Who has used this tap for bottom tapping?

[Bartlett]

I am putting my ARP Studs in . In doing a search I found some older threads with part numbers for taps that work well for bottom tapping. I have the MSC #49715881. It is mentioned in one of those threads(this is where I got the part number from). This doesnt look like any bottoming taps that I have ever used. The short hairs on the back of my neck stand out straight when this thing digs in. I have not been able to bring myself to start "cutting " in the new threads. The possibility of this thing snapping off:{... ... ... ... . well I dont want to even go there. Has anyone used this tap succesfully for this purpose? Just want to make sure this is the "correct" usage of this tap

Mike

 

[gitchesum]

Not sure why you are bottom tapping for studs on a CR. There should be no clearance issues requiring bottom tapping.



When I re-installed my head, I installed ARP studs without tapping, just required a little grinding on the lower rocker cover.

 

[Bartlett]

Every thread I can find on here says this is the "correct" way to install the studs. I would like not to have to but I think it has to be done???

 

[gitchesum]

It doesn't have to be done.



If you have the head off and want to do that's one thing, but I wouldn't do it if you're replacing them one by one with the head on.

 

[Bartlett]

No the head is not off. If it were then a different story. I just dont want to go through all this work to find out that they needed to be tapped.....

 

[DF5152]

usually the purpose of Chasing the threads prior to installing studs is just to clean them for a more accurate torque reading. The studs will thread in or should as along as they are not messed up. also they make tools specific for chasing threads a tap is designed to cut them and sometimes can cause the stud to become loose in the threads... .

 

[Bartlett]

Yes ,I am not talking about chasing the existing threads(as I know this needs to be done). The way the holes in the block come,there is about 1/4 inch or so of drilled hole that does not have threads cut into it at the bottom of the hole. Bottom tapping allows threads to be cut in this area thus full engagement of the coarse end of the stud. It also seems like there is slight variation to how deep the threads were cut into the block at the factory. I have installed a few so far without bottom tapping. The number of threads above the nut varies from stud to stud and I am sure that each stud has been bottomed out then backed off 1/16 tirn or so.....

 

[DE Jeeper]

I bottom tapped mine when I installed the ARB studs. I think that is the correct tap, but I can not find my order when I got it. The tap was pretty sharp and it didn't take much force to get to the bottom. You can feel it when you should stop.



Aaron

 

[DE Jeeper]

Just checked my tool box and you have the tap I used.



Aaron

 

[ENafziger]

Yes ,I am not talking about chasing the existing threads(as I know this needs to be done). The way the holes in the block come,there is about 1/4 inch or so of drilled hole that does not have threads cut into it at the bottom of the hole. Bottom tapping allows threads to be cut in this area thus full engagement of the coarse end of the stud. It also seems like there is slight variation to how deep the threads were cut into the block at the factory. I have installed a few so far without bottom tapping. The number of threads above the nut varies from stud to stud and I am sure that each stud has been bottomed out then backed off 1/16 tirn or so..... <!-- google_ad_section_end --> <!-- / message --><!-- sig -->

You're exactly correct. Bottom tapping is good extra insurance.

--Eric

 

[KVoigt]

Bartlett, Haisley Machine sells the tap, they also recomend this with there head studs to put less strain on the block by using more threads

 

[Bartlett]

Thanks for the replies guys... ... mike

 

[JWadford]

my first engine was not tapped and it held 75 psi with no problems, but i b-tapped the eng that i have now, should be fine unless you want to add alot more than what is in your sig

 

[Bartlett]

I should probably update my signature... ... . unless I want to be in stealth mode:-laf. I have added the BD R 700 twins, Hamilton springs,doing "something" with injectors (not sure yet) an Air Dog and something with my cp3 (arson 3???). Anyways, I see both sides of to do or not to do. I started bottom tapping today using tap mentioned. I ran the tap down and towards the end the resistance got harder(maybe 2 full turns??) and then it came to a "stop". At this point I backed the tap out and cleaned etc. To be honest when comparing to the ones I didnt tap I think I got 1-2 threads less showing on the ones I tapped. I honestly dont know if I bottomed out the tap or not but going by feel I am not about to push it. Quite time consuming. I think the springs were much easier I must comment that although I have added a bunch of "stuff" I drive like an old man and my truck will probably never see over 50psi of boost . Mike

 

[ENafziger]

Ah, it does take awhile, but I'd keep on going. At least it's good exercise!