BP head to B8 block

[Shag]

Me and a friend were thinking it could be done..then I was talking about it on mazdas247 and they said that people over here have done it. So im just wondering; What all does it take to do it, what are the down sides, what are the up sides.

[therieldeal]

you need all the timing belt/water pump stuff, an some other odds and ends

downsides... low compression like a GTX. the sohc pistons are dished.

[jacobrussell]

kinda on subject

im doing this ... well kinda im putting in a BP crank and a bp head on a b8 block, rods, pistons. i was wondering how much boost the B8 pistons would handle with the pressed in retainers VS the snap ring ones the BP uses...

[Shag]

So it can be done..its would be like a frankin BP. Thats a good question..im not sure. I know the most BPs can handel 8-10lbs of boost on stock internals no prob..what is the difference in the b8 and bp pistons?

[5l1mm]

the lower compression will just give you more room to stuff boost into..

[nerd racing]

I believe the B8 pistons are made of a weaker material as well

[therieldeal]

i doubt it, they are probably the same

[jumpncrash]

Yeah my intuition says they're probably the same, maybe even the same as GTX pistons, minus the pressed vs spring clip, but that wouldn't really mean they'd have to do a big design change would it? I have been wondering for a while if there's any way to substantiate it though.

But on topic, sure you can do it, its bolt on.

downsides are the low comp, upsides would be the lighter crank and maybe opportunity to put more PSI in teh cylinders, but ultimately you won't make more power. I'm gonna be boositng on SOHC pistons at first, if I ever get there

Nick

[trailrider098]

all the con. rods are the same in the SOHC or DOHC B6/BP's cause the hieght of the blocks(crank to head) and stroke are all the same. The only different rods are the B6T rods, which are a little stronger, and the GTR's rods which are much stronger. all interchange.

[wheresthericego]

You will need the intake and exhaust manifold. I have a intake mani you can get cheap and you could pick it up to save on shipping...

[redheddude222]

I ran 16 psi on SOHC rods for 2 years with no problems. The B8 rods are different from the BP rods,at least that's what Corksport and my machine shop told me. I tried to have B8 pistons put on BP rods and the machin shop said it didn't work.

[almighty4wd]

B8/BP rods are the same. I had BP and B8 rods side by side. B8 pistons are pressed on, while BP pistons use C- clips. Thats the difference. B8 pistons don't have the groove for the C-clip.

[redheddude222]

I wonder why the machine shop said they were different? Oh well, I'm not using them anymore anyway.

[jacobrussell]

well thats what i figured i was really just worried about the fact they are pressed in with heat and was thinking well raise the cylinder temp with a turbo maybe they might fall out??

i wont turbo on SOHC crank i looked at it its wimpy

[Shades]

I believe the B8 pistons are made of a weaker material as well

Negative, they're all made of the same composite of metal. It's just that the BP uses a full-floating pin versus a pressed-in pin. With a full-floating pin you get more surface areas (between rod and pin, and pin and piston) for lubrication cause the pin can rotate, where as the pressed-in pin you only get lubrication between the pin and the piston. Less change of siezing and screwing things up with a full-floating pin, most aftermarket racing pistons come with a full-floating pin.

The rods are different in that the small end (pin/piston end) is smaller in inside diameter for fitment of the pressed-in pin... either wise the size and length are the same. AND NO, they won't fall out if you put a turbo on it... if you're raising the cylinder temperature high enough for the pin to fallout you're gonna have bigger problems before that even happens. PLUS you're running too lean and you're FIRED from tuning!

You could probably machine the small ends to fit the floating pin but why bother, you're also probably need an oil hole in the top of the rod to lubricate the pin and you'll be taking away material from the small end possibly making it weaker, depending on how much you have to machine out.

Now you've been edumacated...