Yes, the infamous “Mr. Gee murder mystery series” trying to find and eliminate the oil pressure killer has been continued but hopefully now finally resolved.
This could take awhile so you may want to wait till you can settle into a comfy seat with your favorite beverage before you continue. Just sayin’ ……………….
As some of you may recall, last September I left all of you and poor Mr. Gee literally hanging in the Engine Room and have only just now been able to pick up the story as the hung for the mystery oil pressure killer picks up for what I sincerely hope is the LAST chapter in this far too long running series. I will be VERY happy when I can leave all the mystery writing to the true professional author onboard, my beautiful Bride who goes by the pen name Christine Kling.
The Mystery Begins:
If this is new or too long ago for you, the quick summary is that during the first sea trial taking XPM78-01 Möbius out to sea for the first time last April, the oil pressure in the Gardner 6LXB main (and only) engine, suddenly dropped from its normal 35PSI down to almost 20 and so we limped back to port at very slow speed.
After much investigation and …..
……… stripping poor Mr. Gee completely naked, it was determined that the hired test Captain did not have the experience he claimed running of a boat with a CPP Controllable Pitch Propeller.
For reasons that will remain another mystery, soon after clearing the entrance to the port and without any notice, the Captain decided to perform a WOT or Wide Open Throttle test and pushed both throttle and pitch levers to their limits and overstressed the brand new engine, damaging the main crankshaft bearings as painfully evident here on these two connecting rod bearings and ……
……. here on the respective ConRod journals on the crankshaft, and other parts.
Once I had assessed the full extent of the damage, I contacted always super supportive and helpful Michael Harrison and his team at Gardner Marine Diesel and ordered a new crankshaft, bearings, gaskets and all the other parts needed to fully rebuild Mr. Gee a second time.
Knowing how long it takes to get things shipped to us here in Turkey I sent that order in very quickly and was pleasantly surprised when this crate full of all the new parts and new crankshaft showed up in late May (2021)
Mr. Gee Rebuild #2
I completed that second rebuild back in June 2021 and
Mr. Gee started up first crank as usual and oil pressure was spot on factory specs @ 35PSI.
The last week of June we took Möbius out for a day trip to test everything out and have a chance for us to get to know all these new systems as well as some time to practice docking and slow speed maneuvering. All went well, oil pressure stayed steady at 35PSI and so we headed out for a short overnight test run and our first chance to use all the anchoring equipment. It felt SOOOOO good to be at anchor again after all these years being landlubbers and these two short sea trials clocked about 10 hours on the engine including taking it up to full load multiple times with no problem.
In this shot we’re doing 9 knots at 1500 RPM
Beginning of July our two Granddaughters, Blair (in Red) and Brynn (in Green) and their Mum & Dad flew over for a month long visit.
After a few days introducing them to live onboard Möbius, we took them out to the same anchorage for Brynn’s 7th birthday which was very special for all of us. They all loved being on the boat so they decided to join us in moving Möbius up to our new Port in Finike which is about 80 nautical miles West from where we were in Antalya. We decided to anchor again on the way up in what the Granddaughters called “Mermaid Cove” which was a spectacular little cove with sheer rock cliffs for about 300 degrees around us and all was well with the world.
Next morning the girls helped me take up the anchor and we headed on to Finike. Alas, our good fortune was not to continue as the next day on the leg up to Finike the oil pressure again started to drop. It was different this time, dropping very slowly but it continued to drop as we made our way to Finike. Fortunately the Gardner 6LXB engines have an adjustable relief valve that allows you to set the oil pressure correctly after a rebuild so I was able to adjust the oil pressure relief valve to keep the oil pressure up at or above 35 PSI to ensure that no damage occurred, but I had to do this several times as the oil pressure continued to drop so clearly the dastardly “oil pressure killer” was still at large and needed to be apprehended and given a life sentence with NO parole!
Fortunately I had designed the Engine Room with a full size hatch for the roof and reinforced this so that by putting steel beams across I could lift Mr. Gee up into the air with chain blocks and suspend him about 1 meter above the engine beds using multiple loops of Dyneema line. Having already done this once back in May for the 2nd rebuild, it didn’t take me to long to remove everything neccessary to separate Mr. Gee from the Nogva CPP servo gearbox and hoist him up high enough so I could remove the cast AL oil sump/pan to get at the main bearings, crankshaft and main lube oil pipework.
It only took me a couple of days to remove the crankshaft but I spent most of August & September with my Sherlock hat on going to every length possible to flush out and find the root cause of the dropping oil pressure and fix it once and for all. I consulted with literally the world’s experts on Gardner engines as well as my personal list of diesel engine experts from all my years working as a HD mechanic, reading and researching every manual, online forums and doing lots of experiments on the various engine parts I came to suspect and finally found the guilty party, and I will walk you through my detective work below.
Third Time’s the Charm?!
And so began the rebuild #3 and what is hopefully the last of this murder mystery series. Given all that had happened, I was in no mood to take any prisoners nor any chances so I decided to rebuild the entire “bottom end” with all new parts.
So I built a super sturdy wood crate and sent the second crankshaft back to Gardner Marine Diesel in England to be reground with all new bearing surfaces as well ordering all new main and con rod bearings, new oil pump, new oil cooler and a long list of other parts. I was able to get that all packed up and shipped off to Gardner at the end of September just before we flew over to Florida for our long overdue Gramma and Grampa time in the USA and Canada. We were gone for almost two months so I had hoped that the newly reground crankshaft and new parts would be waiting for me when I returned but Murphy and the vagaries of shipping things In/Out of Turkey conspired against me and it did not arrive until last week. (mid Jan 2022) and Rebuild #3 began.
Finding the Serial Oil Pressure Killer
OK, with that as a quick overview of the chronology of this murder mystery, let’s get back to the story of how I eventually tracked down the elusive serial Oil Pressure Killer.
The Oil Pressure Killing Begins: April 2021
For reference, let me briefly go back and review what had happened the first time the Oil Pressure Killer struck on that first sea trials back in April 2021. As you recall, the oil pressure had dropped very quickly to 20 PSI and after tearing poor Mr. Gee completely apart this is what the crankshaft bearings looked like.
Yikes! With less than 4 hours total run time on the new engine, that loss of oil pressure was catastrophic and had completely worn away the protective lining of the bearings and severely scored the crankshaft journals.
This is how the Gardner main and connecting rod bearings are constructed, which is pretty much the same as most diesel engines and so you can see that the loss of oil pressure along with the huge loads when both throttle and pitch levers were pushed past their max positions, both the overlay and Nickel layers had been completely worn away.
Here is a shot of all seven of the main crankshaft bearing shells after the disastrous sudden loss of oil pressure on that first sea trial run. You can see how the bearings are completely worn out after less than 4 hours running since they were new.
For reference, main bearings should last for several hundred thousand miles on average diesel engines and much longer on Gardner engines. When I removed the bearings on the original engine which had been running in a working tug boat for over 46 years, they had just barely started to show a wee bit of copper.
With this much wear on all these Main and Con Rod bearings, the consensus conclusion was that the rapid wear allowed oil to leak out the sides of each bearing lowering the oil pressure which led to more wear which led to more loss of pressure and that cycle continued till I stopped the engine.
The next step was clear if a bit painful; completely rebuild the engine again! I had been in almost daily contact with Michael and his team at Gardner Marine Diesel and he soon had a new shipment on its way to me with a freshly ground replacement crankshaft, new Main & Con Rod bearings, all gaskets, seals and everything I needed to do Rebuild #2. That crate finally arrived in May and as per the outline above, I completed that second rebuild at the end of June 2021, just in time for the arrival of our Granddaughters and family.
The Oil Pressure Killer strikes again! July 2021
You’ve read about the fateful trip moving Möbius over to Finike Marina in July when the oil pressure started to drop again. This time there was no overloading and the pressure had stayed steady 35 PSI for the first 13 hours or so of engine run time but it then began to drop off again. Slowly this time, but steadily dropping. Fortunately I was monitoring this all very closely and was aware of the decline as soon as it happened and this time I was able to use the Oil Pressure Relief Valve to keep adjusting the oil pressure to make up for the loss and keep the oil pressure at 35 PSI and avoid damaging the engine. However, clearly there was a major problem and I immediately knew yet another rebuild was in my future!
I didn’t want to spoil the long awaited time with Lia, Brian, Brynn and Blair, so we didn’t say anything about it and rented a van to take us on a two week driving tour of Turkey. As per this shot, a good time was had by all.
Perhaps the most memorable stop on our driving tour was the three days we spent in Kapadokya where at dawn we all went on a 90 minute hot air balloon ride.
Seeing the sunrise over the surrealistic topography below was beyond words and only one of several other awemazing adventures we had together in July.
Tracking Down the Killer
We dropped off the family at an airport outside of Kapadokya and we drove the 9 hours back to Finike where Möbius and Mr. Gee were patiently awaiting for me to pick up where I had left off with the unsolved mystery. We now return to those two months of intense detective work in August and September and how I managed to finally track down the elusive serial Oil Pressure killer.
I soon had Mr. Gee suspended yet again from the Engine Room overhead hatch and it didn’t take me too long to get the crankshaft out so the investigation could begin in earnest.
Good news was that as you can see here, the bearings were not worn and the crankshaft journals were also untouched. Bad news was that clearly the loss of oil pressure was NOT due to wear on the bearings, so they were off the hook as the guilty party.
Wanting to leave nothing to chance and double check EVERY thing, I took the time to physically measure the gap on each of the Main and Con Rod bearings so that I would know eXactly what the clearance is and confirm for sure that all the bearings were still like new.
I’ve done this many times rebuilding engines over the years and is done using an ingeniously simple product called “Plastigauge” which is a special string like pliable plastic material which you lay along the bearing journal and then reassemble the bearing cap, torque it down fully and then carefully remove the bearing cap to reveal the compressed bit of Plastigauge. There is then a scale you use to measure the width of the flattened Plastigauge strip which tells you the exact size of the gap or clearance.
Good news the bearings and crank were still in like new condition.
Bad news is that the serial killer is still at large!
When faced with conundrums like this I go back to basics and start sketching out, both on paper and in my head, how a system works from beginning to end. So back to the drawing board I went.
Simple is Good Right?
Part of what makes Gardner engines so famously long lasting and sought after is their simplicity and the lubrication system is a perfect example. KISS and simple is good right? It definately is but in a case like this it is also very puzzling when you are trying to figure out how it is possible that oil pressure is escaping somewhere in such a very basic and “simple” lubrication system?!?!
For example, unlike modern engines where the lubrication system is mostly all internal and hidden, Gardner engines have most of their lubrication system flowing through beautiful copper pipes such as those you see here, which are all mounted on the exterior of the engine. This makes it very easy to check and obvious to see if there are any seals leaking there.
More Good/Bad news; all dry, clean and fully sealed. No leaks here.
OK, so no oil leaks in any of the external pipes and no bearing wear so no leaks there.
No oil was exiting the engine and the oil level stayed the same so the oil pressure had to be leaking out internally but how and where?
The only internal connections in the 6LXB lubrication system which are hidden from view is the lubrication pipework that carries pressurized oil to each of the Main bearings along the length of the crankshaft, so that’s where I next aimed my investigative attention and microscope.
Gardner also produced phenomenally illustrated and detailed manuals which I have gathered up over the years and have now become intimately familiar with every page! For example, this coloured illustration below from one of my manuals, shows how the oil circulates through the lubrication system in a 6LXB.
The Brown lines shows the path of the pressurized oil as it leaves the oil pump in the lower right corner, running up through external copper pipes to the Oil Pressure Relief Valve (upper right), through the oil filter and then back down another external copper pipe which delivers the oil into …..
…. the bolted on cast iron fitting on far Left here, which connects up to all the steel pipes and cast iron T fittings bolted to each Main Bearing cap.
If you refer back to the coloured diagram above, this set of pipework is shown in the Brown horizontal lines along the bottom of the crankshaft.
As is common on most diesel engines, once pressurized oil is delivered to the crankshaft main bearings, there are passageways drilled inside the crankshaft which allow pressurized oil to then travel out to each Con Rod bearing, then up through the Con Rod itself to lubricate the piston or Gudgeon pin and then the oil falls by gravity back into the oil sump where the cycle continues.
All as shown in the coloured illustration above.
The Search Intensifies
Trying to keep this a bit shorter than War & Peace, I am leaving out many days filled with investigating every millimeter of Mr. Gee’s lubrication system. I continued discussing this with the team at Gardner, my dear friend Greg who has the best mind and experience with diesel engines I know as well as many others (thanks!) via Email, voice and video calls and sending them probably more than 100 photos I had been taking throughout my sleuthy searching.
As each part of the lubrication system from pipes to pumps, filters to seals, was fully explored, tested and put under the microscope they all checked out fully and were scratched off of my list of possible suspects. The only remaining possibility was a leak internally that was bleeding off the pressurized oil and letting it drain back into the oil pan.
I took a bit of a scientific approach of using the evidence I had collected throughout the whole experience during each of the rebuilds, sea trial data, research in manuals and online and then coming up with LOTS of different tests to gather more data.
Like this setup I created to pressure test all the oil tubes inside the crankshaft for any leaks due to cracks or otherwise. I filled each tube with engine oil, heated it to about 75C to replicate even hot engine oil operating temperatures and then pressurized to over 100PSI with this bicycle pump setup.
More Good/Bad news as all tests showed no leaks. Double drat!
Having eliminated every other seeming possible suspect, that oil pipework kept coming up as the only remaining suspect and yet it too seemed to be so simple and robust. The experts at Gardner have rebuilt thousands of XLB’s over the years and never had any problems remotely similar but the more I went around and around the more I became convinced that the leaks had to be somewhere in that seemingly simple pipework on the Main Bearings so I rolled up my sleeves and spent the next few weeks maniacally devoted to finding where and then why the oil pressure was escaping inside Mr. Gee and inside my little brain.
Even though Gardner and others kept taking it off the list, I kept coming back to that lube oil pipework as the prime, and in my mind now, only possible suspect and let me show you what I eventually discovered as I dug into this.
One of my tests along the way had been this setup where I bolted each of these cast iron fittings to their respective Main Bearing Caps with one of the steel pipes inserted into its O-ring sealed hole in the fitting and the other end of the pipe capped off. I fabricated a threaded adaptor that I could insert into the oil hole in the Cap and pressurized this with my bicycle pump to test for leaks and they all seemed to hold but I was still not sure so I kept looking closer and closer ……………………
At first glance, all looked well with those rubber O-rings but lets look closer …….
…….. something’s not right here, let’s look closer …..
……. what’s going on here? Looks like this O-ring has been getting squished or pinched?
OK says Holmes, we need to quite literally put this under the microscope.
I’m going to take some “literary liberty” to again condense down what was more than a week’s worth of truly microscopic investigation, more Emails, more phone calls and more testing but here’s the quick recap.
As Christine will quickly confirm with a roll of her eyes, I’m a bit of pack rat when it comes to engine and boat parts and this case shows why. I had kept all the O-rings, bearings and other parts from all the previous rebuilds so I was able to now dig them up and put all of them under the microscope and here is what I found.
These are the O-rings from the very first time I rebuilt Mr. Gee in 2020 and were in the engine when the first sudden loss of oil pressure occurred after only 2 hours of run time. You will notice that there is the same deformation of these O-rings that I noted above.
Here is the set of O-rings that were new when installed in the 2nd rebuild and then experienced the second slower drop in oil pressure in June 2021after about 13 hours of run time.
Here is one of those O-rings as seen through my 10x magnification lens.
Yikes! Do we have flesh eating bacteria’s evil twin on a rubber diet?
Eureka! I think we’ve found the Oil Pressure Killer!
Well, sort of. This seemed to clearly be WHERE the oil was most likely escaping and causing the drop in oil pressure. This evidence seemed to support the evidence of how the oil pressure stayed at 35 PSI for the first few hours and then slowly began to drop as these O-rings wore away more and more, letting more and more pressure escape. But the real question became WHY was this wear happening???
More calls and Emails ensued with Gardner who deserve medals of honour for service SO above and beyond any reasonable expectations which led them to contact the factory that makes these O-rings to see if there was any chance of a bad batch of rubber or any other explanation for this catastrophic wear and failure. I measured and tested all the O-rings on my end including many of the new ones I had in my Gardner parts department and they all came through with flying colours for all their dimensions, hardness, etc. The manufacturer confirmed that there had been no change in the rubber formula nor any recalls or other examples of any problems and GMD checked their records which showed that they had rebuilt more than 100 6LXB’s using these same batches of O-rings before and after both my batches and they were all running fine with no reports of any loss of oil pressure, so they were all as perplexed as I was.
So it was back to scientific mode for me. I took some brand new O-rings and ran several experiments where I would install them in their cast iron fittings and torque them down to their respective Main Bearing Caps. I tried some assembled #2 dry, #3 with some with a light coating of engine oil as is normal and #1 coated with the Gardner “WellSeal” gasket compound in order to test if there was some kind of a chemical reaction going on.
I left these overnight and then disassembled them the next day and at first glance as in the photo above, it looked like all the O-rings were fine and that there was no difference between tests 1 to 3. But the microscopic view showed otherwise and I could see that even these brand new O-rings were somehow being “pinched” and split just by being assembled and torqued down to factory settings. I repeated this experiment three more times with the same results every time so I could not yet explain why this was happening, I could at least replicate the problem and see that the O-rings were being pinched and sliced open upon assembly and then being worn away more and more as the pressurized oil began to flow through and around them.
Another flurry of Emails, photos and calls with Gardner who could only join me in disbelief and mystery. However, true to form, Michael very diligently had a new batch of O-rings made up to even tighter tolerances and shipped those to me. As soon as these arrived I tested them the same as I had all the other new O-rings from the previous rebuilds by bolting to their MB Caps on my workbench as shown above and and was DELIIGHTED to find that when I disassembled them the next day, they all came out unscathed with no pinching or splitting. Whew!!!
By now it was mid September and the clock was ticking in my ear because we were flying out for the Nauti Grandparents North American 2021 tour on October 5th. While the root cause or “killer” was yet to be apprehended I knew that I could not just replace the O-rings with more new ones and put the engine back together for a third time so I made the call to replace the whole bottom end and lube oil system with all new parts and start over from scratch. I put in the order with Michael at GMD for all new bearings, gaskets, oil pump, pressure relief valve and so on and then crated up the 2nd crankshaft to send it back to Gardner to have all the journals machined.
That second crankshaft I had just removed was still in new condition having been freshly ground before it was sent to me back in May and the bearings were all still in like new condition but I simply had to completely eliminate every possible source of leakage so I bit this very expensive and time consuming bullet and put it all behind me so I could move on with getting Mr. Gee back up and running permanently.
Killer Hiding in Plain Sight?
While it did feel good to have found WHERE the oil pressure was leaking out causing the dropping oil pressure, I HAD to figure out WHY this was happening so I could fix the root problem and be confident that Mr. Gee would have perfect oil pressure from now on. Our lives quite literally depend on Mr. Gee in many situations so this is not mere curiosity on my part!
After many more sleepless nights going over and over every possible explanation for the loss of oil pressure, the splitting O-rings, and coming up with every possible theory as to WHY those O-rings were being so rapidly worn away, I again went back to basics and started testing and re-testing every possibility. In particular I tried to make NO assumptions and check EVERY detail and sure enough one of those assumptions turned out to be the key bit of evidence that led me to the true culprit.
Remember those simple cast iron fittings and how the O-rings seal them? The mating surfaces of the fitting and the Main Bearing Cap are flat with a square groove cut into the fitting where the O-ring sits. The O-ring is thicker than the depth of that groove so that when you bolt the fitting down onto the Cap, the O-ring squishes and seals the oil flowing through from being able to escape.
Reasonable to assume that those two mating surfaces are flat right? No need to check for that!
Well I just happened to check and sure enough the surface of all those fittings was NOT flat
It will have to remain a mystery as to why this happened but it turned out that those cast iron fittings that bolt to the Main Bearing Caps were warped. Bowed would be more accurate as even when they were fully torqued down tight as they are here, there was a gap in the middle section where the O-rings sit. In further testing these gaps ranged from 0.3-0.5mm or 0.012-0.02” whereas they should be touching and sealing themselves.
Why is this such a big deal that there is gap between these two metal surfaces?
Well, with the metal surfaces not touching around where the O-ring seals, and with the O-rings being split open for whatever reason, once the oil started flowing under pressure it penetrated the interior of the rubber O-ring and began to erode away the rubber much like a river erodes its banks. The more surface area this erosion exposed the faster the rubber wore away until the seal was breached and oil could now flow out. With the metal mating surfaces not touching there was nothing to stop the pressurized oil from flowing out so once the leak began it increased rapidly and down went the oil pressure.
In this shot you can clearly see how bowed or arched this surface is. I have started to file the mating surfaces of these warped or bowed fittings to make them flat again. After a few passes over the file you can see the shiny outer ends of the fitting have been filed away because the middle area is still low.
I decided to flatten these fittings by hand with a file rather than milling them as I needed to get these surfaces completely flat so they would mate and seal perfectly when bolted to their Main Bearing Caps but I wanted to remove as little metal as possible so as keep the pressure on the O-rings when these are bolted down, to be the same as new.
Here is the fully flattened fitting on the Left while the Right one is just getting started.
All lube oil pipework fittings now perfectly flat and ready for another lifetime of fully sealed operation!
And call me paranoid if you prefer but I will refer to this as taking more of a “belt and suspenders” approach to ensuring these fittings stay completely sealed by using a bit of Ultra Black gasket maker on the outer surfaces for an additional seal. Probably unnecessary as the O-ring will do all the sealing now and the new batch of O-rings are not being split open when assembled, but doesn’t hurt to have this added sealant and additional peace of mind for me.
With the new crankshaft now back in place and the Main Bearing Caps all torqued down tight, it was easy to bolt on the now flat fittings and put the lube oil pipework back in place.
The whole bottom end has now been replaced with all new and some improved parts so time for one last double check.
At last I could carefully drag the 50kg/110lb cast AL sump back into the Engine Room, put on a layer of gasket maker on the outer flanges and lift it up onto the bottom of the crankcase.
I threaded some web straps underneath either end of the sump and ran them up to 6:1 blocks above the engine to lift the heavy sump up and line it up with the studs around the crankcase and then torque all 68 nuts down in stages.
Whew! A long time to get back to this point and now I just have to hope that I have indeed gotten to the bottom of this “murder” mystery and found and eliminated the serial Oil Pressure Killer.
I will leave it at that for this week and be back again next week as I put Mr. Gee back together and back to “bed” on his engine mounts. Now that I’ve had several practice runs I should be able to put him all back together fairly quickly and put those new seals to the test when Mr. Gee finally comes alive again and I can start putting on some hours and loads to confirm for sure that this latest mystery has been solved.
If you’ve made it this far, my congratulations for your perseverance and patience. Hope you enjoyed this murder mystery but as I said at the beginning, I’m looking forward to there just being ONE murder mystery author onboard Möbius, and I can go back to being her trusty crew.
Be sure to put any questions, comments or suggestions in the “Join the Discussion” box below and hope you will be back for more next week.
– Detective Wayne