Please sing a sad song for me....

dfink · 11-11-2006, 07:23 AM

Every thing was going along just fine routine maintenance, fix oil leak, adjust valves with new improved pass/nopass method. Check valve wear by trying to wiggle valve did not even budge. Everything look real good. So I decide to do a leak down test just for fun. Since I have everything apart. I don't have the regular leak down tester. All I have is a hose that is used to hold the valves up when changing springs or seals. Wasn't bought for this car.
Well I did #1 hey real nice don't even hardly hear any leakage. #3 had a little residue on the plug so skip to it and can't hear hardly any leakage every thing looking great. Well might as well try #2 while I'm doing it. Holy crap.... Air is leaking out the exhaust so fast I can feel it coming out the header. I had the CAT off to be replaced. Yes I had the crank in the correct position both rockers were loose. Now tried the old tap exhaust valve with rubber mallet trick to seat it valve pops shut real nice. With the plug out and the exhaust valve in the open position I can see it and It looks fine the area I can see. So I turn the engine around again and retry the lead down again but the air in the exhaust is still there. The plug on this cylinder was perfect so I am sure it was fireing fine. I have only two choices in this situation one is warped/bent valve the other is head gasket. I am hoping for head gasket. All head studs are in place. So I guess the valve seals I was wanting to do will get done now also. Crap - Crap - Crap..... One thing after another. Last week end my tow vehicle hit a deer and rendered it undrivable $6600 to a 2003 suburban. Now this.. I anybody has a better idea on the air out the exhaust let me know but I am guessing I now discover the absolute joy of pulling the heads. Oh and then the studs and then the guides and then the seals and should put in new springs for that extra 1000 rpm. Crap Crap Crap..... by the way 85' 3.2 85,000 miles but OD is off so more likely 80,000. This car pulled 203 RWH last year and still runs just as good as it did. I am hoping for head gasket. I would think a valve would just get worse. However if the gasket has been leaking it could cut the head. Crap Crap again. None of this sound any good.... I am going to go out and see if I missed something..

Tyson Schmidt · 11-11-2006, 07:57 AM

I think you'd know it if you had a vlave bad enough to let that much air by.

I think you should put it all back together and drive it. If you notice a miss, and a loss of power, then worry. But drive it, then recheck the cylinder. Maybe you just messed up on the valve adjustment.

dfink · 11-11-2006, 08:07 AM

The engine tranny was / is out of the car. All valve covers off, all plugs out, side tins off. I haven't done cars for a long time but I did graduate with honors from from a well known (at least around here) trade school with degree in automotive technologies. Because I don't trust myself as I don't do cars anymore other than this one. I have triple checked my valve and crank positions. Both rockers are loose so doesn't matter where they are set it shouldn't leak. I could take the rockers out and it shouldn't leek out the exhaust to the point you can feel the air coming out. I normally skip everyother cylinder when checking my valve just so I don't have to hop around the car so I did again in sequence. Cylinder 4 also has come fair amount of leakage so looks like both sides are coming off. Unless someone has a great idea why there is air coming out the exhaust with both valves closed. Believe me I don't want to have to do this right now but i also won't drive it and possibly stuff a valve if it is warped.
I wish I was an idiot and you were right Tyson but unless I have done something stupid like put the pressure hose in the wrong cylinder for the rockers I am checking then it does not look good for the home team. Speaking of that I will make sure I didn't do that but I remember thinking of that around test number 3.

john walker's workshop · 08:15 AM

if the covers are off, first be sure there is rocker clearance, then hook up the leakdown tester, get your bad reading, and then use a rubber or plastic hammer and repeatedly boink the valve spring end of the rocker until the reading gets better. you should hear a pop pop pop as you hit it. this tends to clear crap out from between valve and seat.
i bought an engine a while back that was passed on by the first guy because his homemade leakdown tester showed 80% in one cylinder. it went down to 4% using the above method. got a good deal on the engine too, because of the first guy's mistake.

Aerkuld · Aerkuld's Garage

dfink - don't panic, yet!
As Tyson said, if you had a leak that bed the car would have been running like a dog.

If you had a head gasket problem I doubt you'd have the cylinder pressure leaking out the exhaust manifold as ther is no path from the combustion chamber to the exhaust except through the valve.

Also, I would doubt you have a bent valve. Short of it hitting a piston, or being bent when it was installed I can't think of anything that would cause this on an otherwise healthy engine.

When you say that the valve seated when you hit it with the rubber mallet how do you know it seated? Were you still checking leakage? If not try that.

I think it is highly unlikely that you have a serious issue here, especially as you said the ening had been running fine.

dfink · 11-11-2006, 08:25 AM

I can try that again. I did that already about 6 times. The valve pops real nice but air just stays steady. I can however try it couple more times. The car ran fine when I brought it in again that cylinders plug is clean as a whistle. #3 is a little dirty but it was the worst one when I replaced plugs last year. #3 soudn real good on the leak-down though. I think maybe I will get a true leak down tester and recheck. Thanks for the reply though. Last time I heard this much air out an exhaust someone had dumped bolts in the intake of a car at a dealership I was working at and a nut got stuck under the exhaust valve. I am hopeing I am just stupid because it is a rediculous amount of air coming out. I have to go check again......

dfink · 11-11-2006, 08:53 AM

OK just to double check myself I made a short movie of how to tell you are having a bad day. Please don't enjoy it too much...

Movie of the leak

Patton · 11-11-2006, 09:34 AM

Ok, I admit I'm a Porsche rookie but I'd pull the headers where you'll you be able view the exhaust valve. Have someone turn the crank and observe it's operation. Seems like that'll tell you all you need to know.

But, again, I'm just a rookie.

Good luck.

William930t · 11-11-2006, 10:13 AM

Your leakdown misfortune is our learning experience, please keep us informed on your finding, thanks.

Jandrews · 11-11-2006, 11:18 AM

Very well done movie, dfink.

I have a question. Can we rewind a bit? Why are we doing the leakdown test in the first place? Was there a running problem, or is this just a "while your in there" test? No problem either way, but I am concerned that maybe we are jumping to conclusions.

With that kind of air flow, there is no way that motor would be running decent at all. It is kind of hard to explain that kind of problem and what could be causing it from here, but I am with Tyson. If it was running good before, I would put it together and drive it. I think JWW advice is great too...see if you can get the valves (either one) to seat better via the mallet method. If you have tried that multiple times, and it truly was running good before (i.e. 200 h.p.), then I would drive it. If you get it back together and it runs like crap, crap, crap, then maybe I would try another leakdown on that cylinder to see if you can repeat the problem after you have driven it. If so, then maybe you can be confident in tearing it down that there is a problem.

Keep us posted.

JA

911quest · 11-11-2006, 01:42 PM

I know you tried to smack the valve a few times with a mallet is it possible that it is just carbon on the seats? If you had that much leakage you would only be runing on 5 cly. you would have been able to tell that before you pulled the motor.

dfink · 11-11-2006, 02:16 PM

In continuing the saga I also have leakage on cylinder #4 not as bad but still air coming out the exhaust. I would think I am f***ing up but the other 4 cylinders are just fine can hardly hear any leakage at all on them. ( I must buy a real leak tester)
Why did I do the leak down. Well I pulled the engine in hopes of replacing the valve seals. Smokes a little on start up. I also had a nasty oil leak that I couldn't find and figured it would be easier with the engine out. (It is way to easy to pull these). The leak turned out to be that I didn't have my new cam tower oil line tight. I have been cleaning up all the nasty oil and finally decided to pull the valve covers and check the valves. I did a valve adjust about 3 years ago in the car and thought as long as its out I'll check with the go/no go method. I had them pretty close. Well in looking at the how tight the area is around the valve springs I decided it wouldn't be very easy to replace the seals so I was going to skip it and just put up with the smoke. I don't have a clue how you get a spring compressor in there. Well since I had the plugs pulled to make turning the engine easier I checked to see if my hose I had to hold the valves up would work and it matched OK. So I thought everything is here I will just do a quick and dirty leakdown test. As I stated before I did #1 and it was great, skipped to #3 because it had a little fouling and it was fine. Was going to skip #2 but decided to do it anyhow and that started the series of Crap Crap Crap...... One must remember this is Nebraska and race season is over so all I can do for 5 months is dink with the car. I really didin't want to spend any real money though. I just dumped a load on the suspension. I had the CAT off as I am looking for a fabspeed bypass.(anyone?) I found I couldn't shine a light throught the CAT. I am pretty sure that I would have still been able to hear it with the exhaust on but maybe not. You can actually feel the air coming out the header. I guess I will have to pull the headers anyhow to get the head off so that may be my next step. Anyone one in Nebraska got an engine mount?
Now the only good thing about this is that if the car was that strong before it should be frigging nuts with everything working. Now I don't know what the HP was right before pulling it, but it dyno'ed 2 years ago at 203 RWH and 187 ft lbs. It still felt just as strong as ever.
Also if you turn the crank so the exhaust valve is open and the spark plug is out you can just see one small section of valve and it looks really clean. I made the video just so you could check out that I had the right plug and valves. I will try to make one of one of the other cylinders for comparison.

Rick V · 11-11-2006, 02:19 PM

It is posible that when you pulled the plugs you disloged a piece of carbon that is now holding the exhaust valve open. It should have passed when you smacked the valve but it is a thought. As stated before if that valve was that bad when the car was running, you would have been blowing flame from the tailpipe.
With the air hooked up rotate the engine to open the exhaust valve. This should allow anything stuck to pass out. Do it slowly.

Early_S_Man · 11-11-2006, 02:43 PM

No head gasket on 3.2s!

Have you checked for a broken Dilivar head stud or two on cylinder #2??? It may not be as prevalent as on SCs, but it DOES happen on 3.2s, too!

dfink · 11-11-2006, 03:29 PM

I don't see any stud missing all the bolts appear to be there. I have had the crank around at least ten times checking and rechecking. I think that carbon would have been crushed by poping the rocker with the rubber mallet. I havn't tried the mallet on #4 yet. If I could get it to clear I would maybe hope it was just a piece of carbon but to hold the valve open enough for air to be felt coming out the exhaust just doesn't seem feasible. Something just doesn't seem right. If there is no gasket then that leaves broken studs with leaking head or valve.

dfink · 11-11-2006, 03:37 PM

What if I hook up a battery to the engine with it out of the car and no spark plugs and turn the engine over to see if the valve seats. I just have it setting right now on the heat exchangers on an ATV stand and the tranny is still attached and is supported by jack stands. Would the torque of the starter cause problems.

Goth · 11-11-2006, 04:09 PM

.

Quote:

It is possible that when you pulled the plugs you dislodged a piece of carbon that is now holding the exhaust valve open. It should have passed when you smacked the valve but it is a thought. As stated before if that valve was that bad when the car was running, you would have been blowing flame from the tailpipe.

Rick V has a good point...

I think the odds of carbon under the valve is pretty good, as the exhaust valve is right under the spark plug. Especially if the valve was open when the plug was removed.

IMO: If the air is coming out of the exhaust, it's exhaust valve/seat related and not head gasket or head studs.

Did you try popping the valve while the cylinder is pressurized a bit. When the valve pops, hopefully the air rushing by will blow out the carbon. Otherwise the carbon may just get crushed in place.

If it were me, I would want to fire it up and then repeat the leak down before I ever tear it apart.

Hope it's just Carbon...

baratta930 · 11-11-2006, 04:48 PM

+1 on carbon.

A friend had this exact same thing happen to him.

He took it to his mechanic (expecting a rebuild), who just tapped the valve with a rubber mallet a few times and then rotated engine through a couple of cycles.

Problem went away

It's worth a try ...

Berardino

Jandrews · 11-11-2006, 05:04 PM

Just in case.... I'm in Kansas City and have a Porsche engine adapter and engine stand if you need it. Also, cam timing tools, oil line wrenches, etc...

JA

dfink · 11-11-2006, 05:14 PM

Well since things just don't make sense I think I am going to finish fixing the small things like fuel lines and put the engine back in and fire it up. I will then do another leak down test and see if the problem goes away. As I mentioned earlier it is not that hard to pull the engine. Much easier than tearing engine apart to find nothing. It does seem odd though that I can't get the valve to clear by tapping it. I did the tapping with the air hose attached. I will try to take another video of a good cylinder though just for documentation sake. If I run it and it still blows air out the exhaust then I guess I will decide what to do then.

What abou trying to turn the valve. Can I depress it somehow and turn it to see if it clears the leak.