165 hp inline 6 cylinder engine swap

Encore985

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Sep 17, 2013
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Does anyone know if there's a v8 motor that would bolt into the mounts of an inline 6 cylinder that's just bolts in and good to go?
 

xxfile

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Re: 165 hp inline 6 cylinder engine swap

From what ive learned in the last 3 months of Sterndrive ownership is that NOTHING just bolts on!!! Everything needs some sort of tweaking.
 

Bondo

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Re: 165 hp inline 6 cylinder engine swap

Does anyone know if there's a v8 motor that would bolt into the mounts of an inline 6 cylinder that's just bolts in and good to go?

Ayuh,.... Welcome Aboard,.... That ain't gonna happen,...

A V8 is wider, 'n shorter, even though the rear motor mounts would work,...

'n you need a taller gear ratio in the drive,...
 

achris

More fish than mountain goat
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Re: 165 hp inline 6 cylinder engine swap

Does anyone know if there's a v8 motor that would bolt into the mounts of an inline 6 cylinder that's just bolts in and good to go?

Going to need a lot more information about what you already have and what plan to use...

The in-line 6s finished in 1981, so it's the wider mounts at the back. If you want something that will be the easiest to change to, then it will also need to be 1981 or earlier.

There is also the issue of the exhaust pipe, and (as already mentioned) the drive ratio. As well as the ratio, the yoke length is different between the in-lines and the Vs of that era. You will also need to fabricate new front engine mounts. The in-lines mount right at the front, the Vs have side mounts...

The short answer is yes it can be done, but it's not as easy as 'bolt in and go'....

Probably the easiest way is to buy a 'donor' boat with the engine and drive of your choice (and a much later model) and do a complete transplant.

Chris......
 
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Bt Doctur

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Re: 165 hp inline 6 cylinder engine swap

inline 4,6,8 SB, 8 BB all have the same bolt pattern on the rear of the block. Flywheel diameter is the wild card. early ones had a wide rear mount for the 14 inch wheels, newer ones went to the 12 inch wheel and 9 inch wide mounts.The exaust Y pipe has different variations on bolt pattern and dimentions.New fromt side mounts will have to be fabricated too, assuming you have the stringers for the support.
 

HT32BSX115

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Re: 165 hp inline 6 cylinder engine swap

Does anyone know if there's a v8 motor that would bolt into the mounts of an inline 6 cylinder that's just bolts in and good to go?

The 250 cu-in inline 6 is one of the best "marine" engines ever made. When I went looking for a replacement a local pickup wrecking yard had 13 of them sitting on shelves in various condition but all were fairly inexpensive.

I would be scrounging an engine to fix that boat. your head is probably still ok. You just have to ensure that the block mounting points match. Any truck 6 will have a cam suitable for marine (wet-exhaust) use.
 

Bondo

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Re: 165 hp inline 6 cylinder engine swap

The 250 cu-in inline 6 is one of the best "marine" engines ever made. When I went looking for a replacement a local pickup wrecking yard had 13 of them sitting on shelves in various condition but all were fairly inexpensive.

I would be scrounging an engine to fix that boat. your head is probably still ok. You just have to ensure that the block mounting points match. Any truck 6 will have a cam suitable for marine (wet-exhaust) use.

Ayuh,.... If I remember right, ya gotta make sure the new block has the hicky with the bolt holes for the front motor mount, forward starboard side corner,...
 

WOEISMEIGOTTA470

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Re: 165 hp inline 6 cylinder engine swap

Ayuh,.... If I remember right, ya gotta make sure the new block has the hicky with the bolt holes for the front motor mount, forward starboard side corner,...

Yup! That's my problem. I bought a rebuilt i6/165 to replace my 470, but I noticed the 165 was built on a truck block that didn't have that mounting flange... Now I got to weld up an adapter bracket to make it work.
 

Bondo

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Re: 165 hp inline 6 cylinder engine swap

Yup! That's my problem. I bought a rebuilt i6/165 to replace my 470, but I noticed the 165 was built on a truck block that didn't have that mounting flange... Now I got to weld up an adapter bracket to make it work.

Ayuh,... I donno where to find it, but Fishermark has built 1, 'n did a photo spread on it,...
 

HT32BSX115

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Re: 165 hp inline 6 cylinder engine swap

That can be a small problem. Of the ones I found I think a few of them did have the "hickey".

I planned to just make a bracket if the engine I used didn't have it..... I was going to use a 292 also.
 

998cc

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Re: 165 hp inline 6 cylinder engine swap

Looks good. How did it work out?
 

WOEISMEIGOTTA470

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Re: 165 hp inline 6 cylinder engine swap

Hmm..interesting solution oldsub86...might try something like that.

Here's the concept I came up with using some angle and square stock welded together...

 

oldsub86

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Re: 165 hp inline 6 cylinder engine swap

Not mine. I just saved the photos - from a thread on here I think.
 

Mbrgr1

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Re: 165 hp inline 6 cylinder engine swap

The 250 cu-in inline 6 is one of the best "marine" engines ever made. When I went looking for a replacement a local pickup wrecking yard had 13 of them sitting on shelves in various condition but all were fairly inexpensive.

I would be scrounging an engine to fix that boat. your head is probably still ok. You just have to ensure that the block mounting points match. Any truck 6 will have a cam suitable for marine (wet-exhaust) use.

He's right, they are great motors, so just do what I did, make it a 12 cylinder! :~)

 

achris

More fish than mountain goat
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Re: 165 hp inline 6 cylinder engine swap

Just noticed the dissy cap... What you got there?

And you might want to have a look at a 'water reversal kit' for those manifolds.....
 
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Mbrgr1

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Re: 165 hp inline 6 cylinder engine swap

Just noticed the dissy cap... What you got there?

And you might want to have a look at a 'water reversal kit' for those manifolds.....

Those are automotive HEI , I have an old pair of correct points distributors coming, I like the idea of HEI, but want it to be safe. I grew up with points, so they don't worry me.

Water reversal? I better look that up! This is a new project boat, so I am learning fast, thanks.
 

achris

More fish than mountain goat
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Re: 165 hp inline 6 cylinder engine swap

When you get your points distributors, put a set of Ignitor IIs in them. ;)

Water reversal kit.

attachment.php


The kit is no longer available, but it not too hard to build it up yourself. It consisted of a couple of hoses, a blanking plate for the exhaust elbow, a 90? fitting for the exhaust elbow and another end cap for the manifold....

In essence. The water coming from the thermostat/distribution housing going into the front of the manifold was change to a long hose that goes into the rear of the manifold though an end plate the same as the one at the front of the manifold. Then another hose is run from the front of the manifold to the 90? fitting in the side of the exhaust elbow. The blanking plate was also fitted between the elbow and the manifold....

The part numbers for some of the part are...
Manifold end cap: -60252
End cap gasket: 27-48043
Elbow blanking plate: -60207 (has a very small bleed hole in it, so don't think it's faulty when you see it)
Couple of elbow gaskets: 27-52076 (for either side of the above plate)
90? fitting: 22-45084, or any hardware store. Take the plug out of the elbow (closest to the rocker cover) and screw in the new brass elbow and point it towards the front of the engine.
Couple of lengths of water hose, I think they are 1". Be the same as the nipples on the manifold end caps....

Chris....
 

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WOEISMEIGOTTA470

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Re: 165 hp inline 6 cylinder engine swap

He's right, they are great motors, so just do what I did, make it a 12 cylinder! :~)
That's whats up! Just looked at your boat purchase thread...that mark twain looks to be in great shape for its age.

When you get your points distributors, put a set of Ignitor IIs in them. ;)
Any more info on where to obtain the petronix ignitor kit for these straight sixes, or P/N's? I've had trouble finding one, also does the kit need to be marine grade? I figure its all solid state so my guess is no?

Also, anyone here know what the typical expected lifespan is on these engines? I know they've been proven reliable, just curious to actually hear those with experience how long it took before a major overhaul was necessary, roughly of course.
Thanks!
 

Mbrgr1

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Re: 165 hp inline 6 cylinder engine swap

That's whats up! Just looked at your boat purchase thread...that mark twain looks to be in great shape for its age.

Any more info on where to obtain the petronix ignitor kit for these straight sixes, or P/N's? I've had trouble finding one, also does the kit need to be marine grade? I figure its all solid state so my guess is no?

Also, anyone here know what the typical expected lifespan is on these engines? I know they've been proven reliable, just curious to actually hear those with experience how long it took before a major overhaul was necessary, roughly of course.
Thanks!

Thanks, it is in good shape, I'm a little intimidated by the transom stringer job, but girding my loins in anticipation of it! I wish I had a garage big enough, I should have thought of that ahead of time.:~)

I just found these online, looks promising, and cheaper that the others I've seen, anyone try them??

Electronic Ignition Conversion Kits for 6-Cylinder, non-vacuum-advance Delco Distributors
 
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