bent valves?

Pimpin Dsmstyle · 05-10-2006

What's the easiest way to find out for sure if and which valves are bent? Symptoms? I'd assume compression test is the place to start. I'm not hearing any ticking from the engine.

My car won't rev past 2k, backfires, blows alot of grey smoke, and it's idling funky. The timing belt is on PERFECTLY correct. I've double checked, re-done it for good measures and it is still 100% correct.

91 talon TSI AWD turbo.

**Halon** · 05-10-2006

I'd do a compression test. If it's low, then do a leakdown test and listen for where the leaking is. If the leaking sound is coming from the intake or exhaust, well then you know valves are leaking. Or you can take the head off and give it someone like Red Rooster and they can test it for you.

Pimpin Dsmstyle · 05-10-2006

Anyone know any typical problems with slightly bent valves? The car does run and it blows alot of smoke. Since the smoke is grey, I am a bit confused. Between the lack of reving and the massive smoke - I'm leaning towards some bent valves. I will do a compression test when I get home from work. Any other advice / information?

**Halon** · 05-10-2006

my car ran like absolute shit, wouldn't even idle for more then like 3 seconds, I had 9 bent valves.

sleepydsm · 05-10-2006

Are you absolutely sure that backing plate you use to line up the crank's timing mark isn't on backwards? I had mine on backwards, and it had the same symptons. We couldnt even get the mark on the crank pulley to come even close the the timing marks when trying to set the timing. Did you check the timing yet?

I had nine bent valves, and my car ran fine. It was just slow.

Pimpin Dsmstyle · 05-11-2006

Compression test eh. The motor should have over 150 but it sure doesn't.

145-130-130-145. The 2 middle holes seem like they are flooded with fuel non stop and the two outer holes are MASSIVELY packed with carbon. These were all new ngk bpres6's as of yesterday.

Does this seem head related or timing related at this point? The compression is pretty weak but the service line is like 120 so I wouldn't think these numbers would create many problems

**Halon** · 05-11-2006

Those numbers, although not ideal, aren't all that bad. When I had bent valves, I had 0 compression in a couple cylinders. The massive smoking could be a few things. Could be bad valve stem seals. My car had that as well when I first bought it, got those replaced and the smoke was gone. Could be turbo related. Everytime I've ever dealt with bent valves, it always involved extremely low compression numbers, which you don't have, so I tend to think that's not it.

**Goat Blower** · 05-11-2006

It's timing related. It's not your valves.

Pimpin Dsmstyle · 05-11-2006

Quote:

Originally Posted by Goat Blower

It's timing related. It's not your valves.

I think the smoke has everything to do with the head. I have no idea why it quit running and won't start but I do think the smoke is head related. The 14b never blew smoke before.

I think it could be possible that if the timing is way off, it could cause excessive smoking? But I'm not sure how that would work. 1 and 4 are at TDC and all of the timing marks are perfectly lined up. The base timing ( i think that's what it's called) is still not set because I haven't snagged up a timing light. I still don't think it should smoke like that.

niterydr · 05-11-2006

Sounds like timing is off...the smoking could be the valve seals on the head, or the piston rings.
Bent valves=0 compression.

Pimpin Dsmstyle · 05-12-2006

Quote:

Originally Posted by niterydr

Sounds like timing is off...the smoking could be the valve seals on the head, or the piston rings.
Bent valves=0 compression.

Can't you have slightly bent valves? Like just enough to drop some compression but not enough to really hurt anything besides efficiency? I don't really know how it could be the timing belt. I could attempt to put the crank plate on the other way, but it looked pretty clear that it was on correctly. However, the person before could have ran it the wrong way too.. hmm

the engine has new OEM mitsu rings std size. It was hoaned but not bored. So I guess having slightly low compression could be to blame on that.

**Halon** · 05-13-2006

I had "slightly bent valves" and I had zero compression. Even looking at the head you could not see that the valves were damaged by looking with your eyes. They were barely even bent, but I had 0 compression in cylinders. I'd say get your valve stem seals replaced.

Thor06 · 05-13-2006

What makes you think the valves were bent? Did your timing skip? I think I'm with them, your timing is probably a tooth off or something and you have some bad valve seals. My car's exhaust cam was off one tooth and it pulled the same numbers in the same spots.

Pimpin Dsmstyle · 05-13-2006

Quote:

Originally Posted by Thor06

What makes you think the valves were bent? Did your timing skip? I think I'm with them, your timing is probably a tooth off or something and you have some bad valve seals. My car's exhaust cam was off one tooth and it pulled the same numbers in the same spots.

I repeat.. Every single timing mark is perfectly lined up. The only possible scenerio I can think of is if the crank pulley sprocket is on backwards. I clearly need some valve seals. The car runs better but not for long.

The car fires RIGHT UP and runs perfectly fine if I put in new / cleaned up spark plugs. After about 10 minutes of idling, it want's to die because the plugs get so fouled out. The odd part is that they are getting packed with carbon AND showing signs of detonation. So I'm a little bit confused. It still seems timing related. Compression is still within specifications. Ideas? We are changing to a different ECU again.

**Halon** · 05-14-2006

So the marks are all lined up, but what about the ignition timing that you adjust using the CAS?

Thor06 · 05-14-2006

Another idea... is there oil on the out side of the plugs? That might be a oil filler cap thats not sealing or those seals that go between the head and the valve cover around each spark plug hole.

Pimpin Dsmstyle · 05-14-2006

Quote:

Originally Posted by Thor06

Another idea... is there oil on the out side of the plugs? That might be a oil filler cap thats not sealing or those seals that go between the head and the valve cover around each spark plug hole.

I have no spark in coil 2 and 3 so the reason I think I'm getting so much smoke is because of massive unburned fuel. Sometimes it seems blue so the valve seals probably do need to be replaced. My problem is somewhere between the ECU and the coil pack, the signal is lost so the coil packs 2 and 3 wont fire. I think that's the only problem left.

I need to find someone electronically capable to fix this. I'm very stupid when it comes to this. The power transistor could not be functioning properly, that is another idea.

The ignition timing hasn't been set. I could have swore that we checked all 4 holes for spark but maybe we just checked one for some stupid reason. So now that I know what the main problem is, I'll attempt to fix that and go from there. The valves shouldn't be bent but the valve seals probably do need to be replaced. All of the valve cover seals were replaced with brand new OEM seals. I can't tell if it's carbon or what but in the 2 hole, there is some liquidy black shit but I put a spark plug that was carboned up in there so I don't want to jump to conclusions until I figure out the spark issue.