1970 mercruiser 165 inline 6

[FishingNYS]

So at some point last year something happened to #6 cylinder and I now have rod knock. After taking the head off because the cylinder leaked down during a compression test, the piston has a lot of wiggle. I'm pricing out a rebuild for it vs buying the reman from Michigan motors. The new base is roughly $2900 +sh and core charge gets returned. 

 

Does anyone have a recommendation for a rebuild? I'm remodeling a Penn Yan Avenger. 

[Bozeman Bob]

Short of going to a local engine rebuilder , MichiganMotorz is your best option , have not heard any negative comments about them .Drawback of local rebuilder , time , this is race season and decent builders are locked in on that crowd of people . I don't think the pricing will be much different between the two as local builder isn't giving any breaks in pricing at this time of the year . Want to fish next week , order from Michigan. 

[FishingNYS]

I'm still waiting for them to tell me if they have a inline stock or not and if not how long it would take to build one. They emailed me on their day off which I was surprised but haven't heard from them today. 

 

I still need to figure out why the motor lost compression in the #6 cylinder and why the oil was milky so I'm not in a huge rush. I have couple friends with boats and I still have a 16' Thompson I can jig Lakers out of and catch perch. I might miss out on the Kings but in the long run this will be better for all future trips.

 

Honestly I wanted a shop to look at it because I thought it was a spin bearing and rings. Figures they might be able to polish the crank and hone the cylinder. Install new rings. 

 

I realize that's probably not idle for the shop to do. I'm sure they rather do a full rebuild.

[LongLine]

Milky oil means water.  Years ago I had an inline 6 cyl chevy in a penn yann.  Found a hole at the rear, in the exhaust manifold aluminum plate that separated the exhaust from water jacket. Figured gas ate that plate.  Did some damage to that cylinder. 

[FishingNYS]

I'm going to pressure check the exhaust. The riser looks new. The exhaust looks used. If I put a new motor in it they both will be replaced. I wouldn't want to take a chance of putting a new motor in and the exhaust runs it after a few short trips ... Shift cable and all that was done 2 years ago. 

 

 

[Bozeman Bob]

Start searching Craig's and Marketplace for a used boat with a L6 in it . Probably pick one up for a grand and get a spare outdrive in the process. Loose rod = full rebuild and crank is most likely shot .

[sherman brown]

Just a guess but with water in your oil and compression loss it could be a blown head gasket or a cracked or warped head. in my opinion you would be much better off buying a new or rebuilt long block from Michigan motors and forget about your old motor. but remember this is just one person's opinion.

[Shakemsam]

Not sure where you're located.

.Martin Engine Machine (formerly Farmer Engines) in Webster NY has a good rep.

[FishingNYS]

So I figured out how water got in. Previous owner used and old riser gasket with gasket sealant. It probably leaked back into the motor causing the damage... Found gasket in the block side of the cooling jacket. The whole block looks like it needs to be cleaned. Michigan motors is working with me on a new block. 

 

I should of looked more closely but shortly after getting the boat I ended up with a bad case of vertigo. Fishing must be good on the Big Lake. Hit a finger last night and they were chasing schools of bait in by the shore

[LongLine]

I used to work for a gasket company.  We always told customers to never put sealant on a gasket...Always install a new gasket on a clean surface and torque it down properly. 

[FishingNYS]

I know... Unfortunately the person that looked it over with me and did the maintenance work missed this... I now know enough about inboards that I know what to look for... I should of done my DD but at the time I was super busy and my fishing partner at the time had more free time then I did so I let him do the work on the boat. It's a costly mistake but in the bucket of receipts for fishing... It's just a drop of water 🤣B.O.A.T. Break out Another Thousand $$$

 

Long term it's still cheaper then buying a new boat or someone else's headaches. Plus I can make it like those old hot rods everyone drives on the road but for the lake 😅

[jereed44]

Try marine engines Inc in Ma. They do some nice work. Have used several of their engines for replacement. Work on boats in Saratoga Springs area