Truevetteman

The other day I was out tinkering on the corvette. Changed the oil, cleaned the throttle bodies etc. I have since drove the car a coupe times and now notice a knock or tick??? I went with the 454 filter from Delco and 10-30 for oil. When I pulled the intake off both throttle body gaskets gave way. So I am messing those. I cant tell where its coming from. The motor only has 60,000 miles on it. Oil pressure is 30-40 at idle its got up to 70 before at crusing but its normally 40-50. The noise goes away when you rev up the motor. But it is loud. I am pretty sure its coming from the injectors its almost like a hammering noise. Could those gaskets stop that much noise? I am freaking out a little I hope its not internal. Thank you in advance.


Also when I put a screw driver to the valve covers its quiet with no noise.

Truevetteman

Anybody?? It almost sounds like upper valve train but like i said if you put a screw driver up to the valve cover..up to your ear its quite. However the noise only comes after its gets warm?? Is it because the butterfly to the throttle bodies are more open on a high idle on initial start up??

leesvet

if it was intrernal the Op wouldn't be 40 @ idle. Its probably NOT 40 at idle now, just a slow gauge, BUT you DO have Op so the knocking is most likely being magnified by something...inj DO tic.

How a noise is described here is the hardest part of this....a tic sounds like a tap...the next guy says knock. Its still a TIC.
If you can't hear parts banging with the hose/ear tool...then they aren't. Fix what you KNOW to be deficient and THEN take another listen. OP tells a lot about the inside.

Truevetteman

Yeah I hear ya.... its hard to describe. It sounds like a hammering almost like a wrist pin or rod knock. But on the upper end like valve train. I am pretty sure its the TB but I was just wondering. I think I am good oil pressure wise. I was just double checking that the smaller 454 oil filter wouldnt hurt anything. Just scary. You cant hear it when the hood is shut. And it goes away when you rev the engine. I wrist pin, rod knock, or valve train it would get worse with a rev. I didnt know if maybe it was a TB problem.... might be a good thing.... might be showing me I dont have a clogged injector LOL. Anyone else??

Cliff Harris

Try running the engine with the serpentine belt removed. Not for long, though -- it turns the water pump.

That can isolate noises in the accessories that the belt drives.

DanielRicany

Did you use a different weight oil last time? And also how much oil came out? Check your dipstick, are you in the okay zone? Have you ever overfilled or are you currently overfilled? How many miles?

Truevetteman

This is the first time I have changed the oil, since the purchase of the car. I believe the right amount came out. Everything looks good on the dipstick. 60,xxxx on the car. 10w-30 oil.

DanielRicany

Maybe it was already knocking and the previous owner put something in the oil to quiet it down so you would buy it?

Although, do you know how many miles since the oil was last changed by the previous owner?

How long have you had the car?

Maybe try adjusting the valves? You have an L83 I believe? My car has an L98 with hydraulic lifters so to adjust that, you losen the nut on the rocker arm until it chatters, tighten it until it stop chattering and go another 1/4 turn. It's a 5/8 nut.

If the L83 uses hydraulic lifters its probably the same process.

If it uses solid lifters you will need a feeler gauge.

I would start there first. If it doesn't go away after that then I would start looking towards some easy knocking diagnosis. Like the other person said, take off the belt. Go around to each cylinder and unplug a spark plug wire one at a time, if the knock goes away then that is the cylinder its coming from. The knock will go away, or become quieter if it is a wrist pin knock or a collapsed lifter. If it sounds like you take a stick and rapidly smack it back and forth in a cup then its rod knock.

Good luck.

Truevetteman

I just went out and started the car. Watched the oil pressure and when the sound started. Oil pressure was good. The noise stared right when the high idle started to come down. I put a screw driver up to the tb housing and put it to my ear. Its difently coming from the Injectors. I believe its more from the drivers side than the passenger side. But its coming from them....Shewww thank goodness. Now I cant tell if thats normal or something wrong with my Injectors.

DanielRicany

Do a carb swap. You'll have a lot less headaches

hooked073

if you can here a loud knock it is not normal. You can have an internal problem with normal oil pressure. just a fast quess is you dropped a peice of the gasket down the TB it ended up in cylinder and it is what is causing your knock. This is just going by you saying you have missing peices. And seen this before

DanielRicany

Never let anything drop into your intake, head ports, or spark plug holes. You may end up having to pull the head if that's the case.