I was replacing the valve cover gasket on my remanufactured 84 2.5L with 20,000 miles on it now, and noticed that all but two of the valves appear to be at zero lash? I could spin them all freely (but not move them up and down), except for two, as shown in this video:







Is this how loose they're supposed be?

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1984 Fiero SE

1 intake and 1 exhaust is under compression. the rest is why L4 has noisy valve train.

GM "design"....

see https://www.fiero.nl/forum/Forum2/HTML/103494.html

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)

The Duke has no valve adjustment. You torque the bolts to spec, and that's it.

Like the Ogre mentioned, some of the pushrods will be under load, which is why those ones won't turn.

Talking about the tap tap tap noise when idling? I was under the impression most of that duke noise is the cam gear and can be adjusted. The 86 I have is quiet, but it was quiet when I bought it. Could also be the wide range of tolerances allowed when they were built.

I'd think changing to an adjustable set up would stop the tit tict tict..

I'd also think the late 86 up roller cams have tighter specs or just the heavier springs..

quote Originally posted by 2.5: Talking about the tap tap tap noise when idling? I was under the impression most of that duke noise is the cam gear and can be adjusted. The 86 I have is quiet, but it was quiet when I bought it. Could also be the wide range of tolerances allowed when they were built.

No, no adjustment for rockers or gear set. Torquing spec just means rocker bolts won't come loose later. Noise is mostly the rockers too loose letting lifters w/ too much slack. Right shim w/ stop that but too thick a shim and can damage parts. (see link. and no, if they did tried it, they didn't posted a source.)

Yes, range of tolerances affects noise. My 87 is loud...

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)

Pull the bolts, install studs, and use the proper adjustment nuts, but is it worth it?
A hot rod L4? not worth it for me.