Top End Engine Knock?

[Sykes]

hey guys, i have an r32 gtr thats always run well, that is untill now.

i started it this morning to move it out of the driveway and theres a massive knock coming from what sounds like the top end.

it gets faster if you increase the revs and sometimes seems to go quieter for a second or two.

the car seems to run fine still, although i havnt gone out and flawed it because that could only make things worse.

i thought it could be a valve, a spring or a lifter but im not sure.

the car is very stock, still with airbox and all. no boost or turbo work.

ive searched for a while and havnt come across anything usefull too.

any help would be greatly appreciated!!

ill record what it sounds like and post it also.

thanks heaps guys!

[Sykes]

this is a recording of it, also theres an elephant noise too, sounds like something slipping.

cheers!

Edited March 29, 2010 by Sykes

[Humbla]

I had this sound a while back,turned out to be valve guides.

[Sykes]

if it is the valve guides, how hard would they be to fix?? ive had a bit of mechanical experience although i tryed to get the gearbox out once and failed on the top bolt.

would i need any special tools also??

thanks!

Edited March 29, 2010 by Sykes

[Humbla]

Cost me 700 for the head reco,33gtst but,not sure what an r would cost,i ended up paying 2600,but i had timing belt an stuff done as well,hope it doesn't cost you to much. Genelle. This is a fairly big job cams an head off,if you arn't sure get a mechanic to do it.

[trel]

from the sound it makes on startup sounds like an exhaust leak? manifold possibly leaking... hopefully that's all it is!