Worrying engine noise!

[MrScott]

I got part way into the valve adjustment yesterday, aiming to finish it today.

So far nothing seems out of whack:
- Axial play is similar on all rockers
- None can be depressed by hand
- The backside method rocks

I'll inspect all rockers to make sure they haven't wandered off their shafts but I suspect consistent axial play indicates they haven't.

On the driver's side half the exhaust cover nuts came off with the studs so before I did the passenger side I sprayed those nuts with PB blaster, all came off properly.

My exhaust gaskets were an unfamiliar green cardboard-like material.

Turning my fan didn't budge the cam pulley and the belt was already '5 shims' tight, thankfully the 6th shim did the trick but I've ordered a new belt to be safe.

I'll post some good closeup pics before the end of the day in case you all can spot something I can't.

I had an 'admit to your stupidity' moment when I went to remove the 2nd spark plug with the factory tool... thought a rubber boot on the plug itself was kind of odd when I removed the 1st, went to remove the 2nd, uh-oh! no boot! has it fallen?! I poked around with a mirror for a couple minutes before putting 2 and 2 together

[rcaradimos]

Valve clearance smaller for more HP?

I'll try to send you a pm w/ a video sound clip of my engine
I think your noise is excessive valve gap.

I couldn't upload the file.

It's amazing how quite a good valve adjustment will sound. Very quite cold, as the engine warms up you will get more sound from the tappets. Did you get a stethoscope? Cheap and a great way to monitor your valve adjustment.

[rwest]

Hi,

Since you didn't find anything out of whack at the valves, I would take off your chain covers and have a look before re-starting. If you lost your tensioner, you could end up with an expensive mess!

Rutager

[James Brown]

Originally Posted by rwest

hi,

since you didn't find anything out of whack at the valves, i would take off your chain covers and have a look before re-starting. If you lost your tensioner, you could end up with an expensive mess!

Rutager

1+

[MrScott]

UPDATE:

Number 5 intake valve (on the passenger side where the noise was coming from) was very loose. I'd been rocking the rockers before setting the gap to get an idea of how off they were -- rocked it a little, felt fine, rocked it harder, whoa, too loose.

Is this indicative of anything? I could have sworn I read that if you can rotate the valve the spring is broken -- can't find the thread though. I can rotate #5 valve but I can rotate the others I've tried as well...

I'm not ignoring the advice about the chain covers but I'd like to take one thing at a time.

I'm going to go through again and check all the gaps, rocker play and valve rotation.

EDIT:
Forgot to mention I realized my feeler gauge was metric. Did some math the convert the backside method:

Gap: .002857" = .07257mm
So GO is .07, NO GO is .08

I compared tolerances in millimeters with the two methods:

.0025" - .003" -> .0635mm - .0762mm -> .0091 (too thin) - .0036 (too thick)
.07mm - .08mm -> .0026 (too thin) - .0074 (too thick)

Seems the metric feeler's more accurate but getting the GO gauge in took some wiggling.

[Eagledriver]

Sounds like you found the problem. I'm suprised you can turn the valve. The clearance on these is very stable so something changed. Could be something stuck under the lip of the vavle holding it open? Could be a bent valve? If you just tighten it and it's staying open you will burn the valve.

-Andy

[jtratza]

Originally Posted by Eagledriver

Sounds like you found the problem. I'm suprised you can turn the valve. The clearance on these is very stable so something changed. Could be something stuck under the lip of the vavle holding it open? Could be a bent valve? If you just tighten it and it's staying open you will burn the valve.

-Andy

Andy, That bent valve reminds me of the sound I had several years ago right after a complete rebuild. The machine shop screwed up but the shop that did the rebuild (SC Repair in Houston) made it right and took care of it. 3 years later still runs great and no leaks!

[MrScott]

Dug into it some more. Re: valve turning, might not be the valve I'm turning as the rest are just like it, so that seems fine.

I am getting a 'clanging' when I rock the #5 intake rocker that I don't get on the others. I'll upload a sound clip later. Also, I went through all the valves a 2nd time - a few had to be readjusted, so it could be my mistake, but #5 might have been more out of spec than the others.

Would a bent or stuck valve cause the noise in my first post? If not I figure I'll button it up and start it, if the noise is still there I'll have it towed to a mechanic -- if not I'll drive it .

[Wayne 962]

Before you take it to someone else - get a little bit more data. Run a compression check on the engine (I don't show how to do this in the 101 book, but it's in my Engine Rebuild book). There's also an article on the site, I believe (under "Time to Rebuild?").

Valve train noise is generally pretty easy to fix. I wouldn't panic yet. But yes, if there is something that "feels" different about #5, then most likely there is some type of problem with that valve.

It would be my guess that perhaps one of the two springs is broken, and it's not closing all the way. This would cause a leak, and would show up in a compression test. In general, you can't see the inner valve spring, so even if everything looks intact, there may be a problem inside.

-Wayne

[MrScott]

Clip of #5 rocker as I rock it back and forth: sound clip
And for reference, the original clip I posted with the engine running: engine noise

They sound similar, so I think I've found my problem.

The 'clanging' happens when the rocker touches the cam, not the valve so does that rule out valve spring and valve trouble? Or must I be mistaken (it was getting late and I was getting tired and I don't have the car with me now.)

Wayne, thanks for the advice. I'll check that article.
And thanks again to all who replied.

EDIT: I just read the tech article, specifically the part about oily plugs -- from what I remember my 4, 5 and 6 plugs were oily indicating "valve guide or piston ring wear" ... Engine had leakdown under 6% cold on all cylinders when I got it a few months ago, maybe some catastrophic failure on that side. Man.

[James Brown]

I know it's hard to see the valve springs but can you use a mirror and a flashlight to check them. It should be quite easily to spot one, if any are broken. yeah, the backside method described in tech article is in fractions not metric. Double check the valve lash on # 5

[MrScott]

Originally Posted by James Brown

I know it's hard to see the valve springs but can you use a mirror and a flashlight to check them.

I peeked around with a mirror but I didn't see any valve springs, broken or otherwise. Tried to search for a pic of what I should be looking for, no luck. I'll try again with more light.

Again though, I'm pretty sure the 'clanging' occurs on rocker to cam contact.

[James Brown]

that's good, look at the tech article there's pictures of the valve springs, just click on them to enlarge

[pete3799]

MrScott,
Did you remove the plugs prior to your valve adjustment?
If so you may have dislodged some crud that may be holding a valve open, throwing
off your valve adustment.
Possibly why #5 was looser then the rest.

[MrScott]

Originally Posted by pete3799

Did you remove the plugs prior to your valve adjustment?
If so you may have dislodged some crud that may be holding a valve open, throwing

I did. Just read that warning in the tech article.
Any suggestions on how to dislodge the crud?

[pete3799]

My Bentley doesn't cover crud removal, don't have Waynes book yet, maybe he has a crud removal chapter.
Hopefully someone else will enlighten us.
It's quite possible that #5 is just out of adjustment, as i had one on mine that was out more than the others when i bought it.
Quited things down considerable.
Hope all goes well.

[coollx]

Btw MrScott, where in NY are you? Would be helpful for us to know.

[MrScott]

Originally Posted by coollx

Btw MrScott, where in NY are you? Would be helpful for us to know.

Certainly. I'm in Manhattan -- the car is in Queens.
Having to take a train to your garage slows the process significantly, especially when you forget your keys at home!!

[MrScott]

UPDATE:

With a mirror I peered into the #5 valve, tough to get my head in the right position with the engine lid in the way but I counted 3 maybe 4 coils which jibes w/the factory spring pelican lists. Top coil was tight against -- whatever it's supposed to be tight against -- valve hat?

I managed to get the suspect valve adjusted consistently; it seemed to me the swivel foot sometimes didn't seat well -- sticking my fingers down and fiddling with it gave consistent readings. This is my first valve adjustment so it could just be a lack of technique. Anyway, play feels normal and movement sounds normal now.

I ordered the gaskets, nuts, etc. from pelican. Going to pick up a compression gauge, button it up and test. Everything seems fine now but a valve going so out of adjustment so quickly doesn't make sense.

Originally Posted by pete3799

you may have dislodged some crud that may be holding a valve open, throwing
off your valve adustment.
Possibly why #5 was looser then the rest.

Makes sense, but if that's the case I'm no closer to finding the source of the original noise...

[James Brown]

fire that bad boy up!!!