SR20DE: Nice engine, but is it right for me?

No! It isn't!

The motor makes 145hp, and weighs less than 120kg. These are intoxicating figures when other engines are compared. It was also free, quite compact, and the turbo version makes 250hp reliably in standard form, which bodes well for this one's aquatic life. For all I know it could be a great marine engine, but the cost and effort required outweigh the potential benefits, and when I chanced upon a marine diesel for less than the cost of a heat exchanger and I realised it was a better option.

Reasons for Rejection:

Cost: A raw water pump, heat exchanger, exhaust mixer and other miscellaneous parts in serviceable condition would've cost at least $800, and may not have worked reliably with the SR. On top of that there was things I didn't immediately think of, like a waterproof box for the ECU ($30), seawater proof wiring and connections ($50), marine engine paint ($60), plus many other little things like that which add up.

Time: I spent several days welding a tank around the exhaust manifold (marine manifolds should be jacketed where possible). I also spent a couple of days making a mount and adjuster for the raw water pump. It would've been more time still wiring the thing, painting it, putting sealing silicone on every injector, plug, and join, as zinc plated connections just don't last in a saline environment. On top of that I'd have to make a water mixing standpipe, which may not have worked first time - it all seemed like a huge amount of work for a result that may not be all that great.

Engine Design: One problem I noticed was the small, shallow oil pan on the SR is mounted at the very front. It seemed likely that when the boat is trying to get on the plane and the bow is lifting, that the oil pickup would run dry, and thus oil pressure would be lost. The engine wouldn't last long if that happened every time.

Also things like the dsitributor being right at the back, and completely inaccessible should a problem arise at sea. Similar story with the air flow meter.

I couldn't help but wonder if having an engine so dependant on electronics was such a good idea. If something goes wrong with an older style petrol or diesel, its much easier to troubleshoot. Having EFI means that the fuel lines are under pressure also, so if the send line becomes damaged it will spray petrol everywhere at 60psi or so.

As such, the diesel was deemed the better option and the SR was keelhauled. I'm a bit miffed at having put so much work into the old configuration, but it was a learning experience and I'm super excited for the diesel!