The cummins engine rebuild thread

[johng39]

I wanna tell you a story, if nothing else let this be a lesson in checking an engine thoroughly and also what it could cost to rebuild and what the actual cost is to rebuild an engine if you are willing to do a bit of work.

A bit about me first......

I love a project, I want to take an un-loved boat and restore it back to a good boat. It has to have a good service history and I want it surveyed properly to see if there are any hidden gems, but I'll take on osmosis, cracked GRP, sad looking interiors / exteriors and will then enjoy the boat before passing it on for potentially a small profit, but mainly the joy of restoring a boat. Now I have been on boats all my 60 years and I have done a few projects now, mainly 40 - 50ft Flybridge cruisers and recently in the South of France, well since 2018 anyway. Even rebuilding a Williams 325 engine for my sins, I'll take on anything if the price is right.

So that little intro done, here is my story, with some images.

I bought a Sealine T50 in May 2023 and oh boy was she unloved. Not because the owner didn't look after her mechanically, he unfortunately passed away and it had been sat for 8 months unused. The previous service was over €35,000 with new water pumps and new aftercooler services, literally everything. The previous history was good too, but the hull had some crazing, some poor gel repairs and the interior was ruined by a cat the previous owner had on board. Exterior was in dire need of a polish, and it just needed some major TLC.

However, what was lurking in the engine was something else...... It had completed only 7 hours since the previous service, all good you would think? I took oil samples having tested it out and they were great, new aftercoolers, water pumps it looked mint. Oh how I wish I had removed the aftercooler pipes at this point. Anyway deal done, and fortunately considerably below the asking price and the value of a good, well maintained example.

I took the boat from it's previous mooring to Port Vauban and happily used it for about 2 months until 1 day it literally took 10 seconds to start!!!! I checked obvious things like the fuel and yes it was not in great condition, so I changed filters and still the issue was there. We were at anchor overnight and the next morning the engine refused to start. I tried several times and eventually it made a hideous bang and smoke came from the inlet, lots of it.

So at this point I had a Cummins specialist come down to take a look and it was diagnosed that at least one injector was faulty and they were removed and a camera down the bore. Oh dear

 

[johng39]

So at this point I decide to remove the head and take a look, which involved getting a Cummins specialist from teh UK to fly down with me. I had been quoted €50,000 from a French company to rebuild the engine, what irked me more than the huge mark-up on the retail price of parts was the 20 days to strip and rebuild, plus the €500 charge for parking!!!!

This is what we found:

 

[johng39]

Effectively the engine had ingested seawater past the o-rings in the Aftercooler that were fitted by the company that had charged €35,000 for the service about 20 hours prior to the failure and more than 16 months ago, so no point approaching them for a warranty.....

The damage was a head rebuild, that was done twice due to the French engineering company leaving water in the head and fitting the valves incorrectly. The turbo rebuilt, the aftercooler rebuilt and a bag full of parts.

Basically new pistons, liners, conrods, bearings and all of the gaskets required to rebuild.

So the rebuild started having removed the 1 bent conrod initially and then the rest of the pistons / liners.

The rebuild took approximately 5 days to complete, the engine has now completed 35 hours of running and all the oil samples are good, which is a relief. The final bill was around €20,000 including around €6,000 in labour / flights etc and approx €14,000 in parts.

So the morale of the story for me is take a bloody good look down the aftercooler pipes to see if it is clean. I've never done that before and accepted that it had been serviced only 7 hours prior as a thumbs up. It's been a tough lesson, but fortunately not to expensive, especially if I had accepted the quote from the companies in the area.

What I would have see, if I looked. and what it looks like now

 

[kashurst]

Wow that must have been a shock! Did you have to take the engines out of the boat first, or did they rebuild it in the boat?
Fingers crossed it's all good now. Unusual to find a pair of Cummins in a T50, where are you based?
PS you have checked the charge cooler on the other engine???

 

[johng39]

It was indeed a shock and yes the port engine was checked immediately and I am removing the pipes regularly.....

All done in situ as loads of room under the engine.

Either Volvo D9 or Cummins QSC 8.3. I have been told some had D12's. That would be a quick boat....

Based in Port Vauban

 

[kashurst]

The engineer who rebuit it did well. It's a big engine bay but still a squeeze for that much work. I had to do a serious repair on a D9 in a T50 we used to own.
Does your T50 have a Seaplex system?

 

[johng39]

The engineer who rebuit it did well. It's a big engine bay but still a squeeze for that much work. I had to do a serious repair on a D9 in a T50 we used to own.
Does your T50 have a Seaplex system?

He was brilliant, absolute perfectionist. Yep I have the Seaplex, which is actually working OK currently.

 

[kashurst]

He was brilliant, absolute perfectionist. Yep I have the Seaplex, which is actually working OK currently.

I had a 2007 T50 with Seaplex and the flybridge switch modules packed in - eye wateringly expensive to replace.
But I found out who made them and had a chat. It turns out the switch modules are NOT waterproof. I took my old ones to bits and the electronics was totally corroded.
The manufacturer said they were never intended to be used in such an exposed location. The electronic circuit board is only laquered.

On the early T50s the flybridge switch modules are mounted on a horizontal surface and prone to getting water in. I think on the later versions with the rear facing radar arch Sealine relocated the flybridge switch modules onto a more vertical or sloping section of the flybridge helm which should reduce water ingress. Either way if you can, it's worth trying to keep them covered and dry as much as possible.

If you can check the security of the bolts/studs holding the radar scanner on too. Mine came undone - fortunately I noticed before it fell off!!!!

 

[johng39]

I had a 2007 T50 with Seaplex and the flybridge switch modules packed in - eye wateringly expensive to replace.
But I found out who made them and had a chat. It turns out the switch modules are NOT waterproof. I took my old ones to bits and the electronics was totally corroded.
The manufacturer said they were never intended to be used in such an exposed location. The electronic circuit board is only laquered.

On the early T50s the flybridge switch modules are mounted on a horizontal surface and prone to getting water in. I think on the later versions with the rear facing radar arch Sealine relocated the flybridge switch modules onto a more vertical or sloping section of the flybridge helm which should reduce water ingress. Either way if you can, it's worth trying to keep them covered and dry as much as possible.

If you can check the security of the bolts/studs holding the radar scanner on too. Mine came undone - fortunately I noticed before it fell off!!!!

Interesting mine is a 2007 and not many of the switches work on the fly. I would be interested in where you found them.

 

[kashurst]

The system is/was made by E-plex in Rochester in the UK.
I think BritBoatParts sell the modules.
They are boat/model specific. If you get yours out there is alphanumeric code on it which defines it, switches button array etc. To get it out is as ever a faff. If you crawl under the fly bridge helm on your back, there is a panel with about ten screws in it. Use an electric screwdriver. If you can get the navigators seat out that makes it easier. Be prepared for a face full of water. The panel has a small internal lip and collects water. I drilled a few 10mm holes in the corners of mine before it went back in.

Take that off and all the fly bridge helm wiring etc is exposed. From memory the switch module has clips you release/press in on the underside and then push it out.

 

[johng39]

I know the panel well, I'll remove it and either chat with Julian at EPlex or look at the britboat options. Cheers