Upgrading a 5.7 mercruiser

[wheels4]

Re: Upgrading a 5.7 mercruiser

You need torque not HP to get on plane.Im a car guy to and learned a lot about boats in the last 3 years.I was told not to do a lot of things I did.Like not to use an auto engine.Remember this all internal parts are the same.Pistons rods crank heads bearings bolts block you get the picture.You can as I did apply your automotive knowledge to build an engine that makes low end torque and upper RPM HP.To think the engine will not last is false it will last mine has not lost 10lbs of compression in 3 years of use(granted its not run every day)just do some research I did and Im grateful for it.I live by a boat yard and the gentleman behind me helped me out a great deal also.Im sure you will be able to upgrade by your self I did and enjoy it whenever I take it out of Montauk and land a bunch of stripers.Good luck.Jonny

 

[bomar76]

Re: Upgrading a 5.7 mercruiser

akriverrat <br /> zz4 engines and wet exhaust don't mix well. reversion. oil and water milkshake. can be done but isn't cheap and easy.

Quite a few marinized ZZ4's around here and I haven't heard of 1 with ingestion problems due to reversion to date. All that I know of have switchable "captains call" type setups, and the conversion work on the engine was limited to head gaskets and freeze plugs (of course the carbs, distributors, starters and other externals are marine units (usually from the prior set up))

 

[akriverrat]

Re: Upgrading a 5.7 mercruiser

maybe its just a problem with the zz4 fast burn. took a lot of head scratching and multiple oil changes to get it worked out in my buddies jet sled.

 

[Jdeagro]

Re: Upgrading a 5.7 mercruiser

I would agree with Tabman II! If the engines are running well, you should have enough power to bring the boat up on plane without too much difficulty. Check the size of the plates and the opporation. If they are working correctly then increase the plate size. In my oppinion this will improve the performance far more than engine swaps. Assuming the engines are in good running condition!