I went out today and took my car to the car wash! Got done washing my car and started the engine! When I started it I heard this rattling/knock sound so I shut the engine off thinkin' it might have been someone else's car! Started my car back up again and I hear it again so I pop the hood and sure enough I can hear a rocker rattling/knocking!! My question is once I take the valve cover off how can I tell if it's just a loose rocker or if it's a stuck lifter!! If it's a stuck lifter and I tighten the rocker down and then the lifter decides to un-stick itself I'm gonna bend a pushrod!! I have TPI and I REALLY don't want to take the TPI off just to take the intake off so I hope there's an easier way! I have my doubts about it being a lifter because I haven't really noticed any loss of power other than the normal "age loss"! The engine has over 200,000 original miles on it! Please Help!!

 

86,

Once you take the rocker cover off the offending bank, the problem should be more obvious. If a stud is pulling (technically, pushing) out of the head, a straightedge placed along the tops of the rocker studs should reveal it very quickly. If a lifter has stuck or collapsed, you should be able to determine which one by starting the engine and pressing the rockers with your fingers (very carefully) to take up the lash while it idles. If you find a stuck/collapsed lifter, you could try to free it by backing off the adjusting nut slowly until the lash is excessive, then slowly adjusting away all the lash. Take the lifter adjustment about a full turn or more beyond the lash point, then loosen it again. Do this several times, then do the final hot lash adjustment. This allows the lifter to fully traverse in the lifter body, potentially cleaning any varnish and deposits from teh lifter body bore and allowing the lifter to adjust freely by oil pressure again.

If you discover a bent rocker or push rod, the repairs are fairly straightforward. Just replace the damaged components and check for interference as you adjust the lash.

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Later,
Vader
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"What a Day..."
Adobe Acrobat Reader

 

Is this done with the engine running?? If I adjust the nut a full turn or more beyond the lash point and the engine is at idle will this bend the push rod??? Just checkin'! I have to wait until my friend gets off work because he has my 5/8" socket so I won't be doing anything until later tonight!!

I did, however, remove the valve cover (drivers side...what a b*tch)!! I started the car and still couldn't tell exactly which one was the culprit!! I watched the push rods as the engine idled and I could see them all spinning at a fairly even rate except the #1 cylinder exhaust side....it was spinning a little slower than the rest! Does that mean anything?? Could this one be the culprit??



[This message has been edited by 86TpiTransAm (edited April 15, 2001).]

 

86,

Yes, final lash is set with the engine running. You will lose some oil and make a mess unless you have oil deflector clips for this purpose. The "exersizing" of the lifters should also be done with the engine running.

As stated, adjust outward first to allow the lifter to fill with oil completely. Once the lifter has filled, slowly tighten to the lash point in steps of about 1/8 turn, then wait for the lifter to stabilize. Go a turn past the lash point, but stop if the force gets excessive. A properly working lifter should have about 0.150" of free lash adjustment travel minimum. The rocker stud screw pitch is 3/8-24 or about 0.041" per revolution of the nut. You should be able to reach the lash point and travel the extra forty thousandths without even getting close to bottoming out the lifter. Again, if the force becomes excessive, stop there and back off the nut again to allow the lifter to refill. You don't want to bend any pushrods or ruin a lobe.

The spin rate of the push rods has a lot more to do with the wear patterns of the lifters to the cam than the hydraulic operation of the lifters.

If you can't identify the loose rocker, just try holding a lifter against the push rod with your thumb to take up the excess lash. If you value your thumb more than a slightly used wood pencil, use the eraser end of the pencil instead.

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Later,
Vader
------------------
"What a Day..."
Adobe Acrobat Reader

 

Thanks Vader! I really hope this doesn't end up being something serious because I don't have the money to build my 350 right now and this is my only car to drive!! Guess I should just be satisfied that I got 200,000+ miles out of this 305! Most engines I've seen don't even last that long!!

 

h

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89 firebird formula

356 10.5:1compression CURRENTLY DEAD!!! BEARING FAILURE!!
comp cams xe262 cam
performer rpm intake
#1405 edlebrock 600
sportsman 2 heads 64cc 2.02/1.60 valves 200cc intake runner
msd 6al
h.e.i. proform 50,000 volt vac. advance ditributor
700r-4 with 3.08 first gear and 3.23 posi 7 5/8 rear end.
b trans shift kit(will kill shifts...suck dong!!)
shorty heddman hedders with custom 3" pipe y-pipe back(no damn cat!) with 40 series flowmaster!


future mods: 406 roller REALLY REALLY REALLY RADICAL!!!!!

current engine underway..sucks not having a car!! Building the same engine but .060 over balanced and blueprinted..decided to get a little more serious this time around!!

 

Vader... I was just at the dealer this weekend and one of the mechs there was telling me about the GM Crankcase cleaner... and how well it works to free a stuck lifter, as well as other maladies. By no means did they imply that this was some sort of magic pill or cure all, but they said they've used it for things like that in the past and have had mostly good luck with it. Bad points?? Well, it's over $12 a gallon, and it's been discontinued so it's hard to find.... know anything about this?