knocking noise

[shelbe67]

Hey there guys I really need help here. I have a 93 cobra ( I know its not a 94-95 but I like it here better lol) It has 34000 original miles I am getting a knocking noise and I cant figure it out. The car has trickflow heads an e cam and 1.7 roller rockers. I and a couple of other buddies that are mechanics seem to believe that its coming from the topend but I cant find it. The car sat for a couple of years and I picked it up it was very healthy. No noises nothing then about a thousand miles it started making a slight ticking noise only to get really loud. it gets faster with rpm and goes away when I put a major load on it I.E. shift from first to 4th gear. I tore it apart replaced the lifters and readjusted the rockers three times now I dont know what I am doing wrong I hope you guys can help me out, I dont really wanna tear out the engine cause its mostly original. All i have done is really just drive it so I dont think that its a rod but I could be wrong thanks in advance

 

[Bosko5.0]

make sure everything is bolted down, it could be piston to valve clearence due to the lift from the e cam and the 1.7 rr not real sure though thats my thought

 

[BlackVert]

i had a real loud clacking noise for a while, turned out to be a couple of loose header bolts.

on my car, i only hear the rod knock is when it is under load.

 

[WHITE94COBRA]

Ok first thing first, how long ago were the heads and cam installed? How many miles since they were installed? What exactly does the knock sound like? Have you heard the detonation knock, if so does it sound like that? Has it been tuned? Are they ped mount rockers or stud? we just need a little more info.

 

[shelbe67]

Thanks for all the replies, THe heads have been on for at least ten thousand miles and at least 3 years so its not piston to valve clearance issue.I have stud mount rockers, I dont think it sounds like a exhaust leak although It might be I wont rule it out. THe knock is all the time We had a stethescope on it it definetly sounds mechanical and from the topend, As far as detonation it wouldnt do that at idle would it? Thanks alot I hope this helps guys

 

[WHITE94COBRA]

I "could" do it at idle but the timing would be waaaaayyyyyy off, and I dont believe the car would run, or run right. It sounds like you may have a valvetrain issue, how did all the valves look when you readjusted them? Did you notice a build up of carbon on any one valve? other than that the only thing I could think of would be a flat spot on the cam, you can check that with a comp. test. Or maybe even a bent valve. There really are too many variables to consider we need to get more info and testing before we can narrow it further.

 

[shelbe67]

I didnt take the heads off but from what I can see there is no carborn buildup timing is set at 12 degrees. when I swapped the lifters there was no abnormal wear on any of the rods of rockers.the rods were all straight as far as the valves themselslves I would see if one was bent somewhat right? Like one of them would hang lower then the others with the rockers off? I could do a compression check in a bit Just goots see if I can get someone over here to help out a bit

 

[WHITE94COBRA]

How does the harmonic balancer look?

 

[shelbe67]

the previous owner put on an sfi balancer it doesnt look outa of round when the engine is running I will double check. I readjusted the valves yet again but no such luck knock is still there but it does seem to run rough, I dont know why I am gonna change plug wires tomorrow when I can get them.they are old I do have an exhaust leak but, that is not the knocking noise I hear.

 

[shelbe67]

by the way thanks alot for your help white94 I hope we can figure this out. Maybe I am adjusting the valves wrong?

 

[WHITE94COBRA]

I'm not sure yet! Did you check codes? hopefully something pops up and it's simple. just out of curiosity what valve covers do you have? if there stockies you might be bangin on a baffle.

 

[WHITE94COBRA]

Ohh and as for adjusting valves it's pretty simple with the stud mounts. there is a write up on here somewhere, if not go to www.flowtechinduction.com this is Ed C's site and he has a fantastic write up on RR setup. I would put up the link but i'm still at work.

 

[blkcobra50]

with the stethescope can you hear it more distinctly on any one cylinder or any one bank?

 

[shelbe67]

I hear it more on the passenger side bank