BOTTLEDZ28

iTrader: (9)

I just got off the phone with the machine shop that did the head work and they said that with 119 psi in that cylinder, the valve is not technically bent. Its more than likely warped slightly. If the valve was bent then I wouldnt be getting any compression at all. He said the warpage of the valve could be due to excessive heat in the chamber. 119psi isnt enough to cause a total failure of that cylinder and it may not even be noticeable on a V8 engine.

He said that the heat could be coming from a vacuum leak at the intake which is now allowing unmetered air into the cylinders chamber throwing off the air/fuel mixture to the lean side.

The kicker with that is that this first did this with the stock TPI setup. I have since added a TPIS intake, SLP runners and a ported stock plenum. I used new gaskets on the runners along with a small bead of weatherstripping on them I find it highly unlikely that the first valve was warped from heat due to a vacuum leak on the stock parts and the second valve warped due to a vacuum leak with the new parts AND all on the same cylinder.

What am I missing here? The plugs dont look all that bad and if I had a lean condition then I would have it on all the cylinders.

Also, there are new injectors in this car.

bigal55

iTrader: (1)

If you have the valve cover off, why don't you check the height of the valves when closed? If you have one of those valve spring compressors that grab the spring and compress the retainer down, use it to compress the spring and "feel" how the valve reacts. Just a couple ideas that might help in diagnosing your problem. HTH!

BOTTLEDZ28

iTrader: (9)

I don't have a valve spring compressor tool.


Is it possible that the injector isn't firing correctly due to an electrical issue? How can I determine if the injector harness for tht cylinder is doing what it's supposed to do? I'd like to verify tht before I rear the top of this engine off.

BOTTLEDZ28

iTrader: (9)

And let's go back to the pics of the plugs. Did I run the engine too lean? It only ran for 5 minutes before I noticed the header turning color.

OrangeBird

iTrader: (1)

Interesting .... When we originally had only 119 PSI the machine shop told us it had a "bent valve" and replaced it . Now that the new valve is in operation and the cylinder still has only 119 PSI they say it's "warped slightly" and go on to infer that it's no big deal with their "119 PSI isn't enough to cause a total failure of that cylinder (BULLSTUFF !!!) and it may not even be noticeable on a V8 engine ? If you want my opinion here it's my belief that the cylinder head has a crack in it adjacent to the #7 cylinder that they missed when (if) they inspected the head for cracks and that is what's causing that one cylinder to run lean and excessively heat and warp the valve . That is , of course , if the lifter on that valve is OK as discussed by Joe earlier . Additionally , if you suspected an injector , couldn't you swap a couple and see if the #7 still glows ? And throw a noid light on it just for good measure , get a good look at the brightness & duration of the flash and then check other (good) cylinders to see that the light flashes the same ?


PS , I say bullstuff because getting hot enough to warp is plenty hot enough to get stuck in it's guide and bend the pushrod , thereby rendering the cylinder inoperative . Bottom line here = if the injector and lifter truly are OK , replace the head ....

anesthes

iTrader: (12)

Is this a MAF or MAP car?

The header is glowing from one of two things. It's either rich and fuel burning in the exhaust, or a bad valve (letting the charge burn in the exhaust).

The fact that your compression is dramatically lower in that cylinder points to a valve issue. (bent, warped, held open by lifter, etc)

The injector wiring wouldn't cause the injector to stay open longer. If anything, a bad injector wire would cause a dead cylinder. A multi meter can be used to check the injector wiring.

I think your head is junk. I think the shop missed it.

What casting number is the head? I just threw out like 4 sets, but I might still have some in the shop. I'd give you one, no charge if I had the right one.

If you want to test it, remove the rockers and do a leak down test. If the cylinder holds and doesn't leak, it's a lifter problem. If it leaks, it's bent and can't return to its seat.

-- Joe

BOTTLEDZ28

iTrader: (9)

Its a SD car with 083 heads. Im hoping I can get a leakdown test done tomorrow. I do not want to take this back apart until I find the cause of this issue. I bought this car in January and put maybe 200 miles on it before I decided to do some engine mods. When I found the issue the first time around I assumed it was from the previous owner over revving the engine or maybe even the transport company show boating the car around.

Now that its happened a second time with just a few minutes of run time on the engine in the garage makes me scratch my head.

Leakdown test should confirm exactly where the leak is.

BOTTLEDZ28

iTrader: (9)

I did a half a$$ leakdown test today. I didnt have a fitting to connect the tester to the compressor hose so I just ran compressed air directly into the cylinders using a compression tester hose with the valve removed from it.

I could hear leaking inside the engine. It was bubbling from the radiator. It wasnt coming from the TB and it wasnt coming from the tailpipes. Where is was coming from was the dipstick tube and valve cover. This contradicts the compression test results since putting oil in the cylinder didnt change the results. Im not wondering if I didnt put enough but, the plot thickens here.

Here is a video of me pushing 80psi into the cylinder 7. compression was 119. The glove is taped to the hose which is connected to the grommet on the valve cover. Should the glove be filling up this fast??


http://vid3.photobucket.com/albums/y...psddiknub2.mp4







Here is the same test done on cylinder 3. Compression results on that cylinder were 180psi

http://vid3.photobucket.com/albums/y...pspplopauk.mp4



http://vid3.photobucket.com/albums/y...pstmmhwvgu.mp4





I also checked cylinder 4 on the other side and it did the same thing. If I put my finger over the dipstick tube and then remove it, I can hear a rush of air come out. Is this normal or is too much air leaking past the rings too fast?

anesthes

iTrader: (12)

Head is cracked.

-- Joe

BOTTLEDZ28

iTrader: (9)

With that beinf said, I shouldnt be getting air into the oil pan from doing those test on the passenger side then right?

I tested cylinder 4 and can still hear air coming from passenger valve cover. Not a lot but I can still hear it.

Ill go and try the test gain to confirm

anesthes

iTrader: (12)

THe air into the crank case is interesting, but possible depending on the extent of the damage.

You've connected the hose to the compressor, and removed both rockers so the valves are closed, yes?

Edit. I watched your videos.

That motor is junk. Unless somehow you're pressurizing the plenum, which is pressurizing the valve cover (through the air hose that goes to the throttle body). But I doubt it.

-- Joe

BOTTLEDZ28

iTrader: (9)

rockers on cylinder 7 are off so valves are closed. rocker nuts are backed way off on cylinder 3 so valves are closed there. I didnt pull the valve cover on the passenger side. I guess I should have done that and backed off the rockers to check cylinder 4. Cylinder 4 was the easiest to get the hose on.

Either way though, the test was done correctly on cylinders 3 and 7 and both were seen in that video.

anesthes

iTrader: (12)

I'd swap motors. For purely education, tear it down and figure out where the problem was, but it's not worth sinking any more time and money into.

I just left Mike's this morning (Concord, NH), I sold him both of my vettes. He had at least 5 low mile L98 vette motors (113 alum heads, etc). Buy one of those.

-- Joe

BOTTLEDZ28

iTrader: (9)

Mike?

BOTTLEDZ28

iTrader: (9)

Cylinder 4 results after backing off rockers and putting valve cover back on

http://vid3.photobucket.com/albums/y...ps7lbdfiel.mp4


http://vid3.photobucket.com/albums/y...psjguoixwg.mp4

anesthes

iTrader: (12)

contact name:
Mike
call:
☎ (603) 566-3429

Runs a ybody salvage yard. Also has a couple of B4C camaros.

-- Joe

BOTTLEDZ28

iTrader: (9)

Finally got a leakdown tester and here are the results.

***test was done with ALL rockers loose. I did not put pistons at TDC


Cylinder-------leakage %--------location or leaking air
1------------------60------------------ valve cover

3------------------60------------------valve cover

5------------------50-------------------valve cover

7------------------70-------------------valve cover



2------------------70--------------------valve cover

4------------------10--------------------valve cover


6-----not tested due to Lokar dipstick and header tube in the way

8------------------35--------------------valve cover




it appears that the leakage was at the rings since I was hearing and feeling air blowing up through the dipstick and out of of the grommets on both valve covers. I am at an absolute loss for how this engine runs like it does with those leakage numbers. You would never ever know something was wrong with this engine when driving it. The engine is nice and quiet and idles and rev just fine. It even put down 225/301 on the dyno in the summer bone stock through an A4 trans. How in the heck is that possible with those numbers?
There is no way this engine messed up in the 50 miles I put on it since the day I took it to the dyno.