After having finished putting my fresh valve seals on and reinstalling my rocker arms and setting valve lash and all, my care is making a loud noise. As far as I can tell, it's at the speed of the crank and coming from the bottom of the engine. The car is also idling at 1200-1500 RPM. Are these two related? Does anyone have any ideas as to what this noise is and/or what I can do about it? I'm going to run a compression test as soon as I get my hands on a tester. Any other ideas would be greatly appreciated.

 

you say you just put in valve seals and now its making a noise it didnt before ?

id check and make sure you got your valve lash adjusted correctly

 

I'm pretty sure it's adjusted correctly. I put them all on there as close to zero lash as I could cold, then I ran the motor, loosened each one until it clicked, then tightened it a bit until it stopped, then did 1/2 turn further. As far as I understand it, that's the proper procedure. If I failed to set the valve lash correctly, what would be causing that sound? Too tight or too loose? Thanks for the respone, I'm kinda at the end of my rope here.

 

Well, I finally got some free time and I took another stab at it. I changed my oil, since it was sitting for a number of months, the oil looks good. I ran the engine, and reset the valve lash on every cylinder. The sound didn't go away at any point. I also ran it and disconnected each plug wire in turn, and the sound didn't go away. The sound is very present at idle, which is usally around 1200, but sometimes goes up to 2000. I know both numbers are high, that is puzzling me as well. If I rev the motor, the sound doesn't seem to get any louder, or maybe I just can't hear it over the normal motor noise. The noise itself is kinda like a bap-bap-bap-bap, and it sounds to be at the crankspeed. I've also done the rubber hose check, and I don't hear it on either of the heads, any of the accesories or the exhaust. To the naked ear it is definately coming from the bottom end somewhere. I haven't gotten a chance to do a compression check yet, but that's next. Any ideas would be greatly appreciated.

 

How many miles are on this engine and was it sitting for a long period of time before you did the seals?
Only thing i can think of is a piston pin which isnt all that uncommon or a rod bearing.
I had a stuck valve on my big block nova once which was from it sitting but thats topend related and man was it noisy
On my other camaro the flywheel tin cover rubbed the flywheel when i first started it.Its sounded bottom endish too.

 

Well, it has 139k miles on it, and it was sitting for three or four months. Thing is that it ran fine before that.

 

Back the timing off a bit till the sound goes away

 

I Put a brand new edelbrock carb on my car then months later parked it just for four months.When i started it back up it was running on half the cylinders,the gas went bad and plugged one side of the carb man what a mess.But thats why they call it sittings desease .Seals dry up water and fuel pumps start leaking,oil leaks that ya never had before apear hehe.Little critters get into your engine and make these cozy little nests.Did you replace the seals before starting the engine up after it had been sitting?

 

It had run for a while before I changed the valve seals, at most it sat for a couple weeks. I've already put fresh gas in it, just changed the oil today. My buddy had an idea that since I reset the valve lash, and the timing is bumped up a couple degrees, I should change the timing to match the newly adjusted vavles. Does this sound plausable? It made sense to me, and seeing as I've checked/set the valved lash about three times since the noise started, It sounds like a good idea to me.

 

i wouldnt say so.If your running a hydraulic cam iit zero lash.That doesnt effect time but checking it is a good idea because as engines wear your timing chain stretches and thus throws your timing off,did you pull the heads when ya did the seals or did you do em on the car?

 

I left 'em in the car.