Engine knock diagnoses

OverDose · 08-25-2010, 03:55 PM

Motor setup, Top down.
Stock cams / BC272 cams, stock rockers, stock lifters, BC titanium spring/retainer kit.
Stock valves
Cometic HG, ARP studs
Arias pistons, Eagle Rods, ARP bolts. Motor has 8500 kms since fresh rebuild with all OEM seals / gaskets / bearings.
Greddy 5l oil pan
15w40 oil. Oil pressure is between 30-100 depending on temp, and rpm.

This motor has been driven with this noise for 500 HARD kms. 20 psi on BC 272 cams putting down ~300whp. Ran a 12.8 @109 on this setup, with this ignorant tick. I think that if it were rod knock, the bearing would have self destructed by now, or the noise would have at least increased in volume / change in sound.
What happens:
When cold (oil cold, first 45 seconds – 1 minute) operating, no knock/tick
Knocking/ticking noise between 2200-3500 rpm, on accell and decal, regardless of load.

What I’ve done:
Changed cams, rocker arms, lifters, to try and eliminate the head as the issue. Now im stumped. Here is the video

Anyone have a similar experience?

richardwbb · 08-25-2010, 10:46 PM

15W40 in an engine with hydraulic valve adjusters? wtf?

dfddfd2 · 08-26-2010, 09:25 AM

The noise doesn't sound like a moving engine part. It sounds like it's the same frequency regardless of RPM. It could be a loose bracket or something outside the engine, or maybe a cracked/loose baffle inside the valve cover? Use a piece of hose held to your ear to try to locate the source of the noise.

Dave

Mrtone · 08-31-2010, 01:04 AM

it might be ur vavles that are ticking...do a valve adjustment on it...it gonna be a pain in the ass to do it on these sr...trust me i've done it myself and the shims are very pricey...i bought mine $20 per...but what you can do is swap shims around and if you get the chance just run to the junk and pocket a few extra shims...you need this sst that only nissan carries there ($500 for one) but there is this other tool you can use it looks like a mounting plate that sits over the where the cams sit...anywho...just make ur own tool...i made mines for under $35....and it worked...anywho...sorry for getting off topic...to test a engine knock is to rev the engine to the point where it starts knocking...leave it there...and start pulling out spark plug wire...if the knock goes away when SPW if pulled out then it mean the knock is coming from that cylinder...(this is for rode bearings)...and if the knock doesnt go away this gonna be crankshaft bearing...it really sucked for me cause my valve was ticking so i not notice the rode knock i did the whole valve adjustment...when i started the car there was not ticking but once you hit 3k rpm the knock came to sound...that when i found out i had a rode knock...good luck hope this has been helpful...sorry for such a long response...

oh yeah one more thing...it might just be ur choice of oil..thats causing the tick also...oil is measure in comparison to water...example: 15w 45(let do ur oil of choice) oil is measure when it cold and when it get hot...so at cold ur oil is at 15w and when it get warm o hot it thicken and become 45w...automotive company does this with oil so that when at cold start a lighter weight of oil can travel to the head faster...and warm up...nowaday you even see 0w 30...its because of emission issues...quicker your car warms up the less smog it emit...my oil of choice has always been 10w 30...sometimes 5w 30...

or might just be ur chain is loose...its normal that this happens...pop the valve cover off there should be a top chain guide where the cam sprocket are at...unbolt it off and look under it see if there is any groves if there is then ur chain is some what loose and its hitting it...out can just leave it out...(in the lower port model nissan took that guide out)

k **** leave it here any question dont mind to ask i will gladly answer...

viprdude · 09-01-2010, 12:01 AM

Quote:

Originally Posted by Mrtone

leave it out...(in the lower port model nissan took that guide out)

You think so? I have a 95 Nissan 200SX SE-R and I have the upper chain guide present.

To the OP, tried a different tensioner?

15w40 diesel oil is a turbo trick o the trade. It works well on turbo cars.

1FastP11 · 09-01-2010, 12:49 AM

To me sounds like sprocket wobble. It's common while installing the big sprocket bolt, to byte off a piece of cam lip (where the sprocket sits, and can be either cam) This manifests when tightening the sprocket down and suddenly feel the resistance of the bolt decreases to then increase again (that's when the biting occurs) Like hard, hard, loose, loose and the final hard. Don't ask me how I know

I suggest to take the valve cover of and briefly start the engine to see if the sprockets wobble, and to confirm the noise is coming from there (although it's pretty clear on the video)

Hope this helps.

viprdude · 09-01-2010, 01:25 AM

meow mix meow mix

1FastP11 · 09-01-2010, 01:34 AM

Threadjacker

I'll be brief.. Yours sounds like a noisy chain. Try that new tensioner you got on the way. Overdose's noise sounds pretty different from yours.

viprdude · 09-01-2010, 01:52 AM

A new tensioner is in the mail as we talk. I really thought these noises sound similar. My videos are not too good compared to his. I know my second video the engine was warm, I just ran it about 25-30 minutes when i got home, I kept it running and took the video.

I am sorry to the OP, but I thought it sounded similar.

99.se.ltd · 09-01-2010, 02:37 AM

sounds like the rod knock that i had. does it start at 2-2.5krpm?

viprdude · 09-01-2010, 02:51 AM

Quote:

Originally Posted by 99.se.ltd

sounds like the rod knock that i had. does it start at 2-2.5krpm?

I do not think this sounds like rod knock. 500 kMs and dyno pulls, track pulls, all sorts of abuse should have killed this engine by now.

That and the sounds, well, sound different between your video and the OP's.

99.se.ltd · 09-01-2010, 08:23 PM

yeah i was speaking about the op