So the first machinist to do my block stripped a head stud hole. I tried measuring these arp studs but something is wrong. They are 1.25 pitch amd from my measurement should be 11mm diameter. I got the helicoil and it's way to big. So I decided to check my headstuds by running my m10x1.25 die over it and that didn't fit either.


Arp doesn't list the specs amd summit had no idea even though they sell the headstuds I have. Any help please. This block has been waiting to be put back together for over a month.

Jeff

 

umm have him buy u a new block. plain and simple.
M10 is huge, i;d expect a M8 orM6

 

This block was first machined 3 years ago. They aren't going to do ****. They torqued the head studs into the block so when I tried to remove them all the threads came with.

The studs are bigger than my m10 die so they are bigger than 10. They measure 10.7mm with my calipers. They are smaller than my m11 so wtf is in between?

 

i think they're m11X1.25. you know when you do a helicoil you do drill the hole out and tap it much bigger. or are you saying the stud won't thread in the helicoil?
rich, if the nissan's head studs were m6, i wouldn't own a nissan

edit.. looking in the arp catalog it says M8 next to vq35...
i would have sworn they felt much bigger than that.

edit again.. i was looking at rod bolts. makes sense. so yeah im sticking with m11x1.25

ross

 

Ya, I test fitted the stud into the coil and I can push it through without having to thread it.

I know the coil wil ber slightly compressed in the hole but that much? I don't want to run my block to test a theory.

 

iirc they dont compress much as they have to be small enough to thread into the block you can mayby test it on something random that dosnt matter though. mayby got some aluminum or steel laying around?

 

that's what i was thinking. I'll see if i can find something to drill into around the shop. The crappy part about that is if i use this 40$ helicoil kit just to "test" it i can't return it if it's the wrong size.

 

7/16-20 thread size and pitch

thank you home depot thread sizer. even summit had it wrong.

 

Sorry I know this is an old thread but they are definitely M11 x 1.25...not 7/16-20. Unless you are talking about the other end of the stud, because the two ends are different and I didn't measure it. But the thread in the block is M11 x 1.25.

 

Someone must have custom ordered and had the block cut for something besides stock because an m11x 1.25 would not thread properly into mine. That's why I had to go looking. Also using an m11 nut it would loosely just flop around on the ARP stud.