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engine for boat help please

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mike.l

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Hi i am looking for a little help i have a 2001 boat with a 4 cyl engine 3 litre engine which is finished beyond repair and needs to be replaced. Its a gm based industrial engine, i have been offered a mercury 3.7 engine from someone after doing a goggle search on this engine its basically a ford engine but the engine mounts and bell housing have been manufactured to fit the gm mercury bellhousing and engine mounts so would anyone know if it would bolt up to my penta outdrive thanks for any and all info. mike
 
mike.l said:
Ok thats why they were cheep whats bad with them thanks mike
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I've seen many guys come in to the marina with those 3.7s, and they all had the same problem: cooling/overheating issues via coolant mixing into the oil/block. I forget exactly what the cooling issue was specifically, but it basically leads them to think they have a blown head gasket because of the symptoms, when in reality it's something to do with the crappy block design and seals not holding up near the crank area and/or the cam area that separates the coolant and oil. So much of a problem, Mercruiser themselves even put out numerous bulletins to try and head these issues off at the pass when it started having such a common occurrence, but it was far too late in the process after they were already manufactured, in the hands of customers all over the world, when the massive amount of problems started rolling in.

They have had all of the following as being REALLY common issues (when saying 'issues', I'm really saying 'faults that happen far more in this motor, than they ever should, and far more than they ever arise in other likewise motors in the industry under even average to very light use"). So, here it goes:

- The impeller is driven via the end of the camshaft and it has an 'after the fact' bandaid seal to separate out fluids/oil/low-water that ends up going bad from warpage due to even normal engine temps. (This is the head gasket issue many people dig in and "fix", only to find out after all that work, that it was never the head gasket to begin with).

- most of this above stems from the poor choice in what they used to build this engine: cast iron heads with aluminum block... -_- That alone is asking for trouble back then, because the whole era was an engineer's wet dream as it still hadn't really been thoroughly figured out yet like a lot of today's stuff (they still hadn't figured it all the ins/outs and ask the do's/dont's in the weight saving area of engine efficiency yet, and various other specialty areas of the engineering of everything, so they would do wonky things like over engineer things that didn't need touched, and not address issues that really should've never happened to begin with, ie- aluminum block with cast iron heads. Going the other way would've been more acceptable (cast block and aluminum head) but they didn't do that. They were trying to shave some weight, and "aluminum everything" was becoming the new wave trend in the market. So, to stay competitive, they rolled out the 3.7 the way they did, and it just didn't work out.)

- there were Electrical/charging issues out the wazoo. Something to do with the way they set up the wiring on this engine being sub-par and the stator always crapping out nonstop on these things with seemingly no rhyme or reason as to why.

- a few other issues that show up here and there. But, the main ones are the block seals going bad/leaking/mixing coolant with the oil because of faulty 'after the fact' rig jobs they pulled (remember the service bulletin I was talking about earlier? It was for a "fix" for the crappy seal due to all the warping that would go on in the block/crank area) and the mixture of an aluminum block with cast heads being the other huge issue.

Sorry for the long winded reply. I just didn't want to see you get burned like I've seen happen to many people over the years with the Mercruiser 3.7. It was a good idea they had, being semi modular, but it just didn't work out as well as it looked on paper.
 
mike.l said:
Ok that's why they were cheep...... whats bad with them? thanks mike
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Mike, I'll add to what Walleye said in post #4.

The 470 (3.7L) was Mercruiser's own design.
The cylinder block is aluminum with steel sleeves.
The cylinder head is that of the Ford 460, making this in-line 4 cylinder engine rather unique in that the intake ports are on the Port side, and the exhaust ports are on the Stdb side.
They do not dynamically balance out very well.
The charging system was a crankshaft mounted stater and rotor affair, and was very problematic.
The charging system regulator was a proprietary seawater cooled unit.
The seawater pump for these was in the Alpha stern drive.
The engine coolant circulating pump impeller is driven by the front of the camshaft.
The seal between these two (the oil side and the coolant side) is problematic.
The front cover in this area is prone to warpage.
All were fitted with a Closed Cooling System.
They lived a short life, meaning that Merc dropped production after only a few years.
 
Well you got my attention i will stay away from that combination it seemed a good idea when i read about it i will just say thanks guys mike
 
Why not just rebuild your existing engine or get a drop in replacement? Even if block is freeze damaged you can find anywhere from a used take out to new base engine depending on your budget.
 
HI Thats what i would like to do but its that chevy industrial engine and not a lot of blocks around found another engine volvo but from earlier years and i think the 2001 is when they changed and built them in mexico. cannot find info as to if the blocks will exchange with early ones exhaust manifold looks different to start with and mine is cracked the option of a drop in motor at $5500 is just not an option
 
In 1990 3.0 switched flywheel size to 14" and went to a one pice rear main sealas long as donor motor is one th same side of that change you are good.
 
Thanks guys i will keep it in mind about the engine and you guys just saved my bacon again as someone has just offered me block from a 1980 engine but now i know it will not work for me i need the larger flywheel and one piece rear seal thanks mike
 
mike.l said:
Thanks guys i will keep it in mind about the engine and you guys just saved my bacon again as someone has just offered me block from a 1980 engine but now i know it will not work for me i need the larger flywheel and one piece rear seal thanks mike
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Mike, if you're OK with your boat having an earlier 3.0L engine in it, the 1980 3.0L engine can be made to work.
The 2 pc -vs- 1 pc rear main seal is not a deal breaker.
The rear engine flange for the flywheel cover is the same.
The crankshaft flange and smaller flywheel would require an earlier drive coupler.
The smaller flywheel requires a different bolt pattern starter motor.
 
Hi Guys Started to think outside the box. not sure that's a good thing but would a 4.3 motor be a option to transplant and would it couple up to the volvo penta outdrive or would that be a bigger can of worms. Also been offered a 86 engine but the manifold looks a lot different mike
 
Ayuh,..... The V-6 would require new front motor mounts to be glassed into the hull, 'n the drives gear ratio is wrong,......

The earlier motor might work, if the flywheel is the right diameter, 'n yer drive coupler bolts to the flywheel, 'n not the crankshaft,....
 
Think i had better get back in the box before i get myself into great big hot water

think i should add a little story here This morning i put a add looking for volvo penta engine on a buy sell website, and i had a guy email me telling me he had just what i needed it was a 1992 good condition 100 hours on it flywheel and manifolds. He was in a different province so he said and was leaving today for a week in ontario the emails kept on coming and then he gave me a price $600 i said that would work would he bring it with him. Then the ball dropped half now before i load it and half when he got there well i then told him no cash deal only, and that i was born at night but it was not last night , not hear from him from there on mike
 
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mike.l said:
Hi Guys Started to think outside the box. not sure that's a good thing but would a 4.3 motor be a option to transplant and would it couple up to the volvo penta outdrive or would that be a bigger can of worms.

As Bill said..... "The V-6 would require new front motor mounts to be glassed into the hull, 'n the drives gear ratio is wrong,......"

Also been offered a 86 engine but the manifold looks a lot different mike
A 1986 Volvo Penta 4 cylinder engine would be an AQ series OHC engine.
By the time Volvo Penta began using the GM 3.0L 4 banger, they had taken over OMC and started producing the Volvo Penta SX style stern drive along side of the AQ series until 1996.

The AQ series OHC 4 is an excellent engine, but cannot be made to work with the later Volvo Penta SX gimbal system stern drive.
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Hi Well got a email from a reasonable local person today, he has a 1995 engine complete as far as i can find from mr goggle it will fit and work for me. but you guys got hands on knowledge on this sort of thing. Will it work for me or will i have to use just the block, as he want a good price for the complete engine i do not want to have to throw half of it away thanks for all help mike
 
mike.l said:
Hi Well got a email from a reasonable local person today, he has a 1995 engine complete as far as i can find from mr goggle it will fit and work for me. but you guys got hands on knowledge on this sort of thing. Will it work for me or will i have to use just the block, as he want a good price for the complete engine i do not want to have to throw half of it away thanks for all help mike
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mike.l said:
thanks for everyone for help think i will get her bought next week. mike
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Suggestions:

See and hear it run while on a water supply.
Do a cylinder pressure test.
Get a receipt from the seller stating that it is a working engine...... no "as is" sale.
Pay via a traceable means..... Pay Pal, cashiers check, money order, etc., and keep a record of the payment means.

Good luck!

 
RicardoMarine said:
Suggestions:

See and hear it run while on a water supply.
Do a cylinder pressure test.

This is good advice... see it run and do compression test, if you can also test oil pressure especially hot so much the better.


Get a receipt from the seller stating that it is a working engine...... no "as is" sale.
Pay via a traceable means..... Pay Pal, cashiers check, money order, etc., and keep a record of the payment means.

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This wont happen for a private sale of a used engine, if you want a warranty go buy a reman or new base engine, for which you will pay much more.
 
Dieter said:
This wont happen for a private sale of a used engine, if you want a warranty go buy a reman or new base engine, for which you will pay much more.
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No one said anything about asking for a warranty!

Any seller, who is halfway honest, will allow you to do a cylinder pressure test and to hear the engine run.
If by chance the seller is not willing to do that, I would walk away!
 
RicardoMarine said:
No one said anything about asking for a warranty!

Any seller, who is halfway honest, will allow you to do a cylinder pressure test and to hear the engine run.
If by chance the seller is not willing to do that, I would walk away!
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Agreed on he test run and compression test, but what is the point of getting a receipt stating a running engine vs as is and a traceable form of payment unless you expect some recourse if it blows up or doesn't work ?
 
Dieter said:
................................ but what is the point of getting a receipt stating a running engine vs "as is" and a traceable form of payment unless you expect some recourse if it blows up or doesn't work ?
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mike.l said:
................ but i hope the dealer will be very fair. Mike
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Mike is apparently buying this engine from a dealer, and not from a private party (see above).
Even if from a private party, the seller alleges that this is a running and usable engine.
A cylinder pressure test is great, and test running the engine the engine is also great.... however, it does not fully prove that all else is OK with it!

Now, let's put you (Dieter) in the buyer's (Mike) shoes!
After the testing, would you pay for this engine without some type of receipt with verbiage stating that it is a good running engine?
I would not, and I would hope that Mike would not!


That's all... no argument..... I'm just simply stating my reason for mentioning it.
It's ultimately up to Mike!


Mike, good luck. I do hope it is a good one!


.
 
Hi Lets go to the other side of this coin the seller has no knowledge of all the internal parts of this 24 year old engine something could well be perfect now but break when put into a different stress situation lots of give and take when buying and selling old stuff Mike (are these engines known to crack in the block area a lot was it a common fault i was under the impression it was a freeze problem )
 
.................
Mike in post #19 said:
..... Well got a email from a reasonable local person today, he has a 1995 engine complete. .................
May we safely assume that this is the GM 3.0L engine?
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mike.l said:
Hi Lets go to the other side of this coin. the seller has no knowledge of all the internal parts of this 24 year old engine. something could well be perfect now but break when put into a different stress situation.
What different stress situation? This is a Marine engine...... yes/no? Why would the stress factor be any different?
And by the way, the GM 3.0L was offered as an Industrial and a Marine engine. I don't recall that it was ever used in a car.


lots of give and take when buying and selling old stuff.
(are these engines known to crack in the block area a lot was it a common fault i was under the impression it was a freeze problem )
I am not following you on that one!
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Mike, if you have concerns, play it safe and don't buy it!
 
lots of give and take when buying and selling old stuff.
(are these engines known to crack in the block area a lot was it a common fault i was under the impression it was a freeze problem )
I am not following you on that one!
I was just asking a general question is the block on the 3Litre marine engine a known problem area answer to other questions i am a big boy i walk around with my eyes open i do bump into things on occasion Mike




Mike, if you have concerns, play it safe and don't buy it!
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