engine knock

[Chris_32212]

My LT5 is knocking noticeably after a hard pull at high RPM. It will eventually go away and stop knocking until the next high RPM throttle application. Any ideas and or recommendations would be appreciated. I think I saw a forum post a few years ago about something similar but I can't remember the details and I don't have the time right now to search the archive. (too much college homework). Any help would be appreciated.

Chris

[Chris_32212]

I thought that I would add some more information about my car and the knock in general.

97,000 miles
Stage two clutch
Fidanza flywheel (I am very accustomed to the gear clatter, that is not the source of the knock)
stainless works headers
B and B tri flow exhaust (x pipe in place of resonator)
K and N filter
Genaric performance Chip from Exotic Muscle

I bought the car in 2007 with 89,000 miles on it. As far as I can tell, I am way harder on the car than anyone else has ever been. I drive hard. The car sees the rev limiter more than I would like to admitt. I drag race it a few times a year. The first time I noticed the knock which is more of a loud ticking sound, was at PIR. It was after a perfect run, no missed gears, no rev limiter, no mechanical over reving has ever occured while I have owned it.

As far as I know, the injection system and ignition system are factory.

Power feels strong (normal), and the idle is right at 800 and feels smooth. I have not tried the nickle on edge trick though.

It is more of a loud ticking sound and is quite loud. Very noticable. It matches engine RPM and is most definately under the hood. I have never heard it from out side the car because it only happens for a min or two after hard throttle and high RPM.

[Chris_32212]

Reading some other posts on here, I wanted to add some more information again.

The car has excellent oil pressure during all opperation. However, I did do an oil change just before I started hearing the knock at high RPM. I did not change the oil in the oil cooler.

I think I may start with another oil and filter change. Then replace injectors and coils since I am sure they need to be done.

[sammy]

sounds like you have a good plan of attack to find the problem , might i suggest, you do the oil and filter and then ck the car out. the nproceed with the coils and injectors. jon at ficinjectors sells. what he calls webuilt and flowmached injectors with a 3 year warrenty for aprox 380 to your dorr ,he also has some new injectors that are flowmatched also but i am not for sure on the price . i have his injectors in both my cars and love them .i pulled out a set of rcs to put his in one of the cars . hope its something simple

[Kb7tif]

Pop a fresh oil filter on there. Sounds like something might starve for oil.

[tomtom72]

Originally Posted by Kb7tif

Pop a fresh oil filter on there. Sounds like something might starve for oil.

I agree and I would just make sure that the injectors are not sticking open & dropping fuel to dilute the oil.

not to be a wise guy....but once at COSTCO in my haste I grabbed the wrong M1 oil. I grabbed 5w-30 because I was in too much of a hurry! That didn't go over well with my motor at all after doing some elevated rpm work on the twisties I noticed a distinct lowering of my oil pressure readings after some sustained road work. I checked and was down to the add mark the next morning. I reached for the left over quart to add and to my everlasting embarrassment saw that I had bought 5w-30.

[Chris_32212]

I use royal purple but ... um ...I'm not sure what weight it used. What weight do you guys recomend??

Chris

[tomtom72]

I'm now using a 10w-40 weight.