So after I had removed all the head studs from the case, I noticed a couple had come out real hard, as if something was wrong with the threads. After cleaning the threads of the stud, I couldn't thread them back in the two suspect holes.

I got a 12mmx 1.5tap and chased those holes. Now, the head studs go right in and they wiggle!! Even after I bottom them out, they can be moved relative to where they exit the case.

Is the case shot? What did I do wrong?

They should thread in tight like that. The only time you tap them is when you are installing ARP head studs.

A standard tap, the one everybody has, is NOT meant to chase threads. Odds are, you've recut the threads and they're now too deep. The Cap'n

Seeing as I screwed up only one of the case halves, can I replace just the one case half, or are cases halves sort of matched to each other?

You should be able to have a threaded insert installed to save the case. Not sure what you might have if you tried to replace one side of the case. Cases are not that hard to find. I have a few extra ones. I would sell a whole case for $50.

Bruce

While you were cleaning the studs, did you notice aluminum trapped in in the threads on the studs that came out hard?

If so, that might explain your loose fitting stud/hole combo...

Inserts are the only way to fix that, and don't use a hand drill. They need to be installed with precision machinery to ensure the studs don't cock. By precison, the case has to be held flat on the machined surface and either a drill or a mill comes in perpendicular to the machined surface to ensure the inserts are oriented correctly.

And NO to using two different case halves. They are a matched set.

Take it to a machine shop and have them fix it. It will be cheaper than buying the kit to do it yourself and they'll do it right.

Thanks for the replies. Looking back on what I did, it's pretty obvious now that I shouldn't have done it. I do have 2 core motors, so I have a couple of backup cases just in case. I will look to have a machine shop put in a threaded insert.

How about getting ARP studs? (And tap the other holes.)

That is an expensive option. $329 for just the studs. Yikes. I can't even find a machine shop to put in the threaded inserts.

I think I'm going to use the case from one of my core motors. I've already got one down to a short block.

[EDIT] My bad - I was thinking exhaust studs. Disregard[/EDIT]



Step studs are cheap. There's room to retap if you get the right size. My local VW shop carried them.

You should have used a thread chaser, not a tap. The chase has much shallower roots and doesn't create this issue.

Now that it has occurred you can drill the case 2mm over size and install a time-sert. Thats your best bet for something thats fairly easy to do and inexpensive.

I hope others learn from my mistake. I contacted my local Time Sert dealer and the kit plus the correct size inserts is a little over $100. Do I need to have a machine shop drill and tap the holes in order to keep everything square or is this something I can hand drill and tap?

Definitely have a shop do it, and a good one at that. I had a case messed up by some hack where the studs ended up pointing every which way like some bucktoothed hillbilly. The studs need to be square or it will confound your torque values. It would be a bummer to blow $100 on inserts then toss the case.

Do you have a drill press?

Rich

Just make sure your table is square to the spindle otherwise big problems.

Most drill presses aren't an option....

That is, the table is usually way too small to support the case, and the depth from the drill axis to the drill press support shaft may prevent the case from fitting.

An end mill, there's a real tool for the job.

A drill press with a large top bolted in place will work quite fine considering he will be drilling simple bottomed out holes that are 5/8 inches deep.

While you might be tempted to spend all your money at a machine shop, have some confidence and drill the two holes, put in the time certs and call it a day.

Rich

Thanks for posting this mistake. I have done similar and didnt know it. Now I get why I got the results that I did. I dont know everything and still find enlightenment in many posts around here

I agree. I've done exactly this with a TI case and a drill press. I've even done it with TI heads on the plug threads. After I drilled the hole I swapped out the drill bit for a tap. I tapped the hole by spinning the chuck by hand with just a little down pressure. That way I knew it was threaded straight.

Is a thread locker required when reinstalling the head studs? Also, it looks like the 30mm timeserts are the right size. It's the longest size they make. 12Mx1.5 right?

http://www.mcmaster.com/#inch/metric-threa...inserts/=59bj7w

http://www.mcmaster.com/#catalog/115/3234/=59bl4f

Before you go and spend $100 on the TimeCert kit... Consider this.

I had a local machinist install a time cert for $25. Now, granted, if you have to install 6 or 7 of them, its cheaper to do it yourself. But if you only need one done, its cheaper to have it done for you.

Zach

I must live in a strange part of the country because there are probably 100 machine shops and the first 10 I called knew nothing about time serts. Hmmmm.

They have different names. Same animal. Automotive machine shops may not know, precision machine shops all will. Two different animals. With the ones I listed earlier, no special tools are required to install them, just a drill, a tap, and a screwdriver. Notice that the metric I.D. ones with a metric OD one is more than the metric ID / SAE OD. The tap for the SAE will be cheaper to. Still gives you the metric threads for your studs.

I'm getting a headache.

I think I'll just start with a new case.

Just out of curosity, why did you remove a head stud. ?. and if you have a choise, and a spare case, (which you do) I agree that you should use it. Inspect it carefully. Murray

Brockton, Dedham and Newburyport.

There are others, but those are THE ones that get used the most up here.

Collect all your projects and bring it all at once to a shop.
Its one trip for all the parts.

Rich