g3t0ut

Hi all I have a '05 got that just hit 65k only thing it has is k&n drop in and kooks LTs and last week i noticed that it started making a knock like sound. It only happens when its fully warm and not always even then. If you are driving and don't really go over 3k it won't start. the harder you drive it the louder it will be. Once the car has been parked and is started again its gone. At first i feared rod knock but after more inspection i don't believe thats what it is, then I thought it sounded like pushrod or rocker but now I'm just not sure at all.
I know i won't get a definite answer here but any thoughts on it would be great..

here is a vid when its at its worst-



after doing some more youtube surfing i found this

to me my car sounds almost identical. let me know your thoughts

Sinister_Z28

Have u put a mechanics stethoscope or long screw driver to different parts of the engine? Couldn't hurt to drain the oil and check for metal in the oil.

g3t0ut

thanks ill do that all tomorrow. what would you like me to listen for just location?
I checked oil pressure and it was fine

Sinister_Z28

Yeah just take a long screw driver and put it on the valve covers and valley cover while its running. Basically if u plug one ear and put the handle of the screw driver to ur ear and listen. It allows u to hear whats going on in the inside.

When i built the engine in my sig like a week into the break in i had a tick i could hear. It scared the **** outta me. So i did the old screw driver trick and u can hear the inside, for me it turned out to be a exhaust leak. Also when i drain the oil i let it run through my hand and i just rub my fingers over my hand to feel for metal. Hope this isn't anything serious, but it definitely sounds like a knock to me.

g3t0ut

well i have built a 403 block but i really am not ready to put it in yet, but worst case i drop it in. haven't gotten around to doing oil yet i thought i had some oil and a filter laying around but it happens i don't and I'm not going out to get anything today
it certainly sounds like it comes from the top end, and i have listened more carefully and it is extremely faint on start up and when cold.

Sinister_Z28

I hear u on not going anywhere tonight. Is the engine bone stock or is it modded? I would check the oil, then if that doesn't work u could check for a bent pushrod. And while ur in there u could check for a loose rocker but that makes more of a tick than a knock from what i understand. So if I'm understanding u correctly the noise is faint on a cold start up but then gets louder as the engine warms up?

Another thing u could do when u check the oil is put a small magnet in the oil drain pan to also aid in looking for metal. And i don't know how u have a built 403 that hasn't found its way into ur engine bay lol. I have a mild setup and its power is awsome and addictive.

g3t0ut

yes louder as it warms up the hotter the engine gets while it was running the louder it will be.. as in if I am to romp on it a little thats when its loudest. if i cruise and shift conservatively it stays extremely faint. I was concerned about oil pressure at first because randomly the GTO will pop the oil message up, i then immediately check the oil and its right at full line on the stick; not even in the middle..
It is completely stock other then the kooks 1 7/8 long tubes and catless mids and k&n drop in filter

lol I have had the car for just over a month.. (I checked everything real good before buying it and did a few good pulls and listened to the engine and it was completely normal then, used my obd scanner checked live data link everything was normal!!)..

the 403 was going to go into my rx7 and then i decided to get this and wanted to get some nice heads, and an fast before dropping it in. honestly it is still hard to hold out.. well see what happens.. also wanted to do a couple things to the gto before dropping it in.
I will definitely check the oil and was considering going with a heavier weight as it doesn't get to cold here and don't think it will do any harm.

I did find it odd that that other video sounds almost identical and he said after new lifters all was good. it didn't quite sound like a bad lifter would normally sound like to me either but the whole thing seemed a little odd all together.

Sinister_Z28

I see what u are saying. That other vid sounded like a bottom end to me. Bottom ends knock and top ends tick, but that's what ive been told for whatever its worth. What weight oil are u running now?

I would do a search for vids of rod knock and all the other things we have talked about. Im not saying its a rod but my stock LS1 knocked like the knock u hear in the videos before it spit a rod and piston through the block.

Heres what I would do. Drain oil and change filter and look for metal. Then pull the valve covers and check each rocker to see if one is looser than the others. If the rockers are fine I would loosen them and pull each pushrod one at a time. Take each pushrod and visually inspect them to see if they look bent. Next find a flat clean surface and roll them gently across it. If it rolls straight its good, if it rolls off to a angle its probably bent. U do this kinda like how u check to see if a pool stick is straight by rolling it across the pool table. When done checking wipe off the pushrods and reinstall them. Make sure to retorque the rockers in the correct order.

Do a search on google on how to perform all these procedures I have been telling u about because there are tons of info on all this on the web. Something I have learned when googling stuff for our cars is to type in ur search and put ls1 at the end of the search phrase.

Just some advice. I basically dropped in my 408 to a stock car, bad idea. Then I put all the umi suspension stuff on it that I have in my sig. Car runs great and pulls like crazy but traction is non existent in first gear lol. I bet tires would fix this but since I still have my stock 10 bolt that wont be happening till I get a stronger rear end in the car.

Also do a search on oil weights because to thick of a oil with to tight of clearances can cause oiling issues. Just do a search. If ur running synthetic u could try switching to a conventional of the same weight and see how that goes. Some people believe that todays synthetics are to slippery, because todays synthetics are more advanced than the synthetics from 8+ years ago.

Basically research is ur best friend. Let us know if u have any more questions or what not.

g3t0ut

thanks a bunch, i have done top end work before but I don't consider myself an expert so i like to check and see what people that know more then me think. ill post once i get all that done.. hopefully all goes well..
hope i don't split the block i would like to have an extra laying around!

Sinister_Z28

I hear u there. Hopefully its something simple and easy. Good luck