noise in valvetrain

[timk]

my 98 cobra has 43k miles on it. it has lived an easy life, except the previous owner did NOT change the oil very often, evidenced by the syrup-like oil i drained out of it.

now, there is a "noisy lifter" sound on the drivers side, cylinder 5. tapping just under the cam cover, goes away by 1100-1200 rpm or so....but it's there at idle.

i changed the oil 3 times in succession, nothing. then, tried a pint of Sea Foam. that helped a lot, cutting the noise in half.

so....is the noisy hydraulic tensioner dirty, perhaps clogged from the dirty oil? or, is it ruined, like a collapsed lifter on a 5.0, and in need of replacement?

i have no desire to worry about a valvetrain problem with a motor that revs to 7k.

thanks for your help in advance, as i am a complete DOHC novice.

 

[timk]

any advice on the matter?

 

[az_r2d1]

any advice on the matter?

How long has it been doing it ?
I would run either more seafoam or some synthetic oil and see how it sounds in a couple 1000 miles. Might want to have the oil-pressure measured.

 

[sinisterblack98]

I have similar noise from mine at only 15,000 miles, noticeable when the driver's side is next to a wall. Some valvetrain noise is "normal" with our engines. I listen to every other Cobra I get a chance to compare but haven't determined what is normal yet.

Kinda drives you crazy though, I'm always checking the oil level to see if it's low.

I plan to change out the followers and lash adjusters when I pull the heads for porting next year. It can be done on the car with a special Rotunda spring compressor ($100), and air pressure in the cylinder w/o removing cams and heads.


What is SeaFoam? Is that a new "motor flush" mechanic in a can?

 

[timk]

i'm with you...valvetrain noise in a 32v is always present anyway, but this sounds like there is a slight misadjustment. the lash adjusters themselves aren't such a big job, it's the removal of the brake mastercylinder and such.

sea foam has actually been around a long time. it's in a white can with red lettering. i only found it at a small local parts store...all the chain stores don't carry it. it's not quite a flush, because you can keep driving it, but it is a solvent of sorts used to free stuck lifters.

 

[fireman2004]

I have the same noise in my 96 cobra, some people say it could be the timing chain tensioners,had one guy tell me it was the forged pistons I have slapping the bore when there cold,but I notice the noise damn near all the time, although it did get a little more prominent when I changed the oil. I used motorcraft 5w30 like it calls for,but I'm wondering if I should go with a different weight oil any opinions?

 

[Nicks98Cobra]

Probe GT's have the same problem. I noticed what helped mine alot was an engine flush and synthetic oil. In the probes its the HLA's getting clogged and not doing their jobs. Im lucky my cobra with 124k miles doesnt have any engine noise except that damn alternator.

 

[timk]

nicks98cobra...does your alternator chirp?

 

[Nicks98Cobra]

No, just whines.