95 Chevy 3.1L SFI OHV 6cyl, stuck valve lifters after making tick-tag noises on 1995 Chevrolet Lumina

My 95 Chevrolet Lumina-Sedan/Coupe 3.1L SFI OHV 6cyl, has some hydrolyic valve lifters stuck after the engine quits. The engine had been making tick-tag noises for awhile before. Now the engine can be restarted and run but very rough, not all cylinders running from open valves?. Can these stuck lifters be removed then replaced? what about the camshaft lobes? damaged? Want to replace both cylinder heads, will it work? Thank you in advance for your prompt advices.

by in Moorpark, CA on February 07, 2013
2 answers 9 comments
ANSWER by on February 07, 2013
I would start with a compression test
COMMENT by on February 07, 2013
a compression test confirms that one cylinder head is leaking from the valve area. My important question is that: can the stuck lifter be removeable and then replaced? and the camshaft lobe condition? thank you for your advice.
COMMENT by on February 07, 2013
Has anyone pulled the valve covers and checked the rocker arms for push rod wear through? Have seen it on this engine! I have to agree with zip!! (Answer 2) I like the way you/we think! Even if it is sorta weird (sometimes).
ANSWER by on February 07, 2013
Pull the valve covers off and check for bent push-rods.
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COMMENT by on February 07, 2013
done that, and checked push-rods, found okay! Could someone tell me if the stuck lifters are removeable for replacements, and chances for camshast lobes damaged? the lifters have rollers on their bottom though. No engine's overheat as well. thanks
COMMENT by on February 07, 2013
Tear the engine down and replace the worn parts!! Cam lifters ect! Yes all of it can be replaced.
COMMENT by on February 07, 2013
Thank "wetry" for a quick reply. Some said that the camshaft's lobes could have been worn down as well. But if my engine can still run with some roughness from these possible-worn-out camshaft lobes, it is fine with me; I only plan to use this old car for a short commute. How bad the camshaft's lobes would be so that the engine will not run okay? Anyones have experience? thanks!
COMMENT by on February 07, 2013
The affected cylinder(s) may not fire properly (or at all) dumping unburned fuel into the exhaust trashing your converter , causing it to not run ,or before that , overheat and blow a headgasket rendering it completely useless.Maybe diagnosing and fixing it right once will be more effective , even for short commutes.
COMMENT by on February 07, 2013
Thank Ziptie for reply. You used the word "may not fire properly" so the cylinder can also fire okay! it might be worth why just to replace everythingelse, except the camshafts and test fire the engine?
COMMENT by on February 07, 2013
Cam lobe height (lift) can still be measured by push rod travel. When covers were off were any rockers loose? And were they removed and inspected for wear at the pivot and push rod saddles? Also engine pop or backfire through intake should be indicative of valve not opening when throttled up sharply. I bet it is a rocker arm(s). We just trying to help!!
COMMENT by on February 08, 2013
Thank wetry! your idea is great, just measure the push rod travel to see if the camshaft's lobe will be okay! With a new hydrolyic lifter installed, how many mm or fraction of an inch, should an okay camshaft lobe push the push rod up? BTW, when I open the cover, about one or two arm rockers were lightly lose. I believe due to worn-out arm rockers'balls. Rockers are non-pivot type. thank for yours help.