Your thoughts?

[Yennes]

Cracks on my 516 cylinder heads valve stems. What are your thoughts?

 

[gkent]

Common issue when new guides are pressed in. Now you have to wonder how far that crack goes and does it extend into water passages.

 

[Yennes]

Common issue when new guides are pressed in. Now you have to wonder how far that crack goes and does it extend into water passages.

It was installed already and I pumped water trough it. Seems like it had no leaks.

Can you usually drive the car with that kind of cracks?

 

[gkent]

I don't think it will be a problem then.

 

[rickseeman]

I would say yes, it just makes you mad. There was plenty of material there. It was just too tight of a press fit. If you already have them on the car you can run it. But if you ever see milky oil, just put new heads on it. Don't ask questions. I would just put new heads on now. But that's me, not you.

 

[Jerry Hall]

Machine shop should be held responsible. 516 heads are still pretty plentiful.

 

[Yennes]

They were installed, but the engine was never run. I suspect the machine shop made a mistake when planing the surface, but I will never know for sure. I replaced the camshaft, and I am not sure if the crack was already there before disassembly.

I was considering new heads anyway, but I wanted to get your opinion. I do not want to risk ruining the entire engine because of a problem I was already aware of.

 

[Dutchrebuild]

Of course if the crack leads to a piece breaking off and gets into something else...could be problems. Random metal chunks falling towards the bottom end can wreak havoc on everything in-between

 

[oldkimmer]

That’s pretty much par for the course when guides are pressed in. I see those are knurled so it looks like there are a lot of miles on them. Kim.

 

[hunt2elk]

Maybe a good excuse to throw on some aluminum heads?

 

[BSB67]

Looks like cast iron guides were pressed in probably long ago, then on the latest rebuild they knurled them, is my guess.

I wouldn’t worry about it. Not uncommon.

 

[Nxcoupe]

It should be ok. They can be removed by having bronze guides installed. The cut all that old guide out usually and press in the new bronze guides. How loose are the valves in the guides? A new set of trick flows or 440 source heads would solve the problem permanently.

 

[Yennes]

It should be ok. They can be removed by having bronze guides installed. The cut all that old guide out usually and press in the new bronze guides. How loose are the valves in the guides? A new set of trick flows or 440 source heads would solve the problem permanently.

Seems line they all fit well. First ever for my „building“ an engine.

The guy from the machine shop also said that it should be okay, not the best solution but it should work.

 

[Yennes]

Looks like cast iron guides were pressed in probably long ago, then on the latest rebuild they knurled them, is my guess.

I wouldn’t worry about it. Not uncommon.

Thank you for your opinion.

 

[dvw]

If it bothers you the guide boss can be trimmed down to .500". This would allow the use of Comp Cams valve seals (514-16). Also gives clearance for double springs.
Doug