1988 Crew Cab 454 TBI Knock

[1975 K20]

I have a 1988 Chevrolet crew cab with the 454 TBI. Awhile ago it started having a light knock that would go away as it ran. But, just recently the knock started getting worse and won't go away. It has good oil pressure and it has oil. The knock sounds like it is on the passenger side and gets faster as the rpm's go up. Any help or info on what this could be would be great! Thanks!

 

[gmbellew]

sounds like it could be in the valve train or maybe a lifter that isn't lifting anymore?

 

[1975 K20]

How would I check for that? If that is the case how do I go about fixing it? Thanks!

 

[bucket]

It could be a number of things. Does it seem to match RPM, or is it half speed of RPM? Can you get a video?

 

[1975 K20]

Yes, it seems to match rpm. Can you post videos on here or should I put it on YT or something and give you the link?

 

[1975 K20]

Here’s the link the the video.

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[Ricko1966]

It could be a number of things. Does it seem to match RPM, or is it half speed of RPM? Can you get a video?

I stayed out,due to the multitude of things it can be. If you can't hear wrist pin knock,from,a cracked flex plate from a collapsed lifter,or a bad efe valve etc,etc,etc.. You should take it to someone that can. A knocking noise diagnoses by text just isn't the best option IMHO.

 

[ByrdDog]

Maybe stick a borescope into all the cylinders to check for damage? At least start eliminating possibilities. I think just trying to judge by the noise, you're going to get as many different opinions as people you ask.

 

[1975 K20]

Thanks! So I should pull all of the plugs and stick a camera in there and check for broken pistons/scarring?

 

[gmbellew]

I’d try and figure out where the noise is coming from first. Driver, passenger, top, bottom, etc.

 

[1975 K20]

Thanks! The noise is coming from the passenger side and it sounds like it is coming from the top. Maybe under the valve cover.

 

[xm20k]

I hear a clicking that sounds like a lifter but under that a deeper sound that sounds like a rod.

Mabey just sound quality of camera/video but that's what I hear.

 

[1975 K20]

How do I check if it is a lifter?

 

[gmbellew]

If it is top and under a valve cover, pull the cover and see what you see. Can also run the engine with the cover off and see if the rockers are all moving properly.

 

[1975 K20]

I pulled the valve cover and everything under there was fine. I then drained the oil and as i was dumping it into the used oil tote I saw some glitter. So I shined a flashlight at it and saw a reasonable amount of metal. I finished changing the oil and started it and it seemed a bit quieter. But before I go jumping to conclusions could it possibly be the air injection system because it seems to run fine besides the knock or is my engine shot?