Cracked valve stems :o

[SkidBro]

Hi Fam

I'm currently in the process of rebuilding my 1HDT. The engine seems to have had a hard life in it's 380thou k life time. Cylinders require machining oversize, crank requires undersizing and the cam bearing journels (#2-#7) are out of spec, according to the FSM.

Anywho, back to the title.. iv just removed the valves and noticed 3 of the 6 intake valves have small hair line cracks.. iv yet to measure the valve guides, fyi. Are these cracks normal?? In my googling, I cam across a forum that advised that this is the norm, but I honestly find that hard to believe. Has anyone come across this before, is this REALLY that normal? I would appreciate the input of someone with more experience then myself

Thanks! Skid

 

[SkidBro]

The cracks in these photos are all of the same side of the stem, on cylinder 4 intake. The crack starts from the top and travels down to the bottom. It spiders out in the center. I can't help but suspect the stem and/or valve guide is worn.. allowing the stem to flex, causing these cracks? Possible side load from the cam an bucket? But if these cracks are normal, and the oil clearances are in spec, I don't want to fork out for new valves where it isn't necessary

 

[SkidBro]