ARP Head Studs Too LONG!!!!

nosman4

Member
Nov 10, 2007
133
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16
Bend, Oregon
Anyone ever had this problem? I could understand seeing this problem with a head and block that has been machined, but this car hasn't had either and they are still too long. I am having the head machined so this makes me worry even more. There are about 5 threads sticking out of the block still after the stud is bottomed out. I cleaned the threads in the block with a tap so I know they are not just dirty. Is 5 threads normal? Also the threads in the block stop about a 1/4 inch or so from the bottom of the hole. I am re doing a metal headgasket for a friend and I suspect this is why it blew in less than 1000 miles..... In addition to not being machined the first time..... Am I the only one that has seen this problem? I called ARP to make sure the stud was the correct length and it is according to them... What do you guys think??
 

cinderMK3

I want all the HAm
Apr 13, 2015
134
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Akron Iowa
Did you measure the depth of block holes then insert the stud. Then measure amount left on stud showing just to be safe? I know its re-dudent but just a double check.
 

nosman4

Member
Nov 10, 2007
133
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Bend, Oregon
Yes I did, The depth of the hole is 1.1 inches or a little under. The length of thread on the stud is just under 1 inch, there is about .250 thou left to thread in. That means there is about .300-.350 thou in the bottom of the hole left unthreaded, which looks about right. This thing just doesn't thread all the way down to the base of the threads, just wondering if this is how everyones is? Or are the holes threaded differently on different blocks? I'm pretty sure this is a used Japanese motor if it makes any difference.
 

nosman4

Member
Nov 10, 2007
133
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Bend, Oregon
GC89;2054965 said:
Did you clean out the holes in the block with a bottom tap before installing like the instructions say?

Did you read my post before responding? Anyways, I shortened the studs so that they sit flush with the block. This is the second set I have done this with and the 1st is holding up great. It just made me nervous when I measured everything and it was very close, plus I removed some off the head when surfacing, so I decided to give myself some room to breathe. Just not sure why ARP would make that much extra stud when it doesn't even screw down into the block. No reason for it....
 

GC89

1J-THIS
Jun 13, 2007
938
3
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38
Spokane, WA
^ Yes there is a difference between a standard tap intended for a nut and a bottom tap for holes like in the block. You stated that measuring proved they were not threading in all the way so obviously the threads are not clean and straight all the way down. Also did you put lube on the block side?
 

nosman4

Member
Nov 10, 2007
133
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Bend, Oregon
GC89;2055001 said:
^ Yes there is a difference between a standard tap intended for a nut and a bottom tap for holes like in the block. You stated that measuring proved they were not threading in all the way so obviously the threads are not clean and straight all the way down. Also did you put lube on the block side?

Yes I used a bottoming tap. I have been working as an auto tech for 10+ years. The threads are clean. They were pretty much clean before I even started. I have not put lube on the studs yet as I am not ready to install them. The studs are threading all the way to the bottom of the threads in the holes. There are not threads for more than about 3/4 of an inch.... This is why they won't thread all the way down, not because the threads are not clean. Does your block have threads all the way to the bottom of the hole??? Anyways, I got the answer to my question. It sounds like it is normal for the studs to not thread all the way in. If the block was threaded all the way down they would thread in perfectly, that is why I suspect there are some blocks out there with threads all the way down... Otherwise why would ARP design the stud like this. Thanks guys.
 
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GC89

1J-THIS
Jun 13, 2007
938
3
18
38
Spokane, WA
Not questioning your knowledge or credentials, just a question. The 3 blocks I have done have all had varying but slight amounts of threads still showing but .250 seemed like more than I recall on any of them.

If they thread in easily and are reaching the bottoms of the threaded portion you should be good to go as others have said.
 

nosman4

Member
Nov 10, 2007
133
0
16
Bend, Oregon
supraguy@aol;2055220 said:
I've personally never seen threads in any blocks' headbolt holes that DIDN'T have a bunch of crap in them.
Ill take a picture for you if you want? If I can get one that is.....