HomemadeTurbo - DIY Turbo Forum - Turning it up a notch...

Well my motor for my BMW is done. But, I am not excited about it - I mean I am, but its still 2.5L and using stock pistons (Ceramic coated, teflon coated) and stock (strong, forged) rods film lubed, but I dunno... I have a 76gts and all other supporting big boy parts, I figured I might as well do it right.

So, I bought another block and am prepping it for some fun. Boring it and stroking it - ~3.0L fully built. I also decided that in order to run 35 psi from my PT76GTS, I need to do some significant "fastener" work. The stock BMW blocks are provisioned for a 10mm bolt/stud. I had ARP studs for it, which actually taper thinner in the middle to about 8.5 - 9mm. They're only able to torque to about 60 - 65 ft lbs which is fine but when running super high boost, you can lift the head. So, I called ARP and ordered a custom stud in the same length as the off-the-shelf 10mm, except in 1/2" and a US thread 1/2-13 on the block and 1/2-20 on the stud end.

Not too many people have done this in a bmw engine - so, it took a significan amount of dedication to drill holes in the new block i just picked up. But, did that today and it all went well. I first plotted the stock head holes and numbers so I can make a torque plate, as the new 1/2" studs will be torqued to 95 - 105 ft lbs which might warp the block some.

Anyway, here are some pics as thats a hell of a lot more interesting than words. Thanks to my friend for teaching me how to use the mill and doing this ---- myself.

Got my rods in, ordering pistons tomorrow

http://blowneuroz.com/mygallery/E34%...uild/rods3.jpg

Manifold nearly done

http://blowneuroz.com/mygallery/E34%...omanifold3.jpg

Gathering data on existing holes:

http://blowneuroz.com/mygallery/E34%...machining1.jpg

About to mill it out!

http://blowneuroz.com/mygallery/E34%...machining3.jpg

First hole is the scariest, the rest were only mildly disturbing

http://blowneuroz.com/mygallery/E34%...machining4.jpg

Running the tap through it

http://blowneuroz.com/mygallery/E34%...machining5.jpg

After all the holes were bored and tapped, I went back and counter bored it more to relieve the threads at the deck

http://blowneuroz.com/mygallery/E34%...machining6.jpg

Then went back around to open the tap again and now the fun part!

http://blowneuroz.com/mygallery/E34%...machining7.jpg

http://blowneuroz.com/mygallery/E34%...machining8.jpg

Don't fear the block - just normal surface scale that will be blasted off. If you've seen my other engine, you know how much I pay attention to detail :)

Next up is boring the head out, the machining the torque plate and boring the block out. Then assembly when I get the pistons!