Hi, yesterday my engine decided to destroy itself..
Under normal driving conditions i lost power, short after low engine oil warning (i know 100% it was filled up)
Everything leads to low compression, probably blew a piston ring. I would like to know what engine options i can consider..
i'm planning to rebuild the engine.
If you guys can help me out, which directions i could go that would be great!

 

if the block is still in good condition.
Just swap it with cp pistons and rods from the a90 supra catalogue or b48 ( which is not listed for some reason).
Seem to hold about 380-390 to the wheel without any issue.

 

Supertech is 4032 material
CP is 2618 material

for daily 4032 is ideal, no noise and less wear.
i'm planning to keep power output around 350-380hp. I ran 300hp with no problems on stock pistons until now. (135 000) km.

Anyone experience with running different material types of pistons on the B48?

 

I looked at the same goal before and decided to go with Mahle Superpak pistons. Not trying to slam on supertech, but after some extensive research, the only upside to supertech pistons is the 4032 forged alloy. But feature wise and compression options into consideration, I think Mahle's superpak, CP, Ross, or Wiseco's B58 pistons will all work. To go beyond 300+ HP, you best try to lower that final static compression ratio. I'm targeting 350HP and compression of 10.5 is what I'm going for, I even think that's a bit on the high end. Therefore, you're next best bet will be CP or Ross. Those can become quite pricy once you start adding their bells and whistles options. It'll all come down to your budget.

While I suspect our F56's will become much less streetable beyond 350HP, I think a budget build is the way to go (I'm not taking it to the tracks).

CP, Eagle, and MaxSpeedingrods are my choices for connecting rods. Then you'll also look into King's bearings and ARP bolting components all over.

 

I've mailed Lohen in the UK and GPGARAGE in Italy.
Both said i should go with Supertech. Just because i think the 2618 needs more piston to wall clearance. If my bore is undamaged, the 4032 is a more OEM fit. At the moment i don't know that yet..
I'm not looking for crazy power output, just stronger than original. My car is with guys from Pure Turbos. So every choice is possible. Just depends if there is more damage than expected or not..

 

The B48E using the M pistons 9,5 that's a good choice if you know where to buy

 

I've checked for original parts on the BMW site
and they offer a thicker headgasket. .3mm thicker.
standard gasket is 0.7mm. So that would be a 1mm headgasket. Is it a good idea? Then i would have a bit lower compression.

Going for supertech pistons and rods.

 

Yes you will lower compression ratio by 0.24 with a 0.3mm thicker head gasket. I've done the math in this post: https://www.northamericanmotoring.co...ion-ratio.html.

with a 1mm head gasket, you will end up with 10.76:1 compression ratio.

 

Just got some pictures from my engine builder





See the little cracks between valve and spark plug

Builder said it's pretty normal.

Need some opinions

 

Are those actually cracks in the head?! Not sure I would call that normal...

 

Definitely should replace the cylinder head. Get the forged pistons like you're doing with Supertech. Or OEM rods are supposed to be quite good, it's drop forged, so you can re-use if you want to, those should be good for at least 500HP. Do yourself a favor and upgrade to ARP connecting rod bolts and cylinder head bolts especially if you are going with the 1.0mm head gasket. More deck height you acquire from head gasket, more assurance in clamp force you'll need from that head bolt, really need to consider an ARP set for performance build. Just my opinion, what do I know from years of tinkering with engines, right?

 

I agree with your opinion. Where can i find the ARP set?
Tomorrow i'm going to see my engine, i will discuss the options if the head is fixable or not.

 

I bought mine through Amazon.

For head studs, I went with 201-4601 and for main stud, I went 201-5001. Rod bolts I didn't need to buy because there's an ARP set coming with the forged connecting rods I bought.

Ask if your build shop has these: It'll help putting the correct torque onto all your bolts.

 

Spoke to Pure Turbo, the guy that builds my engine works there. They have multiple B58 engine's. And they are willing to give me the pistons and rods for half the price of new. They have exactly the same specs of the B48. Tomorrow my engine will be measured for clearance's just like the b58 piston. If it's within specs. I'm putting B58 pistons and rods in it

 

Very cool- good to know that there's an OEM+ option!

Do you mind saying what tune and mods you've been running? And / or a guess as to how much boost?

Thanks!

 

Unfortunatly it doesn't fit. Looks like the B58 has a bigger bore?? Pistons are bigger.
I'm running a custom map with around 20-21psi

 

This is a weird discovery. I ordered my B58 PowerPak pistons from Mahle and it fits my B46 motor with no issues, actually perfect clearance. (Mine's been honed 1mm larger)

 

What i've heard is that when you order aftermarket
pistons for the B58, you need to get the clearance right of the cylinder. You need to add nikosil to the walls. Guys at pure turbo did this and still have issues with high crankcase pressure. So i assume the aftermarket pistons for the b58 are too small and right for the b48. (82mm)