1987 citation cabby with 3.7 ford

[HYPER82MUSTANG]

just bought this boat few days ago came with known issue, was told head gasket was bad and even was shown gasket. was also given a second complete engine so i figured why not....lol...well too good to be true was just that, im a car and bike mechanic after bringing first head down to machine shop and valves removed, noticed large none repairable crack between intake and exhaust valve openings.
so now i have second head loaded in truck, its seemed ok at first glance howeever i will be tearing it down and cleaning it up and hope not to find any cracks.
my question is will heads of a 7.5 ford 460 work with this in a fresh water environment, if so it seems front frost plug was removed and a coolant pipe was installed, how is this pipe removed and or is there a replacement pipe available as well as would it make a diiferenc if it was a left or right handed head fron lets say a truck engine. if all goes well the 2nd head will be ok but i would still like to rebuild this second engine, thanks for any and all help

 

[Scott Danforth]

welcome aboard.

if you would have came here before buying your boat, you would have been warned not to buy anything with a 3.7 liter in it (or anything with OMC, 2.3 or ford anything)

the motor is not a ford motor. it is a Mercruiser only POS. ford pistons and rods, modified ford head, custom block, custom crank, GM style flywheel and flywheel housing. you need to run the Mercruiser OEM head gasket as they are the only ones that survive in the 3.7. no the 460 head gaskets wont work.

yes, the ford 460 head can be modified to work with a bit of machine work. I suggest getting an aluminum head vs cast iron. the reason the head gaskets go on the motor is that the head is iron and the block is aluminum with iron sleeves and non-supported cylinder walls. so the bores are moving all over creation compared to the head. this causes the head gasket to wear out. if the motor so much as gets 10 degrees warmer than it should, the head gasket goes.

the motor also needs all sorts of band-aid fixes, such as cam bearing sleaves for the waterpump drive and an alternator conversion.

I personally would simply repower with a 4.3 V6. it will be a better motor and cheaper than rebuilding the 3.7.

however if you want to continue with the 3.7, its your boat and your wallet.

 

[nola mike]

If you're sure the bottom end is good, I'd stick with it. The 4.3, while a good upgrade, isn't quite a simple drop in. If you just need a head and can get one cheap, go that route. I'm still not convinced that these are any less reliable or more expensive than any other 30 year old powerplant. Probably the most difficult/expensive things to replace are exhaust manifolds and heat exchangers, so if you have spares, you're in good shape. I also have a spare engine, had thoughts of rebuilding as well. I've decided that when the time comes that I'm going to go with the 4.3, but I'll be damned if this thing just keeps on going
Some of these v8 guys are a bit jealous of the economy and weight of these engines I think...

 

[stonyloam]

Scott doesn't like 470s, but they are not so bad . I think it is the left head from a 460 ford. You can find 470 heads on eBay, probably less expensive than modifing a Ford head. Yeah use a OEM Mercruiser head gasket. Keep track of the pushrods, valve lash is set by pushrods length, same as a 460. While you have the head at the shop you might consider having hardened exhaust seats put in. Mine is 30 years old this year, so far, 1 head gasket and 1 set of cam waterpump seals. Get a manual (Merc #8) try boatinfo.no and follow the head gasket instructions EXACTLY, including retorquing the head bolts after bringing it up to operating temperature the first time. When they run they RUN, but you need to take good care of them.

 

[HYPER82MUSTANG]

UPDATE
well after cleaning and magnaflux second head, there is a small crack no 1 cylinder intake/exhaust valves it didnt go beyond the valve seat so its a good thing.... im taking all advi ce i get into concideration ecxept i will stick to my little ford engine lol....ive taking plenty of 4.3chevs out at track with my little 2.3 ford...lol...i will hve head done by weekend going to try and get her working for at least a month on water before winter storage, then decide what to do with other engine over the winter....any wiring diagrams out there this poor thing was hacked so many times just going to cut it all out from bow to stern and restart, not taking out on maiden vage to have electrical fire...lol

 

[Alumarine]

Here's a link to the manual stonyloam mentioned.
It has the electrical info as well.

http://boatinfo.no/lib/mercruiser/manuals/mercruiser8.html#/0

 

[Benny67]

Man, these 3.7's aren't so bad. Mine have been chugging along for 3 seasons for me and I like them.

Everyone who craps on them just doesn?t get the fact that you need to just pay close attention to them and they will treat you well and give you plenty of power vs weight and fuel economy.

Bigget thing is keep em cool...do not let them overheat