IT'S BACK!!! Added pic of lifter!!!!

[FreeBeeTony]

Tha same problem I had last year is back.

While returning from a fishing trip this morning........the engine sputtered momenterily while deccelerating. My son and I looked at eachother in disbelief. I slowed down to an idle, seemed fine, temp, oil gauges, etc, all ok. Throttled back up and sure as sh!t it started to miss at ~3000RPM. On the way back I performed my "contribution test" by shorting out each plug at the distributor and found #3 not making power under load.........just like last year!

Once back at the dock I pulled the valve cover to check rocker adjustment. I found the intake rocker on the #3 cylinder to be too tight.......took ~2 turns for it to start to make noise. I then tightened 1/4 turn after making it quiet and proceeded to check the rest of them. I found the rest of the rockers to be adjusted as I left them in the spring....1/4 turn past being quiet. However, the intake on #3 is not repeatable..........I adjusted this valve multiple times...........there were times I had the rocker nut almost flush with the stud before it started to "clack". Something doesn't seem right here...........do I have a bad lifter?

I am thinking the lifter was not compressing, causing the intake to hang open. I haven't taken it out after my last adjustment. And when looking at the location of the nut with respect to the stud it is visibly not as tight as the others.

I cannot belive this...................although I am fairly certain it's the lifter this time!

 

[Reel Poor]

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Re: IT'S BACK!!!


That sucks Tony and it doesn't sound good.

With a small ruler check the hight of the spring on the valve in question, and compare it to the hight of one of the other intake springs. It sounds like it may be swallowing a valve into the valve seat. This would cause the valve to be held open. It would also not allow the rocker nut to be tightened down as on the studs as the rest of the nuts.

If this is the case it is caused by a lean fuel condition, or improper timing/timming curve.

 

[FreeBeeTony]

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I doubt it's a valve spring...........same problem different heads/intake manifold and carb.

 

[Don S]

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I think it's time you replaced all those lifters. All you did last time (as I recall) is back off the adjustment to make it run. That alone didn't cure the problem, all it did was cure the running problem you had.
Who knows what kind of problems the PO had with it. Water in the oil, gas in the oil, who knows. But the fact is, the lifters are not doing what they should be doing when adjusted properly.

 

[Reel Poor]

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I doubt it's a valve spring...........same problem different heads/intake manifold and carb.

I'm not saying it's a "spring" problem. I'm telling you to measure the hight of the spring while it's still installed, rocker arm off. Then measure the hight of another one on a good cylinder, rocker arm off, and compare the measurements.

If the valve is being sucked up into the head, the hight of the questionable valves installed spring hight will be taller because it has pulled the valve deeper into the valve seat area. In essence the valve stem hight is taller than the other valves because the valve is seating deeper in the valve pocket and not where it should. Hence the tight rocker, it has collapsed the lifter to it's extreme and is now holding the valve open.

If the valve is being sucked up into the head, loosening the rocker would be a temporary cure, until it would be sucked in a little more.

You indicated this as a possible problem when you stated, and I quote from your first post, "And when looking at the location of the nut with respect to the stud it is visibly not as tight as the others."

 

[ziggy]

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that seems like pretty reasonable diaganosis rp. i like to hear the expination. the therory i like. that always leads to the answer i think. the practical experience i lack........fbt, sorry to hear yer gettin hosed again. perhaps yer ontoit this time around.

just a question. ddidn't ya have the heads gone thru prior to installation, a hip new 3 angle valve job? new springs and stuff, didn't ya R&R the lifters on general speaking terms when ya did the heads?........not that i think that, that would mean yer hip by any means..... remanufactueres prodouce sh!t that is out of tolarance too....... even oem for that matter........

ps, i got me a different L6. seems pretty hip so far. on a convertable hard top boat to boot.....so far i'm pretty happy. i like them L6's.......only thing i don't like is they is gettin old. wish oem would stay with something that works good......like the L6........nothing real special, but runs richous.....now if i can keep the 75 boat in a sevicable condition?......

 

[Buttanic]

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I doubt it's a valve spring...........same problem different heads/intake manifold and carb.

I'm not saying it's a "spring" problem. I'm telling you to measure the hight of the spring while it's still installed, rocker arm off. Then measure the hight of another one on a good cylinder, rocker arm off, and compare the measurements.

If the valve is being sucked up into the head, the hight of the questionable valves installed spring hight will be taller because it has pulled the valve deeper into the valve seat area. In essence the valve stem hight is taller than the other valves because the valve is seating deeper in the valve pocket and not where it should. Hence the tight rocker, it has collapsed the lifter to it's extreme and is now holding the valve open.

If the valve is being sucked up into the head, loosening the rocker would be a temporary cure, until it would be sucked in a little more.

You indicated this as a possible problem when you stated, and I quote from your first post, "And when looking at the location of the nut with respect to the stud it is visibly not as tight as the others."

Seems highly improbable that a different set of heads would have the same problem in the same cylinder and same valve.

 

[lilmandavis]

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not if its a running lean issue. bust out another thousand. do leak down test

 

[Reel Poor]

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not if its a running lean issue.

Or caused by a faulty lifter on this cylinder to begin with. (I believe I read in a post the lifters were never changed.....) Leading this valve to be improperly adjusted from the begining, i.e. not sealing tight in the seat due to riding solid on a lifter that won't collapse properly. Typical example of coincidental damage.

 

[FreeBeeTony]

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No..........I didn't change the lifters when I replaced the heads (GM Performance Parts) last year. NOw I sure wish I had.

Would running with a lifter that wouldn't collapse properly and an imporperly adjusted valve cause any damage?

I am thinking my season is done and plan on winterizing then replacing the lifters in the spring.....any suggestions on where to get the lifters? Maybe online?

 

[FreeBeeTony]

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Well...............lust got back from a test run.

This is defintly the problem.......pushed it to ~4000RPM.......didn't want to go to WOT........

Have the lifter "soaking" in MM oil............hoping this gets me through the end of the season ............will replace them (lifters) in the spring.

 

[Reel Poor]

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If you don't have a valve problem already, you very well could have if you continue to run it like that.

To determine a valve problem you need to do a cylinder leak test.....AND.....check the valve stem hight of the affected cylinder and compare that measurement to some unaffected cylinders.

A problem like this has the potential to wipe out a cam lobe also.

Fix it before you run it anymore.

 

[Buttanic]

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Worse case is a burned valve from lack of heat transfer to the head because of the valve not seating. More likely on the exhaust than intake. A leak down test on that cylinder should answer the question. Unless you plan on changing the cam too I would only change the one bad lifter. You could cause more problems of premature cam ware by putting all new lifters on an old cam, never a good idea unless it is a roller cam. If the new lifter eats up the cam lobe and you have to change the cam at least you haven't thrown away money on 16 lifters. Some will say a new lifters on an old cam is OK but the odds of long cam life are against you. I know, I have seen it. Even a new cam and lifters is iffy if you don't break it in properly.

 

[FreeBeeTony]

Re: IT'S BACK!!! LIFTER IS NOW TOTALY COLLAPSED

Re: IT'S BACK!!! LIFTER IS NOW TOTALY COLLAPSED

After soaking in MM oil, the lifter is now totally collapsed and will not pump-up.

I started the engine and was going to re-adjust, was clacking a bit and before I could even wlak back to the engine box to make the adjustment it went quiet.........what I found was that the push rod was so low it wasn't even making contact with the rocker. Can't tighten the rocoer enough for the rocker to make contact. I can push down on the push rod and feel the movement of the cam...............

How far can a lifter collapse? Looks like it must be ~1/2"

Any tricks on getting this to pump back up? Or am I looking at pulling the manifold?

PS..........it's a roller cam............should I replace all 16 or just the 1?

 

[180shabah]

Re: IT'S BACK!!! LIFTER IS NOW TOTALY COLLAPSED

Re: IT'S BACK!!! LIFTER IS NOW TOTALY COLLAPSED

Any tricks on getting this to pump back up?

Yes, replace it::/

 

[rodbolt]

Re: IT'S BACK!!! NOW LIFTER IS TOTALLY COLLAPSED!!!

Re: IT'S BACK!!! NOW LIFTER IS TOTALLY COLLAPSED!!!

trash or varnish has created a binding plunger.
the leakdown advice should be taken before ANY further disasembly.
make sure the valves are not damaged before continuing with repairs.
that lifter is very precison ground, you can leave the body at 65 degrees and hold the plunger in your hand for 10 min and odds are high it wont fit the body anymore.
normal preload on a chevy is someplace between .05 and .100". I use a wire feeler guage when asembling one rather than the feel method unless the studs are the later style that only require torquing the rocker nut.
be sure to use the specified type assy lube on the lifter face when reassembling and follow the cam/lifter manufactures advice for cam breakin.

 

[FreeBeeTony]

Re: IT'S BACK!!! NOW LIFTER IS TOTALLY COLLAPSED!!!

Re: IT'S BACK!!! NOW LIFTER IS TOTALLY COLLAPSED!!!

Looks like I now will have to pull the manifold and replace the lifter. Think I am going to just replace the bad one and try to do it while the boat is still in the water.

What type of assembly lube do I need if it's a roller cam?
Does the lifter need to be imersed in oil overnight prior to being installed?

 

[Buttanic]

Re: IT'S BACK!!! NOW LIFTER IS TOTALLY COLLAPSED!!!

Re: IT'S BACK!!! NOW LIFTER IS TOTALLY COLLAPSED!!!

Put the lifter standing up in a container with enough oil to completely submerge the lifter. Using a philips scredriver like a push rod force the lifter piston down, you will see bubbles come out of the holes in the side of the lifter. Do this until no bubbles come put and the lifter piston can not be push down. The lifter is now full of oil. If it's a roller you don't need to do any special lubrication, just take it out of the oil ad put it in place.

 

[FreeBeeTony]

Re: IT'S BACK!!! NOW LIFTER IS TOTALLY COLLAPSED!!!

Re: IT'S BACK!!! NOW LIFTER IS TOTALLY COLLAPSED!!!

Thanks buttanic............going to go to the boat and pull the manifold now...........will hopefully post a pic later.

 

[FreeBeeTony]

Re: IT'S BACK!!! Added pic of lifter!!!!

This how the lifter came out!!!!
The plunger was laying in the lifter valley...........was more than collapsed!

This is getting scary.........it only took me 1 hr to pull the intake and remove the lifter............