Broken Head Bolts 346 engine

[gary griffin]

Hi,   my shop was remvoing an after market oil filter bracket and snapped off two head bolts. What size,and grade are they  and what thread count do they have? I assume they are ASME threads?

This will slow down mt resoration a few days I assume.

[TMoore - NTCLC]

If you can get the old ones out, then you can order the correct ones here:

Terrill Machine, Inc in  DeLeon, Texas. (254) 893-2610 (no website)

I honestly think that if you removed two of the bolts that were in sequence, you might want to consider taking the head off and replacing the gasket.  I don't really know if the seal will remain intact, but, I am not a pro, so you probably know better than I do if you have a chance for a leak at this section of the head.

Good luck - let us know how it works out.

[Classic]

My favorite method for removing broken head bolts is EDM (Electrical Discharge Machining).  Others will have their favorite methods.  Any machine shop that does a lot of engine work will have an EDM machine (or at least know where there is one.)  Google EDM for a description of the EDM process.  You will need to remove the head regardless of extraction method, so order a new gasket and all new head bolts from Terrill Machine.  Ez-Outs typically don't work and often break off compounding the problem, so I'd avoid them.