An All-Aluminum 1.9L NA VW Diesel?

[nicholastanguma]

I have a friend whose company makes completely custom engines and parts, including engine blocks. One of their specialties is taking factory iron blocks, scanning them into CAD, and then CNCing all aluminum recreations, with whatever over-bores and stroke clearancing the client may want for his racing car/motorcycle/jeep/boat/whatever.

I was talking to this guy about my fascination with VW's legendary 1.9 diesels, especially the naturally aspirated variant. Diesels, of course, operate under tremendously high compression ratios, especially when turbocharged, which is what necessitates that diesel engines be manufactured of iron.

But a VW naturally aspirated 1.9 diesel is about as mild as diesels can get without being entirely useless for a road machine; seems to me this engine would be great candidate for rebirth as an ultra lightweight all-aluminum mill, destined to be stuffed into a Suzuki SJ. So, aside from astronomical cost, obviously, what might be a reason or reasons that such an engine simply wouldn't actually work in real life?

 

[Buliwyf]

I can't think of any that they aren't already tackling. Steel sleeves?

Actually compression ratios are reduced on diesel engines. I've seen as low as 15.2:1. NA is often 18 and up to 22. BMEP, or pressure, is what is more, on turbo engines.

A billet I6 head is $8000!

 

[cody c]

How many bolts on the main bearing caps on the 1.9? Reinforcing that area, or re-engineering it to use steel inserts and oversized bolts might be smart. Same for the cylinder head to the block. Something like a helicoil insert, which will give more material to grab onto for the studs/bolts.

Not sure why you would want to build a diesel to not use a turbo.

I believe the duramax diesels use an aluminum head, so I guess the temps are ok. The only other thing I can think of is nickel plating some surfaces, and improving exhaust flow/decreasing heat soak in those passages.

 

[javajoe79]

Lots of expense for a lightweight NA diesel turd. I would never want an NA diesel.

 

[crazysccrmd]

Actually compression ratios are reduced on diesel engines. I've seen as low as 15.2:1. NA is often 18 and up to 22. BMEP, or pressure, is what is more, on turbo engines.

What engines are you referring to? Most of my NA gas engines have been between 9.5:1 and 10.5:1 compression ratio. Turbo gas engines 8.5-9.7:1, the only DI turbo engine I owned was 11.7:1. The two turbo diesels I’ve owned were 16.5:1 and 18.5:1.

 

[Buliwyf]

The lowest one is a MTU large yacht engine. 20+ were little naturally aspirated Yanmar's, JD's etc.etc. 15-22 isn't abnormal at all. My twin sequential turbo Volvos are really low as well. But they have heated intake screens and block heaters. Sailboat engines can have really high ratios, but they only use 1 tank of fuel per year.

I can get these in 15.2, prime power, or 16.4, standby power:
https://www.boatsales.com.au/editorial/details/mtus-series-2000-diesels-8193/

I built a gas v8 that was all the way up around 14.2. But it had massive valve overlap, much of the compressed mixture went out to exhaust. I think 9 is the lowest of my gas engines, 12.5 is the highest.

NA diesels can have much higher comp ratios for cold weather start-ability and fuel efficiency. The more turbo you add, the more power, but you need to start lowering your comp ratio to keep your EGT's in check. Go too low, and you'll have trouble starting in cold weather.

Small turbo engines like the original B, or early Toyota diesels are my favorite designs. A good compromise, but dog slow. Too slow for the American market sadly.

I'd love a NA diesel in a jeep yj. Instant torque, simple reliability. Sure it'll be slow, but as long as it can hit freeway speeds on 35's, I'm fine with it.

 

[nicholastanguma]

I'd love a NA diesel in a jeep yj. Instant torque, simple reliability. Sure it'll be slow, but as long as it can hit freeway speeds on 35's, I'm fine with it.

This sentiment, exactly.

An NA diesel in a rig even smaller and lighter than a YJ, such as Suzuki LJ or SJ, makes even more sense. In fact, an ultra lightweight all aluminum VW 1.9 NA diesel would be my personal dream powerplant for a LJ or SJ.