1999 454 Mag MPI just quits - videos

370Dancer said:
Just did a deeper inspection and found a couple of things. Some cylinder gasket water issues, right at 4/6 and 3/5, so that's starting to explain the water in the cylinders. Wasn't burned through, but definitely visible.
2nd, that changes the schedule somewhat is he did find some scoring on the cam at 8 for sure, where the pushrod had punched through the rocker a couple of years ago, and light scoring on a couple of others. So, we're this far, time to finish tearing the front off, and move the water lift to swap it out. Now, can I find a cam soon enough in today's environment? bleah.
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Interesting. I'd replace it with a stock style cam. Try to avoid bumping things up and avoid the chance for reverb. Sounds like you'll be into things for $1500 in parts +/-.
 
might as well pull the motor at this point. Hone, re-ring new bearings, unless you enjoy this kind of work.
 
douglee25 said:
Refresh my memory, but did you ever do a leak down test?
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Yes, last year. This engine has had multiple issues, in every category. Been like a Vo-Tech experiment. Thankfully the labor rate is very reasonable (free), and I have the time, slowly to push through.
 
scoflaw said:
might as well pull the motor at this point. Hone, re-ring new bearings, unless you enjoy this kind of work.
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I need to buy a yard. Can't just throw it on a trailer, and yank it with an A frame. And then, everyone else has to get involved with their hands out. We don't have haul outs that will let you do your own work anymore. Too many lawyers in the way. Heading towards the darker part of the tunnel...... Hello, Michigan Motorz? How ya doin on short blocks?
 
370Dancer said:
I need to buy a yard. Can't just throw it on a trailer, and yank it with an A frame. And then, everyone else has to get involved with their hands out. We don't have haul outs that will let you do your own work anymore. Too many lawyers in the way. Heading towards the darker part of the tunnel...... Hello, Michigan Motorz? How ya doin on short blocks?
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Can you make a mobile style A-frame lift that is assembled on the dock? Yank it out and slide it onto a cart. The block doesn't weigh that much since you stripped it down. Could you take it to the shoreline and have a mobile crane on a truck pull it out? Just run it back to the dock on a single motor.
 
douglee25 said:
Can you make a mobile style A-frame lift that is assembled on the dock? Yank it out and slide it onto a cart. The block doesn't weigh that much since you stripped it down. Could you take it to the shoreline and have a mobile crane on a truck pull it out? Just run it back to the dock on a single motor.
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Yes to all except the A frame. I'm a side tie, skinny dock. I'll probably take it to Cortez and let Andy yank it in the travel lift basin. If I go that far, I'll likely just get a short block and start over. Dambit. Good news is I'm still way ahead on these plants.
 
damper is stuck.jpeg
All the way down to pulling the damper. Bolt's out, but the thing is on tight. Tried air, breaker bars, looking at maybe heat. Hate to do that in the bilge.....
any ideas?
 
370Dancer said:
View attachment 115879 All the way down to pulling the damper. Bolt's out, but the thing is on tight. Tried air, breaker bars, looking at maybe heat. Hate to do that in the bilge.....
any ideas?
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A couple of things..."The MAG MPI Horizon is somewhat unique in that there is no valve lash torqueing per se. Each rocker bolt is set to 40 ft lbs." Your Horizon motor is just a Gen 6 454. Same as in a truck, van, whatever. Just a different cam. 40 lb torque on the rockers is fine and will get you where you need to be. Scoflaws method was right on to make sure.
You'll want to use a harmonic balancer puller that has a bearing. I have the OTC 4531. Priceless. Sometimes available for a loaner at the Zone etc for free. NO HEAT!!!!
Your lower end is probably fine if you wanted to run it and not pull it. I'd leave it in your situation being on the dock. No noises right? Winding motors out and not lugging them all the time helps. Burns the carbon and doesn't let the oil build up as much on your heads. You might have a little blow by and you might not.
Heads. New rockers, valves etc are probably not necessary. Chances are you can just reuse what you have after a good clean up. Lap the valves and see how they're sealing.
Be careful with cams. As has been said, everywhere you look you hear about cam reversion issues.
 
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Things got a whole lot better this morning, and then went South a little bit ago.
I changed to a non-china puller, greased everything up well, and the damper came right off early this am.
The timing cover was next, and then pulled the camshaft. Definitely had enough scoring to justify getting where we got. The timing chain was as loose as your grandma's bra, so that explains a lot of the rattle in that side, that I originally thought was misfire. We were getting ready to call it a day, when I noticed that the timing chain cover was missing a piece of the lip on the inboard side. It was a fresh break. We were not heavy handed on the cover, knowing that the lip went over the front of the oil pan and gasket. pot metal. weak? maybe. Regardless, it broke and the errant piece is not in the bilge, it's in the oil pan.
Time to go play guitar and forget about it for a while. The only snowball's chance in Hell is if I could drop the pan far enough to get something in there to find the piece, but I don't think I could even get to all bolts without removing everything else around it. I believe my next stop is a boom truck or travel lift. And if it comes out, it's getting rebuilt/replaced anyways. Scof wins, as usual.
 
Learned my lessons over the years of doing things half way. Go through the whole thing and it will last a long time. Good luck

You have a forged rotating assembly, bet your parts are in good shape.
 
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Down to 2 bolts holding the block to the flywheel cover, and 2 holding the block to the motor mounts.
Need a boom truck, a pallet to transport it, and a place to work on it now. Do you think it's light enough now to just bolt some chain to the 5/8 bolt corners of the block, slide forward to clear the bell housing, and lift? Here's the last time.
leaving the transmission in the boat 2017.jpg
 
You can run chain either right to the head bolts or at the front and rear corner. Whatever is easiest. It should weigh around 550 lbs +/- without the heads.

Doug
 
Here's a stupid inquisition.
Can I get a less aggressive cam and "prevent" saga #5 of reversion on this poor vessel, yet leave everything else alone?
And, at the expense of what, top end? the ability to get on plane? The need to do it twice (STBD runs Great! (for now))
Inquiring minds are,.... well you know....
 
The MPIs were 380hp I believe. The 330hp were less susceptible and the 310hp were even less than that, although I do believe it can still happen.

Could you find a cam with less overlap? Yes, and you could probably derate it 30-50hp. Would that decrease you chances? Possibly? You may have to reach out to someone with some more experience.
 
I wouldn't go that route, too iffy. Merc says rev it up before shutdown ? I don't have that problem with my gen 6 and not sure why. What would be the difference between our engines? What does your exhaust look like?
 
scoflaw said:
I wouldn't go that route, too iffy. Merc says rev it up before shutdown ? I don't have that problem with my gen 6 and not sure why. What would be the difference between our engines? What does your exhaust look like?
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I'm sure there are differences in our exhaust setups, and I typically had not done a rev up before shutdown. I'll take that under consideration.
Exhaust Manifold to 6" riser to 4" elbow, about 3 ft of hose to a water lift muffler system that has a 5" underwater exhaust, and a 2" out the side exhaust ports.
Full time salt water.
 
BTdoctur did a write up with photos about extending the riser with a section of pipe. Said it worked well.
 
scoflaw said:
BTdoctur did a write up with photos about extending the riser with a section of pipe. Said it worked well.
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Yes, I mentioned that before, and sent the link from Offshore Only where they were talking about it. I'll see if I can find BTdoctur's thread. I am a bit puzzled by the attachment though, the exhaust hole is more of a D than an O. By the way, I got the 2 pieces of the timing cover lip out of the oil pan. I have been all over the pan with my borescope camera. 12" tweezers for one piece, and a vacuum cleaner down to a ice maker line for the other. Been fun trying to figure out how to get them.
EDIT: Not finding any post by BTDoctur re: elbow discharge extensions. a different board maybe? Or was that the Offshore Only thing?
 
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I thought I saw it here, but he frequents Iboats or he did I don't go there any more.
I thought you pulled the motor out? Not sure what your fishing for.
 
scoflaw said:
I thought I saw it here, but he frequents Iboats or he did I don't go there any more.
I thought you pulled the motor out? Not sure what your fishing for.
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The only reason I was going to pull the block is because the lip of the timing cover had a fresh break on the lip that goes over the oil pan gasket, and the pieces went into the oil pan. Now that I have all the pieces, I don't HAVE to yank the block. We're taking another hard look at it to make sure there is nothing else to consider. It might still come out, but at this point it's not mandatory.
 
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