pics

should i be able to rethread these to 9mm without any drilling?

Tap drill for a 9mm is 7.8mm, so if a 8mm stud already pulled out, the hole MAY be too big already to get good thread engagement on a 9mm.

http://www.kramerusa.com/DrillTapChart.htm

good point.

what is the next best option that does not require a machine shop?

jim

Jim you need to tap them for M10x1.5 step studs. Use an 11/32 drill bit.

The tapping operation will go easier if you find a 16point socket that fits your tap so you can use a long extension. Aside from making it easier to drive the tap the long extension will help serve as a guide to keep the tap straight.
Go slow and good luck!

I did this same fix upside down on my first 914 (learned later that the funny bracket in the trunk was to support the rear exhaust :-(

I drilled it once and used the inserts.

When it broke again (still hadnt installed the rear ex support bracket) I bought the step bolt and the next size up heli-coil.

So I rebuilt mine twice with no machine shop.
They held for many years after that (and installing the bracket).

So no need to be afraid.
I still have both heli-coil kits from 25 years ago...

Stu

looks short

http://www.germansupply.com/home/customer/...productid=18135

jim

No need for a heli-coil if you use a step stud. Just tap for the step stud.
But you could tap for a M8x1.25 heli-coil which makes sourcing replacement studs easier.

A Time-sert uses the same size tap as a heli-coil and is a lot easier to install than a heli-coil.

Jim,

Is that a crack on pic#2 (on the boss?) where the stud will mount?

i don't know ???

i should get this engine on a stand.

let me remove the grime and get some better pics.

thanks

jim

--

IMHO Timesert is the way to go.

It's extremely rare for that boss to crack. It's the opposite one that is crack prone. The only time I can recall seeing that boss crack was from a mechanics screw-up.

I see a casting seam, but no crack.

"i should get this engine on a stand."

If you dont have an engine stand for a type IV, I learned that the $59 ones from Harbor freight will bolt to our engines if you jockey the supports around enough.



Heres a pic of the tranny on it, but of course it works for the engine too.



Stu

Here is an even better reason to procrastinate.
It may even be a good reason to stop what you are doing entirely for at least a week or more..
You should head off to harbor freight and go on a shopping spree.

Head studs just suck...they are the worst thing to have to deal with IMHO on these motors.
I would wait until the last possible moment to deal with those studs ....rebuild the rest of the motor...but do not do anything unless someone forces you.

Rich