GB46eu repower

[BrisHamish]

So for those who might be interested, I will post a series of short threads and photos depicting the repower of our 2006 GB46eu last year.

The previous CAT C7s had had aftercooler failures during the tenure of the previous owner in about 2008, and the consequences of salt water having gotten into the engine cores came home to roost in 2020 when the port engine developed a ‘knock’ in no 1 cylinder, leading us (eventually, after eliminating ‘easy’ causes such as injectors) to do a borescope inspection of the internal of both engines. What we found wasn’t pretty.

Glossing over the horror/heartache (which lasted quite a while), I sold both CAT engines with full disclosure to guy who wanted to completely rebuild them, and after taking competing bids for new engines from CAT, Cummins, John Deere, Nanni, Volvo and Yanmar, we chose Cummins QSC 8.3 at 550hp.

The new engines are v smooth and smoke free, and use very slightly less fuel that the CATs they replace even though they develop more power and torque.

Photos follow.

H.

 

[BrisHamish]

More photos…

 

[BrisHamish]

Again, for those interested, in terms of engine choices available for me here in Australia, the Volvo D8 was by far the cheapest option, the CAT C7.1 was the most expensive, the John Deere 6090 would not fit (due to length), the Nanni version of the JD6090 would fit (it has a different shape marine cooling system) but there was a 4 month wait on orders, and price wise the Cummins QSC was the second most expensive followed by the Nanni and then the Cummins QSL9 after that.

I had a spreadsheet comparing all the various options, which I will try to dig out and share.

With the new engines we opted for new ZF286A transmissions (I sold the old ZF280As with the CATS).

Cummins has been excellent to deal with - I would absolutely recommend that brand - and Cummins also offered the most ‘complete’ package in that their price included Glendinning electronic throttles and also the display screens whereas other brands had some of these as ‘extras’.

H.

 

[Comodave]

Very nicely done.

 

[Insequent]

Hamish
Very sobering story. Very long time between aftercooler failure to engine issues, which surprised me. I don't know how survey etc could have saved you from the time & expense.

Thanks for sharing the story and the engine choice and selection, or elimination, process.

PS. I took the liberty of rotating some of the photos for you.

 

[BrisHamish]

Thanks Brian for photo rotation, that bit was beyond my powers!

Yes, sobering story all right. I now have a very specific and personal understanding as to why Tony Athens and other experienced mechanics always recommend pulling and inspecting/testing raw water cooled aftercoolers on a bench…

I had a survey before we purchased, but as you rightly say it could not have detected this problem - the only way would have been a borescope inspection of the cylinders and valves (and I guess few sellers would be willing to allow a potential purchaser to undertake that kind of invasive test).

On a positive note, our boat is a cracker now!!

Hamish.

 

[Ken E.]

Thanks for posting. Such a shame the Cats were so short-lived. I also repowered with Cummins and am very happy with them.

 

[Peter Pegasus]

Please do share your spreadsheet for others Down Under to refer. txs

 

[BrisHamish]

Thanks to Comodave and Ken!

While we had the engines out (which was actually a major component of the expense), we repainted the engine room, replumbed/replaced the entire fuel system, installed new twin Racors, put in a 3 inch exhaust bypass to make sure there was no exhaust back pressure (photo attached), installed a large continuous duty extractor fan at the rear of the ER (photo attached), installed a new externally regulated Balmar alternator on the port engine transmission for the 12v house bank, and repainted the black iron fuel tanks with some kind of ‘tough epoxy’ (?) paint.

On the black iron fuel tank question, we also borescoped these to look for any internal rust and there wasn’t any, nor was there exterior rust. So we decided to keep them and repaint them, as well as replacing all the deck fillers to stop any water leaks onto the top of the tanks. Photo of the new deck fillers attached.

Hamish.

 

[Comodave]

You did a lot of the same work I did except I didn’t replace the engines, just pulled them out so I could clean, paint and clean up wiring. On the deck fills you might think about routing the teak decks back away from the filler and glass in some G10 to raise the fillers up off the deck and get the teak away from the fillers to prevent leaks and water getting to the fuel tanks.

 

[BrisHamish]

Hi Comodave,

That is a good comment re the teak decking near the deck fill. We did try to address that issue as I describe below, although perhaps we might have a ‘better’ attempt as per your suggestion one day!

So as a more recent GB, our boat has a glass deck with teak then (unfortunately) screwed on top of it.

The teak planking runs lengthways up the walkway, and I assume the deck fill holes were originally just cored through it (after the teak was laid) and then the deckfill fittings were screwed into the teak planks. What we did was ‘rout’ around the deckfill hole, and then insert a new teak ‘ring’ around the deckfill and epoxy that ring directly to the fibreglass deck, the idea being that any water that got ‘underneath’ the teak planking but above the fibreglass deck could not then drain into the deckfill hole. If you look closely at the photo you can see the new teak ‘ring’ we inserted around the deckfill.

Also fortunately, because my GB is a later model, the deckfill doesnt go direct into the top of the tank by rather into an elbow on the stern end of the tank, making any water that ever does get in track to the stern side of the tank and run down it, rather than sitting on the top and slowly rusting away…

And finally, I always now fill up diesel AFTER each trip, which is a bit of a pain, but it hopefully means no internal tank corrosion because the diesel is all topped up.

Hamish.

 

[DavidM]

We have been preaching the need for proper inter/after cooler maintenance on this site for years to avoid exactly the problem you had. But yours is the first documented case of such failure I have seen reported. I suspect there are hundreds of more cases like yours out there.

Before your engine internals failed, did you find evidence of inter/after cooler leakage?

David

 

[BrisHamish]

Hi David,

It seems the failures occurred in 2008 (2 years after new), we bought the boat in 2014. Turns out the new/upgraded CAT aftercoolers had been installed on each side after the failures in about 2011, so when we bought the boat they both performed like ‘new’.

After purchase I immediately had the aftercoolers and heat exchangers pulled and serviced, and had them re-serviced every 12 months. Plus oil changes ahead of schedule, new HEUEI pumps, replaced the exhaust sprayers, etc.

Never any sign that anything was wrong, all oil analysis samples were OK and none changed markedly from one service to the next.

And then this knock in the port engine started in 2020. Not much but noticeable at first, it got louder. When we borescoped the engine all the inlet valves were covered in rust/corrosion, the no 1 cylinder all the cross hatching was rusted and scored, the piston head was pitted, and all exhaust valves were starting to corrode. Such a mess, and yet prior to the knock, not a clue at all that something was amiss.

If I had to guess, many don’t want to talk about it? It took me 12 months to be philosophical enough about the event to post this!

Hamish.

 

[DavidM]

Hmm, with all of the corrosion you found it is surprising that there was no outward sound of trouble brewing when you bought it.

I wonder if our resident guru Ski in NC or others could comment on what inspections might have caught this problem earlier, short of a boroscope. Also is a boroscope inspection that invasive. Seems you can poke one down the injector hole after removal which is a small job and I would suspect most sellers would allow it but only if there were more evidence pointing towards problems.

David

 

[twistedtree]

I had a survey before we purchased, but as you rightly say it could not have detected this problem - the only way would have been a borescope inspection of the cylinders and valves (and I guess few sellers would be willing to allow a potential purchaser to undertake that kind of invasive test).

I'm curious if such a thing would show up in an oil sample test? I would expect it would?

 

[twistedtree]

Fantastic job, and I really like the transmission PTO driven alternator. I've never seen that before.


I used to have a GB 47 EU, so just a couple years newer than yours. It had QSC 500hp engines and they were fantastic. I think you will be very pleased.

 

[rslifkin]

I'm curious if such a thing would show up in an oil sample test? I would expect it would?

It might have shown some extra wear metals from the damaged cylinder walls.

 

[gsholz]

Nice job but you might have had some other issues going on. Hard to believe that an aftercooler failure in 2008 would be responsible for the knock and corrosion in 2020. Usually engine problems appear within 1-2 years (e.g. early 3196 aftercooler failures with subsequent engine failures).

The new exhaust system seems well designed. That will eliminate one potential saltwater ingress source.

 

[BrisHamish]

I would be interested to hear what Skin in NC has to say about this, he has always been v helpful with any CAT related questions I had.

We did oil sample analysis with every service, always done by the local CAT people Hastings Deering, and it never raised any flags with them. The last one done was in 2019, we didn’t bother once the knock had set in in 2020 (had we done an oil sample analysis in 2020, I presume the oil would have been full of tiny little bits of metal). I don’t know this, I am just guessing, but I suspect that when the PO had the new style coolers fitted after the failures that he flushed/changed the oil several or many times in quick succession in order to clean it all up a bit, and it stayed ‘clean’ for a long while afterwards and hence we got clean and consistent oil sample analysis reports.

David is correct to say that a borescope inspection is pretty simple - it doesnt require pulling the head off or anything like that - and if I had my time again its what I would do when buying a secondhand SWAC engined boat. And if a seller would not consent to the inspection, I would pass on the boat. The things you learn!

I also am of the (uneducated) opinion that once those coolers failed in 2008, the engines were basically doomed to either a rebuild or a replacement at some point thereafter. In Australia a rebuild is not much cheaper than a brand new engine with a full warranty (unless you are in the rebuild industry or very ‘handy’ and can do a lot yourself), hence the choice for us of repower versus rebuild was fairly simple.

Twistedtree, yes I remember your GB47 well. From recollection you made some excellent posts about your installation of stabilisers on the GB47, which I had close regard to when we decided to put stabilisers into our boat.

Hamish.

 

[BrisHamish]

And now attached is an early version of the engine comparison spreadsheet I created in order to assist in making a final decision. I went through many versions of this document, it records my views as they developed plus bits of data sourced from manufacturer’s spec sheets - these are not documents prepared by a professional engineer!

Am just sharing this for anyone interested.

Hamish.

 

[Peter Pegasus]

txs for posting the spreadsheet. It didn't include the Nanni...I was surprised as I found their estimate to be slightly more than competitive with Deere in a recent enquiry, although both had supply delays except for a small stock of engines that were already in Australia.

 

[BrisHamish]

Hey Peter,

Yes, the attached is the first version of the spreadsheet and I hadn’t included Nanni at that stage.

On the next version, the CAT c9.3 dropped off and the Cummins recon also dropped off because neither was available for retail in Australia. The Cummins QSB also dropped off on advice from Cummins (due to the weight and hull shape of my boat). In their place I then added Cummins QSL9, JD6090 and the Nanni JD6090.

The JD6090 would not physically fit, so it dropped off and the next version added Volvo D8 and a Yanmar 550hp engine. I made a personal choice not to go with Volvo even though it was by far the cheapest option, and the Yanmar engine did not have a water cooled turbo so I dropped it as well.

It turns out none of the options could continue with my exisiting ZF280A gearboxes - the c7.1 would not fit them, the QSC and Nanni had rpm/power combinations that required something larger.

In the end, when I fully investigated price and what was/wasn’t included, and added the cost of new ZF286A transmissions, the CAT c7.1 was the most expensive option and the Cummins QSC8.3 was the second highest. But Cummins also had the most ‘inclusions’ such as Glendinning electronic controls. And Nanni could not deliver for many months at best.

The most ‘interesting’ option for me was the Cummins QSL9. It was available, and it was a bit cheaper. But the ‘technology snob’ in me got the better of me and I went with QSC instead!

Kind regards,

Hamish.

 

[twistedtree]

Did you consider Scania at all? It's moot now, of course, but I'm curious. The DI-9 might have been a good fit too.

 

[BrisHamish]

TD,

I didn’t consider Scania, mostly because I have never seen a Scania powered boat of GB46-ish size in Australia, and I am not aware of Scania having a market presence in that size range in Australia? (If they do have such a market presence here, it isnt widely known).

That said, more recently I understand Fleming has been looking at Scania and other reputable brands are installing them as well, so presumably they are a quality product.

The ‘Australia factor’ does limit choices somewhat. It’s a small market at the very end of the supply chain. For example, if the Cummins recon option was available here, I suspect I would have most likely just done that and not chased around after new motors.

H.

 

[Fletcher500]

Very nice looking install. It is obvious you were very methodical with the process based on your spreadsheet.

I could have put a Cat, Volvo, or any other make in to our new build, and also went with the Cummins. I have nothing but good things to say about the QSB. Very quiet, no smoke, runs smooth, access to the key engine parts and maintenance is very straight forward. I have had many people remark how quiet it is when we pull up, as they literally can not hear us coming. Granted, that's also good sound proofing in the engine room, but the engine itself is very low on the DB meter. I bet your larger cousins will do the same.

Best.

 

[mliemon2]

BrisHamish- We have a 2008 GB EU 48 that’s new to us. Aftercoolers we’re never serviced. I just pulled them and Tony Athens said to replace. How did you know yours failed and caused damage to the engine?

I’m not sure if mine failed and water go into the airside or not. It starts fine, and runs well, with zero indicator that somethings wrong.

 

[BrisHamish]

Hi m2,

I suspect you have a 2008 GB47 not a 48? (The GB48 is a much older design, it was not in production in 2008).

First up, I am not a mechanic of any kind, I am just an owner with an interest in this stuff! So if Tony Athens, who is one of the best Cummins mechanics around and generously shares his advice, recommends you should replace the aftercooler cores and/or housing, then I would follow that advice.

Secondly, the aftercoolers on my CAT engines did not fail during my ownership of the boat - they failed back when the boat was owned by the PO, and were replaced by the PO with the latest aftercoolers available. So when I bought the boat, it had pretty new aftercoolers which I serviced every year thereafter and tested for leaks (there were never any leaks). And both engines ran perfectly for me - until they didnt...

How did I find out that the aftercoolers had failed prior to my ownership? The answer is that once the port engine developed a knock and we borescoped both engines and found the internals on both to be full of rust, I had CAT do a full service record print out for me for each engine and those service records revealed the failures and the dates of the failures.

As to whether your aftercoolers have failed, you need to pay a professional mechanic to pressure test them on a bench and you will learn the answer straight away. If they havent failed yet, that is great news (and if I were you I would replace the cores and/or housing as per Tony Athens advice and then service them annually and not worry further). However if your bench test reveals one or both have failed, then the affected engine has been inhaling a mist of seawater and possibly at some point down the track you may have a problem like I had. If my experience is any guide, that affected engine will likely run fine - until it doesnt...

Hope this helps.

Hamish.

 

[markic]

Nice write up, keep the story coming and thanks for sharing ��

Again, for those interested, in terms of engine choices available for me here in Australia, the Volvo D8 was by far the cheapest option, the CAT C7.1 was the most expensive, the John Deere 6090 would not fit (due to length), the Nanni version of the JD6090 would fit (it has a different shape marine cooling system) but there was a 4 month wait on orders, and price wise the Cummins QSC was the second most expensive followed by the Nanni and then the Cummins QSL9 after that.

I had a spreadsheet comparing all the various options, which I will try to dig out and share.

With the new engines we opted for new ZF286A transmissions (I sold the old ZF280As with the CATS).

Cummins has been excellent to deal with - I would absolutely recommend that brand - and Cummins also offered the most ‘complete’ package in that their price included Glendinning electronic throttles and also the display screens whereas other brands had some of these as ‘extras’.

H.

 

[Ralsy]

Hi Hamish, I was wondering what the installation cost were?
Very nice job on the extras with the engine installation.

 

[BrisHamish]

The total net cost (net of the sale of the CAT engines/transmissions) was about AUD $260K inclusive of GST. These are all Aussie dollar figures, and reflect prices over here.

Of that AUD $260K, the Cummins/ZF engine + transmission package was about AUD $160K.

To rebuild the existing CAT engines and refurb the existing ZF transmissions was estimated at AUD $70K (although with a rebuild you may not know the true cost until you properly open the engines up and see whether new heads are required, whether each block is within tolerance for re-boring etc), with very similar install/removal costs as new engines.

So we took a big deep breath and went for new engines.

H.