other than cooling and cam what else changes? And what r u putting it in?

 

Damn sure no need to change the cam.

 

i think they have a different cam, injectors and cooling for sure water to air ic and such... thats the main thing is the cooling and why they make so much more power in marine versions is they can keep the air and motor cool

 

can the water ports be opened up any on these motors? also has anyone figured out what the marine cam does different?

 

i think its ground so that it can maintan max hp at high RPM all day long since in a boat they usually hold a constant rpm for long times unlike our trucks that varie the rpm all the time

 

Marine cam.....7.3.......

:shrug:


Hanging a 7.3 off of an outboard Foot doesn't mean too much to me.

 

I can't find anything on a marine 7.3 powerstroke.... do they even make one?

 

Pretty sure they probably don't label it a powerstroke in marine applications...

 

yea im pretty sure they do i googled it and found some stuff on them

 

Mercruiser. 7.3 on top of an Outboard Foot.

Engine looks to be the exact same. Check the performance specs.

 

That would be a badass boat! I know you are thinking about doing it Danny! lol it would be pretty funny to see a boating pouring black smoke across the water!

 

So pretty well all that would have to change is the cooling system? FWIW, iirc the Mercruiser 7.3 does use a different cam as described before. But I don't think it's NECESSARY to make the truck motor work. Just curious what'd take to make the truck motor work.

 

You're just gonna use a DI cam anyways!

Danny look at these

http://www.sea-pro.com/mercurymarine/mercruiser/sterndrives/diesel/D7point3L-D-Tronic-LD.htm
http://mercruiserparts.stemtostern.com/MercBlockDisplay.aspx?DocNumber=803737

I spoke with a mercruiser technician back when I first got my truck asking him how the engines do in a boat. His answer was simple: Not Good. The engines suffer from valvetrain failure because they were not designed to sustain high rpm at full load for hours on end. They were having problems with bent pushrods, bound springs, dropped valves, bending rocker arms. It wasn't a good list of things to break. The problem lies in that the engine just isn't designed to sustain 3600 rpm for hours on end.

Yes you guys are getting HUGE hp out of your race trucks, and you are exceeding 3600 rpm by quite a bit, but it is only for a very short amount of time. That high rpm pounding had a bad effect on the longevity of the engines. The application was so rare that i've never even seen one. it was only used for about 10 years, and for boats in that size range of a single bigblock outdrive, most people probably wouldn't bite for the extra cost of the oil burner. Remember, 10 years ago gas was dirt cheap, especially when you get a tax credit for the road tax charged on marine gas at the end of the year.

oh BTW, i saw the article about the D-max and its fighting weight is 2600lbs. What are you going to try and get the fordota down to?

You think Danny is gonna throw in a stock motor and call it good? I think not!

 

well if you just want it to run like a truck motor i guess you could really only have to figure out the cooling

 

Water:Air intercooler and a Water:Water heat exchanger for the coolant.

Done.


But you'd better find a tough ass Outdrive because they are not usually rated for anywhere near the torque input, nor will they have the right output shaft speed with a 3krpm engine spinning them.

 

http://cgi.ebay.com/ebaymotors/8061...Cruiser-diesel-7-3-270-marine-heat-exchange_W0QQitemZ280186996314QQcmdZViewItem

 

Danny look at these

http://www.sea-pro.com/mercurymarine/mercruiser/sterndrives/diesel/D7point3L-D-Tronic-LD.htm
http://mercruiserparts.stemtostern.com/MercBlockDisplay.aspx?DocNumber=803737

I spoke with a mercruiser technician back when I first got my truck asking him how the engines do in a boat. His answer was simple: Not Good. The engines suffer from valvetrain failure because they were not designed to sustain high rpm at full load for hours on end. They were having problems with bent pushrods, bound springs, dropped valves, bending rocker arms. It wasn't a good list of things to break. The problem lies in that the engine just isn't designed to sustain 3600 rpm for hours on end.

Yes you guys are getting HUGE hp out of your race trucks, and you are exceeding 3600 rpm by quite a bit, but it is only for a very short amount of time. That high rpm pounding had a bad effect on the longevity of the engines. The application was so rare that i've never even seen one. it was only used for about 10 years, and for boats in that size range of a single bigblock outdrive, most people probably wouldn't bite for the extra cost of the oil burner. Remember, 10 years ago gas was dirt cheap, especially when you get a tax credit for the road tax charged on marine gas at the end of the year.

oh BTW, i saw the article about the D-max and its fighting weight is 2600lbs. What are you going to try and get the fordota down to?

 

I'll search .....I know I saw a marine version somewhere..

 

Marine Camshaft

http://mercruiserparts.stemtostern.com/MercBlockDisplay.aspx?DocNumber=803737

Sure ain't worth what they want for it!!!

 

The reason they make the marine cam is I bet the marin engine rotates in the opposite direction as a auto engine. I know this is true for most boats in the gas world. When i swaped out the volvo straight 6 for the 351w I didnt have to change the cam or the starter since the volvo motor was just a converted car engine and the outdrive was already a LH turn drive. But for some reason most drives are RH except when you run more than one then you have a RH and a LH.

 

It wouldn't cost a lot to buy some of those parts and compare them. I think I've also seen somewhere that the Compression Ratio was lower.

 

It wouldn't cost a lot to buy some of those parts and compare them.

I thought you were going to say Banks has a kit for it...

 

The main difference is the clearances. The marine motors run cooler due to the fresh water intake and the pistons run hotter, this is the reason for the extra clearances. You can get away with it but you cant beat on it. The other thing is that you will need to add an oil cooler, a different carb with transfer tubes and a different distributer. The carb is different in that it needs an overflow transfer so it doesn't have a chance of fuel over flow in the engine compartment and the reason you cant have the HEI distributer is it will ignite gas fumes in the engine compartment. And the last is an electric fuel pump. I just put a ZZ502 GM crate motor in a buddys boat this summer and a 500HP 502 mercruiser in mine.

 

You make some good points here but we are talking about a diesel engine. Carburetors, distributors, and gas fumes do not apply.

 

opcorn: opcorn: opcorn:

 

I don't think the rpm was to blame for the valvetrain issues at all. The actual valvetrain works fine at those engine rpms. But no valvetrain works worth a damn if it's got no lube oil pressure.

Hearing that it had valvetrain issues clenches the fact that they did not address the oiling one bit.

 

Do they coat the water passages or will the cast iron block hold up to the freash/sea water.

 

Do they coat the water passages or will the cast iron block hold up to the fresh/sea water.

It's called "Fresh Water" cooling as oppossed to "Raw Water" cooling.

In "Fresh Water" cooling the internal block and head cooling is a closed system with a heat exchanger and the "raw" water only runs through the exhaust manifold risers.

In "Raw Water" cooling the "raw" water is pumped through both the block, head and the manifold risers.

This is why you never want to buy a "Raw Water" cooled boat that has spent anytime in salt or brackish water


And yes I know what I'm talking about

 

I would run a Liquid:Liquid heat exchanger and never run the fresh/salt water through the engine. That way you also have antifreeze in the cooling system of the engine so no worries about winter time split blocks...

 

there was a small side note in one of the last few months diesel mags with that very kit...

i will try and find it.

 

Cool, thanx.