Stuck lifters

[jhall]

Hi all,

I am reworking a '97 4.6L and need some info.

Some of the valve lifters appear to be "stuck" - I can press the contact point where the valve stem goes and the lifter will move in and out on some of them.

Other lifters are rock hard and do not give at all - even when I put them on the bench and press with all my weight using a wood dowel on the valve contact point.

Seems like some lifters are stuck - any ideas? Do they need replacing?

[growe3]

The lifters sound normal, from your description.

Assumption: The engine was not run for a few days at least before disassembly.

Lifters that have had spring load on them will usually have a little movement, as a small amount of oil has been pressed out. Lifters with out a spring load will tend to be full and not give at all.

To really tell if a lifter is stuck, it needs to be observed while the engine is running; or disassembled, cleaned (with a product like Berryman Chemtool), and then reassembled with only a drop or two of oil. After assembly you should be able to easily push the lifter through its full range using a pushrod, by hand.

If you decide to disassemble the lifters for cleaning, it is vital that you do them one at a time. The lifter parts cannot be intermixed, handle with care. Each lifter contains highly machined parts that takes on its own wear characteristics. Each lifter must be reassembled with its original parts.

Personally unless you know for a fact one was sticking I would not advise disassembling them. They are very durable items and taken apart can be easily damaged by dropping or rattling the parts together while cleaning them.

For anyone that is dealing with a stuck lifter(s) in a running engine I would advise adding 1 quart of Marvel Mystery Oil to the crankcase; do not over fill. Usually you will get good results in minutes; really varnished ones may take some hours of driving normally to free them up.

Bottom line, unless you are positive the lifter(s) were sticking before you removed them, they are probably fine. The lifters also need to be placed beck in their original locations on the camshafts as each one has worn differently. Just placing them back in any position will, in all likelihood, cause premature cam lobe and lifter face wear.

-George

[Scotty]

I don't know anything about your lifters but in the old days I used to take them apart one by one, keeping each lifters parts in its own container and clean them up, use compressed air (NO RAGS), fill them with oil and reassemble them... Can you do that with your lifters, they use to have a D-clip that you could remove and dump out the components.. I always manually cleaned lifters as part of a valve job, and replaced any that looked dished or worn.

If I am not mistaken you can submerge them in oil and pump them up by pressing on the plunger.. (in the old days anyway)... I DO NOT know if this applies to the NS lifters, but that is what I would do

[growe3]

I don't know anything about your lifters but in the old days I used to take them apart one by one, keeping each lifters parts in its own container and clean them up, use compressed air (NO RAGS), fill them with oil and reassemble them... Can you do that with your lifters, they use to have a D-clip that you could remove and dump out the components.. I always manually cleaned lifters as part of a valve job, and replaced any that looked dished or worn.

If I am not mistaken you can submerge them in oil and pump them up by pressing on the plunger.. (in the old days anyway)... I DO NOT know if this applies to the NS lifters, but that is what I would do

Hi Scotty,

Thats pretty much what I've done in the past when I had to try and save some money, or just get the car running. Now days I find it generally cheaper and a lot quicker to just replace them. And then came the Northstar, with 32 of the pricey little devils.

I would run MMO for a few days to a week, before deciding to replace the lifters or not. If I still had a noisy one or two, then I'd try cleaning or replacing them.

Often by the time it is realized that the lifters are flat or dished, the cam(s) are also ruined.

-George

[franey]

I HAD a ACURA , with lifters which part of them were just like you described , Take a old empty coffee can fill half full of MARVEL MYSTERY OIL, drop lifters in can and allow to soak for about 4 to 6 days, every other day take out of can and push on plunger portion of lifter , after several days of this , they will free up. When i put them back in the engine , not more stuck lifter clicking, . I HAVE done this twice , cleared up lifter problem both times.

[jhall]

I guys,

Thanks for the responses. A bit more info tonight:

I took a good look at the lifters and do not see where they can be disassembled. They appear to be pressed together and I can not see any means to separate the plunger from the body. The Helms manual does not address the lifters in detail.

Forcing compressed air into the oil hole didn't do anything to dislodge the plunger on the stuck lifters, so I'll try it on one of the free ones tomorrow to see if the plungers can be pushed out.

The lifters have been out of the heads for a couple of months (in a clean area), so they were in a relaxed position for a while - or at least had the opportunity to return to full height if the internal spring is OK.

I'm pretty sure I should be able to press the plunger on any of them and get some oil from the fill hole. Some push out oil, but there are a few that will not move - though the plungers do rotate OK on the stuck ones.

I took one of the stuck plungers and soaked it in mineral spririts for a while. It has loosened ever so slightly after using a hammer to tap on a wood dowel held on the plunger contact. I'm assuming something is making a few of them stick, even though there is no evidence of deposits - the lifters (and other engine parts) are very, very clean even after 130K (regular oil changes per the DIC).

I appreciate the responses. Any other ideas would be welcome. New lifters are $55 for original GM and about $16 for Cleavite brand replacements.

[jhall]

Guru,

Thanks for the info.

We're on the same thought path with measuring the plunger heights to identify ones that may be "stuck". I'll have more details tomorrow.

Want to get this done right. Got most of the seals / gaskets to put the engine back. Picking up the rest of the parts this week.

[jhall]

Here's an update -

Took a clean 8" C-clamp and rag and used the clamp to depress the "stuck" lifters.

It took some heavy pressure with the clamp to move the plunger. Much more than would be necessary to move the valve. Interestingly, I did not see any oil exiting the weep holes of the "stuck" lifters as the plungers were compressed.

After releasing the clamp, the plungers would move easily and I could flush oil out of the lifter by pressing the plunger with my thumb.

I can't explain the reason why some of the lifters are "stuck" and don't displace any oil when compressed. I would expect a lifter full of oil to squirt some amount from the weep hole when compressed - and it does not seem an extremely heavy pressure would be needed to do this.

I also located what appears to be the disassembly point for the lifters. The top portion of the lifter (the cam contact surface) is actually a separate piece and it appears this can be removed. Don't plan on doing this since I am able to use the clamp on the "stuck" lifters and flush the old oil with mineral spirits. I'll reprime with fresh oil before reinstalling.

More to follow.

[jhall]

Well,

I did this on the lifters in one head (some were already empty) to educate myself and to see if there were any problems.

I'll get the air out before I reinstall them - no worries here.

Thanks for the info on the low / high pressure internal cavities. This makes sense about not seeing the oil leave the weep (supply) hole.

Overall, I'm satisfied I won't have any bad surprises with the valve train components and I'm planning the reassemble the other head this week.

[jhall]

Guru - Thanks again for the wonderful technical info. I greatly appreciate the "tricks of the trade" regarding the engineering and manufacturing processes.

I've worked on various types of engines but having the specific technical info about each one is an excellent educational experience for me.

As a kid in the 70's I used to sit a read the old Chilton's manuals just to see various system designs and the repair methods (this was "geek' prior to the computer age).

I'll post some pics in the next couple of days.

[BodybyFisher]

I wish the guru's posts were still in this thread, I had the same issues where some plungers were able to be pressed and others could not.

I suspect that the NS lifters can not be disassembled.

I sent a PM to jhall to pick his brain

[Logan]

They can be taken apart. Brutal and time consuming to do....

[Logan]

First pic is a Saturn lifter. Vise grips used to pull the plunger.

Second pic is not mine...I think it's a Miata lifter. Anyway...GM internals are nearly identical.

The lifters can get over-pumped with oil. Internet says they can't but not so...the fast way to get the

extra oil out is to take them apart.

[BodybyFisher]

Hey Logan, thanks!

When they become over pumped with oil is there a negative affect?

[Logan]

In normal conditions....they will not get over pumped....

But...if you have something like a timing belt failure...bent valve...or if the valve sticks in the guide...the lifter can suddenly get over pumped.

The expensive fix would be a new lifter. Well...at about $25 each...that can add up quickly.

You will ruin a couple pairs of vise grips popping them apart. It wears the teeth out on the vise grips...Saturn has 24....Northstar has 32 of them...

[BodybyFisher]

I suspect that an over pumped lifter creates a misfire then?, as the lifter is open too far and can not attain proper lash?

Thanks for the info Logan, I want to disassemble the lifters in the #8 cylinder that had a misfire to see if it collected debris from the badly failed timing chain tensioner.