kingrich

I am installing a new crate 1998 GM 5.7 L vortec truck engine in my 1997 wellcraft eclipse 20 ft. The old engine was marine 1997 GM 5.7 L(non-vortec-2 barrel-12 bolt manifold-hydraulic roller). The new one will have a 8 bolt edelbrock air gap with edelbrock marine 600 cfm, holley blue electric fuel pump and hydraulic roller marine cam. Will the ICM and distributor from old 2 barrel non vortec head engine provide the proper timing for the new setup. Also the timing cover on new vortec has the crank sensor hole in the bottom. Will I need to have the crank sensor with new carburated version vortec and also will I need the knock sensor and module? I have had a previous post and got lots of good information and am trying to get some last opinions before I drop engine in boat. So far the differences in using auto crate to replace marine engine applications aside from all of the external marine goodies seem to be limited to the cam and valvetrain. This has been a active topic as to the lift differences between stock and marine cam profiles. I still am unsure exactly how much of a valve lift difference this is between the two when it comes to bottom end torque characteristics. The marine cams have .480-.500 lift at intake/exhaust where the stock looks like about .420-.440 at the same. It seems like enough difference to change because on crane or comp cam sites the marine specs are rated closer to bracket racer type cams then to stock. Anymore help on all of the above is greatly appreciated and will post when all is done the results that I have learned on this site and several others I am frequenting to put these problems to rest.

Thanks Rick

tj309

Not sure about your tech questions but be sure you dont use the stock oil pan. Marine oil pans are designed to provide enough oil even under rough sea conditions whereas the stock one would run out of oil during rough sea operation.

ACrooks69

iTrader: (1)

I disagree with the cam not holding up, but if you want to up the power a little more ( I'm not sure what cam you have in there) but I have a Comp Cams XE264HR (212/218 @.050) sitting in a box. It is used, but in great condition as it is a hyd roller. I when I had the 383 built this is the cam I used. I decided I wanted a bigger cam so I upped it to the XE274HR (224/230). Anyway, the cam is just sitting in wrap and I have just never bothered to do anything with it. Since you aren't fuel injected this cam would work very well in your motor. If the cam that came in it is around the same specs (I think the lift is .503), it should be a pretty good cam. I had the same cam in a 350 prior to the 383 and was an awesome cam. Loved to run around 4900-5100rpm. Anyway if anybody is interested I figure 100 bucks is a fair price. This is for the roller cam blocks not a retro-fit block.

FlyFast

Rick,

A few years ago I went from my stock 96 350 2 barrel to a vortec motor. I kept the stock boat non roller cam. My boat never had a knock sensor or a crank sensor so your ignition system might be a little newer than mine is. My ignition system worked great with no modification.

I like the idea of a crate motor because you good quality for low cost. The machine shops in my area use green card labor and most of their work is not sutiable for a boat. I put a gm crate motor in my old chev truck a couple of years ago and it has been a great motor.

If My boat motor were to go I would check the cam and then use it in my boat in a heartbeat. I do run full closed cooling with antifreeze so gasket and freeze plug problems do not worry me.

Good Luck

FlyFast

Oh the oil pan thing,

My stock boat motor had a splash pan that transfered over the the vortec motor. It was a splash pan inside the oil pan that is similar to the off road splash pan. I would recommended you reuse your old one.

Good Luck

kingrich

I have posted the idea of using a new truck block in marine applications a few times in the past two weeks hoping to learn more about it. I have received mostly feedback along the lines of what I thought might be, that is that there is not much internal differences in the blocks. I also posted this thread in boated.com and now I get told that the crank and rods are forged, the pistons are silicone hi temp cast or forged and that the cylinders are bored slightly larger(using stock sized pistons) to accommodate the increased swell in cylinders due to increased oil heat in bottom end of high revving marine application. He goes on to say that building a engine that I have described will only last two seasons. I am getting confused. Is anyone actually using the same application that has worked over time. I am honestly not trying to cheap out but just like the idea of a new truck crate(up to date engineering and quality parts as opposed to early chevrolet blocks-powder sintered rods, cast nodular crank, hyperneutic pistons, 4 bolt main and hardened valve guides are part of the stock crate I purchased). How much different could an actual marine block be then that?

I will be changing oil pan and splash pan and already have marine cam(the hydraulic roller cam and lifters from old engine had low hours and look to be in excellent shape). Have a look at other forum as your thoughts on this topic are appreciated.

Thanks Rick

kingrich

Just finished talking to a friend of a friend who rebuilds mercruiser GM engines for marine dealer here. He rebuilds them to GM specs. He said there is absolutly no difference in cylinder bore from stock and anything with hyper in pistons means they are silicone cast. I am building my block as ski/pleasure and not high performance? He cross referenced all parts in federal mogul book and all are the same as marine application with the exception of cam which does list the stock vortec roller cam as marine application also.
Rick

Bulldog

One concern is the exhaust valves. A boat normally has water cooled exhaust, which means there is a water jacket in the manifolds, risers, etc. There are gasketed joints between these parts, and if you do not do PM on them, the gaskets will fail. The result is water gets to the exhaust valve.

Cool water and hot valves dont mix, and the valve disintegrates and you soon have holes where you don't want holes. The best valves are made from Inconel or other exotic material. They are more resistant to water damage, but are not fool-proof.

The head gaskets on marine engines have stainless cylinder rings.

I would look into these 2 issues from other more knowledgable sources. You can replace these parts rather cheaply now as insurance.

Good Luck!
Bulldog

Scott

Kingrich,
The Boatered type boards will give you help on how to change out your permeated holding tank waste hose or how to change a bilge pump but would not be my first or last stop when looking for HP advice

A lot of their "experience" stems from wives tales. I have friends running crate motors with no issues after 5 years and still running strong. I don't no if they made cam and pan changes but I do know they did not have to touch the bottom end.