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WTF?! ARP head stud installation and 13mm 12point socket doesn’t fit head

605 Views 12 Replies 6 Participants Last post by  Jonqdiesel
Has anyone ever ran into this problem on their GE vvti heads when trying to install ARP head studs?! I’ve search and searched and searched and found nothing and am extremely frustrated.

the 13mm 12 point deep thin wall socket does NOT fit inside the groove of where the head studs bolt down. I can start 3 of the nuts on the head studs but that’s it. I will post a photo for reference.

am I supposed to hone out where it doesn’t fit? I thought these were supposed to be drop in, install and go.

please let me know if someone has ran into this problem and what they did to solve it. I really DO NOT WANT TO drill out the spots that won’t accept the socket but don’t think theres anything else I can do??


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You got a lathe? You will need to turn that socket outside diameter down so it will fit the wells in the head. I tried every socket I could find and had the same issue as you. It wasn’t real fun turning down that hardened tool steel but it did it.

You can see it here:

Really appreciate the quick reply! I don’t have a lathe but do have access to one at the place I work but have never used it. I guess it’s time to learn? Does making the socket skinnier compromise its ability to reach 80ftlbs of torque like ARP recommends? How much did you take off as well? Like 0.005? Or more?

also I searched a whole bunch of different things on you tube and this form and didn’t get a single thing. Any tips on finding things like this in the future? I hate to start new posts on already discussed topics, I know that’s something that bothers everyone on the form including me when it’s silly questions.
Thanks again for the quick reply.
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Man so it made me nervous shaving that much off the socket. It didn’t affect its strength that I can tell. I put the head on and took it off several times, each time torquing all 14 of them bastards to 80ft-lbs. The socket worked fine. I’d have to go measure it to see how much I took off. I’d say 3/16” of an inch?

It’ll be a good “get acquainted” project for a lathe. Chuck it up in a 3 jaw and go slow.

I don’t think it’s a 13mm btw. Should be a SAE 1/2” 12 point. 13mm may “work”.
Good to know. I didn’t know you could torque and re torque head studs like that and no replace them. Or did you when you took them on and off? I assume no because that would be EXPENSIVE.

I did try the 1/2” on the nut and it fit but didn’t try it in the head. I will do that tomorrow as well as my father has a 1/2” and 13mm thin wall 1/4” drive that appears to be slightly smaller. I’m going to try that and cross my fingers that it fits. If not after reading your post I will either try the lathe or use a drill and sand paper like someone recommended.
The piss off is I just had to buy a $600 socket set from crappy tire after calling; confirming they had the 14 piece socket set, racing there before closing, only to get there and find out the “””tech”””” I called has no idea what a 12 point socket is and doesn’t even have a 14 piece socket set in stock after confirming on the phone he did. That mixed with the anger of the socket not even fitting after having to buy the $600 set was almost enough to drive back to Canadian tire and wait for the “””””tech””””” to show up and next day and let him have 21 years of built anger and aggression… lol. Decided to take the high road instead, hopefully it all plays out in my favour!

thanks for the input and citing your forum post. Lots of useful information in there about the machine shop screwing your valves, how To clean old gasket and a mysterious over heating problem.
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thank you all for your replies!! All great suggestions that I was going to use if my initial plan didn’t work.

what I ended up doing was buying a 1/4” drive 1/2” 12 point (which was a better fit then the 13mm 12 point) and welding a adapter to the end of it because I snapped a 1/4-3/8 one already trying to reach 80ftlbs (didn’t think it would make it but gave it a chance because I’m gonna return the socket set from crappy tire)

the smaller socket was able to get in there and now I am a happy man.

Another quick question/opinion I need from y’all. I have the head torqued down now, and was about to put the cams in when going through my gasket set I saw all the valve stems and gaskets needed to rebuild the head. I’m realllllllly wanting to just keep the valve train the way it was as I am only putting back in the stock cams for now and it still has stock valve springs and so on. I plan on rebuilding the head next winter but have a goal of the car running by June first. I don’t have all the tools needed to replace the valve stems and my motor ran flawlessly before pulling it with only 180xxxkms on it. Didn’t smoke at all on decel. Or accel.

In your opinions should I order and wait for the tools to show up needed to do the valve stems or just send it and wait till next winter to rebuild the head completely? I’m probably gonna send it but wanted to check with the forum gods to see if this was truly a bad idea?

I appreciate all the good ideas though and replies. I promise to pay it forward like y’all are doing helping me with my questions once my build is done and writing out every single problem I encountered as a complete engine building noob once I am done my build!!
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