Marinising a 304

[VK SL 3800]

Im putting a 304 roller cam engine into a ski boat. Has a 308 but the old engine is a bit tired.

Theres not a lot of information on how to marinise a 304 exactly, I've got it pretty well sorted i think but after some opinions of people who have done it and what mistakes can be made etc.
Basically i am copying the 308s cooling system, blanking off the thermostat and going to tap some 1/2 fittings into the rear cylinder head disch
arge in the intake manifold. I believe this is d
one because of the angle the engine sits so you dont get a massive airlock at the rear.
Im going to fit a thermostatic control as well.

The old sump also has a basic oil cooler, just
a 3/4 pipe inside the sump submerged in oil. Its plumbed on the suction side of the water pump and the raw water gets drawn through before getting to the pump. It wasnt connected to the 308 but i was thinking i might as well hook it up.
Is it worthwhile having?

I bought a VS SIII ute, its a 2000 model. Its says its a 195i but i dont know how to confirm that.

 

[EYY]

304/308 are the same block, assuming both are turbo pattern. So you shouldn’t have any issues there.

195i has VN prefix block, standard roller cam engines have VM prefix. Slight difference in cam profile and different tune.

 

[VK SL 3800]

Ill have a look at the prefix when i pull it out, the old 308 is trimatic pattern so ill have to redrill the bellhousing or buy a new one.

 

[VK SL 3800]

Pulled the engine out, looks like VM prefix will have to clean to read it properly.

Heres the rear coolant port in the manifold i have to tap out, its flat so that should make it easier to drill. 1/2 fitting will be a tight squeeze, might be better off getting a 1/2 outlet tig welded in not sure.

The manifold gaskets have been leaking, the utes been sitting a while and it appears the coolant has just slowly leaked in.

 

[EYY]

I’d try to investigate the cooling system a little more. Being so close to the corner of the manifold you’re probably better off having a fitting welded in as you suggested, but that means you’d need to pay to have it resurfaced too since it’ll warp the faces.

What are you doing for engine management? Is efi the reason you’re doing the conversion, or is the 308 just tired?

Best way is to redrill the block to trimatic pattern but that also involves filling two holes and redrilling. An adaptor plate is another option if you have the ability to space things out. Adaptor plates are supposedly nowhere near as bad as they’re made out to be, but I don’t have any first hand experience with them so can’t say for sure.

Also, check the lifter retainer plate for cracks or damage - that’s the major cause of engine failure for the roller cammed engines. And if you can be bothered at this stage, the code on the memcal will give you an idea of whether the engine ‘should’ have been the 195i and not the 179 (probably been replaced at some stage if it’s a factory 195i).

 

[VK SL 3800]

308 had the oil pickup come loose, oil pressure gauge wasnt working and the old owner have been running it on low oil pressure so all the bearings are buggered, pistons are ok still. It actually ran pretty well, no flat spots etc but id like something a bit nicer and a mate had the ute and sold it to me for a good price.

Ive decided to buy a whole new marinising kit for the 304, the dog clutch was worn out, bellhousing mounts are different, manifolds dont swap. Itll be better to have it all new and reliable then trying to patch up worn out crap.

Ive sent The1 a message about getting the Vats deleted but he must be away, hoping you can also turn off the 02 sensor and maybe lower the desired idle speed a bit so the dog clutch is a bit less crunchy to engage if you have to take it out and put in when running.

I will post some pics when i get more done for future reference, i cant find much information out there on marinising 304s so it might be handy for others.

 

[EYY]

Best off selling the loom/pcm from that one and going with an 808 or 424 map based system in that case.

Probably don’t need sequential injection and a maf in a boat lol. I know the older models like vn etc didn’t have o2 sensors enabled in the tune so that shouldn’t be an issue.

Not sure what you’d do on the VSS side of things in the tune, but I’d like to know. @delcowizzid you there? Lol

 

[VK SL 3800]

Im gonna see how the MAF system goes seeing as i have it.
The VSS shouldnt be a problem, im just leaving the sensor plugged in and it should be fine. In theory its the same as reving it on the spot but with some load, see what it does.
I had the VATS turned off, the O2 sensor code deactivated and the desired idle speed reduced to about 650rpm to aid with dog clutch engagement.

Ive had the intake manifold done, just waiting on the exhaust manifolds and a new dog clutch to arrive then i can put it in and test!

 

[RiCeY]

First Commodore that's meant to handle like a boat.

 

[VK SL 3800]

Nearly got this ready to go in, been waiting on a few bits and pieces and they showed up today.
Dog clutch involved a lot of drilling into the crank which seems sketchy, worked out fine in the end.

Have to work out the thermal control setup with a bit of trial and error i think. I can use the front heater hose outlet as a discharge if the 2 1/2'' outlets in the manifold dont flow enough.

Currently not sure how the water pump is going to fit, have to wait and see how much room there is with it in.

Been Busy with the hull in the meantime:

Found a rotten section of stringer, not sure why it rotted up the front but the rest was ok so we just cut down to good timber and put in a new section and bolted a reinforcing beam on the back well past both ends of the repair.
My Fiber glassing wasnt the best but itll seal it all together nice and strong.