i'd like to get everyone's opinion on a new issue.
the car started with 7 gallons of shell 93 octane + 2 bottles of octane boost. (After draining out all the old gas because it smelled bad)
yesterday the car had a faint knock at idle (which its had since the first initial start)... the only tune so far was to change the injector constant for the LSJ injectors... i ended up taking the car home last night and back to work with me today to put some break-in milage on the car. (about 27 miles each way)... once getting out here last night, i filled the car with 93 octane sunoco gas. i parked the car here and drove it to work this morning. on the drive this morning, i noticed almost a rattling sound everytime i hit the throttle and only when i was on the throttle (if i down shifted, it would rev high but only make the odd noise under load), and when i pulled in to work, the motor was knocking its ass off at idle, and would quiet down when it was reved up.
the knocking sounds like its coming from the exhaust cam tower region, its a lot louder when cold, and quiets up a little when warm. The car seems to get power normally through out the gears in the 3000 RPM Range.
any ideas??
Edited 2 time(s). Last edited Wednesday, March 24, 2010 4:59 PM
thats what my Z was doing before the motor blew Id be willing to bet that your rod bearing is gone
I just cant drive 55
Did you use some clay to check your piston to valve clearance?
"The FACTS are always subject to CHANGE once the TRUTH is applied"
"In the entire history of man the only stupid questions are the ones that don't get asked"
the rod bearings are like 2 days old... so that would be real quick for them to die (like 50 miles)
i did not use clay to check piston to valve clearance, however, i would assume i would have detected this problem before now if the pistons and rods were touching... i know have wiseco 10.5:1 pistons and the head is shaved .020 however karo assured me that .020 wouldnt affect clearance with these pistons.
That much lift and duration is going to make a lot of difference from HO cams. Pull at least one of the plugs and try to barrow a bore scope or something so you can look at the tops of the pistons and see if there are any marks on them.
"The FACTS are always subject to CHANGE once the TRUTH is applied"
"In the entire history of man the only stupid questions are the ones that don't get asked"
i'll see what i can do... and let you know..
whats your head gasket thickness?
Cometic, OE size...
accordding to Zyaaaa, Paul had .070 clearance on HO cams with my pistons. so take away .020 for the deck and .030 for the extra cam lift, thats .020 clearance
anyway, the tuner came out and set my idle tune... we noticed that i have a small exhaust leak (which i will pinpoint and correct tomorrow). Throughout the tune, the knock got quieter and quieter to the point where its back to the way it was before it got real bad yesterday. i do hear a mild knock still, but we're thinking between breakin noise, all the stuff in the motor, and the exhaust leak, that this could be contributing to the noise i hear now...
Glad you are headed in the right direction with it....
I don't really see how the exhaust leak would contribute to this sound tho? I have a badd exhaust leak on my SS at the header/DP connection.. It just sounds like chipmunks after about 5-10% throttle.
If I understand correctly... you heard a quiet "knock", it got louder after being driven, then you tuned it and it got quiet again?
Orr was the loud knock temporary and just covering up the quiet "knocking "of possible break-in noise?
Im no expert... just trying to help ya bounce ideas around...
Im just concerned that if the knock isn't going away, that something isn't right, or damage was caused when it started knocking bad. I know you said before, even when it was "quiet" it didnt sound like valve-train noise/tapping, you described it as a knock. My other concern is some of these parts are used, like the lifters, they shouldnt be experiencing the same "break-in" that new parts would have. Soo I wouldnt think those parts would be making much more noise than they would normally.
I rebuilt my LSJ with all new part: New bearings/pistons/piston rings, motor was resleaved, all new valvetrain, etc... didnt make any more sound that it does now... my LN2 lifters made a lil more noise after I rebuilt it, but that was cause they were new V-8 spring swapped lifters which are still pretty damn noisy. I can only help based on my own experiences, hence the comparison.. but I just dont think normal break-in noise will cause that much noise. But I havent heard it myself... maybe you are being paranoid? lol I know Im guilty of that.
Jazer wrote:Glad you are headed in the right direction with it....
I don't really see how the exhaust leak would contribute to this sound tho? I have a badd exhaust leak on my SS at the header/DP connection.. It just sounds like chipmunks after about 5-10% throttle.
If I understand correctly... you heard a quiet "knock", it got louder after being driven, then you tuned it and it got quiet again?
Orr was the loud knock temporary and just covering up the quiet "knocking "of possible break-in noise?
Im no expert... just trying to help ya bounce ideas around...
Im just concerned that if the knock isn't going away, that something isn't right, or damage was caused when it started knocking bad. I know you said before, even when it was "quiet" it didnt sound like valve-train noise/tapping, you described it as a knock. My other concern is some of these parts are used, like the lifters, they shouldnt be experiencing the same "break-in" that new parts would have. Soo I wouldnt think those parts would be making much more noise than they would normally.
I rebuilt my LSJ with all new part: New bearings/pistons/piston rings, motor was resleaved, all new valvetrain, etc... didnt make any more sound that it does now... my LN2 lifters made a lil more noise after I rebuilt it, but that was cause they were new V-8 spring swapped lifters which are still pretty damn noisy. I can only help based on my own experiences, hence the comparison.. but I just dont think normal break-in noise will cause that much noise. But I havent heard it myself... maybe you are being paranoid? lol I know Im guilty of that.
it was a quiet knock at first, then i drove it, it got ultra loud, and was paired with a knock sensor circut failure code, and a crank position sensor code.
The tuner came out and tuned the idle VE table as best he could. he said that the wideband may or may not be as accurate depending on where the leak is at. As he tuned it, the knock got ultra quiet again and continues to be a quiet knock. As of now, its somewhat loud on cold starts, and quiets up after a few minutes, and its kinda like a random tapping sound, not really in time with it self, but as i rev it up the taps become more consistant, but do not get any louder. the knock code has returned though...
150 miles on the motor now... imma pull it in this afternoon and check where the exhaust leak is at, i'm also going to check to see if the knock sensor came unplugged, and if not, look in to replacing it with the IAC.
Pull the dip stick and look for micro shiny flecks. Hate to say it but you might have bearing failure...
"The FACTS are always subject to CHANGE once the TRUTH is applied"
"In the entire history of man the only stupid questions are the ones that don't get asked"
Yeah as long as your knock sensor isnt faulty, it's concerning its throwing a knock code. I would be real careful driving it. Deff make sure the tune is 100% correct so that is atleast canceled out as a cause for knock.
You installed the bearings correctly? lol.
What kind of oil are you using?
~2014 New Z under the knife, same heart different body~
______________________
WHITECAVY no more
2012 numbers - 4SPD AUTOMATIC!!
328 HP
306 TQ
7 qts 5w30 with lucas engine break in additive.
well wouldn't the knock throw an out of range code or something instead of circuit failure. i always thought a circut failure code meant the sensor wasn't reporting back to the ECM either because its bad or unplugged.
I think that is too much oil for your engine, you don't have a turbo, and you don't have an oil cooler(I assume)
Anyway, try throwing some thicker oil in there and see if the noise goes away. Maybe 10w40 or 15w50.
~2014 New Z under the knife, same heart different body~
______________________
WHITECAVY no more
2012 numbers - 4SPD AUTOMATIC!!
328 HP
306 TQ
well i have the miller modified pan... clyde told me to run 7qts.
last time i ran 15w50 (almost 2 years ago) after 6 months of use i ended up blowing up a lifter. i'm not 100 % positive the oil caused this, but now im hesitent in running 50 weight oil
When I broke in my LSJ I ran 5w30 conventional... did an oil change at 500, then a 2nd at 1000. At 1000 I switched to 5w30 fully synthetic. (this was a full engine rebuild).
On the LN2 I stuck 5w30 fully synthetic in it right away because I didn't pull the pistons and they cylinder walls already had nice hash marks.
Since u replaced the pistons and all, Id be hesitant putting a thicker oil in so soon, because you want those rings to wear in properly in the cylinder.
Edited 1 time(s). Last edited Friday, March 26, 2010 10:31 AM
Oh ok. Well, just try some 10w40 and see what happens.
~2014 New Z under the knife, same heart different body~
______________________
WHITECAVY no more
2012 numbers - 4SPD AUTOMATIC!!
328 HP
306 TQ
you know... it kinda sounds like my LN2 with roller rocker arms on cold start up, but then it gets quieter
Websense = no youtube... i'll post a vid of how my motor sounds tonight when i get home...
another buddy of mine suggested that i may be seeing the knock code because ive removed the balance shafts and lightened the crankshaft 3lbs... any ideas there?
Im anxious to hear this noise, did you post a video of it? Just wondering because the 2.4's have a noisey top end anyway because of the lifters. My balance shafts are gone and my crankshaft was lightened so I wanna compare noises.
My noise used to come from my lifters, after I switched the weight of the oil and after the oil reached up top it quieted down significantly.
~2014 New Z under the knife, same heart different body~
______________________
WHITECAVY no more
2012 numbers - 4SPD AUTOMATIC!!
328 HP
306 TQ
I would think it is possible that it is sensing false knock due to the added vibration.
i honestly think its a lifter being stubborn and not pumping up.
and the noise on cold start up that goes away is surely the forged pistons.
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