Fiero v6 knocking (Video Clip)

[MetalMutantFiero]

Hi people!

I just bought a -85 Fiero v6 GT
and I have a problem with a knocking noise in the engine, it seems that it comes from the upper parts of the engine.
Has anyone any idea what´s the problem
You can download a short videoclip (5Mb) I did so you can se the engine and hear the knocking:

Right click and Save As...

http://hem.passagen.se/mutant1/FieroKnocking.mpg

(I'm Sorry for my poor english, Im from sweden)

/Peter

[robby1870]

That sounds a lot like what mine sounded like when I broke a guideplate, knocking a rocker off a valve......but, I dont know for sure what your problem is, but like you said, it is in the top of the motor...so thats a little better

[jmgtp]

I had a engine (was a 60* v6 just not a GM one) make a similar sound when there was a considerable amount of water in the fuel tank. It seemed to run ok other than the top end knock and required a lot of cranking before starting. A bottle of dry gas and some fresh premium grade fuel cured the knock within minutes. Something to check at least. I hope its something as simple as that and not mechanical damage. Good luck!

[gpse3400]

Sounds like either excessive valve lash or an exhaust manifold/gasket/headpipe leak. Maybe even a loose spark plug.

[MetalMutantFiero]

Hi !
Thanx for your replys, It apperantly can be many differient things,
so It's just one thing left to do... start dismantle the top(s) and hope it's a easy repair..

I've bought the Chilton Fiero repair manual so lets hope for the best
I'll be back with a report
Thanx
/Peter

[MetalMutantFiero]

the knocking Fiwero Part2

Hi there!

I'm trying to identify some problems with the valvetrain.
And it seems to me that the most rockers are kind of loose :/ I did take some video clips, With the engine in TDC 1 to TDC 6.
First I did a up and down movement on the rockers then a left and right movement,

you can view it here:
Right click and choose Save as...

http://hem.passagen.se/mutant1/Fiero.html

I really don´t know how it´s suppose to be, so maby someone can identify a valve lash problem, and if it's a lifter problem or is it just a valve lash adjustment problem...


I don't want to remove the lower intake unless it's really necessary ...

A very big thanx to you all

/Peter

[MetalMutantFiero]

Knocking fiero v6 - Problem solved?

Hi guys!
well... I think I found what caused the Ticking/Knocking noise in my v6 engine, but I want your point of view also...
One of the lifters to the nr 2 cylinder was totaly stuck, not in the bore but I could not push down the thing in the middle of the lifter.. I removed the lifter and try to press down the thing in the middle and it was impossible!
I even put it at the floor and use a screwdriver trying to force the inside of the lifter to move... But the it was totally stuck at its highest point...
There were no visible wear at the stuck lifter bottom end so the cam lobe is presumably good
There were no problem at all with the other 11 lifters, I could move the inside of those lifters with ease..

So what are you guys think, am I at the right track?

Thanx
/Peter

P.S You who have'nt seen it, can look at the video clip here http://hem.passagen.se/mutant1/Fiero.html

[geoffinbc]

I would say so. May be a good idea to replace them all.

[MetalMutantFiero]

Hi there guess what!
I have just replaced the defect lifter and when I started the engine the knocking/ticking sound was still there maby I should have replaced them all but I could'nt find anything wrong with the other 11 lifters...
I adjusted the rockers by follow the Haynes manual directions.

What the f*ck is wrong?

/Peter

[dodgerunner]

You say the lifter seemed stuck, did you compare to any others? I would hope these are hyd. lifters, and you can't normally push them in since they are filled with oil and should not leak down very fast. I would guess the others would be the same.

Don't know what your problem could be, but does not sound like lifter to me. Sure you don't have a rod knocking?

[akira]

That just sounds scary!! I had a similar problem on a ford 5.0L I worked on. The harmonic balancer was loose and a wrist pin was shot. I dunno about the rest of you but that doesn not sound like top end to me! I did have a knock like that (alot quieter though) in my S-10 but I pulled the motor before it got that bad. Turns out it was the crank. It was pounded out of round by over 0.060" aka junk. Good luck but I think you need to pull it.

[ouch1011]

Almost sounds like piston slap to me...

[Banana]

my fiero sounds like but its 10x worst and you cant take it above 2 grand or the car will shake like a madman. im gettting a new engine

[RacerX11]

My '84 X-11 2.8 had a knocking sound very similar, turned out to be a loose timing chain knocking against the timing cover. That sound is definitely not a lifter or valvetrain noise. I say either the timing chain, or a rod.

Marty