Mystery Engine Knock

It was an intake valve on cylinder number 3. I fidn't know they made hones that small either, they come even smaller than 11/32 too.

Valve springs were checked, they are all brand new and very strong.
 
It was an intake valve, so the problem has been fixed ?

I don't think you'll find a hone that small, but, you can find a reamer.

I've loosened them up using grinding compound.

Most of the time the valve is fitted OK, maybe a tad tight, and will start hanging up because of 'crud' [ technical term] usually from sitting around not being used.
 
They do sell ball hones that small, specifically a company in California called Brush Research. I bought some from them and I am waiting on them to come.

I verified it was an intake valve by watching the engine run with a valve cover that has the top half cut off.
 
Update: still have the sticking valve. Mechanically it does not make any sense as the guide has plenty of clearance for the valve, a different valve and spring were put in with thr same results, and the lifter works fine. I am unsure of where to go from here as I have run out of ideas and gotten sick of tearing the engine apart after 4 or so times!!
 
GRutter said:
Why keep sending private messages?
We all benefit from each others experiences and shared knowledge.
If you have something to say, please just post it so we can all benefit from it.
Click to expand...

After you've been on here a few years and you get tired of the "professionals " picking your posts apart you'll be sending private messages too.

Marshall has more Model A experience than most of the members on this forum and is very helpful.

Bill
 
chrs1961815 said:
They do sell ball hones that small, specifically a company in California called Brush Research. I bought some from them and I am waiting on them to come.

I verified it was an intake valve by watching the engine run with a valve cover that has the top half cut off.
Click to expand...

Interesting, i have not heard of the cut valve cover before.

1: Did it stop the oil splatter?

2: How high up did you cut the cover?

I ask because I need to do the same thing, but instead of cutting a cover I will make one from sheet metal.
 
old31 said:
Interesting, i have not heard of the cut valve cover before.

1: Did it stop the oil splatter?

2: How high up did you cut the cover?

I ask because I need to do the same thing, but instead of cutting a cover I will make one from sheet metal.
Click to expand...


A picture would be great too. [emoji106]


Sent from my iPhone using Tapatalk
 
Chris, I am sorry you are having so many problems. In my mind, the only thing that makes sense is a sticking lifter. Unfortunately fixing a sticking lifter will require some work. You will have to take the pan off and remove the cam. You can keep the lifters up with cloth pins. You will have to remove the valve keepers and springs.

How have you determined that the lifter "works fine"?

The only other thing that I can think of is to use a heaver valve spring on that valve. I assume you have checked the spring. You could take the heaver spring out after a few thousand miles. I have stretched springs to increase the spring force.
 
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old31 said:
Interesting, i have not heard of the cut valve cover before.

1: Did it stop the oil splatter?

2: How high up did you cut the cover?

I ask because I need to do the same thing, but instead of cutting a cover I will make one from sheet metal.
Click to expand...

The valve cover is cut in half horizontally more or less, maybe little taller than half. When running, there is not any oil splatter but the galley does fill up almost to the top of the valve cover which is why you have to be careful when you cut it.

Btw, Marshall was suggesting the valve could be bent but the original one and the new one was checked for straightness. Plus they are stainless so they are pretty hard.
 
nkaminar said:
Chris, I am sorry you are having so much problems. In my mind, the only thing that makes sense is a sticking lifter. Unfortunately fixing a sticking lifter will require some work. You will have to take the pan off and remove the cam. You can keep the lifters up with cloth pins. You will have to remove the valve keepers and springs.

How have you determined that the lifter "works fine"?

The only other thing that I can think of is to use a heaver valve spring on that valve. I assume you have checked the spring. You could take the heaver spring out after a few thousand miles. I have stretched springs to increase the spring force.
Click to expand...

I spoke to an engine rebuilder who told me to the check if the lifter comes up and down fine and turns in the bore. Sometimes what happens is when people remove the old lifters they can nick the hole.

Btw, I should mention that the valve guides and valves are modern and the lifters are the adjustable type.
 
chrs1961815 said:
Update: still have the sticking valve. Mechanically it does not make any sense as the guide has plenty of clearance for the valve, a different valve and spring were put in with thr same results, and the lifter works fine. I am unsure of where to go from here as I have run out of ideas and gotten sick of tearing the engine apart after 4 or so times!!
Click to expand...

Possible problem w/the camshaft?
 
It just seems like it has to be the lifter or something in the lifter bore. I don't wish that frustration on anyone.
 
I am trying to think of how you might loosen up the lifter without taking it out. It may be possible. Try removing the valve cover, removing the valve spring keeper and spring, and tying up the valve. Then lift the lifter with the camshaft by moving the engine into that position. Then put a heavy-duty rubber band around the lifter and turn it by hand or with a drill motor until it loosens up. May take a long time. You can make a heavy-duty rubber band by cutting a slice out of an old inner tube.
 
This is a real mystery, isn't it. I have run out of ideas. If it was my engine I would try a stronger valve spring.
 
Are you running a new cam, reground cam or original cam? A bad lobe might overheat the lifter?
Can you lift the lifter up and spin it or does it get tight at the top of its travel?
Does the adjuster on the lifter show wear like a hollow in it? Maybe it is not hardened?
Could the valve spring or keeper catch on anything (doesn't seem likely).

I am just trying to trigger a thought that will point to the cause of the problem. It seems like you have ruled out the valve end of the problem.
 
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