compression Test Results

[FuddyMucker]

Hi Guys

After having done all of the basic service stuff, the VX is still running rough.
Although there is no oil in the water or water in the oil I have done a compression test and it goes something like this

1 = 190
2 = 170
3 = 180
4 = 0
5 = 170
6 = 165

I all happy with all the cylinders results (after 260000 km) except for cylinder #4.
I am trying to think of a reason why I would get this sort of result as it is not the standard results of a blown head gasket.
Thinking maybe stuck valve or broken con-rod or maybe even a hole in the piston.
Any other ideas??

[crotchrocket]

Of all of those, i'd say sticky valve although im not sure if that applies, Do we have hydraulic lifters????? Normal valves????? cant remember on the 3.2?

The con rod would have made a mess inside and the hole in the piston would surely blow crap out the spark plug hole when opened wouldn't it?


I take it knackered piston rings wouldn't give a reading of '0' would they??

Looks like head off for a better look inside

[FuddyMucker]

I think your right, for knackered piston rings not to register anything they would both need to be completely gone.

I'm hoping on the valve because so far that seems to be the easiest to fix, if (as you pointed out) there not hydraulic.

[FuddyMucker]

OK I am quite sure I have found the problem!







Because of this I have now ordered a new head gasket and am trying to get a new valve.

Anyone else had this issue?

[Ldub]

OK I am quite sure I have found the problem!

Yep, that looks like it might cause a reduction in compression...

Anyone else had this issue?

That's a first in my memory, don't remember seeing that before.

Good luck with getting it back together soon...

[VX crazy]

Oh my, that sucks....makes me want to run out and get a compression test....that looks like *** with all that carbon buildup!

[Cobrajet]

How do the piston and cylinder bore look? I once ingested a carburetor bolt (anybody remember those?) down my intake and it ended up notching the top of piston, which eventually burned a hole through the piston. I was able to get away with just a new piston on that cylinder because it didn't scar the cylinder wall. I later bored the engine .030 over and fitted balanced piston/rod assemblies.

[VX KAT]

OK, translation please....what's happened there? I'm always curious....

[Moncha]

Actually for 260k km that looks pretty clean! Not very much carbon build up at all, at least on the head.

Depending on what the valve seat shows, I'd say bad valve. If the seat has a chinger in it, then maybe foreign object. Maybe a chunk of carbon. What's the top of the pistons/cylinder look like? Was the ring intact?

After looking at it more; looks like incomplete burn or oil build up.

What did the spark plug look like? was the electrode intact?

What's that cylinder look like?

Did the gasket survive enough to take pics?

[FuddyMucker]

Spark plug was intact and looked ok
Piston rings look ok and have standard slack.
Head Gasket shows no sign of leaking (but I will replace it anyway).

Thank goodness the chip of valve got blown out of the engine and didn't fall back in to the cylinder (the cylinder wall also looks good for 260,000)

[VX crazy]

can you give us a tad more info, what made you get the compression test done, how was it running etc....

[FuddyMucker]

It was running Rough, it wouldn't idle but would hunt between 550 to 1200 rpm
noticable lack of power (more so at low revs).
This was one of the last checks I did after replacing the sparkplugs, checking the MAP sensor, checking the MAF sensor, checking each coil pack, checking the fuel pressure in the line, looking into the EGR system, checking for water in the oil, checking for oil in the water ect...
Put it this way, it didn't seem like a compression issue but I was running out of other things it could be.

[Moncha]

Hate to be a PITA, what's the valve seat look like.. I see a small nick out of the valve just to the right of the chunked out part but, it's not part of the seat. This one doesn't look like it's been seating for a bit as there is quite a bit of crap built up. That could just be from trying to run it while diagnosing but.... I'm tempted to say from the looks of the valve and the lack of other damage any where else, the valve just failed. Maybe to much valve slap from mal-adjustment but, that should show in the seat. What does the stem head look like?

[FuddyMucker]

Sorry for the quality of these snaps, Im at work at the moment and only have the camera on my phone.

Here are some snaps of the valve seat after I cleaned the carbon off (typing with dirty hands, eerrr)







Seat looks good to me
What do you think?

[VX crazy]

It was running Rough, it wouldn't idle but would hunt between 550 to 1200 rpm
noticable lack of power (more so at low revs).
This was one of the last checks I did after replacing the sparkplugs, checking the MAP sensor, checking the MAF sensor, checking each coil pack, checking the fuel pressure in the line, looking into the EGR system, checking for water in the oil, checking for oil in the water ect...
Put it this way, it didn't seem like a compression issue but I was running out of other things it could be.

Great.....mine rough idles sometimes...not all the time, today was just perfect running......I need to clean my EGR too.