Mercruiser Inliner Swap Progress...165 Rebuilt I6 replacing the old 470

[WOEISMEIGOTTA470]

Hello folks...

Figured I'd update progress in swapping out my inline 4, merc470 (ford head) engine, for a rebuilt inline 6 merc165 (GM 250).
This is eventually going into this (old pic):

So here are the specs:The cooling system:Loose Ends:
Just a list of things I need to finish before a sea trial.

• Fabricate a front engine mount adapter (old block missing two 3/8-16 hole flange on front starboard side)
• Figure out throttle bracketry and linkage
• Finish glassing in new wood for front engine mount
• Clean and reinstall fuel tank
• Glass in new floor section
• Clean and reinstall transom assembly
• Install engine
• Install outdrive

So far I've found this site very helpful as a great resource of information! I hope that I too can help contribute my experiences to others who share the same passion.

-Jim

 

[WOEISMEIGOTTA470]

Re: Mercruiser Inliner Swap Progress...165 Rebuilt I6 replacing the old 470

PICS!!

 

[WOEISMEIGOTTA470]

Re: Mercruiser Inliner Swap Progress...165 Rebuilt I6 replacing the old 470

VIDEO of running it for the 1st time last weekend!

The oil pressure had me a little concerned at idle...once revved up it bumps right up to 40psi...could be the gauge or sender. Also is that slight whine typical for these engines cause of the timing gears?

 

[WOEISMEIGOTTA470]

Re: Mercruiser Inliner Swap Progress...165 Rebuilt I6 replacing the old 470

Latest picture of the boat...the engine bay had to be elongated to make room for the longer 6 cylinder engine. To do this I also needed to shift the gas tank forward. I had already replaced the floor 5 years ago, so I only removed the center section to do the work.
As is sits I have the bulkhead pieces removed and am in the middle of prepping the replacement pieces to go back in.

New Halloween costume?

 

[jasoutside]

Re: Mercruiser Inliner Swap Progress...165 Rebuilt I6 replacing the old 470

I just wanted to stop in and say your new engine is preeeety:becky:

 

[WOEISMEIGOTTA470]

Re: Mercruiser Inliner Swap Progress...165 Rebuilt I6 replacing the old 470

I just wanted to stop in and say your new engine is preeeety:becky:

Thanks!! It'll look even better when it's in the boat!

I got a lot of cleaning and grinding done in the bilge today. There were several voids in the fiberglass from the factory that I needed to grind out.
Tomorrow I plan on getting wood pieces cut and fitted. This includes the front engine mount, tank subfloor, engine bay bulkhead, and 2x3 supports for the center floor section.

If all goes really well I may even get to start glassing!

 

[WOEISMEIGOTTA470]

Re: Mercruiser Inliner Swap Progress...165 Rebuilt I6 replacing the old 470

UPDATE:

Got a whole bunch of work done. Finished working on all the new wood pieces and glassed most of it all in.
The keel section was 1st on the list; I cut out the old poorly encapsulated fiberglass covering the keel, sanded, cleaned, and re-glassed with 1708 10" wide tape.

Stringer sides were next; loose fiberglass removed, sanded, cleaned, voids gaps & holes filled, corners filleted with PB (peanut-butter) thickened resin mix. A layer of 1708 down the length of each side tabbed into the deck, floor, transom, and front bulkhead.

Next was the eng. comp./tank rear bulkhead (consisting of two 3/4" BC ply sandwich) and front engine mount support (2x10). Engine mount support was prepared & wrapped like a present with layer of 1.5oz cloth prior to installation. Installation involved bedding it in with PB, and glassing it into the stringers and bulkhead.

Last night I finished glassing in the fuel tank support, 1/2" ply cut to 14" wide and 49" long.

I'm really pushing hard to finish all the major fiberglassing work involving the hull before it gets too cold. I've been fortunate with the 60-70deg weather we've been having so far here in NY. I currently have a 10x10 popup tent with plastic down the sides to keep things dry and from the leaves falling in.

 

[WOEISMEIGOTTA470]

Re: Mercruiser Inliner Swap Progress...165 Rebuilt I6 replacing the old 470

 

[WOEISMEIGOTTA470]

Re: Mercruiser Inliner Swap Progress...165 Rebuilt I6 replacing the old 470

 

[WOEISMEIGOTTA470]

Re: Mercruiser Inliner Swap Progress...165 Rebuilt I6 replacing the old 470

New update:

Got the engine bay pretty much finished up. I added in some drip rails along the front and sides of the engine compartment to keep water out, only letting it enter in the back near the transom. For the rails I used 3/4 x 5" poplar board glued to the stingers with PL Premium and glassed them in with 2 layers of CSM. I also finished PB fillets on all the corners and added some more reinforcing CSM layers along the floor and corners. I also added a block ~5"x7" to the starboard stringer to mount my fuel filter.

Lastly I applied a layer of CSM and some lightweight cloth cut to 2" wide tape, to fill in and waterproof the I/O keyhole cutout.

After all this and lots of sanding, I smoothed a quart of white gelcoat over the entire area. Looks good but wasn't expecting it to come out flat, thought it would cure glossy. It still looks nice though.

I hafta say I'm really happy with the results, I got lucky with the weather again as this past weekend was 60 degrees! Now I should be able to focus on the mechanicals again, and begin reassembly of the transom parts soon! The rest of the floor and other fiberglassing work will most likely need to wait until springtime!

That's all for now

 

[WOEISMEIGOTTA470]

Re: Mercruiser Inliner Swap Progress...165 Rebuilt I6 replacing the old 470

 

[WOEISMEIGOTTA470]

Re: Mercruiser Inliner Swap Progress...165 Rebuilt I6 replacing the old 470

 

[Bondo]

Re: Mercruiser Inliner Swap Progress...165 Rebuilt I6 replacing the old 470

Ayuh,.... Just how Thick is that transom,..??

The factory Spec is 2", true level, parallel, 'n Flat gasket surface,...

2, 1/4" is the Max. allowed thickness,....

If too Thick,....
Not only will the mountin' studs be too short,...
The drive shaft will be too short, engagin' the splines short,.....

 

[Brickie]

Re: Mercruiser Inliner Swap Progress...165 Rebuilt I6 replacing the old 470

Looking great! That engine bay looks great. Is the gelcoat easy to apply? Before you know it you will be scootin across the lake :joyous:

 

[WOEISMEIGOTTA470]

Re: Mercruiser Inliner Swap Progress...165 Rebuilt I6 replacing the old 470

Ayuh,.... Just how Thick is that transom,..??

The factory Spec is 2", true level, parallel, 'n Flat gasket surface,...

2, 1/4" is the Max. allowed thickness,....

If too Thick,....
Not only will the mountin' studs be too short,...
The drive shaft will be too short, engagin' the splines short,.....

Bondo...you have a great eye..or should I say...AYE!!

Yes, you are correct in that it leans on the thick side, if I remember right last I measured it was a little over the max. spec of 2-1/4". I regret not having the information at the time I did the transom work ~4-5 years ago. I agree all the concerns are justified, and I too was a little worried once I had found the specs.
Thankfully last time I had the transom and drive all together, I had enough thread length on the studs the drive shaft still had good spline engagement. It all lined up proper and I ran the boat with no issues for a while until the last engine ate it. Upon disassembly, I found no uneven or odd wear on the splines, or any other parts which is good. I'll certainly will be paying close attention this round of rebuilding.

Thanks for looking out!

 

[Bondo]

Re: Mercruiser Inliner Swap Progress...165 Rebuilt I6 replacing the old 470

Bondo...you have a great eye..or should I say...AYE!!

Yes, you are correct in that it leans on the thick side, if I remember right last I measured it was a little over the max. spec of 2-1/4". I regret not having the information at the time I did the transom work ~4-5 years ago. I agree all the concerns are justified, and I too was a little worried once I had found the specs.
Thankfully last time I had the transom and drive all together, I had enough thread length on the studs the drive shaft still had good spline engagement. It all lined up proper and I ran the boat with no issues for a while until the last engine ate it. Upon disassembly, I found no uneven or odd wear on the splines, or any other parts which is good. I'll certainly will be paying close attention this round of rebuilding.

Thanks for looking out!

Aye Aye, My two eyes thought it looked more like 3" or so,....

Spline engagement is the issue,...
The further ya are out from the ideal 2", the Quicker the splines go,...

If you've got the ole MC-1 transom assembly with the I6 motor, you could put an Alpha input shaft on yer drive, 'n gain 'bout an inch,...

 

[WOEISMEIGOTTA470]

Re: Mercruiser Inliner Swap Progress...165 Rebuilt I6 replacing the old 470

Aye Aye, My two eyes thought it looked more like 3" or so,....

Spline engagement is the issue,...
The further ya are out from the ideal 2", the Quicker the splines go,...

If you've got the ole MC-1 transom assembly with the I6 motor, you could put an Alpha input shaft on yer drive, 'n gain 'bout an inch,...

Hmm didn't think of that...I still have all my MC-1 parts (transom assy AND drive!), I was plannin' on sellin' those parts but have held on to them just-in-case!

My real plans are to mate the I6 to all newer Alpha 1 gear (transom assy, and drive). I'm using a flywheel cover housing off of a 3.0L GM I4, along with the (offset) exhaust elbow assy. from the 3.0L. I got fresh motor mounts pressed into the flywheel cover also :joyous: I'll have to do some careful measuring to estimate how much spline engagement I should end up with.

So are the driveshaft splines something that always wears out over time? My understanding was that if everything is properly aligned there shouldn't be any wear...I guess nothing lasts forever

 

[WOEISMEIGOTTA470]

Re: Mercruiser Inliner Swap Progress...165 Rebuilt I6 replacing the old 470

Obviously things could wear prematurely just for the fact of less than satisfactory spline engagement...but my question is pertaining to ideal conditions...

Thanks Bondo

 

[Bondo]

Re: Mercruiser Inliner Swap Progress...165 Rebuilt I6 replacing the old 470

Obviously things could wear prematurely just for the fact of less than satisfactory spline engagement...but my question is pertaining to ideal conditions...

So are the driveshaft splines something that always wears out over time? My understanding was that if everything is properly aligned there shouldn't be any wear...I guess nothing lasts forever

Thanks Bondo

Ayuh,.... Ideally, yer right, practically, probably not,...

The splines need Grease, as there's always a bit of movement,...
Trollin' is waayyy worse on the splines than jackrabbit starts, in that the splines are Constantly loadin', 'n unloadin',...

For different reasons, but the same scenario, when I pulled the 3.0l outa my hull, 'n dropped in a 4.3l Alpha 1, I reused the input shaft of the ole drive, not knowin' it's 'bout an inch shorter,...
Within a very short time I found myself miles from shore in a boat that didn't move anymore,...
Got towed in, 'n I of course pulled the drive to find 1/2 the splines, Gone,...
A new coupler, 'n longer input shaft fixed it, 'n that was 'bout 15 years, 'n 2000 hours ago,...

If yer goin' to the Alpha transom assembly, you no longer have the option of a longer shaft, as it uses the long shaft already,..

 

[WOEISMEIGOTTA470]

Re: Mercruiser Inliner Swap Progress...165 Rebuilt I6 replacing the old 470

Ayuh,.... Ideally, yer right, practically, probably not,...

The splines need Grease, as there's always a bit of movement,...
Trollin' is waayyy worse on the splines than jackrabbit starts, in that the splines are Constantly loadin', 'n unloadin',...

For different reasons, but the same scenario, when I pulled the 3.0l outa my hull, 'n dropped in a 4.3l Alpha 1, I reused the input shaft of the ole drive, not knowin' it's 'bout an inch shorter,...
Within a very short time I found myself miles from shore in a boat that didn't move anymore,...
Got towed in, 'n I of course pulled the drive to find 1/2 the splines, Gone,...
A new coupler, 'n longer input shaft fixed it, 'n that was 'bout 15 years, 'n 2000 hours ago,...

If yer goin' to the Alpha transom assembly, you no longer have the option of a longer shaft, as it uses the long shaft already,..

Gotcha. Yeah, I got stranded once 1st season I ran the boat, when all the sudden my boat came to a screeching halt and the smell of burning rubber...I had just blown a coupler. That was cool to look at when I had the part in my hands.

Hey do these newer style couplers have longer splines? or are they just a protective sleeve? Looks like they have a handy grease fitting as well?
MerCruiser 12-3/4" Engine Coupler
View attachment 217911