Bell housing crack

[Sangster21]

I am taking apart the transom assembly of my new to me old boat. I wanted to replace all bellows and gimbal bearing for a bit of a fresh start. Engine is a 1976 mercruiser 165 I6. Drive is of the same vintage so I believe it is MC-1. I removed the pivot pin and discovered a crack in the pin boss of the bell housing. Doesn't look like a fresh crack, but I would imagine the only solution is to find a replacement. The gimbal housing also looks pretty corroded especially where the trim hoses pass through to the manifold. Would I be smarter to try to find a complete replacement assembly? If so, am I limited to only the early year or would an Alpha 1 work for me?
Alan

 

[achris]

Re: Bell housing crack

Yep, that looks pretty unrepairable to me... (was thinking of another word, but this is a family show )
It's definitely an MC-1, but I suspect it's a bit earlier than '76. It's not using hinge pin trim senders, I think they finished in '74 (happy to be corrected on that).
You could use any transom assembly for an in-line engine from about 1969 to 1982 (From 1983 on, the distance between the rear engine mounts changed, so an Alpha One will not work.)

Chris.........

 

[Will Fish]

Re: Bell housing crack

I'm in the process of doing the same changes, since I had the 165 engine out. I'm installing an alpha one gen 1, but like achris said there are other components you will need to change. The inner transom plate on the alpha has narrower mounts (I think its 9 1/2" wide, as opposed to approx 14 1/4" - this is from memory, so I may be slightly off.) In addition to the housing, gimbal ring, etc, additional parts you will need are the inner transom plate, flywheel cover, and exhaust tube.

I have not put everything back together yet due to time, but it looks like it will all bolt up. I plan on getting this all done and in the boat within the next 2-3 weeks, but the only thing I can foresee being an issue is the hose which mates the exhaust tube to the riser (there is a straight version and an offset version) and possibly the spline on the outdrive.

 

[Sangster21]

Re: Bell housing crack

Thanks for the information. I do believe the outdrive was "rebuilt" many years ago after a run in with some debris. Perhaps that accounts for the cracked pivot in the bell housing. I have been looking on e bay for replacement transom assemblies. Don't really want to jump from the frying pan into the fire.... they are all old. One seller seems to specialize in mercruiser parts and is selling a good condition assembly MC1 (slide hammer pin) for $600 and pre alpha 1 assembly for $700. He has 100% pos feedback and certainly claims to be selling only quality parts. Is there much of an advantage with the slightly newer version? Does the slightly newer version have a larger diameter water hose compared to the older one? Not a huge difference in price, would like to make the best choice!
Thanks,
Alan

 

[Harritwo]

Re: Bell housing crack

The crack can be repaired if you can not find another peice based on what i can see from your pics. It would have to be tig welded, with someone that knows how to weld aluminum. It needs to be cleaned extremely well as it has water contamination and is also a casting but it can be done. The corrosion that is shown, based on the pics would be extremely expensive to do a weld repair but another option might be JB weld type buildup if you can find no replacement that is affordable. Again, it has to be extremely clean and is time consuming to do, but it is an option.

 

[Will Fish]

Re: Bell housing crack

I would keep looking around. I found a guy local who had a transom assembly from a fresh water boat in perfect condition for abou 1/2 what ebay is looking. I personally would not just buy something like this online without inspecting it first.

 

[Sangster21]

Re: Bell housing crack

I had the crack repaired, I hope it holds up. At least it is visible and I will be able to keep an eye on it to see if it returns.
Alan

 

[Sangster21]

Re: Bell housing crack

I am going to try to save the gimbal housing. What the heck are the two openings just below the exhaust opening? I have been scanning the manual, but haven't discovered it yet.

 

[achris]

Re: Bell housing crack

I am going to try to save the gimbal housing. What the heck are the two openings just below the exhaust opening? I have been scanning the manual, but haven't discovered it yet.

Idle relief passages. They should be connected to the main exhaust passage. The exhaust pipe encloses them when you put it on....

Chris......

 

[Sangster21]

Re: Bell housing crack

Thanks for the reply Chris. Could you please explain in a little greater detail the function of the idle relief passages.
Regards,
Alan

 

[achris]

Re: Bell housing crack

Allows exhaust gasses out from the side of the gimbal housing, so they don't have to be pushed all the way down to the thru-hub prop. The exhaust pressure at low engine speeds isn't enough to push it all the way and would probably stall the engine....

Chris.....

 

[fishrdan]

Re: Bell housing crack

My MC1 transom assy had similar corrosion and it came out OK. I cleaned up the corrosion with a SS wire brush to see how bad it was, and it wasn't too bad. There was 1 area in the exhaust port that had some thinning, so I used an aluminum brazing rod to build it back up. Though, I probably could have gotten away without repairing the exhaust port. For pitting I took a small bit on my Dremel, ground down to bare aluminum, filled it with JBweld, then filed it flat with a fine pitch file. All the raw aluminum (and corrosion I couldn't reach far up in the trim manifold pocket) was treated Jacso MetalPrep, a coat of zinc chromate primer, then several coats of Rustoleum.

For the bell housing repair, is the lube channel still open, or did they weld it closed while doing the repair? I'd remove the screw on the end of the channel and see if it's still open, if not, run a drill bit down it to open it back up.

 

[Sangster21]

Re: Bell housing crack

The welder (me) did not completely close up the grease passage when he welded up the housing I am still confused about the two openings below the exhaust. I can see the two ports inside the exhaust opening, but there are two oval holes that look like they have o ring grooves for sealing. I tried poking with wire and compressed air, but they seem to be dead end? I am going to have to put on my welding hat and build up the 3rd mounting boss on the exhaust tube. It seems to be missing! I think it is thick enough that I should be able to build it up and machine it flat.
Alan

 

[Sangster21]

Re: Bell housing crack

Fairly pleased with myself, managed to weld up the missing ear on the exhaust tube and even managed to put the hole in the correct location. I made up a transfer screw to transfer the threaded hole location to the ear on the exhaust tube.