Topic: "tick" "tick" - 400 rebuild - exhaust leak OR lifter?

[Daniel78ta]

Ok guys...

Last summer I had my W72 400 rebuilt in my 1978 trans am..  A local machine shop did the rebuild and assembly.! (they have been building motors for over 35 years).    Plus, i added the oversized Ram Air restoration header manifolds along with their X-over exhaust. the total for the motor rebuild and exhaust plus, all the other stuff was around $8,000..!

I have about 350 miles on the rebuild - but, it has started ticking upon warm-up.!  from about 100 degrees to 200 degrees a tick will start on the passenger side front of the motor!  It's driving me NUTS! 

Could it be a lifter?   Could i have an exhaust leak?

Do i need to pull the valve covers and give them all a quarter turn?  OR completely re-adjust the valves?  OR replace that passenger side exhaust manifold gasket? 

this has been eating at me and id like to fix the "tick"! 

any help would be much appreciated.
thanks guys.
Daniel78ta
iowa

[Squirrel]

had the exact same thing happen after my rebuild, chased it for years and never found the fix, then sold it.  tried all those adjustments by several mechanics.  never figured it out, just dealt with it but it bugged me, car was mint to.

[Daniel78ta]

not exactly what i wanted to hear Squirrel.. 
Im going to have to chase down the cause of that "tick"... its haunting me!! 
the car has been with me for 21 years - doubt i could sell it...  that "tick" will do me in before I could bring myself to let it go...

thanks for the reply..
Daniel78ta

[72blackbird]

Daniel,
The quality of Pontiac lifters has gone into the toilet since manufacture has gone overseas- it's not uncommon to hear about the dreading "ticking lifter". If you cannot adjust the ticking out by setting the lash "hot" while the engine is running, it's most likely a bad lifter (I set lash at a 1/4 turn past the point where the rocker stops tapping). Pull the intake and valley cover, inspect the cam for flat lobes, and remove the noisy lifter. Replacement lifters are cheap- if you cannot find Johnson lifters, use a well-known brand like Comp cams. Soak the lifters before you install them, and be sure to coat the new lifter with break-in compound so it doesn't eat the cam lobe. Zddp additive should also be used to extend cam lobe life.

Geno

[Fahad_Qatar]

I had the same issue after the engine(400)  was rebuilt. However, the builder told me to come back to the shop after 1000km (620mi) after the rebuild. So I took the car to him and I don't know what he done to the car but the sound is gone. All I see in the bill is an oil and filter change! mabe you should try that.

Oh one thing to mention is that most of the engine builders here do what they call "Valves adjustment" after 620mi and its part of the rebuild so they don't charge you for that. Maybe thats what he done. But I don't know what they actually do in this "Valves adjustment" process.   

[Daniel78ta]

Hi Geno...

I think I'm going to try to re-adjust the Valves..  We used Crower Lifters that came with the spring kit.  luckily I have not seen any sign of metal shavings in the oil. I will make sure i soak them and use break in oil on them if i need to re-place a lifter..

Keeping my fingers crossed its just a quick valve adjustment.. 

thanks guys for your input..
Daniel78ta

[72blackbird]

Most people freak out at the idea of adjusting the lash on the valves, but if you have a hot rod Pontiac with a more aggressive cam, more compression than stock, and make more than double the stock output, you should expect that regular adjustments are part of ownership. Adjusting the valves is really not all that difficult if you understand what you are doing- you're putting a preload on the spring inside the lifter, and combined with the oil pressure that preload puts the right amount of pressure on the cam, pushrod and the rocker. Too little and the valvetrain rattles, too much and the lifter eats the cam.

Geno