Crack in cylinderhead

[JosephJoe]

Gentleman,

I found a crack in the cylinderhead of my Panhead '59.
The crack runs from the plughole to the valve seat (see picture).
Is it necessary to repair, and if so, what is the best way?

Thanks in advance,

Joe
Crack in Cylinderhead.jpg

[Jerry Wieland]

I would leave it alone. That is common on almost every pan rear head. Welding generally makes it worse.

Jerry

[JosephJoe]

Thanks Jerry,

My mechanic gave me the same advice.

Joe

[JosephJoe]

Gentlemen,

Has the crack influence on the performance of the engine.
Mine is a bad starter.

Merry Christmas,

Joe

[Jerry Wieland]

Joe

I would look elsewhere for hard starting problems. The only problem I have heard claims of were 'dieseling' or engine trying run after it was shut off probably caused by glowing carbon in the crack.

A hidden cause of hard starting is intake vacuum leaks although ignition piints can also cause it.

Jerry

Gentlemen,

Has the crack influence on the performance of the engine.
Mine is a bad starter.

Merry Christmas,

Joe

[sirhrmechanic]

There are repair methods that don't use welding... see my earlier thread on Irontite plugs. These are also available in aluminum. Small plugs can be stitched in to both fill and stabilize the crack. You may need to remove the seat and plug insert, however. Ultimately, a new (uncracked) head is probably cheaper.

Something else you could try is Vacuum impregnation. VI will fill minute cracks and is stable in the heat of a head. It won't stop a crack from propogating or fill a hole. But that crack is stabilized at the ends by the seat and the plug insert. So vacuum impregnation might be a good route. Again... finding an uncracked correct head may be cheaper.

And as folks have said above, it probably does not affect starting. I'd be looking at timing, starting mixture, etc. And unless this crack extends outside the head, it's probably not doing anything more than looking bad...

Cheers,

Sirhr

[TimR]

I used this product to seal nipples in a flathead cylinder. Company claims it will fill small cracks. Good to 3000 degrees F.

http://www.silver-seal.com/product/30333/Seal-Lock-Fluid-Weld-2-oz-Bottle.html