Anybody know what M12x1.25 thread chaser will fit in Subaru block. I want to clean out the holes for more even head bolt torque after doing head gaskets.

 

Edited November 30, 201510 yr by steve56

Head bolts should be M11. Use a regular tap with an extension. http://www.airgas.com/product/Tools-%26-Hardware/Cutting-Tools/Taps,-Dies,-Chasers-%26-Threading-Tools/p/VIS21212?utm_campaign=airgaspl&utm_medium=product_listing&utm_source=google&gclid=CLDQ8Kf_tskCFRAWHwodcjcEXw#fo_c=306&fo_k=1e9841671e670d0cc10b1fde16826ed0&fo_s=gplaus

Thanks for catching my error. My thread checker dosn't have an M11 size. Something  didnt feel right when I had the head bolt in M12x1.25 thread checker. Whats the thread pitch on the M11 head bolt?

Should be 1.25.

Grab a spare bolt from a yard and file or grind a v notch down the length of the threads, you know have a backyard thread chaser.

Grab a spare bolt from a yard and file or grind a v notch down the length of the threads, you know have a backyard thread chaser.

 

I have done this in a few situations, if you wield a dremel carefully and get a very sharp square edge it works quite well.