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Old 03-26-2007, 09:31 PM   #1
Mike1967
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Default Leaking Valves?



Seems like my luck keeps taking a bad turn on this project.

I recently had a valve job done on my heads. I cannot remember if I checked them before bolting my engine back together (what can I say...it has been a hectic month) :-( Anyway, I strapped everything back together and fired her up 2 weeks ago only to hear the same clicking clatter that I had heard before I tore her down and did the valve job. I then did some research and learned about spun rod bearings. I pulled the pan and saw significant metal shavings in the pan, so I am very confident that I had a spun rod bearing in my shortblock.

Anyway....I have since bought a replacement block ( I will post pics of that further down this thread). Since I was tearing down my old engine rebuild I decided to do a quick flashlight test on the valves........upon doing this test I discovered that I could see light through one of the valves. So I assumed that I had either bent a valve from the piston with the faulty rod bearing, or the machine shop did a crappy job.

So this morning I decided to fill all 4 intakes with tranny fluid based on feedback from another member of this forum. When I came home from work today I noticed that I not only had 1 leaking valve....but 4. The 2nd valve from the left had a completely empty intake reservoir....all the fluid leaked out. This valve had shown no indication of light when I did the light test. The valve that had the light showing through had a reservoir that was half full. Note: The heads sat with the fluid in the intake ports for approximately 9 hours.

First Question: Is this definitely indicative of a faulty valve seating?
Second Question: Could a spun rod bearing have cause damaged to the valves? When I put it back in, weekend before last, I had it idling for a total of approximately 20 minutes while I tried to isolate the sound with a stethoscope. So I suppose I could have damaged the valves while it was idling?

I am already leaning on the machine shop to redo the job....but I do not want to hold them accountable for something that I could have caused
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Last edited by Mike1967; 03-26-2007 at 10:10 PM.
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Old 03-26-2007, 09:57 PM   #2
Mike1967
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Pistons on the replacement block. I have not cleaned them yet.



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Old 03-26-2007, 10:03 PM   #3
Mike1967
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Default Cracks in block

Are these cracks normal and only cosmetic???????????


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Old 03-27-2007, 12:03 AM   #4
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Yeah, they're normal. They're left behind from casting flash (grammerer?), if you were to look at almost any cast aluminium block closely you would see them. Just surface inperfections.
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Old 03-27-2007, 03:46 AM   #5
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Quote:
Originally Posted by my4isflat View Post
Yeah, they're normal. They're left behind from casting flash (grammerer?), if you were to look at almost any cast aluminium block closely you would see them. Just surface inperfections.
Thanks!

I was pretty confident that these were nothing to worry about....but that nagging doubt would not go away
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Old 03-27-2007, 04:24 PM   #6
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Well...my posts should be entertaining if nothing else

I ran a modified valve leak test last night per a previous write-up on this forum. I laid the heads flat, combustion side up. I then filled the combustion area with tranny fluid....after screwing in the spark plugs.

After letting it sit all night.....you can see that there was very very minimal leakage. (see pic below)



Only two things changed between the test in my first photo at the beginning of this thread and this test in the photo above.

(1) I removed the rockers
(2) I poured the fluid in the combustion area instead of in the Intake ports.

I do not expect that a valve would only leak one direction and not the opposite direction.....so....I do not think that variable #2 above was the cause of the change in results between the two experiments.

It has to be tied to the rockers....which means that my lash adjustment procedure was for crap. But what has me scratching my head is the fact that I was able to insert a feeler gauge between the spring pin and the valve pin. I would expect that if there were enough force on the spring to be pushing the valves open even a few mils....then I would not be able to insert a feeler gauge between the end of the valve and the end of the spring.

But incorrect lash is the only thing that I can see that would cause the results to change. Unless I am wrong about valves not leaking in one direction.

If it is the lash...then that would also explain why my leakdown readings were for all over the map...prior to my last tear down.

I am going to reinstall the rockers and then repeat this test procedure to see if the leaking reoccurs.

If it does, then I will adjust/loosen the lash settings on my rockers and redo the leak test per the above photo.

Pretty sad when you cannot even do a basic procedure with feeler gauges.
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Old 03-27-2007, 06:15 PM   #7
Matt Monson
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#2 is the reason for the change in results. Think about it for a bit. You will get it.
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Old 03-27-2007, 06:23 PM   #8
Mike1967
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Quote:
Originally Posted by Matt Monson View Post
#2 is the reason for the change in results. Think about it for a bit. You will get it.
Hmmm...I am thinking 1 of 2 things.

One - the valves are designed to keep pressure in....not keep pressure out
Two - there is more weight from the fluid due to the depth of the intake bore?

Am I warm?
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Old 03-27-2007, 07:09 PM   #9
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Can anybody else answer this riddle ?
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Old 03-28-2007, 10:38 AM   #10
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Bump

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Old 03-28-2007, 01:47 PM   #11
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You might want to recheck your valve adjustment. If the rocker arms are installed you might see some leakage if the adjustment is off, also some noise. valve noise sounds alot different than rod bearing noise.
It does not make a flip on what side you pour fluid in, if the valve is unseated it's going to leak.
Did you buy a used short block? you may want to take a look at the bearings on that one if you did.
and just to clear things up for me, you did adjust the valve lash after the valve grind.
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Old 03-28-2007, 02:01 PM   #12
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Quote:
Originally Posted by crampfan View Post
You might want to recheck your valve adjustment. If the rocker arms are installed you might see some leakage if the adjustment is off, also some noise. valve noise sounds alot different than rod bearing noise.
It does not make a flip on what side you pour fluid in, if the valve is unseated it's going to leak.
Did you buy a used short block? you may want to take a look at the bearings on that one if you did.
and just to clear things up for me, you did adjust the valve lash after the valve grind.
I did reset the lash after I got the heads back.

The noise I heard after I put everything back together was definitely not the valves. I am pretty sure it is rod bearing knock. I dropped the pan and found about 2 tablespoons of metal flakes. Also, there was no indication of valve to piston knock when I tore the engine back down this past weekend.

I did drop the pan on the new block and there is no metal in the pan. The engine only had 23K original miles on it....so I was not expecting any issues with rod bearing throw. This came out of a car with massive backend damage and some front end damage. The driverside Cam Sprocket was shattered, the timing belt cover was shattered, and the thermostat was shattered. But the Cams were in one piece and the heads appear to be in good order. The Block looks new other than the gunk that has built up from sitting in the yard for a period of time.

I just want to make sure that I got a fair job for what I paid for on the Valve regrinds. This particular machine shop mainly deals in larger engines. I am down here in Texas...so a lot of V8's. I am thinking that their tolerances are not as fine as what I would get from shop that specialized in high RPM engines like the Subaru.
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Old 03-28-2007, 03:31 PM   #13
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Valve jobs a valve job, you should not see any daylight past the valve seats. If you can see daylight past the valves, take the heads back to the machine shop, and tell them they owe you an gasket kit too.
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Old 03-28-2007, 03:40 PM   #14
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Quote:
Originally Posted by crampfan View Post
Valve jobs a valve job, you should not see any daylight past the valve seats. If you can see daylight past the valves, take the heads back to the machine shop, and tell them they owe you an gasket kit too.
Sounds good
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Old 03-28-2007, 03:41 PM   #15
Mike1967
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Quote:
Originally Posted by crampfan View Post
Valve jobs a valve job, you should not see any daylight past the valve seats. If you can see daylight past the valves, take the heads back to the machine shop, and tell them they owe you an gasket kit too.
Gasket kit meaning head gaskets only? Or exhaust gaskets as well?
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Old 03-28-2007, 05:20 PM   #16
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Gasket kit, what ever you had to use when you put the heads on. If they goofed it why should it cost you? If I installed a set of heads that did not work the machine shop would be paying my parts ,antifreeze and oil as well as my labor. (if they wanted my business again anyway)
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Old 03-28-2007, 08:34 PM   #17
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Mike I believe the answer to your riddle is during your first test you only tested the intake side. During this test you tested both sides. You can see the fluid coming out of the exhaust port.

Did I win?
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Old 03-29-2007, 11:26 AM   #18
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Quote:
Originally Posted by Tim Sanderson View Post
Mike I believe the answer to your riddle is during your first test you only tested the intake side. During this test you tested both sides. You can see the fluid coming out of the exhaust port.

Did I win?
Nope

It leaked a lot more when I only had fluid in the intake ports. It leaked much less when I turned the heads on their sides and put fluid over both the intake and exhaust valves.

One would think it would leak faster in the second instance because now you have 8 seals instead of just 4.

I believe that it is a combination of the weight distribution of the fluid and the angle cut of the seats. The fluid is much more concentrated with more weight at the seal on the first example. Also, the angles are cut to keep pressure in...not out....so I beleive that from the backside of the valve the cuts actually channel the fluid into the seal thus causing more leakage.

But I am pulling all of that out of my butt.
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