PDA

View Full Version : Elbow Leak



zelatore
06-28-2011, 05:18 PM
So I have an '89 Merc 454 with a miss....
(this is a 44 Tollycraft CPMY)

Ran compression, 125# on all but no. 4 which is at 80#. I can also see signs of rust under that cylinder and on the elbow/riser. Looks like the classic leaking Merc elbow.

Customer wants to contain costs so I shoot him a price to re-work that head and replace the exhaust on that side (inboard side fortunately!) as a minimum but caution that that is all based on what we find when the head comes off.

Here's what I found in the center two cylinders. (4 and 6) Hard to make out anything in the crappy phone pictures but you get the idea. No big scratches, but #4 looks pretty crappy and #6 clearly had water sitting in it at some point. Not a lot, but some judgeing from the marks.

I've just forwarded this on to the customer recomending we pull the engine - if you're going to do it, you might as well do it right. Of course, that's going to crank the price up significantly since it means hauling the boat, removing the salon window and running a fork lift stinger in to lift the motor out, tearing the motor down, etc.

The question: if he doesn't want to pony up for doing the motor, what do you think the odds are those cylinders will come around?

Rumblefish
06-28-2011, 05:50 PM
The question: if he doesn't want to pony up for doing the motor, what do you think the odds are those cylinders will come around?

I know you already know the answer Don.. looks like a tired glazed cylinder. No leak down? ( that would have atleast hissed out the breather)

Going from your description.. I would pull it.

MOP
06-28-2011, 06:47 PM
Having seen so many that is no matter how you cut it a tough call, if it were mine I would go the route. But in retrospect I cannot count how many we put back together due to the customers not wanting to drop the $$$, in all honesty many with stained bores yours look a heck of a lot better than some we buttoned up. They all seemed to make it abet a few used some oil but that to the owners was far cheaper than a rebuild. Tell the guy it is 50/50 chance it will fail an engine survey when he goes to sell, showing both low compression and oil contamination.

BUIZILLA
06-28-2011, 07:43 PM
Customer wants to contain costs so I shoot him a price to re-work that head and replace the exhaust on that side (inboard side fortunately!) as a minimum but caution that that is all based on what we find when the head comes off. if he's cost concious, i'd do the above and give it a whirl, i've seen a helluva lot worse than that go several hundred more hours, you might be surprised, what I see isn't a 45# compression loss, that's in the valve or seat area

zelatore
06-29-2011, 08:50 PM
Got a voice mail from the customer today. His first response after seeing the pictures was 'just hone it and throw it back together'.

Er, that's great, but I can't exactly hone it with the short block still assembled!

Gave him a call and ran through the options. I told him 50/50 on if this will be a problem; that it might smoke a bit/burn a little oil, or have so/so compression on that hole. The final verdict: do the head and exhaust and put it back together.

On the one hand, I understand. The cost would triple to do the whole engine and really he just putts around at about 10 knots in the bay 99% of the time. Aside from that, I'm pretty sure he's planning to sell the boat anyway. He's jonesing pretty hard for diesels. (and besides, who ever heard of a 44 Tollycraft with gas power???)

On the other hand, I know the right thing to do was pull the motor.

Right or wrong, he's writing the check so we're doing it his way! The head is off at the machine shop now. They're a little backed up + we've got the holiday coming so I'll probably be 2 weeks before I put it back together. I'll try to remember to follow up with the outcome.

silverghost
06-29-2011, 09:20 PM
Why not turn the crankshaft to bring the piston all the way down & then run a glaze-breaker hone down the cylinder bores as far as possible ?
Not the correct way to do it the right way~

Kind of a Half~A** job.
Not to MY liking~
But better than doing nothing at all.

zelatore
06-30-2011, 04:44 PM
Why not turn the crankshaft to bring the piston all the way down & then run a glaze-breaker hone down the cylinder bores as far as possible ?
Not the correct way to do it the right way~

Kind of a Half~A** job.
Not to MY liking~
But better than doing nothing at all.

I did consider that, but the idea of honing half (well, a little more than half) a cylinder didn't sit all that well either.

I didn't take any pics of the head, but the valves looked pretty crappy, especially on #4. I'm sure that's where most of the problem was so there's a fair chance it'll come around just doing the head. We'll find out soon enough.

zelatore
08-22-2011, 10:12 AM
I never followed up on this, so I thought I'd share the outcome.

When I started looking at things closer I found various other problems. Like bent push rods and bad lifters. I also took a closer look at the other head and convinced him it would have to be done as well. When I pulled that side apart it was obvious it had been getting water in it as well.

I also went ahead and ran a hone on the center cylinders of each side. Not something I liked doing, but I figured I might as well. They cleaned up somewhat, but obviously didn't look like new.

So two refurbed heads, a pair of manifolds, risers, and elbows, a set of lifters and push rods later I start putting it together only to have a head bolt strip on the third and final round of torquing. (85 lbs). Great...

I pulled the head back off and heli-coiled it. Put it back on and...pulled anther one.

Pulled it off again and another heli-coil and it held the third time although at least one more didn't feel great. But I got the 'click' on my wrench and I wasn't going to touch it again!

Then I started on the other head and exactly the same thing happened. I only got to the second round of torquing (50 lbs) when one of the bolts pulled. With the head off, I could see this hole had be previously repaired with a heli-coil, so I parked the project and ordered a set of Time-Serts designed to go over-size and repair a previously failed heli-coil. In the end I had to put 3 of them on that head. And to be honest after taking the heads on and off all those times I was getting pretty scared and only ran the last round down to 80 lbs instead of the recommended 85. This motor isn't going to build any monster compression, so I took the gamble.

Good Lord! I've stripped a bolt here and there before but never 5 on one engine! That block was just rotten after 40+ years. It still ended up costing him less than the replacement long block I had originally suggested, but a lot more than the original estimate when we were only going to do the one head an exhaust.

The good news is it now starts easy and idles smoothly at about 8-900 and 700 in gear. I actually like to set gas idles a little high on big boats like this because they need all the punch they can get around the dock. This hull is pretty rare with gas; almost all of them were built diesel with good reason.

This was also the first time I'd used Time-Serts. Nice - much better than heli-coils although they are a bit more expensive.

gcarter
08-22-2011, 10:56 AM
For the benifit of your friends all over the country, you could get a real camera..............:wink:

Don, ya did what ya had to do. probably the best solution.

zelatore
08-22-2011, 10:43 PM
A new camera is on 'the list' - probaly as a gift for Michele for christmas.

The real problem of course is I rarely carry a camera when I'm working. Or think to take pictures until it's too late!