Shim Under Valve Spring Seat

[Neil Harvey]

I hope this helps. Makes reading easier when the dial is up out of the cam Housing.

[Neil Harvey]

[Neil Harvey]

[Neil Harvey]

[Neil Harvey]

Had to resize images

[Henry Schmidt]

We have the factory tools but in a pinch this works.

[RSOHC]

Henry,

What is the diameter of the wire used?

Lauran

[RSOHC]

I have finished the dial indicator readings for determining the spring height of exhaust #6.
The values in mm were 36.30, 36.32, 36.37, 36.40.
The average of these values is 36.37mm
My exhaust spec is 35.5mm.
The average of the measured values minus the spec is 0.87mm
Dividing 0.87mm by 0.25 results in the number of shims to be installed and is 3.5.
I will be installing four 0.25mm shims

[Neil Harvey]

I think its time to give up and let someone who knows finish what you are doing. You are not getting the process, it appears.

Take the average of the reading you measured. That would be 36.35mm.

Subtract 35.50mm from 36.35mm and end with0.850mm. Divide this by 0.25 (shim thickness) for the number of shims to add. That would be 3.4 shims. So add 3 shims or if you get nervous add 4.

Simple.

[RSOHC]

Neil,

The measured valve spring height is greater than the specification.
Therefore, the value for the number of calculated shims would be negative not positive as you have stated.

Lauran

[Neil Harvey]

Indeed. The measured value is 36.35mm. This is the retainer height without a spring, between the lower seat and the underside of the top retainer.

The spec the spring installed height is 35.50mm , you said. So the difference is the amount of shims to add.

36.35mm - 35.50mm = 0.850mm. Now divide this by 0.25mm and that answer will be the amount of shims to add.

Do you understand now?

[RSOHC]

Yes, I now understand.

I will add 4 of the 0.25mm shims.

Thanks

Lauran

[Neil Harvey]

Originally Posted by RSOHC

Yes, I now understand.
My table is wrong.
I will add 4 of the 0.25mm shims.

Thanks

Lauran

Well done. Now repeat for the other 11 valve springs.

[RSOHC]

I am having trouble removing the white valve stem seal on #6 exhaust. Any tips would be appreciated.

[dannobee]

A pair of spark plug boot pliers will work too. If still not getting it, a strategically placed screwdriver or pry bar will help.

[RSOHC]

All of the intake and exhaust springs have been replaced.
The leakdown numbers are as follow:

Cylinder #1 ******* 0 % leakdown at 100 psi
Cylinder #2******** 18% leakdown at 100 psi
Cylinder #3******** 12% leakdown at 97 psi
Cylinder #4 ******* 0% leakdown at 100 psi
Cylinder #5 ******* 14% leakdown at 100 psi
Cylinder #6 ******* 3% leakdown at 100 psi


The engine is still running rough with all six spark plug wires connected and smooth with #6 spark plug wire disconnected.
I am thinking that there may be a problem with the camshaft lobes for cylinder #6 or the possibility of a bent rod for cylinder #6.
What are your recommendations for next steps?

Thanks

Lauran

[RSOHC]

On December 1, 2023, I did a compression test (dry). The results were as follow:
Cylinder #1 144 psi
Cylinder #2 140 psi
Cylinder #3 140 psi
Cylinder #4 149 psi
Cylinder #5 152 psi
Cylinder #6 150 psi

[RSOHC]

On December 1, 2023, I put the left carburetor on the right side of the engine and the right carburetor on the left side of the engine.
The engine speed still increases when I disconnect the spark plug wire from #6 and engine speed decreases when I reconnect the spark plug from number #6. Therefore it seems that the carburetor may not be the problem.

[PeteKz]

The compression test numbers for 1-5 look okay. What about #6?

Are you SURE the spark plug wires are right?

It must miss on #6 when you disconnect the spark plug wire (and I hope you are grounding that wire to the engine, not letting it hang loose). If it runs even rougher when connected, that would indicate it's firing at the wrong time.

That's about the only explanation I can see for your description.

[RSOHC]

As a reminder, I decided to pull and then reinstall the ignition wire off each spark plug one at a time to see how the rpm of the engine changed.

For cylinder 1 though 5 the rpm decreased from 666 rpm 630 rpm when the spark plug wire was removed and went back to 666 rpm when the wire was reinstalled.

However, for cylinder number 6 the rpm increased from 666 rpm to 766 rpm when the spark plug was removed and went back to 666 rpm when the wire was reinstalled.