rb30n/a engine knock

[zedls1]

Hey zedder's, i'm hoping i can get some feedback. I'm hearing a knocking noise from my rb30n/a in my Z. It's there when you first cold start and when the idle settles it's not there, but after she warms up it's there. As you rev the engine the noise increases in revs. Oil pressure is ok, oil levels good and clean, theres no odour or smoke, i'm no mechanic but i used a long screwdriver and tried to pick up where the knock is coming from and it sounds like the front end but not sure. Could it be a rod? bearings?

 

John

[RBZ 260]

lol i had the similar issue few weeks ago on my rb20det.

 

since the conversion it was runing silent as. than suddenly this ticking knocking sound coming from the front of the engine. but lot lower near the sump area.

 

i asked around and got pretty bad news :ie my big end bearings are gone and need replacing etc...  couldnt come in terms with it i started to pin point the frequency and location of the noise.

 

closes i got it wasnt the valves/cam and top end but defiently low in the engine closer to the left hand side of the car.

 

if u listen under the car its very annoying. when cold it was quiet maybe one or two hard knock and silence. than when warms up sounds like an old magna. the more revs the more annoying ticks.

 

not sure what else u have on your engine but in my case the ticking noise was from idler pulley bearing on the air/con compressor. found out by removing all the belts and startign the engine without it. from then onwards never heard a single knock since LOL (sound like a ultra tune commercial)

 

i would start looking and disabling the easy things before ripping the motor appart. i been told by proffesional that he guaranties its the big end bearing. well that tell you about it try anything first before spending big money relying on pros to tell you whats wrong with your car.

 

if you dont have a/c or any of these pulleys probably check the idler pulley and tensioner bearings on your timing belt. apperently they do similar noises when gone bad.

[zedls1]

Hi rbz 260, thanks for the reply. I'm not running a/c, so i'll start with your recomendations. I'm epxecting the worse but hoping for the best.

 

John

[RBZ 260]

ive been told by 3 rb nuters that my big end was in trouble.

 

except one mate that drove the car said that its not.

i even drained the oil flushed the engine checked oil pressure (not that accurately  but close enough) and all checked to be ok. besides that annoying knock.

 

though the 3 rb nuters also told me it could be the belt tensioner and idler too. but it sounded lot lower than where these items are.

 

apperently if u load the engine heavily ie: take off in higher gear ie 2nd or 3rd and if its the big end you will be able to hear it quite badly.

 

drain your oil and if u dont see any brass metalic in your oil than should be good.

 

 

 

 

[zedls1]

I spoke to a mate who although works on ls1's and ls2's he know's a bit on the rb's and will be checking mine out shortly, by what i told him he doesn't think it's main end bearings which is a relief so i'll wait till he check's her over.

 

John