Horrible Knocking Noise.

[vitz_n1]

Hi all,

I have an RB25 that is pretty unhealthy atm i think.

I bought the motor off a dude (anjrod) on this forum and it has blown rings in cylinder 2.

I got it started and was listening out for any noise's. Everything was sweet, then i started it again and after a few seconds was making this TERRIBLE knocking noise which sounds like its coming from under the rocker covers!

I have a feeling its to do with the valves but im a bit unsure cause its FKN LOUD!!! It dosnt make a noise when just cranking it over, only once its running

Could this be to do with the hydraulic lifter operation? i dont know how these operate so thats my guess atm.

I really need to know so i can decide on whether to rebuild the motor or buy a new one and start fresh and i only have 2 months till i get my license back, geez!!

Thanks in advance for any help.

Ryan

[FineLine]

Near every big end noise I ever heard sounded like it was coming from the valve train. Dont mean to be a doom prophet but I am guessing billy bigend is at residence in your engine bud.

[vitz_n1]

yeah i would agree with you 99% of the time, and i hope its the case because im pullin the motor down, but i just dont wanna rebuild bottom end and still have the prob.

This noise is LOUD!!! it literally sounds like it banging the rocker covers.

[(B1) MR_fanny]

i had a similar noise but its only occured 3 times from memory on very hot days. check my thread in the forced thread

http://www.skylinesaustralia.com/forums/Ch...ne-t213453.html

does it sound similar to this?

[Godzilla32]

The big end knocks i have heard have all gone away after a few seconds of running, after they get enough oil pressure to take up the extra gap of the worn out bearing. If its there the whole time its prolly more a lifter noise like you said as i have heard some pretty bad knocking from either unbled lifters (hydraulic like yours) or just worn out ones. Can i ask why you bought an engine with stuffed rings? It'll need a hone at the least...

[AdamsFast1]

get ur friends together, cause it'll be messy. pull the rocker covers off, have a good look at your cams etc, and if need be start it up with the covers off and just hold fingers over oil journals. could be a broken cam lobe. i'll cross my fingers for ya.

[NRV155]

Did the dude you bought it off know that it was stuffed?

[vitz_n1]

i didnt buy the motor knowing it was stuffed, i thought it was a working motor, it a lesson learnt for sure...... Apparently he didnt know, but who's to tell.

im still only 99% its a ring issue cause if this nois is valve related, maybe its just not sealing and thats why it has no comp (wishful thinking).

I took the head off and put a thicker gasket on before dropping the motor in and the pistons and bores looked great, no sign of glazing or detonation...

Mr_fanny, its kinda hard to tell but i reckon that might be it. pretty sure its the same actually.

Adams fast, i took the cover off and turned it by hand and everything seemed to be fine, would that be sufficient or do ya reckon i should still turn it over?

So how do i bleed the lifters?

[AdamsFast1]

lol, by hand would have been sufficient enough. thought you might get lucky with top end. If i sold a bad motor i'd be expecting a floggin comin my way. We live and we learn i guess. if you still have the head off the car, try to spin the valves with your thumb. they shouldnt be able to move. or pull the cams off and inspect lifter adjusters more closely. If you live in sydney you can drop the head off at nepean engines in penrith and they can check it over and do some machining while it's apart.

Edited May 1, 2008 by AdamsFast1