sulzer rta engine
sulzer rta engine
(OP)
this is a 9rta 76 engine. i am having problem with one of the showing low compression pressure. the peak pressure is normal.fuel valve and exhaust valve operation is ok.what can be the resons for low compression pressure





RE: sulzer rta engine
head gasket leak
worn rings
leaking exhaust valve
loose spark plug
leaking spark plug(internally)
holed piston
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: sulzer rta engine
RE: sulzer rta engine
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RE: sulzer rta engine
RE: sulzer rta engine
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But, from general problem solving principles, have you checked or swapped your pressure sensors?
respectfully
RE: sulzer rta engine
The pressure of course is very, very, very, closely linked with the compression ratio. If in the process of reconditioning, the top of the piston or the head had much material removed you would see a large shift in pressure. How hard would it be to "cc" the cylinder at TopDeadCenter? Compare it to a cylinder you're happy with. That would eliminate that possible issue.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: sulzer rta engine
Any leakage would certainly interfere with resulting combustion pressure. As mentioned in previous post, I'd check or swap pressure gauges.
RE: sulzer rta engine
cheers
Mark Hutton
RE: sulzer rta engine
I have seen problems with compressors, but the areas from which metal is typically removed during a rebuild generally results in a greater compression ratio and pressure, not less.
A couple of suggestions from first principles;
1> An air restriction during the intake cycle.
2> A new compression (head) gasket installed without removing the old gasket. This is easier to do by mistake than you may think.
3> Too much cooling. Possibly a baffle or diffuser was left out of the cooling circuit for this cylinder.
4> Instrumentation errors. Check your pressure transducer.
respectfully
RE: sulzer rta engine
AM
RE: sulzer rta engine
The rta engine has been in production for a large number of years nad as such has been subject to continuous development. Without more information it is difficult to nail down but I would add the following to those made earlier by Waross
The engine has both VIT and VET both of which if not operating correctly will affect peak pressure. I would check for slippage of the fuel cam and lift of the fule pump. I would check the condition of the cam followers ( I have seen a number of failures), the condition of the pump espcially the anti dribble device. I would check that no bespoke fule limiters of pump lift devices have been inadvertently activated.
Apologies if this has been mentioned but some korean built rta's suffered from excessive bore cooling and porr scavenge demisters resulting in huge wear rates in the cylinder ( I know of a batch of engines running liners out in 5000 hours with piston ring packs lasting as little as 250 hours. Yes I do mean two hundred and fifty.
Operating the enginer with one unit significantly underperforming leads to extremely serious torsional vinbration and critical speed issues and you should consult the manufacture for advice on operating the engine in a degraded condition.
I like the idea of a sensor failure.
RE: sulzer rta engine
First thing I would like to investigate is the instrument: I was accustomed by an old fashioned Chief Engineer to use Digital to quick check, then the usual spring loaded paper ribbon MAIHAK recorder to have a GRAPHICAL readout of the pressure transient. It gives a lot of Hints
It is my direct real experience that on another marine engine the use of reconditioned piston rings caused a lot of problems. If someone fitted one of the compression rings upside down nobody notices until compression is too low.
What about exhaust gas temperature? maybe ten to twenty degrees below the next cylnder?
Do you have original testbench readouts, the one stamped by Classification Society?
I do agree that a misfiring condition is a definitely limited time, limited power takout situation, while I have a very limited experience with 2stroke engines.
If you have a "spillable" oil mist detector sample piping, you may check for abnormal oil mist from the obseved cranck section.
Any way, if you are the Chief, report to the Superintendent and limit the power out: you may be in a dangerous situation.
Let us be informed....