Crack or Weld? In rear cyl intake

[mcraeav]

I was haveing trouble starting my 62 FLH when it is hot so replacing the intake gaskets and after removing the intake manifold and looking inside toward the valve seat I notice a crack or maybe a weld just next to the intake valve? I can't really tell; do they sometimes weld around the seat?
Anyway I was not really wanting to remove and get into the heads if I can help it; the engine seems to run good, just hard to start hot. Would it hurt anything if I just left it alone?

[mbskeam]

if the seats are the original then they will not fall out.....

on my heads they had been ported and the area right in your pic was missing material in the same spot.
it was showin valve seat on both heads, the material had just cracked and flaked/cracked off....

did not hurt the way it ran....

[NightShift]

Dear Mcraeav,

Uh oh, air can get sucked in there just like a manifold leak.
Clean them up good and bubble test them.
If they are hard seats, I bet they aint round no more either.

'Spectful,

[mcraeav]

Where would I see bubbles appear if the crack is next to the valve like that?

[NightShift]

Dear mcraeav,
You better hope you can see the margin of the seat outside of the valve OD. It shouldnt seat on aluminum.
If all else fails just use big corks on the seat and the port mouth both, and a littler cork with a hole in it or tape around the tubing to put the air in at the guide. Try low pressure first cause its gonna take clamps or kungfu grip to keep them from spitting out and hittin you in the eye.

'Spectful,

[mbskeam]

Uh oh, air can get sucked in there just like a manifold leak.

from where?
the combustion chamber?

the valve seat and that crack are right over the top of the cyl.....

and since the fuel/air mix is basically getting pulled/sucked into the cyl as the valve opens, I would think that it would not pull in anything from the OUTSIDE. except thru the carb, and if there is not a leak at the manifold then it would pull air from there also...
the only thing that it at that place in the head is the air/fuel charge....

[NightShift]

Dear mbskeam,

Whether carbed air is sucked into the combustion chamber through a leak or hot mix is forced out into the port either way its trouble. Dont forget that the flow out the exhaust has a "scavenging" effect and you dont want to mess up your mixture for the next stroke. Or worse yet trigger it and set your carb on fire.

'Spectful,

[james]

I would put a compression tester hose in the spark plug hole and (if you have a compressor)
pump in compressed air with both valves closed. Spray some soapy water over whatever it is inside the intake portion of the head and look for bubbles.
That would be the easiest way and you'll know for sure if it's a crack.
You may have to change the male fitting on the compression tester hose to fit an air hose female connector from your compressor.

jim

[NightShift]

Dear James,
Thats a gooder idea!
Come to think of it, just kicking it might make bubbles.

'Spectful,