R6n350GT

iTrader: (1)

Engine has had this noise since it was built, i have tried numerous oils, changing fuel systems, tuning ect but cant figure out what the issue is.

Before i just pay someone endless amounts of $ i would love some help identifying some potential things this could be that i can either check or give the list to the mechanic.

sometimes if car is not run for days i can hear a knocking noise for few seconds when starting.

http://vid40.photobucket.com/albums/...pszlab8cfg.mp4

Thank you very much, really appreciate it.

michaelmoon912

Sounds like something in the timing assembly, probably related to the chain guides or loose timing chain. It has way too much rattle to sound like its coming from anywhere else is my guess.

R6n350GT

iTrader: (1)

ALso engine was rebuilt for FI, new everything inc tensioners. Would a correctly installed tensioner / guide / chain be an issue if i turn the car off once stated and then start again and no more noise until oil is all drained ~ 30mins +

may be a separate issue or the same but sometimes when initially turning over you can feel / hear a knock. ill try and get a video of this

hulkout

I had a sound pretty much exactly like that that showed up about 200 miles into my forged rebuild. I can't tell if it keeps going after initial startup or not. Mine continued as long as the engine was running. I narrowed it down to a faulty timing chain tensioner.

I'm probably over explaining this. But that's kinda how I am. Bear with me.

Basically, the tensioner is oil pressure actuated. So when oil pressure is present that pressure is transferred to the body of the tensioner which pushes the shaft out of the tensioner and applies pressure to the guide and tightens the chain. When you shut the engine off, the oil pressure drops to 0. The tensioner has a ratcheting clip type mechanism that keeps the shaft from going back in under a 0 pressure condition but allows the shaft to Continue to move outward and keep a steady tension as the chain stretches.

So if something is faulty in your tensioner that is allowing that shaft to receed back into the body of the tensioner, then yes, the noise could definately be worse/louder/whatever after the car has sat and the oil has drained back to the pan.

qew

iTrader: (1)

As ^^^^ Hulkout ^^^^explained exactly what I was thinking sounds like your tensioner isn't locking. Sounds like the primary tensioner,but very well could be one of the 2 secondary tensioners.How long ago was it built?I would've taken it to the person/company who built it.
If you open up the timing cover, the tensioner /tensioners that is most collapsed the most is more than likely your culprit if that is where the noise is coming from.

hulkout

+1 on taking it back to whoever built it if you had it done by someone else.

Pic credit to rrmedicx on the "other" forum. He had a great build thread over there.



You can remove the black plastic cover on the left of the front timing cover you can inspect this main tensioner... Sort of. But if you see the tensioner gas malfunctioned you may want to pull the whole front cover to double check your timing. If the chain got to loose it may have jumped a tooth or two. I'm not sure if you would notice the car running differently or not if this was the case. But better safe than sorry.

qew

iTrader: (1)

Thats right totally overlooked the little covers that give access to the tensioner and water pump. There is actually a video on youtube,2 guys changing out the water pump in their garage,one video taping seems to be owner and the other looks to be an infinity mechanic. Might be helpful if your gonna end up doing it.