valve spring, sticking valve?

[jaredts]

I'm doing a cylinder leakdown on my bad cylinder of my 350, and I believe my biggest problem (probably not the only one), is in the exhaust valve of #4.  If I push down on the valve it fairly easily drops 1/8" or more before I feel strong spring pressure.  I don't really feel it come back up and the leakage is much worse.  If I then wack the valve (rocker arm really) with a rubber mallet it seals back up.  That's not right, right???  I am sure I'm at or near the top of the compression stroke.  I haven't done any other cylinders, but in a compression check a while back this one was the problem.  Should I put the valve cover back on and try a seafoam treatment before I go any further?

[jaredts]

Oh yeah, I hear the air escaping out the exhaust, and after pushing down on the valve to get it to leak more its louder at the exhaust pipe.  Its getting late, I might do all of the cylinders tomorrow, or at least a couple others for comparison.

[HAULIN IT]

What are you "pushing the valve down" with? You are correct in assuming that this isn't good. Do you have the rocker arm removed? You want to try to isolate the item causing the problem.
At this point I think I would get the piston to TDC & remove the spring. You can use air to hold the valve closed, however I'd use the rope fed in the sparkplug hole in this case. I would want to move the valve up & down to see if there is resistance near fully closed...bent valve maybe? I hate to be thinking negative, but I think purchasing head gaskets is in your near future. Lorne

[jaredts]

Originally I just whacked it lightly with a rubber mallet, and the leakage decreased.  Repeated hits with the mallet after that didn't change anything, so I pushed down on the valve with my fingers and the leakage increased.  Tap it with the mallet it seals up a little better again.  I've had myself convinced that I have bad rings, but haven't yet seen evidence of that with the tester, so pulling the heads and not changing the whole motor would be good news.  checked #6 last night and it was good at 20% leakage.  I'm not going to tear into this motor at all if I find air coming from the dipstick tube on any cylinders, so I need to test all cylinders.

[jaredts]

I guess my bottom end is good, best I can tell.  My head numbers come up as crack prone, poor flow, etc.  Now I guess I'm looking for assembled heads that don't require all kinds of other new parts.  I'd go vortec but rockers, hardened pushrods, and an intake seems to jack the cost up.  Is this the best thing going for a budget oem style replacement?
http://www.summitracing.com/parts/SUM-152123/

[Grim 82]

I can't find the link but I think it was Lorne that mentioned some budget minded china heads for sbc that seemed to be pretty comparable.

[jaredts]

You must be talking about the eq heads in this post:
http://forum.73-87chevytrucks.com/smforum/index.php?topic=19333.0
I haven't found them at a great price, and would like assembled heads.  I'm open to anything at this point.  In the past I would just yank the heads and get a valve job, but now this darn internet and all of its info tells me not to mess with smog era heads, and that my casting number is one of the worst (462624).  I found a deal on Edelbrock e-street heads for under $800 for the pair, assembled.  Still trying to decide.  Should I spend $800, $1200, $3000?  My head's spinning.

[big bear]

whats your budget? and whats the goal?

[jaredts]

My goal is to spend little, but have something a little better than crack prone, low flow heads.

[VileZambonie]

If you can open the valve with your finger there's your issue. If the spring isn't broken you need to pull the head.

[jaredts]

Thanks everyone.  I'm guessing its a worn valve guide full of crud, so I got a price on reworking the heads.  $160 each but seats and guides are extra and if I have all new seats and guides done it will cost something like $600 for both heads.  From what I gather this would be a dumb move as these heads are garbage.  Anyone have an opinion on the summit head I posted or know of another way to get this done for under a grand?

[HAULIN IT]

so I pushed down on the valve with my fingers and the leakage increased. 

When you find why you can push the valve open with your fingers...you will know the cause of your leakage.
Earlier you mentioned "drops an 1/8" fairly easy before I feel spring pressure". Sounds to me the spring has broken. Look around it to see if Two wraps are laying on top of each other.
A guide full of crud should be HARDER to open by nature, but it CAN'T be easier! That reasoning can't apply if your pushing the valve open with your finger. Lorne
 

[jaredts]

Hmmm.  I looked, but maybe not closely enough.  I've got the valve cover back on it now, so it might have to wait a few days to look again.  I'm going on the assumption that I didn't miss anything and I need some heads.  I'm having fun just looking for now, but what the heck, its only a little more money to get into vortec heads, I might go that route.     Heads still spinning a little (lots of options).

[1979C20]

You do know there are 2 springs per valve, right? One inside the other.

[TexasRed]

I wouldn't feel too hesitant on using those summit heads. Summit Racing owns Trickflow, so that's probably the company making them. They should make some good low end torque.