I think the title is pretty straight forward. I want to try keeping the head on with just some ARP's until I can afford the machine work. Has any one successfully bottom tapped the holes with the head in place? If so, where do I find a loooooong 12mm tap?

 

There was a long tap part number floating around, it was high dollar IIRC. Short story, to do it right, pull the head.

 

Bottom tapping pulls a lot of crud out that will cake in the crack between the block and the head of you try to do in with the heads on. This can cause leaks around the bolts unless you do one bolt at a time. Even then, it's still bad to have that coating on gunk in there!

 

I dont want to pull the head yet. I figure id save that $100 headgasket and $400 machining for later.... Can I reuse my old gasket if I have to pull the head? (sounds dumn even to me)

 

The whole point of head studs is to increase the clamping force. If you plan increasing the boost like crazy (therefore necessitating studs), then you will be spending a lot more than the cost of machining the head and a new gasket.
I would wait until you need the studs.

 

Im going to need them, remember:
https://www.dieseltruckresource.com/...ear+ilikebikes

 

Your like me, do a bunch of sweet stuff and try and cheap out at the end when you run out of money...never works for me, always have to buck up

You got an external wastegate dontcha? You could just keep the boost down for a bit till you want to do the head proper. (like thats gonna happen)

Have fun... Should really be done anyway, soooo...

 

why not try? youre doing the job over the top, every thing is still torqued down, no debris is going to interfere with a torqued head, take care blowing out each hole as you tap, a litttle at a time, it will work, get more boost sooner, joe.

 

Lots of people have done it with the head still on. One of my friends took an old dull porting bit and cut the head off. Then he tig welded the shaft to the short tap. We just took our time and made sure to go easy and it turned out fine.
We did one at a time. We pulled out the bolt, sprayed brake cleaner down the hole and blew it out with the air nozzle. Then just oiled the tap and went slow. After the tapping we repeated the brake cleaner and air. Each one was torqued to 95 ft/lbs.

After they were all in we retorqued to 125. Then we started the truck and let it get ti 170 degrees or so and retorqued. He drove it for 5 or 6 days real easy keeping the boost down under 30psi then retorqued them again.

About every 2 or 3 months he has been taking off 1 nut at a time and lubing and retorqing them.

Stock gasket with 150k miles and has been holding 55psi daily.

Since then he bought another head he had ported and o-ringed. We still havent blown the stock gasket. The brand new head is still on the shelf till then.

 

12mm by ?? try the machine tool companies msc
KBc

 

Yea he'll need studs for them twins hes putting on [cool]

 

12mm x 1.75