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BUDGET valve clearance job


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agreed. i wonder why they get tighter in the first place - i made some guesses in post #11, but I'm sure there's more to the story. and why (at least what i saw anyway) they might continue to tighten up a little more after that.

 

it's conceivable that clearances could get larger (due to wear for example). it just seems that our engines are more prone to clearances getting smaller.

BtSsm - Android app/Bluetooth adapter. LV, logging, gauges and more. For 05-14 Legacy (GT, 2.5, 3.0, 3.6), 02-14 WRX, 04-14 STi, 04-14 FXT, 05-09 OBXT
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The valve seat wears into the head over time which causes the clearance to shrink. I prefer to set on the higher side of the spec. As long as you don't go too far the change in noise and wear is negligible (in my experience).

 

Valve clearance can get larger if the face of the cam wears prematurely or if the bucket seizes in its bore.

 

For anyone considering machining their buckets - make sure you keep the face of the tool flat, parallel, and concentric to the face of the bucket nub. Try to get a good surface finish too - the bucket spins on the stem of the valve.

Edited by Underdog
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I'm sure this has been discussed but I haven't found the correct search. Has anyone thought of a community lifter collection. I have 10 lifters after doing my engine that I would be willing to swap out for different sizes (the person needing the lifter would send their trade ins' and pay the shipping). Just a thought.
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I'm sure this has been discussed but I haven't found the correct search. Has anyone thought of a community lifter collection. I have 10 lifters after doing my engine that I would be willing to swap out for different sizes (the person needing the lifter would send their trade ins' and pay the shipping). Just a thought.

 

That is a good idea actually. At least I'll keep you in mind in case you have a lifter I need in the near future ;).

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So for the exhaust valves, target is .35mm with the largest 'tolerable' clearance being .40mm. How high would you go then?

 

Strictly up to you :) Maybe split the difference between "target" and "largest"?

 

EDIT: oops I see you were asking underdog. maybe he's got a different suggestion?

BtSsm - Android app/Bluetooth adapter. LV, logging, gauges and more. For 05-14 Legacy (GT, 2.5, 3.0, 3.6), 02-14 WRX, 04-14 STi, 04-14 FXT, 05-09 OBXT
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I would just try to get it in the upper half of the tolerance zone (.35-.40mm), rather than in the lower half. This recommendation is for someone trying to work with parts they have; I usually have my machinist mix and match buckets and machine the valve stems to get everything as close to nominal as possible, but again biasing to the high side.
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Thanks guys for the feedback. I am actually looking forward to do this :)

 

sounds like you enjoy a good challenge :)

 

btw, if you're swapping buckets around on an engine stand, with the head you're working on facing up, a small magnet makes it really easy to pull the buckets out of their bore.

 

But I believe you said you're going to give it a go while the engine is installed? I haven't tried that personally. But I would imagine that if you pull the exhaust cam, all 4 buckets will slide out and bounce off the floor - just be ready to prevent that :)

BtSsm - Android app/Bluetooth adapter. LV, logging, gauges and more. For 05-14 Legacy (GT, 2.5, 3.0, 3.6), 02-14 WRX, 04-14 STi, 04-14 FXT, 05-09 OBXT
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sounds like you enjoy a good challenge :)

 

btw, if you're swapping buckets around on an engine stand, with the head you're working on facing up, a small magnet makes it really easy to pull the buckets out of their bore.

 

But I believe you said you're going to give it a go while the engine is installed? I haven't tried that personally. But I would imagine that if you pull the exhaust cam, all 4 buckets will slide out and bounce off the floor - just be ready to prevent that :)

 

Yes. I will probably use some 'macgyver' method to keep the buckets in place before I pull the cam. I will also probably mark them before I remove the cam too. In any case, I will be sure to keep you posted!

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  • 3 weeks later...

The first head I flipped over, all the buckets fell out. At least I'd sort of prepped for it by having the head over the work table with clean cloths on it. The second one I flipped quickly from a low height. A light tap with a plastic hammer released them all.

 

After I'd lubed everything up with moly-lube on re-assembly, I had to pry each one out with my super finger grip. The magnet approach would have been a better idea.

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  • 2 weeks later...

My cylinder #2 has had a yucky misfer for a few thousand miles and after trying every other conceivable fix I just checked my valve clearances (oil still on my hands... and now keyboard).

 

The buckets for my exhaust valves only have .008" clearance so I'm definitely in need of an adjustment. I work at an aerospace manufacturing shop so I'm gonna try to sweet talk the best guy in our tool room and hope I can convince him to machine my buckets on one of his mills. I have a drill press at home, so if all else fails I'll try the unmodified heiche method.:cool: If I end up buying new buckets what's the harm in jacking up my stockers?

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My cylinder #2 has had a yucky misfer for a few thousand miles and after trying every other conceivable fix I just checked my valve clearances (oil still on my hands... and now keyboard).

 

The buckets for my exhaust valves only have .008" clearance so I'm definitely in need of an adjustment. I work at an aerospace manufacturing shop so I'm gonna try to sweet talk the best guy in our tool room and hope I can convince him to machine my buckets on one of his mills. I have a drill press at home, so if all else fails I'll try the unmodified heiche method.:cool: If I end up buying new buckets what's the harm in jacking up my stockers?

 

Congrats on finding your misfire issue! FYI my car is running better than ever, now on E85 (with BNR 16G turbo), and it's been 1.5 years and 5K miles since I first did this procedure.

 

btw, the little grinding stone i used was like this one, although I swore it was a dremel brand. maybe not, can't remember. It was a tough little guy though. I had started with some larger stones that i had for an air powered die grinder, but they didn't last (they started to wear). I ended up trying a small dremel stone in there, and it turned out to be the best stone (longest lasting). It's the one pictured in post #1. I think I only used 2 of those.

 

So whether it's your aerospace guy that does the work, or you do this on your drill press, please keep us posted!

Edited by heiche
BtSsm - Android app/Bluetooth adapter. LV, logging, gauges and more. For 05-14 Legacy (GT, 2.5, 3.0, 3.6), 02-14 WRX, 04-14 STi, 04-14 FXT, 05-09 OBXT
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If this fixes my misfire I'll buy your app just to say thanks ;)

 

You should still buy it regardless. Best app ever for our car to monitor engine health and catch potential issues before they get worse.

 

Btw, I have also found similar issues in the same cylinder. See here http://legacygt.com/forums/showthread.php/my-turn-adjust-valve-clearances-242071.html

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It looks like I'll be trying out the heiche method this Saturday morning as long as my TB and cam sprocket don't put up too much of a fight.

 

Does anyone know the approximate overall height of our buckets?

I'm not about to go out and buy a micrometer so I really need my [employer-owned] 0-1" mics to work.

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Just checked one... they are exactly 1" tall. A 0-1" mic should work, that's what I used. You only have to open the mic about 1/4" or more to sort of "hook" it around the open end of the bucket.

 

One important note is that when you mic a bucket, try to center it as best as you can on the nub. However, you don't want the inner arch of the mic to be contacting the edge of the bucket. Allow for a little space. You'll see what I mean. Just make sure the mic arch isn't binding with the bucket.

BtSsm - Android app/Bluetooth adapter. LV, logging, gauges and more. For 05-14 Legacy (GT, 2.5, 3.0, 3.6), 02-14 WRX, 04-14 STi, 04-14 FXT, 05-09 OBXT
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Just checked one... they are exactly 1" tall. A 0-1" mic should work, that's what I used. You only have to open the mic about 1/4" or more to sort of "hook" it around the open end of the bucket.

 

One important note is that when you mic a bucket, try to center it as best as you can on the nub. However, you don't want the inner arch of the mic to be contacting the edge of the bucket. Allow for a little space. You'll see what I mean. Just make sure the mic arch isn't binding with the bucket.

 

I just checked and my mic actually opens up to about 1.060" so i should be fine. The frame looks to be about 1" deep so I don't think I'll have any clearance issues measuring all of the way into the center-most point of the bucket. My mic

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