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Discussion Starter · #1 ·
I tested the compression of each cylinders of my 2GM20F. Cylinder #1 270psig and Cylinder #2 250psig. :confused: These numbers seems way too low as expected is 370-450psig. I should have squit some oil into each cylinders before trying again to see if the pressure will come up. If it does I suppose it means my piston rings are wore. But I forgotten about this step. :mad: I'll schedule anither day for this test again.
Comments anyone?
 

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Discussion Starter · #4 · (Edited)
Puddin', "wet test" by that I suppose you meant squirting abit of engine oil into the chamber. I'll do that.

Paul, I've no problem cold starting. Cold here in SG is ...like 25degC. I guess that's pretty warm for some sailors. Day temperature is 30 degC in shades and 35degC under sun. Anyway next time will 1)warm up engine before test 2)Squirt some oil then test again.

Appreciated your comment/reply. :)

Lesson learnt:
Remove only the Injector of cylinder to be tested. Rest of Injector/s to be left tighten inplace. I made a mistake of remove both Injectors first then run test on one. In 2-3 cycle of engine chamber gaskets, insulators and all blew right out of the other cylinder and include a fair amount of carbon dust :(:eek:
 

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Discussion Starter · #6 ·
I'm not getting the power I expect of the engine. Most of the time, I've to run at 3000rpm to make 5kts in slack tide. I've tried changing props several time (pitch & diameter) and in the end summise that I probably have some wore rings. I do return couple of years back, I made a 500nm passage (engine most of the way) and at the end of trip found the oil level to be alomost zero. I could only drain out 0.5-1 litre. I could have abused the engine on that trip. That's my suspect.
 

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Discussion Starter · #10 ·
Prop I used are: stock 2RH 15"Dx10"P, CSP 3RH 14"Dx9"P, & 7"P, & 6"P, KiwiP 3RH 16"Dx20deg, & 18deg.
I've tried SAE40 and SAE15W40. I don't find any difference. I've tried adding STP Oil Treatment (Silicone base). It helps raise max rpm by 100-200rpm.
 

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Discussion Starter · #20 ·
I can't swing a larger or higher pitch prop as it would not reach 3200rpm. I forgot to mention I've a 2 blade 15"D x12"P Flex-O-Fold as well. Max it could make is shy of 3300rpm.
So far all checks and feels points to rings wear. Compression test seems to confirm that. Anyhow, I'll try the "Warm" and "Wet" test and post results here. Unfortunately, test analysis of crankcase oil isn't common or known here.
 

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Discussion Starter · #30 · (Edited)
Slight white smoke on starting. No smoke after warm up. Of course reducing pitch will bring max rpm up. Which i did when repitching the CSP as well as KiwiProp. But even that did not give the performance expected as reported by many other boats when comparing displacement and engine power. Thats why i suspect my engine has wore some and probably tire. Need refreshing :)
However i do get black sooty exhaust when i gun the engine on reverse in anticipation of hitting the dock... (KiwiProp).
Oh another observation, I notice some/a little oil sheen on water after i ran the engine but didn't check if its from my boat or others. Will take a closer look this weekend.
 

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Discussion Starter · #36 ·
Christian, you mentioned on coolant leaks. I did notice coolant level in reserve tank dropping over time (a long time) its so small, i just ignore it. Its like drop by 1cm over 2-3years. Nothing to be concern I suppose? Or am I waiting for a big hit?
 

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Discussion Starter · #46 ·
I'm the original owner. In early years I don't know much about diesel so within 2 years I choke up the U Mixing Elbow with enough coke & rust to stop the engine running. Got engine fixed in workshop. Shouldn't have to actually. As I learn more of diesel, I guess I got careless/complacence. 3 years back discover only about 1 litre oil in engine after a 500nm passage. Silly me for not checking. So I might have caused excessive wear in rings.
As maintenance, I change oil & filter every 100 hrs. Oil turns black after couple hrs of driving. Not sure if that's normal or results if wore rings. No water in oil so far. Only oil sheen on water at stern when at berth, yet to confirm if from my engine or others.
 

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Discussion Starter · #53 ·
If there's any knocking, I'm not aware or able to discern. Great we've narrowed down to some actionable items. Heavier weight oil is one that I'll do. I've a can of STP on hand.
Appreciated. :D
 

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Discussion Starter · #61 ·
The CSP 14"Dx9"P max out at 2700rpm. Which prompted me to start lowering the pitch. 6"P was the ideal maxing out at 3400rpm. These was about 5+years back. The Yannar tachco rpm was only +50 against handheld tachco.
I'm not too keen to send the engine for overhaul just yet. I'll see what the engine condition is first. It has to be for a significant if i were to overhaul the engine.
 

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Discussion Starter · #65 ·
Curiously, for "wet" compression test, how much oil do I drip into the chamber? Couple of drops or 10mL ....?
 

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Discussion Starter · #79 ·
It would be interesting to know what you find.

Paul T
I will report my test results here. I won't be able to do the retest till later June. I would want to post some pic of my Compression Gauge setup but there seems to be an uploading problem. I'll check again.
 

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Discussion Starter · #80 ·
Your are right. I even bought a oil pressure sender and gauge. However there is a question on the yanmars as to if is is best to install a tee fitting so you have both pressure gauge and press switch (with buzzer and light). Once the Tee fitting is installed, the vibaration of the engine (and with the weight of the gauges/switches hanging off the end of the Tee fitting), there is greater likelyhood of the Tee fitting breaking or leaking. In the end, I have not installed the gauge because it seems it makes it much more likely to have an oil leak at the connections.
Yes sometime we introduce a new component and along came new problem. Mr. Murphy is always lurking somewhere :puke :eek:
 

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Discussion Starter · #86 ·
The results are in!! I've warm up the engine and check the compression, then squirk some oil into the cylinder and test it again annnnd the result IS ...No Different!!? 260psi.
Same as when I first did the test. So what does that tells me?
 
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