TheFlyfish

I have a 4.5 16V euro engine I'm planning to convert into marine use an drop in my boat, instead of the 4.3 L V6 GM iron engine. I have already figured out most of the issues I will encounter; building a set of watercooled exhaust manifolds, installing a raw water pump and heat exchanger, bellhousing adaptor etc. But there is one thing I would like to hear some thoughts about. The oil sump on the engine is in the front, because of the placement of the cross member in the car. For the marine use, this is a bit unfortunate, because of two things.

1. It will collide with the original structure in the boat, for the original engine. It is fiberglass and wood and can be removed/changed, but I would prefer not.

2. In the boat, the engine will always have the front pointing upwards, which means that a certain amount of oil will accumulate in the back of the oil pan. I'm not sure this is good in the long run. Off course, the car can go uphill, and this will be the same, but only for a limited time.

So I'm looking a bit into building a new oil sump, with the reservoir to the rear. The starter is off course a bit in the way, but I think it will be ok.

Thoughts ?

The Forgotten On

Both the water pump and oil pump are part of the timing belt tensioning system and required to be in place the keep the engine running.

Porsche did build a few 928 S4 engines to be used in boats though.

DR

Check out this thread, some of the info there may help you.

https://rennlist.com/forums/928-foru...highlight=boat

Happy Holidays,

Dave

dr bob

Put a starter on the drive aft of the coupling. It's not at all uncommon in marine applications. No "flex plate/flywheel, as the shaft coupling bolts directly to the end of the crankshaft. That will certainly let you build a sump that's deep at the rear. Remember that the pickup tube and supports will need to be adjusted to allow oil from the rear, but that's not at all difficult. I've never looked at the original sump and the mate-up with the girdle to see if it can just be turned around 180º once the starter motor is out of the way.

GlenL

Th pan won't fit reversed.Another option would be to use a dry-sump system. For that, people have welded on a dropped box at the rear with a suction line on it.

You're right that the front sump system won't work for you. The crank comes very close to the stock pan and once oil builds up back there it's being fed right into the rotating assembly.

V2Rocket

can you just mount the engine backwards, with a V-drive?

TheFlyfish

Good point, actually, but unfortunately not possible. The engine will be coupled to a Volvo Penta SX stern drive, in the back of the boat, so it must be orientated as in the car.

TheFlyfish

The boat has a Volvo Penta SX sterndrive and when the engine is mated to this, I'm not sure there is room for the starter in any other location, than where it is originally. Having it installed, pointing the opposite way, is going to be a tight fit, if possible (It will also demand a counter rotation starter) But I will investigate this, since it will be nice to have the starter placed a bit higher, so it is easier to access.

waynestrutt

"Thoughts ?"

A paddle!!! springs to mind.

James Bailey

Interesting you wish to have less horsepower and more weight ??? Few would see that as having much benefit.

TheFlyfish

Well, the 4.3 V6 I have in the boat now, is a 175 hp version (two barrel carb), that will do approx 4600 rpm with the hammer down, the Euro 4.5 engine has 240 hp (if they are all at home) and should easily do 1000 rpms more. I've had both engines hanging in a crane scale, I' don't recall the figures now, but have them documented, the 928 engine was heavier yes, but only marginally. The V6 can be beefed ud to 205 hp with a four barrel carb. If you need more than that, special equipment is needed, I guess. I don't believe that I will see less power and a boat that is lower on the water.
If I just wanted more power, I could drop in a GM 350 engine with a four barrel carb, everything single marine part for that engine is available. But I would rather have a nice 928 engine in the boat. The boat is for fun, not really common sense.

James Bailey

Is it being overly optimistic to think that a 36 year old 928 engine is going to be "NICE" ?? Boats are lots of fun when they run. Less so when they do not But sitting at the dock with the engine cover open it will be a conversation piece !!! But go for it since it will sound much better

TheFlyfish

I know that many people would say that this is a crazy idea..... I don't really see the problem in a close to 40 year old 928 engine. I believe it's a well engineered piece of mechanic. Not too complicated but still not too old. The small block Chevy was introduced in 1955, talk about stone age engineering :-) As long as there is good oil pressure and compression, new head gaskets, seals everywhere, what's the big deal? I know that a 36 year old 928 car can be troublesome, but I will only be using the engine along with the K-jet. A new fuel pump and an MSD-6 ignition will keep that thing running like a champ. Electrical wiring in the boat is simple. I have the engine standing in my workshop, with unnecessary stuff for the marine application removed. With the correct maintenance, not much on this engine can go wrong, that can't go wrong on any other engine.

James Bailey

I would suggest that you pull the heads off and inspect the 928 engine BEFORE getting much further into this project. Corrosion of the heads and cylinder tops is very common as are scratches in the bores. When I needed a short block for a 79 I think Greg Brown took apart three engines before we had a usable block. Then sit down and list the costs of all the needed parts and machine work to refresh your 928 engine. I realize this project is probably more about the journey the destination.

TheFlyfish

That is also more or less what I intend to do. I plan to start the engine up, before I take it apart, just to hear if there is something obvious wrong; rod knock, valve lifter ticking etc. I already have another engine, from which I have removed the heads. They are in good shape, but could need some cleaning, maybe valve grind and stem seals. The block is in good shape also, but a piece close to the T belt tensioner is broken off, so I would rather use the other engine, that is still assembled, since it is in one piece. But we will see about that.