swapped shims and the 2.42 was too big and would always be tight. I ground the bucket side of the shim from 2.42 to 2.20 mm and clearance was 0.008". Was that shim simply a mistake, too big from the factory?
June 26, 201411 yr I'll say that if this valve is in an 'easy to reach' (as if) location maybe check it in 10 or 20k... What range of shims is available for purchase? It would be alarming if the ideal shim for you was thinner than the thinnest available.
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