Mercruiser MCM 170 info needed

[eZZi Bob]

Hello Everyone,

I am new to the forums and I have been reading over the forums for days now getting as much information that I can but there are a few questions I can not find the answers to. I have just received a 1986 19 foot Wellcraft with a Mercruiser MCM 170. But the engine is seized and the floor is rotted. I have figured out the floor problem from these forums and I am excited to start the work. But I can not get the information that I want on the engine. Like I said it is a MCM 170 and it is seized. Is it worth trying to rebuild or getting a new one? Or is there another engine that is compatible with this engine? Does anyone know where I can find this engine or on that would be compatible? I am knowledgeable in cars, trucks and motorcycles. I have completed 2 engine swaps and built 2 motorcycles. I have never rebuilt and engine before but I do have a friend that rebuilds aircraft engines for a living. Any advice would be greatly appreciated.

By the way I ordered that manual that I saw on a post. People said it was a must have. It is on the way.

Thanks in advance
Bob

 

[Bondo]

Re: Mercruiser MCM 170 info needed

Ayuh,... Hi Bob,... No Good News for you, you have the infamous 470...

Type 470 into the Search,+ you'll see what I mean....

 

[eZZi Bob]

Re: Mercruiser MCM 170 info needed

Oh this sucks, I have just spent the last hour reading terrible information about my engine. Am I better off just trashing the boat. Or just downgrading to the 140 or another engine that would fit? Anyone have any sugestions with an engine to use?

Bob

 

[stonyloam]

Re: Mercruiser MCM 170 info needed

The 470 is not well liked around here, and for some good reasons. It is not an engine for the mechanically disinclined. I have had one for 20 years now and have dealt with some of the problems (water pump seals and voltage regulator) but mostly it has been a good strong little engine. If it has the 4? heat exchanger it may not have been overheated, so it might be worth rebuilding if you feel up to it. You can get a rebuild kit on e-bay. If you have to pay someone to rebuild, forget it, not worth it. You could try to free it up, it might be as simple as the rings are stuck in one of the cylinders. The 140 would probably be underpowered for your boat, so if I were doing it I would look for a good used (complete) 190-205 hp 4.3 l V6. It?s a good engine and you would not have to change the gear ratio of your outdrive. Just my opinion. Anyway that is a great looking boat, good luck!

 

[HT32BSX115]

Re: Mercruiser MCM 170 info needed

Bob,

The good news is that you don't have to stay with that engine!

You can go to an inline 6 (The 250 cu-in gm 6 is a great engine), a V-6, or a V-8. (I swapped out an OMC 460 Cobra and installed a 454 Bravo....all by myself.........so anything's possible.!!)

Since you're planning to do some fiberglass work you can just switch to something else unless you don't want to put any time in that boat. It might also be "cost effective" to just junk the whole mess and find another boat (if you don't have much in it......If it's a "free" boat......well you can see it's really not all that "free"!!!)


Regards,


Rick

 

[artificialreef]

Re: Mercruiser MCM 170 info needed

If you do decide to abandon it i read there are some kind of oval track or someother type of racers that love that block. You may be able to get a decent buck for the block if you figure out who it is that digs it. I am stuck with 2 of them in my boat so I am learning to deal with it. (along with the dissing)

 

[eZZi Bob]

Re: Mercruiser MCM 170 info needed

How do you all know what engines can be put into the boat? What do I have to look for? Like I know with cars (hondas) and b sereies engine are interchangable. Is it somthing like that with boats.

Stonyloam what is this 190-210 hp 4.3 engine?

 

[stonyloam]

Re: Mercruiser MCM 170 info needed

Stonyloam what is this 190-210 hp 4.3 engine?

It is a Chevy V6 that has been converted for marine use. As far as engines for your particular boat, you could do a little research and see what was offered by the factory in your year and model, I would think any of those engines (marine of course) could be adapted for use in your boat. One thing to consider though, is that for best performance you should match the new engine to the gear ratio of the outdrive that you have. check out http://www.seilermarine.com/info/mercruiser-drive-ratio-chart.htm and you can see that your 170/alpha 1 has a gear ratio 0f 1.84, as do all of the V6's. If you went with a 3l or V8 you should change the gear ratio of your outdrive, trouble and expense. Just like matching engine, drivetrain, wheels and tires in a car. Good luck