Topics one should cover in a "new head" walkthrough video

[old31]

Jack brings up an interesting question. How many are using a 6.1 or higher head feel you have to go with a mechanical advance?

Alex is using NU-Rex. Any others, feel you have to go mechanical?

With my 6.1 Snyder, just once and a while do I have a knock. If I do, I adjust it.

I kinda look at the Nu-rex as just one more failure point.

[Bruce of MN]

I'm using the stock manual advance with my 6:1, but it does require attention in hilly country. It becomes habitual with driving it several times a week and hour or more long trips.

[alexiskai]

Originally Posted by old31

How many are using a 6.1 or higher head feel you have to go with a mechanical advance?

I got the Nu-Rex a couple of years ago (when I still had the stock head) because my wife drives the car occasionally and I wanted to reduce the number of things she has to keep track of.

[Plainsman30]

I had a blown head gasket soon after my motor was rebuilt. I replaced it, and soon had a scored piston. When we took the engine back apart, I noted the water hole passages were not drilled all the way through the casting on the new high compression head. I am not sure if this was a contributing factor to the problems or not, but I asked the vendor to send me a different head. It was better, but still did not have the water holes drilled out properly. although it was different water holes than the first head. I then had 3 heads on my bench, and the only one with the water holes drilled out properly was the original stock head. I drilled/ chased out the holes myself on one of the high compression heads, which is not hard to do and have not had any additional problems.

[alexiskai]

Originally Posted by Plainsman30

I had a blown head gasket soon after my motor was rebuilt. I replaced it, and soon had a scored piston. When we took the engine back apart, I noted the water hole passages were not drilled all the way through the casting on the new high compression head. I am not sure if this was a contributing factor to the problems or not, but I asked the vendor to send me a different head. It was better, but still did not have the water holes drilled out properly. although it was different water holes than the first head. I then had 3 heads on my bench, and the only one with the water holes drilled out properly was the original stock head. I drilled/ chased out the holes myself on one of the high compression heads, which is not hard to do and have not had any additional problems.

Huh. I would be interested in covering this in the video, but I'm not sure what to tell folks to look for. Do you have a pic of a bad head?

[old31]

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Plainsman, please tell us whos head you are using so that we can be aware of the holes.

[1crosscut]

Something that I do to protect the paint on a newly painted head while going through the torque in process is to put an o-ring around each head nut to keep the socket from marring the paint.

[alexiskai]

Originally Posted by old31

Plainsman, please tell us whos head you are using so that we can be aware of the holes.

He wouldn't say, but he sent me a picture of the face of the defective head and it looked like a 5.5 head. Can't be sure who made it. I think we should exercise this kind of diligence no matter who the source is.

[Jack Shaft]

Originally Posted by Plainsman30

I had a blown head gasket soon after my motor was rebuilt. I replaced it, and soon had a scored piston. When we took the engine back apart, I noted the water hole passages were not drilled all the way through the casting on the new high compression head. I am not sure if this was a contributing factor to the problems or not, but I asked the vendor to send me a different head. It was better, but still did not have the water holes drilled out properly. although it was different water holes than the first head. I then had 3 heads on my bench, and the only one with the water holes drilled out properly was the original stock head. I drilled/ chased out the holes myself on one of the high compression heads, which is not hard to do and have not had any additional problems.

Are you talking about the 1/4" holes? Did #4 piston score?.Its difficult to cite cylinder head water flow for piston scoring due to the water jacket on the block side controlling cylinder cooling. The major cylinder head water flow ports are in the casting mold, irregular shapes.

[Plainsman30]

It was the 1/4 hole between pistons 3 and 4 that was not drilled out fully into the water jacket. On my second HC head, a different 1/4 hole was not drilled out.

Back 2 pistons (3 and 4) were scored. The scored areas face each other and both face the divider between cylinders 3 and 4 where the water hole is located.

The scored pistons were just the start of a long, very expensive, and frustrating problem. I don't know for sure what all caused the problem, but I recommend checking the water holes the head to be sure they are open before installation.

[Jack Shaft]

Piston to bore clearance is critical,too tight and the piston will score.Tough break Mike..