350 Buck Truck Project engine revival

These heads were sent out to another shop. They came back with rust crud in the water passageways and the drainback holes still plugged. Maybe that is a clue as to the level of crafstmanship at the head shop.

I will measure installed valve height next and record the numbers. The hammer handle while running is on the list too. I will also cut the first filter up and looksee.
 
A. Where do I need to measure exactly when I remove the rocker shaft assembly to check for installed valve height (what part of the head)? What should the spec be cause its not in the manual?


B. Why are these lifters not pumping up when I pump them with a pushrod submerged in kerosene on the bench? As far as I could tell there was no debris in any part of the #2exh lifter that I disassembled a couple of days ago.

C. What about the 2 new lifters that I just got that I could not pump up by hand in kerosene? Why was the 4th lifter in the new batch of 8 able to pump up so easily while the others would not?
 
Last edited:
Do you have a 304a or e? Valve guide height could be 1 3/32 depending on the 2 possible engines according to my man.

Not what you are concerned with. Valve tip above the head is not in the service man. Because inorder to alter tip height enough to cause major lifter preload problems the seat would need to be machined as much as 1/8 deeper do to the rocker arm ratio.

Measure from the major milled flat plain like where the rocker stands seat.
 
Last edited:
304a is stamped on the side of the engine.

I wanted to mention that at one time in the past before I got this truck someone put in 2 pushrods that were of different color and a bit short. The finish was like the blueing on a gun. So if they monkeyed with the pushrods these heads might have been sent out or exchanged or modified in a bad way somehow before I got my hands on it.
 
Last edited:
Dude I measure them all of the time. The dimension is from the
valve stem tip to the plain that the rocker stands seat (already wrote that). Not much to them. Before and after the head work is done they should remain the same and close to each other. That is the machine shops responcibility and how it is done in the industry. Like I wrote, unless some major error occured they are likely ok. I can give you a height from a virgin head I have and you can use it as a base line. I'll be t a local antique auto swapmeet early tomorrow so if you want the heights from my assembly let me know.
 
Robert, I'm not being deliberately obtuse, but I haven't rebuilt an engine in 15 years...

If the correct procedure is to measure from the plane of the rocker stands to the tip of the valve-stems, we still need to know what the correct limits are.

Above, there were a few posts that intertwined the specs for the valve stems with the valve guides...
 
Robert that would be fantastic to get an installed valve height on a virgin head. All I can check for at this juncture would be to see if there are any significant differences in my installed valve heights.
 
I took measurements that are easier to get especialy on the angled exhaust valve.

Exhaust:
stem tip : top of stem to top of rotator. 2.300
spring installed length: 1.850 to top of .050 washer

intake:
stem tip : top of stem to top of head surface. 2.150
spring installed length: 1.850 to top of .050 washer.

In a perfect world these should all be +/- .020 but +.040 and -
.025 the lifter should still be well with in its range.
 
I don't think I have mastered the art of pumping up lifters by hand yet. Both of these are right out of the box but I could not pump them up on the bench 2 days ago in 5w20 oil. The first one is in mineral spirits (kinda like kerosene the manual mentions). The second one is in 5w20. Is there anything wrong here or is this normal?


I grabbed another one out of the box and it farted a steady stream of bubbles on the first stroke. Second stroke it bubbled again and began to firm up. By then end of 4 strokes it had pumped up.

I posted this in basic tech too in case someone is not following this thread but has some answers.

Edit: I still don't know if these lifters are good. I am spending a little time with them on the bench because it is a diversion until I get the energy to get up on that block and pull the rocker shafts to check installed valve height against roberts #s. Also I need to have a sit down with the machine shop and grill these guys again as to their valve work methods related to the nature if IH non adjustable drive trains even though they assured me already they were savvy. One loophole is I don't know if the po did anything to alter the geometry of the valve train like shave the heads. I am going to chase this thing down even if it means tearing the motor down again. To verify that these lifters are good I will send a sample today to Robert k see what he can determine. Maybe you can't fill these lifters on the bench by soaking and stroking unless there is vacuum present or oil pressure. The only thing I know at this point is that the lifters that primed easily on the bench required almost no effort. Just a few slow, firm strokes and they were solid.
 
Last edited:
You are doing a great job working through all of these problems and don't want to take away from your conclusions but I just want to add a quick note for the time being.

One thing to remember about the environment in which the lifter lives. First and foremost the annular oil undercut is supplied with some amount of pressure. The pressure will have the effect of motivating the oil in to the lifter body and the air out. Just sitting in the container of liquid May not be enough to accomplish that. Yes some did pump up but the other say 6-7 did not.

This situation is not conclusive as never has an individual that I know has ever had 6 of 8 new lifters fail to pump up in an engine. Remember I have never pre-pumped up lifters in my life only dip them in engine oil and never had one fail to pump up. I have had bad wear characteristics but never a flat one.

My fear is that the readers will conclude this as a valid test that shows johnson or any other lifter is bad and that they should be avoided.

That is why I want to see one or even one of the new ones you are having trouble with. If they look and function then I would bet on another issue. But I won't jump to any conclusions till then
 
Robert's right. No way multiple new lifters are bad.
Robert, what do you feel is a comfortable pre-load measurement on a hydraulic lifter in this (mostly stock) situation? I've always went about .030-.070", though I have never seen any number published in the manual.
 
I finally found a technique for pumping up lifters on the bench that won't pump up easily in a cup of oil. I found that laying them on their sides for a soak in mineral spirits that they would begin to release bubbles on their own. Then I would shake them one at a time and soak them again on their sides and more bubbles began to come out. I repeated these steps a few times. Then I would very slowly apply even pressure with a pushrod and hold. Some of them would release a nice steady stream of bubbles after just a few slowww plunges. Some took a little longer and I just repeated the earlier steps a few more times. All lifters on the bench that I thought would not pump up did. There was a small amount of metallic colored dust left in the bottom of the cottage cheese container I was using to submerge the lifters in mineral spirits by the time I was done.

Each of these so called "problem" lifters took about 10 minutes of gentle massaging to begin to pump up by hand.
 
dealbreaker74 said:
What do you feel is a comfortable pre-load measurement on a hydraulic lifter in this (mostly stock) situation? I've always went about .030-.070", though I have never seen any number published in the manual.
Click to expand...

Probably a good range .050 being nominal. I would stay at the higher end closer to .050-.070 so you could absorb more wear.

I consider .030 an absolute minimum.

Recommended lifter preload for a typical GM lifter is 3/4 - 1 turn down on a 3/8-20 stud = .050 at the fulcrum and .083 at the lifter end assuming the rockerarm is rotating around the valve and while the fulcrum is moved down .050.

All lifters used in similar vintage push rod applications from a design and function standpoint are a like. An IH spec lifter has like usable range so one can conclude both will function properly with similar preload.
 
Robert kenney said:
probably a good range .050 being nominal. I would stay at the higher end closer to .050-.070 so you could absorb more wear.

I consider .030 an absolute minimum.

Recommended lifter preload for a typical GM lifter is 3/4 - 1 turn down on a 3/8-20 stud = .050 at the fulcrum and .083 at the lifter end assuming the rockerarm is rotating around the valve and while the fulcrum is moved down .050.

All lifters used in similar vintage push rod applications from a design and function standpoint are a like. An IH spec lifter has like usable range so one can conclude both will function properly with similar preload.
Click to expand...

Copy that. Thanks.
 
6cd3beef.jpg


#4 int preload measured like dealbreaker74
 
Good idea. Use the resources at hand so kiss rules again.

.070 is spot on in my book. If all are similar look else where for root cause.
 
Okay, now you're getting some solid info. Did they all land somewhere close to this? If yes, then like Robert says, check pushrods off your list and move on to something else.
Keep in touch. We really want to know what's really causing this drama!
 
You must log in or register to reply here.
Back
Top