Having issues with my new motor... Need help

[AMiran02GT]

There was a spun bearing in my original cobra motor so I got a shortblock out of a mark viii and put my h/c/i on it. When i started it up at first it was fine but then it started knocking a little when i reved it up. Now it is knocking at idle. It doesn't sound like the rod knocking in the last motor. It sounds to me like its in the valve terrain somewhere. Anyone dealt with this?


Here is a vid of the car running
[ame="http://www.youtube.com/watch?v=DFIZgDKGRsg"]YouTube - 99 Cobra Knocking[/ame]

 

[nitemarestang]

sounds like a old farm tractor. why not drive by xxx and let brad take a look?

 

[Quadcammer]

ok, heres my thoughts and keep in mind this is hard to diagnose over the internet.

When you revved the car, the sound didn't get louder, but actually seemed to go away a bit. This would point to something that quiets down with greater oil pressure.

Henceforth, I would say that you may have a marginal chain tensioner. Does the noise seem more prevalent from the front of the valve covers?

Try using a mechanic's stethescope or a long metal extension to listen to various points of the engine to try to pinpoint.

Doesn't sound like a rod bearing to me, but I hope that you replaced your oil cooler prior to installing it on your new motor.

 

[coolguy10786]

ok, heres my thoughts and keep in mind this is hard to diagnose over the internet.

When you revved the car, the sound didn't get louder, but actually seemed to go away a bit. This would point to something that quiets down with greater oil pressure.

Henceforth, I would say that you may have a marginal chain tensioner. Does the noise seem more prevalent from the front of the valve covers?

Try using a mechanic's stethescope or a long metal extension to listen to various points of the engine to try to pinpoint.

Doesn't sound like a rod bearing to me, but I hope that you replaced your oil cooler prior to installing it on your new motor.

+1
Sounds like a tensioner, but as quad said that oil cooler will keep metal shavings and whatever else in it from your old motor no matter how well you clean it out.

Do you have a mechanical oil pressure gauge? If so, whats your oil pressure reading?

 

[AMiran02GT]

Ill take a listen with a mechanic's stethescope and see where exactly its coming from.

I am not using an oil cooler right now it has a gt setup and I am putting a remote cooler on once i get it running right.

I dont have a mechanical oil pressure gauge in the car, just the stocker which is showing full pressure.

 

[lancec2c30]

Are you sure you got the timing right? Another member on here not to long ago had a similar top end knock.

Turned out to be his timing was off enough that he was having valve to piston contact.

 

[AMiran02GT]

I don't think the timing is off unless it jumped. It didn't do it until I let it run for a little while. If the timing was off I would think it would have done it right away.

 

[AMiran02GT]

It was the L side tensioner.. Thanks for the help guys!

 

[99cobra09]

Are you sure you got the timing right? Another member on here not to long ago had a similar top end knock.

Turned out to be his timing was off enough that he was having valve to piston contact.

Yea bud that was me , Yea i have to agree sounds like there's PTV clerance by one tooth or so.