Turning it up a notch...

[Jon K]

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%20525i%20Motor%20Build/rods3.jpg

Manifold nearly done

http://blowneuroz.com/mygallery/E34%20525i%20Motor%20Build/turbomanifold3.jpg

Gathering data on existing holes:

http://blowneuroz.com/mygallery/E34%20525i%20Motor%20Build/machining1.jpg

About to mill it out!

http://blowneuroz.com/mygallery/E34%20525i%20Motor%20Build/machining3.jpg

[Jon K]

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

http://blowneuroz.com/mygallery/E34%20525i%20Motor%20Build/machining4.jpg

Running the tap through it

http://blowneuroz.com/mygallery/E34%20525i%20Motor%20Build/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%20525i%20Motor%20Build/machining6.jpg

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

http://blowneuroz.com/mygallery/E34%20525i%20Motor%20Build/machining7.jpg

[Jon K]

http://blowneuroz.com/mygallery/E34%20525i%20Motor%20Build/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!

[Macv]

Wow, manifold is turning out great. Amazing skill

[Sam-Son]

Thats Crazy I can't wait to see how this ends up

[632 Regal]

way overkill on the fat studs man, distortion ediquite once torqued but might hold it all down nice. You talking alighn bore the heads with the torque plate torqued to spec with the fat studs? Might make for an interesting cross hatch pattern when opened and untorqued.

[Nick.Hay]

You are a crazy, crazy bastard Jon!! :D

Its going to be a work of art... That manifold already is!!

[Ferret]

Question!

Are you going to be using the B25 head?

If you are, how the heck are you going to stop the head from cracking? The general conspiracy theory shows that they're prone to cracking from studs to bore/compression chamber - there's not really enough metal there. Surely boring it out to take bigger studs is going to cause a problem?

You could torque it down *really* carefully I suppose to get an absoloute even torque down across the block, but following a 3 step procedure is likely to cause the dreaded crack?

You could use a B20 head to get extra compression I suppose, but you'd need a slight spacer in there - last time I did it the engine self destructed after the big ends started to wear - turning the zero piston-head clearance into an interference!

[Jon K]

Heads don't crack because they're torqued down, they crack when over heated. There's absolutely no reason clamping the head down will crack it. There are other guys who have done this as well. I am running a B25 head - not considering a B20 head because 1) they're not available easily 2) i've never dealt with one and 3) I can't afford to raise compression.

[Dave M]

Jon, we've got to find you another hobby, or a girlfriend (don't tell us you have one ;) ).

Very, very, interesting. I won't toss my old M50 just yet. If you pull it off, I may have to try something next winter.

Good Luck,
Dave M

[Jon K]

Jon, we've got to find you another hobby, or a girlfriend (don't tell us you have one ;) ).

Very, very, interesting. I won't toss my old M50 just yet. If you pull it off, I may have to try something next winter.

Good Luck,
Dave M

Thanks dave :) I do have a girlfriend of almost 3 years - fortunately she puts up with my crazy ways

[Morgenster]

Jon, I admire the work and care you put into it.
I also, however, wonder if you're ever going to finish it:D . Seems to me you'll just keep finding faults or ways to get more power and just start over again.
Will you ever drive that engine?
The reason I'm asking is because I'm hooked on this and want to at least see it happen or experience it vicariously.

[nizmainiac]

should be pretty sweet when its all done jon, whats the manifold in the cardboard box for jon?

[Jon K]

should be pretty sweet when its all done jon, whats the manifold in the cardboard box for jon?

That is an old manifold from my former build. I bead blasted it to show the smart asses over on bf.c that i did not crack.

[Ross]

It must be nice to have access to all those machines.
Would O-ringing the block be helpful for your application?

[Jon K]

It must be nice to have access to all those machines.
Would O-ringing the block be helpful for your application?

It would be, but o-ringing can be harmful to the bottom end. If the engine does decide to knock, I want a gasket to pop out. O-ringing rarely lets go, and the usual result is bent rods and broken pistons.

[ahlem]

Did you do any internal grinding to your manifold as you welded it up?

[Booster]

Herewith we witnesseth Jons' "While your at it Syndrome":D ....I've suffered for years,its not even curable when money runs out......it simply MUST die with you.;)
I wouldn't like it any other way personally....what say ye JonK ??
Lol,Vinny

[Jon K]

Did you do any internal grinding to your manifold as you welded it up?

Not very much at all - my fit up is pretty perfect.

[Brandon J]

So, no 2.5? Going to the 3.0L is always a good idea. I always say, if starting from scratch, do it right. The madness. The cost. The time. The power will be good in all rpms. Keep us updated so that some of us can wither follow in the BMW insanity or learn from your ways. Hmm, BMW madness relating to power......I think a few of us suffer from this illness.

[Barney Paull-Edwards]

Your insanity is amazin! Keep it up,I can`t help wondering if the rest of the car will hold up in the face of what must be insane HP????!! Those studs are actually larger than the GP BMW engine, and that had 1300hp, occasionally.

[Jon K]

Thanks for the praise guys - it is quite involved but its most fun putting it together - its less fun when its done believe it or not! So, as I work on this engine...I keep my eyes on the future :)

[AngryPopTart]

For some reason, this reminds me of sex. Someone told my brother, when he got married, that there are three kinds of sex. First, people have anywhere sex, which means basically having sex anywhere in the house. Then they have bedroom sex, which is due to there being children in the house. Finally, they have hallway sex, which consists of them passing eachother in the hallway and saying, "Screw you!"

[Jon K]

I am sort of confused by that analogy

[Barney Paull-Edwards]

Think what he means is that you enjoy building them more than anything else!

[CharlesAFerg]

So you have engines... Where are the cars?

[Jon K]

So you have engines... Where are the cars?

The car is... waiting for the engine