Which years to buy for head/block cores?

doublespaces

Administrator
Oct 18, 2016
8,869
AZ
I've got a 2009 335, am considering picking up an engine for a potential build in the future. Is there a difference in the head/block throughout the years the N54 was produced? Best/cheapest way to go? I'm looking on car-part but I don't want to buy a working engine, just one that can be reconditioned with upgrades.
 

AD-ENG

Corporal
Oct 22, 2016
122
2/09+ is 6 Bolt crank. Other than that you'll want lower mileage cores to keep the parts list down on the head.

Everything in the shortblock gets replaced, so no issue there
 
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doublespaces

Administrator
Oct 18, 2016
8,869
AZ
2/09+ is 6 Bolt crank. Other than that you'll want lower mileage cores to keep the parts list down on the head.

Everything in the shortblock gets replaced, so no issue there
Is there any variance on the head? Or just minimizing miles?

My car is a 2009 but door jam date is 10/08. So I'm 8 bolt then?
 

AD-ENG

Corporal
Oct 22, 2016
122
I have seen a thread about a change in the water cooling jacket through the block and head but I don't remember where
I'm not sure, but even if that were true the head gasket is the same part # for are n54 years. Plus, you'll be buying a Longblock core so it will match regardless.
 

AD-ENG

Corporal
Oct 22, 2016
122
You can replace cranks?!

For some reason I thought block+bedplate would be really costly to match to a new crank

This is good info!
Why would you not be able to replace a crank? Line bore is the same and crank journals are the same. Buy the appropriate bearings, check clearance, and good to go.
 

V8bait

Sergeant
Nov 2, 2016
469
Texas
I believe in 09 they had minor changes to the block, dealing with the water jacket as stated earlier. They removed some material around the top of the cylinder liners iirc, there are pictures floating around of the differences. I wouldn't really worry about those differences though, they haven't proven to be an improvement or a detriment. The early year N54's have been generally regarded as slightly better built, but those claims are all unsubstantiated and if you're building they are unimportant anyway.
 
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Corporal
Platinum Vendor
Oct 25, 2016
149
Houston, Texas
For all intents and purposes, cranks and bearings should stay with the block.

Bearings have 25? Variations for the main bearings. 6 for the top/bottom rod bearings.

I've said this multiple times. These are not a standard easy-peasy engine to assemble and make right......and the bottom ends go stupid when you unbolt the bedplate.
 

veer90

Lieutenant
Nov 16, 2016
1,000
West Nyack, NY
I have this wild-ass guess that the pistons changed from forged to cast when the engine changed from an 8-bolt to a 6-bolt crank. however I don't have any concrete evidence to back that up. It's only a theory. My thoughts are since it's a parts revision, in addition to the endless debates whether the oem N54 pistons are cast or forged, with supporting evidence on both ends.

To answer OP's question, if I wanted to build some crazy high powered N54 I would probably pick up an '07 or '08. BMW overbuilt the internals intentionally because the N54 was their first turbo production engine in a long while, and they didn't want anything to break. The way I see it there's always the possibility they revised it with more cost-effective (read: weaker) parts down the line.
 

AD-ENG

Corporal
Oct 22, 2016
122
I have this wild-ass guess that the pistons changed from forged to cast when the engine changed from an 8-bolt to a 6-bolt crank. however I don't have any concrete evidence to back that up. It's only a theory. My thoughts are since it's a parts revision, in addition to the endless debates whether the oem N54 pistons are cast or forged, with supporting evidence on both ends.

To answer OP's question, if I wanted to build some crazy high powered N54 I would probably pick up an '07 or '08. BMW overbuilt the internals intentionally because the N54 was their first turbo production engine in a long while, and they didn't want anything to break. The way I see it there's always the possibility they revised it with more cost-effective (read: weaker) parts down the line.
All n54s I've opened have had cast pistons. Never seen an oem forged piston in a n54.
 

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Corporal
Platinum Vendor
Oct 25, 2016
149
Houston, Texas
I have this wild-ass guess that the pistons changed from forged to cast when the engine changed from an 8-bolt to a 6-bolt crank. however I don't have any concrete evidence to back that up. It's only a theory. My thoughts are since it's a parts revision, in addition to the endless debates whether the oem N54 pistons are cast or forged, with supporting evidence on both ends.

To answer OP's question, if I wanted to build some crazy high powered N54 I would probably pick up an '07 or '08. BMW overbuilt the internals intentionally because the N54 was their first turbo production engine in a long while, and they didn't want anything to break. The way I see it there's always the possibility they revised it with more cost-effective (read: weaker) parts down the line.


......and the forged piston rumors fly again.

They never had forged pistons. Ever.
 

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