new 4/01/03
Sorry for the delay in response to the list, but Sunday night I was able to find out the cause of the noise. I have been in contact with Kirk who has been invaluable in trying to help me find the trouble with the motor. After tearing the valve cover off the front bank, the Cam Sprockets are tight and the Welds are still as beautiful as the day they were laid. The first indication that there was something NOT right was the # 8 cylinder spark plug had the metal piece bent all the way into the electrode. (See the picture) After a suggestion was made to me that it could be a valve and Kirks suggestion that the Valves are STEEL and would be magnetic led me to the local hardware store to get a magnetic tool picker up'er. After fishing around in the cylinder, I was able to pull one decent sized chunk of MAGNETIC metal out of the motor the size of 3/4" long and a few other metal shavings. (See picture) After fishing these particles out of the cylinder I proceeded with a compression test. The #8 cylinder has ZERO...0 compression. The other three cylinders (5, 6, 7, ) on the front bank have 180 psi compression. It looks like this motor, with 65,000 miles, ate a valve!!! All these valves on the front bank and cylinder 8 are free and moving there full range with no indication of sticking. After looking into the cylinder and feeling around with the flexible magnetic tool, I could not observe any hole in the piston and have eliminated anything to do with the piston. My guess is maybe it is an exhaust valve as the exhaust smelled like unburned gasoline. Whatever it is, the head is going to have to come out and I am pretty sure that involves removing the motor....correct?
For what it's worth, I have always changed the oil every 3000 miles with Mobil 1 5w-30. The motor underneath the valve cover is extremely clean and Kirk can vouch for that. The weird part about this is that the day before there was no Indication AT ALL of an impending
failure. The day before I drove it to college and back and didn't redline it but didn't granny it either on the acceleration...so in other words...drove it like normal. The next morning (Friday) I went to start it up and as soon as the car caught and fired up, the knocking began. It turns out this knocking noise was a piece of the valve bouncing around in the cylinder and the reason the car had a tough time running is because the the car was running on 7 cylinders.
Gregory Brown
1997 TR SHO (now dead)
Welded
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Tim-
I REALLY hope that this isn't the next trend in the SHOs. I think I've already gotten rid of the previous e-mail about the odd failure at Ray's. But this sounds VERY familiar... Any thoughts? I don't want to cause wide-spread panic, but the timing of these two events seems to point to something that's not very good.
-John Breen
Gregory,
It's difficult to tell from here, but those pieces metal could just as likely be from a compression ring. I hope not, but you might have a burned piston, as Paul did. A leakdown test would tell the story.
Take care,
--
Rob Parker
La Porte City, Iowa
I don't think the car burned a piston in my opinion. The car started doing this on START-UP and ran fine the day before with no indications of problems. All the pieces that were picked out of the cylinder were a MAGNETIC metal...therefore eliminating the possibility of a
piston (hopefully) due to them being aluminum. There was also no visible damage to the
piston (that I could see) and feeling around with a metal magnetic flex rod, I could not find a hole in it. What do you guys think? Thanks
Gregory Brown
The metal looks as though it has been melted and it is pretty bright. What about a piece of a ring? I know it would be hard for it to end up on top of the piston but I guess anything is possible. Check e-bay maybe someone is selling a lighted endoscope that you can use to look around that cylinder
with.
Chris A
99 SF
Any possibility that something got sucked down the intake? It's academic at this point. No compression, metal bits = bad. Time for exploratory surgery.
Take care,
--
Rob Parker
La Porte City, Iowa
I understand. It could be several things. Don't forget, he is making the statement about no hole in the piston by looking in through the spark plug hole. Not a large field of vision. The lack of compression could be several things. For example, when I had my 1988 Honda Civic Wagon, I skipped a tooth on the timing belt and bent 12 of the 16 valves. They were bent enough to lose the seal (no compression) but not actually break the valve or the piston. In this case, it could be that a portion of the valve broke and that is what was pulled out with the magnet.
Anything I am mentioning is pure conjecture at this point as well. I am extremely interested in seeing pictures once the head comes off.
The more I hear about the design shortcomings of the V8 (cams, using only one of the valves to inject fuel, interference engine), the further away I plan on staying.
Paul L Fisher
Looks like welding slag.
John Hamilton
Ida,ON,CA
Looks like all three pieces are of the same mat'l and have been bouncing around in there for a while. Could have started out as one piece. Looks like a straight pin that accepts circlips, the end at the bottom looks somewhat defined. I'd take a good look for missing components from the intake on, or it's just foreign.
Bummer. Hope there's not much damage.
John Hamilton
Ida,ON,CA
Not necessarily stuck open, but bent. I had a 0 compression test in my '87 Riviera. Once I tore the head off I was amazed at how slightly the valve was bent. You had to shine a light down the port to see it at all. But during the test the needle on my tester didn't even pulse. Stayed flat on 0.
Rich Larsen
96 TR - Kirked in Tulsa
It could also be a valve seat. Obviously with these being aluminum heads, the seats are pressed in hardened steel. If one came out or broke, you would have no compression but might still have a 'straight' valve.
As someone else indicated, its academic now. The head has to come off. And no, the engine doesn't have to come out to do that, especially with it being the front head.
Dave Garber
Pittsburgh, PA
99 White
Have you drained the oil yet? This might yield more clues, won't hurt anything, and if there is anything there, you don't want it there.
Richard Nathan
Rob:
You make a very valid point. I want to learn more about this stuff so understand, I am not questioning anybody's ideas or knowledge in my
questions. Ok? But first - Gregory, this isn't meant to advise you in anyway what might be wrong or not with your engine. So you might be better
off not reading this post ok?.
Here's my first thought. I agree if the magnet pulled out a chuck of metallic metal, it's not the piston. If it is either the valve spring or a
ring, these would be metallic right? Either one of these failures could lead to no compression right?
Second, could a broken ring or valve spring lead to a broken piston where the piston isn't turning with the crankshaft? Or where the piston is no
long connected to the connecting rod or the crankshaft. That would lead to a whole bunch of noise and no compression as well. Below is a quote cut ad
pasted into this post from the "V8SHO Teardown" for the RSX Website. I have no idea who the author is but it is a fascinating site. Please refer to,
http://www.mercurycapri.com/projectrsx/v8sho/teardown.html
"The piston is held on to the connecting rod with spirolox. The piston is held on with a full floating pin, not a pressed pin. This is how most race
car pistons are assembled to allow quick changing of the pistons on the rods. I was able to easily remove the pin and
separate the piston from the rod.
This rod is a powered forged connecting rod. They take the powered and press it together at high pressure to make the rod. They then break the big end of
the rod and bolt it back together. This supposedly makes the rod stronger. It also makes the rod unusable when it's been removed from the engine. The
bolts are stretch-to-yield bolts which also makes them "use once" designs. I've seen people reuse this types of bolts over again though. As long as you
don't stretch them past their stretch point they should be ok. We'll be replacing them anyways with lightweight aluminum rods.
As you've seen in alot of the other photos this motor was put together and designed like a race engine. Light weight, lots of webbing, short skirt
pistons, full floating pistons."
Any other ideas on what might cause a symptom like this? I just want to learn more about our engine and this is an opportune time I suppose. PS, I'm
not responsible for the spelling mistakes in the quotation! It is in fact, a cut and paste! Thank you to the unknown author, this sure is an
intersting site.
Jim Merriman
It would not be the valve spring, it would have to be the valve. If it were the valve spring, the head would have a fairly large hole in it so that it could make it in to the cylinder.
To allow for the piston to 'disconnect from the crank, the rod would have to break or the skirt of the piston would have to break or the wrist pin would have to break. In all of those scenarios, the connecting rod (or what is left of it) would flair around inside the cylinder bore and would cause major damage to the block, maybe even putting a hole in it.
Paul L Fisher
But what's causing the non compression issue? Either a valve would have to be stuck open, which in an interference engine, will rip the piston and valve to shit, leaving all sorts of debris. Right? And didn't Gregory say that he didn't see or feel any piston issue? Or could it be that the piston isn't generating compression, likely because it's broken either at the top or bottom end?
What do you think? Please remember, for me this is a learning experience not a factual statement post on my part.
Jim
If the exhaust smells like raw gasoline, doesn't that trash the cat converter? Emissions inspections? Now... is there a warranty on emissions and/or parts that can adversely affect same?
Steve '97 TR