Valve noise

[Tat2demon]

I replaced all my shims a few days ago (thanks for all the info btw) and finally got it started back up today. I know they get a bit noisier after replacing shims but one of them was pretty bad. You could pick out which valve it was just by the sound.

After the shim job I turned the motor and realized a cam wasnt bolted. I could feel one of the valve hit the piston but it was a very slow turn with the wrench. As soon as I felt resistance I stopped. Would that be enough to bugger up a valve and in turn cause the extra noise?

[DGXSER]

Best answer is maybe. Try a compression check. If you did bend a valve it will show up in a compression check.

[TopCatGr58]

Hey Nate,

You say you turned the motor with a cam unbolted down. So you had the cam in the head with the cam caps in place, but not the nuts tightened down!? The pressure from the valves/springs would have caused the cam to rise up away from the valve more than pushing the valve down/open! Was the cam chain installed?? Were the cams in time prior to rotating the engine? The resistance you felt may have been the cam binding up in the bearing/slots or just resistance of the cam lobe against a valve bucket more than a piston hitting a valve?? Here's hoping for the best. Like Don said, a compression test will reveal the damage if there was any!

T.C.

[BA80]

After the shim job I turned the motor and realized a cam wasnt bolted.

Wasn't bolted?! That shouldn't make a valve hit a piston. As a matter of fact, just the opposite.

You mean the cam GEAR was not bolted?

[Tat2demon]

Yeah sorry, the sprocket wasnt bolted. Everything else was in place.

[TopCatGr58]

Aha, the plot thickens! Yes, now with a bolted down cam, but not spinning due to the sprocket not being bolted to the cam would cause a valve or valves to be open while a piston cam up to meet it! Also, IF the other cam sprocket was bolted, then that cam would spin, and it could also cause a valve to come OUT and hit a valve already open and bending it!

Good luck!

T.C.

[WMarshy]

Oh boy, you really got yourself into a predicament. These engines are considered interference engines. That means the valve will interfere with the piston if valve timing is off or if the intake and exhaust valves are out of time they can hit eachother (as TC stated). Neither end well for the owner.

I wouldnt advise you to crank the engine over to check your compression. At a minimum you need to get the cam back into phase before craning it over. You would be better off taking both cam out and then pressurizing the cylinder with a compressor (remove the spark plug and use a rubber tip air gun in the plug hole) and listed for air out the intake or exhaust port.

Others will likely chime in on what to do next so that you dont do any more damage. Theres probably more than one way to skin this cat.

[Tat2demon]

Oh boy, you really got yourself into a predicament. These engines are considered interference engines. That means the valve will interfere with the piston if valve timing is off or if the intake and exhaust valves are out of time they can hit eachother (as TC stated). Neither end well for the owner.

I wouldnt advise you to crank the engine over to check your compression. At a minimum you need to get the cam back into phase before craning it over. You would be better off taking both cam out and then pressurizing the cylinder with a compressor (remove the spark plug and use a rubber tip air gun in the plug hole) and listed for air out the intake or exhaust port.

Others will likely chime in on what to do next so that you dont do any more damage. Theres probably more than one way to skin this cat.

When I turned it by hand it was very light pressure and stopped as soon as I felt pressure. This was done with plugs out so there was no back pressure. It happened about a quarter turn with the wrench on the timing plate. Right after it happened I turned it backwards to the T, made sure everything was lined up and bolted down the cam. I turned it by hand several times to make sure all seemed well after that.

The "don't crank it" boat sailed a few hours ago. Ive already had it running for a while tonight. The one valve was a bit more noisy then the others but I don't know if that's normal for a re-shimming or a bad sound. Everything else seemed fine. No backfiring or other strange sounds.

I just ran to Walmart and unfortunately they don't have compression testers. Ill have to run to the parts store in the morning.

[CaptonZap]

I don't want to sound like a spoil sport, but you might want to pull the rocker lid and recheck the gap.
If you went the wrong way with the computations on the shim number, you would have opened one up enough to make it noisy. BTDT CZ

[skids]

yeah sorry, the sprocket wasnt bolted. Everything else was in place.

U R screwed!

[Tat2demon]

Thanks for the insight skids. Not sure what I would do without you.

[skids]

Sorry, but it is the truth. Even if you had light contact afterwords, the stems could be bent not letting the piston/valve contact to occur because the bent valves are open. Here is the positive that you are looking for...you might be lucky. Do you feel lucky?

[BA80]

Sorry, but it is the truth. Even if you had light contact afterwords, the stems could be bent not letting the piston/valve contact to occur because the bent valves are open. Here is the positive that you are looking for...you might be lucky. Do you feel lucky?

What?

[ViperRon]

The best thing to do at the moment was as suggested pull both cams pull all plugs and use an air compressor to blow into all cylinders and see if air leaks. If you hear a hiss then probably a valve problem for that cylinder. If you do not have a compressor you can hand crank it with a finger covering hole. Do not shove the finger deep in the piston will hit it then you will have a sore finger. Don't crank it with starter and your finger in because you will really mess up your finger.

If no hiss do the cam alignment bolt them down bolt the gears in make sure the cam chain tension is good. Get it in time and do a compression check if that is good valves are good. You will have a shim sized wrong or sticking valve.

Now one other thing I have seen people do is bend or damage the lifter barrels that the shims sit in and that will cause valves to stick. Valves need to move up and down smooth and not slap shut or stick.



As far as valves go I have seen them bend just sitting the head on a bench and putting the cams in. It does not take much pressure to bend head of valve or stem.

Sorry to say Skids is probably right.

[Rasputin]

Do not shove the finger deep in the piston will hit it then you will have a sore finger. Don't crank it with starter and your finger in because you will really mess up your finger.

Holy smokes man you must have long skinny fingers! I have a tough enough time just plugging the hole enough to seal it for a quick comp test.
But you are right it will do the trick to see if there is very low compression.