The Lifter Tick

That is not likely a stuck lifter. Once the lifter extends fully, the space under the plunger fills with oil and will feel totally solid. Oil is not compressible, it is metered out of the lifter valving very slowly and only keeps the valve train at "0" lash or slop. The running load that a lifter see during normal operation is several hundred pounds and it resists leaking down under the rapid loading and unloading.

You need to place a load on it ~75# for a 30 - minute to see it move enough to remove the retainer ring while holding the load on it. Leak it down and lock the press quill to remove the retainer.
 
a thought just occurred to me. #4 looked collapsed when the rocker arms were still installed into the head. but the lifter is frozen in the un collapsed position. This may mean the pushrod is bent then. I know, should have checked it riht away....
 
OK, over to the hydraulic press.

Robert Kenney said:
That is not likely a stuck lifter. Once the lifter extends fully, the space under the plunger fills with oil and will feel totally solid. Oil is not compressible, it is metered out of the lifter valving very slowly and only keeps the valve train at "0" lash or slop. The running load that a lifter see during normal operation is several hundred pounds and it resists leaking down under the rapid loading and unloading.

You need to place a load on it ~75# for a 30 - minute to see it move enough to remove the retainer ring while holding the load on it. Leak it down and lock the press quill to remove the retainer.
Click to expand...
 
The lifters do not internally reciprocate with the action of the valves but maybe .001" but they fill back up as the valve seats.. They only maintain a given compressed position. A stuck lifter won't cause a pushrod to bend.
You can't rapidly force the lifter to compress, a load over time will bleed out the column of oil.
 
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This lifter is not stuck compressed. It is fully extended. The plunger is resting on the retaining clip.

Lifter in Press.JPG
 
I took out lifter 4 and took it apart, no obvious gunk. I did the "finger push" test as described in the service manual. Seemed OK

I had surgery on my wrist and elbow three weeks ago so Scout sat for a while. I did buy and receive a lifter cover that I cut in half.

I put #4 lifter back in and then the rocker arm assembly. Cover on driver side, half cover on passenger side. Started it and and very noisy but settled down with still tapping noise. I used a long screwdriver as a stethoscope and it seems that the first four are tapping. the rods rotate with various speeds, the ones with more pronounced tapping rotate faster. BTW, my pushrods don't have holes in the ends, is this correct?

My wife came out and I showed her the rocker arms merrily rocking away. She commented that it sounded better overall, she had been in house and scout running for a while.

I made two recrdings, the first is a look at each rocker and pushrod
the second is pulled back and was made after wife comments so that you can see and hear the whole assembly.

I put them in a YouTube playlist


Harry Scout Lifter Issue

Robert Kenney said:
This lifter is not stuck compressed. It is fully extended. The plunger is resting on the retaining clip.
Click to expand...
 
If it is like that at full idle, I think you are OK. What you are hearing at that rpm is not unusual.
I'll through this out there because it is somewhat common on IH rebuilds. Don't go there unless you have this problem reoccur.
There has been some number of cam bearing failures that were not taken to determine the root cause. The symptoms are ticking after a drive on the highway, random ticking that comes ant goes but eventually becomes permanent. The bearing soft babbitt surfaces are wiped down to the steel backing. That blocks the oil flow to the rear bearing that feeds the lifter galleries.
 
it still taps very loudly and always. Less at lower rpm's. It seems to me that cylinders 2 & 4 lifters are not "rebounding" properly so as rpm's increase they don't maintain constant contact with the pushrod. From the video you see that the lifteers with the strongest tapping noise also have the sloppiest looking pushrods. I am guessing this is the valve and not the internal spring?

The engine runs fine but it is embarrassing as hell to drive around with this loud tapping.

Replacing lifters is no good no how?
 
Replacing any part without good evidence and a chance that it will fix the issue, is not a good plan. The lifter has worn in the to lobo and the cam lobe has worn into the lifter. Wisdom says that a new lifter will not match the particular lobe shape and surface. That means that the new lifter and lobe will make contact on the high spots only. That makes the Hertzian contact stress (only using this term because you are a professor) go through the roof. Bearing interface failure is very likely under those conditions
Have you measure lifter preload?
With the noisy cylinder at tdc on the compression stroke( both valves closed for 1/2 revolution of the crank), is the pushrod loose with up and down play? If you loosen the rocker assembly and watch the pushrod, does it rise like the lifter is extending? If you have a rise of >.035" you are good.

Unfortunately this looks more and more like an oil flow problem.
 
all of the rockers are receiving oil, how can one test oil flow?

Robert Kenney said:
Replacing any part without good evidence and a chance that it will fix the issue, is not a good plan. The lifter has worn in the to lobo and the cam lobe has worn into the lifter. Wisdom says that a new lifter will not match the particular lobe shape and surface. That means that the new lifter and lobe will make contact on the high spots only. That makes the Hertzian contact stress (only using this term because you are a professor) go through the roof. Bearing interface failure is very likely under those conditions
Have you measure lifter preload?
With the noisy cylinder at tdc on the compression stroke( both valves closed for 1/2 revolution of the crank), is the pushrod loose with up and down play? If you loosen the rocker assembly and watch the pushrod, does it rise like the lifter is extending? If you have a rise of >.035" you are good.

Unfortunately this looks more and more like an oil flow problem.
Click to expand...
 
There is not an easy or good way to test oil flow to the lifters other than symptoms.
The lifters are fed by the rear cam bearing. The rockers are fed by #2 and #5 cam bearings.
the fact that the front two on the same side are problematic points to low flow on that side.

What’s your lifter preload?
 
I'd just throw a couple new lifters at it. they will wear in just fine. I ran my 345 with two lifters (replacements of likely china origin) that bleed down after a couple hours on a questionable cam for 4 years and 15k Km. Only just pulled engine due to blow by and an LS swap. I was still getting 12 MPG on this engine. The lifters would tick for 10-20 seconds on start up, pump up and be fine. What do you have to lose at this point?
 
well, the engine runs just fine at this point, the ticking drives me nuts. New lifter could decrease life of cam.

Winchested said:
I'd just throw a couple new lifters at it. they will wear in just fine. I ran my 345 with two lifters (replacements of likely china origin) that bleed down after a couple hours on a questionable cam for 4 years and 15k Km. Only just pulled engine due to blow by and an LS swap. I was still getting 12 MPG on this engine. The lifters would tick for 10-20 seconds on start up, pump up and be fine. What do you have to lose at this point?
Click to expand...
 
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