Turning it up a notch...
12-09-2007, 08:12 PM
#1
1.0 BAR
Thread Starter
Join Date: Dec 2006
Posts: 277
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
Manifold nearly done
Gathering data on existing holes:
About to mill it out!
First hole is the scariest, the rest were only mildly disturbing
Running the tap through it
After all the holes were bored and tapped, I went back and counter bored it more to relieve the threads at the deck
Then went back around to open the tap again and now the fun part!
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!
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
Manifold nearly done
Gathering data on existing holes:
About to mill it out!
First hole is the scariest, the rest were only mildly disturbing
Running the tap through it
After all the holes were bored and tapped, I went back and counter bored it more to relieve the threads at the deck
Then went back around to open the tap again and now the fun part!
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!
