Hey Guys,
Another episode on the "Interesting Times" or otherwise known as the "Don't Double-Time your Lister(oid), It Will Get Jealous!!"
I spent Friday evening in the welding shop, arb-ing around and knocking up some "basic stainless steel 5mm bar racking for a wet environment" (A facecloth, soap and shampoo shower rack doesn't sound nearly as impressive!), while TM1 thumped away beautifully for around a 10 hour shift, I started him running early in the mid-afternoon and ran him all the way through to late evening. He was a little "wandery" in the revs department/governor by late evening, I put it down to a prematurely clogged fuel filter.(This one only did about 100L of prefiltered gunk, as opposed to the last one, same make and model, which did almost 700L or thereabouts.Anything is possible, possibly I contaminated the fuel during filtering, or maybe this batch had some extra fines in it, or maybe .... well whatever, but it happened!
The following day(Saturday) I continued with the leisurely tear-down of TM2, managed to measure the amount of slack that was evident the camshaft gear train....it worked out to 2.4mm that the center-line of the idler bolt was out(That's with 0 clearance on the gears and starting to bind...Allow about .4mm clearance on that measurement or so on an eccentric bush and that should give me a good starting point to get things together. The bulk of the clearance was on the camshaft side of things, there was just a wee bit too much slop on the crankshaft meshing side, a little inwards would do the trick... More on this later...
Once the measurements were made for TM2, I changed the fuel filter on TM1 (Mutter, mutter, mutter... Cross threaded the damn thing and stuffed up the threads... Fixed that minor stuff up and carried on!) Once the fuel system was bled, I started him up and away he went, takes a few minutes to get the last few bubbles out of the lines that trap in the high parts of the crappy fuel line routes I have taken and the new filter cartridge, but nothing serious, no great pain...
Of course, I did do the cursory checks , oil level still above minimum, water present and accounted for, valves and rockers oiled, tappets oiled, governor linkages oiled.... Run up on the starter for around a minute or so(maybe a bit less)... Now, bear in mind, TM1 has been a bit of a thirsty bugger in the sump department up until about the last 120 hours or so ago. Just prior to his last 400hourly service about 100 hours ago, he stopped using sump oil and I have not had to top it up since service, even though I check it religiously before each run. I put that down to the WMO I am using having a higher than Dino lubricity and slowing down the run-in process...
A bit of Background: TM1 (and TM2) both have a sump with "apron" - the oil is picked up through the strainer in the apron and pump to the TRB's / Crankshaft pickup ring after going through an aftermarket canister filter. This system has worked beautifully for the last couple of thousand hours or so. I have added a dipstick to the apron side of the engine, the high oil mark has been calibrated to when the oil level is just below the big end housing/nuts at BDC, the low oil mark is when the apron weir notch is just exposed above the oil by about 1/4 to 1/2" - this is a far more meaningful (to me anyway - correct me if I am wrong) way of checking the oil level - the original dipstick only shows the level in the weir..... The apron could be empty under certain conditions....
Right... Now the jealousy steps in - I am sure that TM1 was getting jealous of the attention I have been giving TM2... He threw his toys out of the cot and stopped his oil pump from doing anything... The bastard even hid it from me... The oil pump is still moving freely, just no oil is flowing....something has gotten stuck somewhere(probably one of the balls in the valves) and oil is just not moving!! - Net result: No oil flowing into the weir to be splashed around, no lube to the cylinder walls, no lube to the big end.... Piston seized in cylinder!! Fuggit!! Tomorrow is another day...
Sunday: Eventually got around to taking off the CC cover and poking around properly... I didn't pull the big end cap, but did feel it for play... Not much, if any, to be felt. I eventually got the bastard turning over and added copious amounts of lube oil to the top of the piston while doing so. Feels like the rings did a nice "jam job" in the upper cylinder. (I didn't pull the head, just gently bumped the flywheel back and forth to break things free.... It seems as if there is an excessive amount of play on the small end bushing, something to be attended to in the near future...)
Well, I figured, my bench is currently full of stripped down and mostly modded TM2... No way I am going to tear TM1 down as well... Lets do what the peasants do when the things gum up and stop working... Add oil, wind it over, see if it starts...
After allowing him a loooong wind over on the starter, I threw the compression relief and pump stop.... He fired right up!
He is breathing a little harder out of the breather, but no oil leaks as yet... Maybe there's broken rings, maybe there's a scored cylinder, maybe a galled piston... Maybe, at the very least, the rings cooked and softened... Who knows? (Anybody want to hazard a guess as to the damage?)
I will tear him down in the near future, but what pee's me off with this is that now my run time on these rings/cylinder with WMO fuel will be skewed... Oh well... just 900hrs of run time wasted from a data collection point of view... (incidentally, he is still running without oil pump... I am just keeping the oil level above the weir in the interim until I can get round to seeing whats crapped out on the pump....I wonder how long he will last?)
Keep it spinning
Cheers
Ed
Edit: On TM2's eccentric bushing for the idler gear - I drilled the casing and trumpet, then reamed the hole out to 20mm. Into this I added a tophat section bushing with the center hole to suit the idler spindle offset by 2mm. This is inserted from the outside and locked in place by the existing spindle. I have adjusted the play evenly on both sides and put a telltale mark on bushing and casing for reference. This has given me around 10 thou play(backlash) in both the crank and cam departments individually... Initially I was looking at an eccentric in an eccentric type bushing, but with the play that was evident, there was just not quite enough real estate available to accomplish this.... This "fix" was a lot easier to do than remaking a stepped idler spindle... Once in place and tightened, it holds well and is easy to install.... Anybody wanting a picture? Just let me know!!