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Using a thread chaser on an Iron head

1012 Views 8 Replies 4 Participants Last post by  Steve Johnson
Rectangular port 188's on a 454. The heads are on the block. I'm concerned about crud and maybe a some metal shavings where they might end up (I am using a true thread chaser kit, not a tap, but I still think some metal may be cut out with the chaser). I see that some of the holes have passages past the threads. I can use grease on the thread chaser but wonder if I'm doing more harm than good. So should I chase the threads in the head or leave them be?
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Which thread chaser kit? I could see with the ARP kit, you could get carried away with it.
Other ones you could make one with a bolt, and cut grooves on the threads.
They are made not to undercut the threads and give the crud a place to go, and straighten slight imperfections in the threads.
Oil it like a tap, blow the hole out first, run it in, just do not twist the hell out of it. Back it in and out like a tap if needed. The blow the hole out again. And continue.
You can use a bottoming tap, as long as you are careful.
ARP set is basically a dull bottoming tap.

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use light oil, and keep it clean, should be fine. How bad are you holes? Crud or rust, rust I would soak first, and what comes out is going to come out.
I actually have a cheap set I only use during assembly for putting lube in the holes, like ARP moly paste and sealant, with the slots and being undersize it coats pretty even. add some on the bolt and good to go.
Also you find holes you missed, like that ever happens to me.:D
Good Luck!
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