Good news for project Chicago! (Patreon)
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Got some updates for you.
I went on Sunday to see another used Alpina H1 engine (an hour and a half away from me) with a verified 160k km (90k miles).
You'll be shocked to hear this, but that one is bad as well. In fact, it's the worst one I've come across yet (pics above). 7 out of 8 cylinders are scored! I repeat 7!
Felt kinda sorry for the guy as he bought it 2 years ago from a seller that claimed the engine is perfect and he never checked it.
So with that, I'm giving up trying to find a good used engine as it doesn't exist.
I know a lot of you told me to buy a brand new block and pistons as that is a sure thing. I agree, if this was E39 M5 or E60 M5, or any other car in the fleet, I'd definitely do that.
But it's not, it's Alpina and given that I personally witnessed 3 Alpina H1 engines with scored cylinders, heard of so many others including a subscriber that spent 25k getting his rebuilt by Alpina, another nice subscriber from California is currently in the same boat, then a shop owner from Bahrain that wrote me had two Alpinas in his shop, I saw several cases in B5/B7 group were the engines failed at around 100k km mark and so on.
All have one thing in common, scored cylinders. This is why in the first place I opted to sleeve the original block, thinking it'll be stronger and last longer, and it probably would've if the job was done properly.
Paying 7.250 euros for parts that are seemingly destined to fail sooner or later, I just can't and don't want to do that. You know I don't mind spending when needed to get it done right, however I simply don't see the point here and giving Alpina that much for something that wasn't designed very well in the first place feels wrong.
If you remember, S85 V10 engine in the E60 M5 swallowed a big chunk of steel from a broken Vanos pump bearing race, got smashed all over the engine and that thing is perfect. Mint crankshaft, mint cylinders, mint top end and here you have Alpina H1 engines that are self-destructing.
Where does that leave us then? Well, the mechanic from Bahrain told me how he fixed two dead Alpinas that he had. He simply got a normal N62B44 block, used a thicker 1,05 mm head gasket to lower the compression (stock is 0,75 mm) and bolted all other Alpina parts to it. They are making good power (they never dynoed them) and running now for 3 years and around 30k km, supposedly the owners are driving them hard and they are still running fine. Later I learned that a couple of other guys have done the same thing.
My initial reaction was no way, that engine can't last long, the compression ratio is totally different: Alpina H1 is 9:1 and N62B44 10.5:1. Nevertheless, it gave me an idea to do more research.
As if the timing couldn't be any better, a well-known BMW engine builder from the US messaged me, Troy Jeup. If you haven't heard of him, he's famous for building S85 V10 E60 M5 stroker engines, as well as many other BMW engines from the early 2000s and up. He's been doing that for 10 years now so the man knows his stuff. He said a customer showed him my video, and that he could help, asked what's my current situation and what am I planning next.
He also told me he never sleeves blocks as it creates more problems than it solves (not the first experienced builder to tell me that now). Anyway, I told him I'm dabbling with the idea of using N62B44 block and he chimed in with some great advice.
Since the compression ratio difference is too big and too high on N62B44, a thicker head gasket won't be enough to lower it down to 9:1 as Alpina did and we would lose power if we do just that. Additionally, a thicker head gasket makes it weaker and more prone to failure so this wouldn't be a proper way to do it and according to him, it'll work but not last long-term.
The proper way to bring the compression down is to machine the top of the pistons and remove enough material to get it down to 9:1 ratio. I then talked to Robert (machinist from the last episode) and he confirmed everything that Troy told me. A thicker head gasket is not a smart idea and machining the piston is the best way to go about it. That's something he's done many times and he could do it for me with no problem.
And that's how we are going to put the Alpina back on the road!
N62B44 engines are plentiful and cheap and I immediately started looking for one. Found one listed for 1.900 euros 45 min away from me. Went to see it and the guy who works there recognized me. Turns out he's a fan of the channels, watches all of the videos and was excited if he could help out.
I carefully looked with a camera into all cylinders and it's very clean, no scoring, scratches or anything like that. Seems like a nice, good used engine. He talked to the owner and ended up selling me the engine for 1k and I'll give them a shout-out in the video. Very good deal and our friend Marian from Bulgaria made it happen, incredibly nice guy!
As you can see from the pictures, I hauled it back to the dojo with project Cologne, the mighty Touring!
Here's the plan of attack: strip this engine down to the bare block, then take the block and pistons to Robert. He'll measure all of the cylinders to make sure the block is still good and within spec. He'll then machine the top of the pistons (I bought him extra pistons so he can practice first) and he already calculated that we need to lose 7 ccm in order to lower the compression down to 9:1, which is nearly 1 mm that he needs to remove from the pistons.
Then I can reinstall the pistons and the crankshaft with new bearings, bolt back the refurbished heads with a stock gasket, reuse newly bought parts and the rest of Alpina parts. Essentially, DIY-ing our own Alpina engine!
N62B44 bottom end is strong and there are many supercharger kits for them that up the power by 100-150hp and that's with their stock compression ratio which means a stressed engine. If all goes well, we'll test drive it and then head to Munich where my friend Oli from OEmotors can put it on the dyno, make sure it's still making the same power and if it needs to be tuned.
Now, I know, it won't be the original Alpina block, but it's either we turn the car into a soda can or we have some fun with this project. I'm actually very excited about this!
I'll also experiment if it's possible to put Alpina crankshaft, pistons and connecting rods in N62B44 block. Alpina crank is forged, pistons are lower compression, and rods are actually the same as N62B48 and they are shorter than B44 ones.
Everyone keeps saying Alpina H1 and N62B44 are different, but no one knows what exactly, the bore size and stroke are exactly the same 92mm & 82.7 mm so we'll see what's possible.
I'll include more stuff and details in the video, but that's more or less it. Hopefully you like the idea.
I'm now working on my E39 M5 and I'm nearly done filming so I can start editing. That'll be the next video and then back with the Alpina. Robert said he doesn't mind us filming the machining of the pistons and measuring the block so it should be fun and interesting content to watch!
As ever, I am very grateful for your support and your patience throughout this! Thank you! I know project Chicago has been a roller coaster, but it's been an extraordinary learning experience for all of us and of great value for future projects.