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Regular Contributor

Re: Breaking Valve & goes inside of G3520C

small questions to all in the forum,

 

PF controlls , we are at 0,99 ind,and  we have resolve some throuble, engine power reading not more 98%, before at 0,95 ind, engine  go in over power some time,

 

can is this the font of throuble ?????

 

 

my engine is over 29.000 hours

Contributor

Re: Breaking Valve & goes inside of G3520C

Hi.

 

Your engines are 1966kW and 50Hz?

We have 6 LGS and we have some failures like you.

 

Contributor

Re: Breaking Valve & goes inside of G3520C

Hi, It looks failures are happening in all parts of world, I am sure valve break is purely attributed to defect in valve metallurgy. I am sure it is not related to emission levels, gas quality, exhaust temperature or any other parameters. Some experts from Caterpillar should analyse this problem and come up with proper solution. Erfan Ahmed India 91 9442166343
Contributor

Re: Breaking Valve & goes inside of G3520C

Dear.

 

I post another post mine because i see similiarity in our failures.

 

"I send an explanation a little more descriptive of our situation, may be you find something that we don't see.

We have 6 G3520C 2012 genset, lgs, 2044kw and 400V each one, in a landfill, in Argentina. 
We use a pretreatment for siloxane removal,( brand PPTek),and made a oil life  about 1000 - 1200 hours due to a TAN > TBN.
The signal of methane level it´s seted every 2 or 3 hours, depending by a GEM2000 gas analyzer, (brand landtec) the fuel correction never change out from 100 to 109. 

We have suffered a fail of 3 cylinders in 3 engines, we have a system control named Terberg, we did a data analyses of exhaust temp (around 620 ºC at full load and at the moment of the failure), fuel correction slightly over 98 in the tree engines. 
Exhaust emissions before failure, O2 8.3 %, Nox 124 ppm, in 2 first engine with failed, and in the last engine O2 8.4% and NOX 204 ppm one day before. 
Inlet gas fuel temp 20ºC, outlet jacketwater temp 108 ºC, manifold inlet temp about 58 °C, and the pressure 2.100 bar. 
In the 2 first gensets the broken valves have made a big destruction of the other valves, but in the last broken engine just one valve has failed, it´s the exhaust side engine, the break of the head valve it´s like a perfect cut of the valve stem. 
The cat knocking detection never show a level more than 1 before the failure.

In 3 failures the first valve brokered was exhaust side engine.
If the problem was the detonation, and it made a valve torch, the cylinder temperature should not be higher than the others? Moreover the only valve broken (I want to say cut from the stem) in the last engine don´t present evidence of torch, only many dents. 
The hours of engine for every failure are about 4.5 k. 
We don't have hard evidence of something more.

Our dealer, based on a consulted to CAT, say that the problem was a little deposit over the valve seat that made a torsion between the valve head and the stem, but we don't have a grate level of silicon deposit over the head, or valves or pistons, and detonation level never was more than 2 but rarely."

 

I´m looking for similar fails and find a real response, i think that is a  fails of the valve material.

 

regards

 

PS:I don't speak english, I was helped by the google traductor, please feel free for ask me, i will try to reply again in a better way

Regular Contributor

Re: Breaking Valve & goes inside of G3520C

beautiful photos and interesting, and say that the C series is born powerful and should be more robust than 3500 standardized, all the parameters of carburetion sonon righteous, greetings Gordini

Contributor

Re: Breaking Valve & goes inside of G3520C

Dear David, Mehdi,

Please see the pictures below failure of valves in our CAT 3520 C Engine recently.

We replaced, cylinder head, piston, liner, conrod bearing etc.......

 

 

SAM_3865.JPG

 

SAM_3866.JPG

Contributor

Re: Breaking Valve & goes inside of G3520C

Dear David,

 

What kind of gas are you running on?-Sour Gas having high content of H2S

What is you CH4 content?-78

What is your H2S content?-25-50 PPM after treatment

Did you have any Detonation alarms on that cylinder before it failed?-No, detonation levels are 1 or below one in all cylinders.

 

If you observed zaman and I have similar failures, breaking of valve stems.

 

Now we started using Bio gas valves in CAT 3520c engine.

 

Regarding you problem with Cyl#17 & 19 detonation, you can cheack the following

 

Interchange det sensors with other cylinder, because for 17# &19 cyl detonation sensor is common.

  after interchange you can figure out, if problem is arising in other cylinder, then culprit is det sensor, or else it could be problem with detonation sensor harness.

 

Pl try above and revert back.

 

Regards,

Erfan Ahmed

 

Contributor

Re: Breaking Valve & goes inside of G3520C

Hello,

 

Interesting problem, I am unable to help you but I do have a few questions for you. I am also have a G3520C running on biogas. I have a bunch of questions I will just list them.

 

What kind of gas are you running on?

What is you CH4 content?

What is your H2S content?

Did you have any Detonation alarms on that cylinder before it failed?

 

I am having a few problems myself that I am tring to figure out. I am getting Detonation alarms on cylinder #17 & #19 and unble to figure out why.

 

Thanks

David

 

Contributor

Re: Breaking Valve & goes inside of G3520C

Dear Mr. Ahmed

Thanks for your replay.

Are you have any idea for cuting of exhaust valve?

Best regards

 

 

 

Contributor

Re: Breaking Valve & goes inside of G3520C

Dear Friend,

 

I gone through pictures of valves, It was observed that there isn't much wear on valves.

 

abnormal deposits on inlet valve with traces of oil, there may be sticking of inlet valve, sticking also may lead to breaking of valve.

 

There may be a condensation in inlet air, may be due high humidity in your place, pl check any condensate drain provision.

 

But within 2000 hrs operation these type of failures are not acceptable, you take up the issue with CAT.

 

Our engine ignition time is 24 deg, we use sour gas as a fuel, different from your gas.

 

Regards,

Erfan Ahmed