High intake manifold temperature

[Duraga]

I have a intake manifold temperature that is way to high (105 by mid day normally 90) that is killing me.I have replaced the aftercooler and rebuilt the aux water pump that supplys the cooling water to the aftercooler as well as cleaned out the secondary cooling marely tower,all to no avail is there any suggestions or advice on how i can troubleshoot and fix this problem.

 

[Danger]

Welcome to PF, Duraga.
I'm one of those who likes to throw ideas at the wall and see if one sticks. In your case, I don't know what you're talking about. When I read the thread title, I expected something about an aircraft or auto engine, but that's obviously not correct. This must be some kind of large industrial application. Can you please clarify what your situation is?

 

[Duraga]

Thank you for the welcome and yes you are right it is for a large 2000 horsepower turbocharged 8 cylinder worthington sehg natural gas industrial engine that is used as a prime mover for a large natural gas compressor.

 

[Danger]

There are people here who know a lot about such things; I'm not one of them. I do have a couple of further questions, though. First, what's a 'marley tower'? I'm getting the impression of some sort of water storage/chilling silo, but that's probablly wrong. Secondly, when along the operational timeline did this problem crop up? Could it be an installation error, or have you been working normally and it just occurred?

 

[brewnog]

105 what?

What's the mixture temperature in and out of the aftercooler?
What's the water temperature in and out of the aftercooler?
What's the water flow rate?

If you've replaced the aftercooler and you're sure the water pump is working (and you have enough coolant and flow), this definitely points to the secondary heat exchanger. You may have cleaned it, but if either side of it are furred up then you might really struggle to dump the heat. (The same applies to the intercooler, obviously, but why did you replace this?)

And Danger was definitely wise to ask when this happened: from installation, gradually, or suddenly?

 

[Duraga]

Thanks for the interest Danger,first off this system is opened loop that consists of a aux pump 24psi then an aftercooler that transfers heat from the turbocharged air for the intake to water that runs through the aftercooler this water then runs outside to a "marely tower" that has cools off the water through a series of trickle down honey comb coils with a huge fan sucking the heat off them and back to the sump to start all over.Secondly this problem acurred over a long period of time the temp getting warmer and warmer it seemed like an aftercooler becoming clogged I know this engine has ran for several years with no problem either the new aftercooler i put in also has problems or i am missing something.

 

[brewnog]

Duraga, if the new aftercooler was of the right type (and new) and made no difference to the IMT, I suggest you check your system flow rate, and temperature differences over the aftercooler (air and water side) and over the cooling tower. Check at full load (I trust the engine is not exceeding its rating, and is otherwise performing well?).

The pump could be functioning perfectly, but if there's a blockage in the system, there'll be inadequate flow to cool your heat exchanger. Similarly, if either heat exchanger (aftercooler or cooling tower) is furred up, the heat transfer won't be sufficient to cool the charge air.

With no further information, this problem is impossible to diagnose further, and can cause catastrophic engine failure. I've seen a good number of gas engines scrapped by piston seizure because a clogged secondary heat exchanger put inlet manifold temperatures high enough to put the engine into severe detonation.

 

[Duraga]

Thanks for your input brewnog i definitely have thought of some sort of line blockage at this point as well but upon inspection at various points throughout the system there is at this time no actual evidence found yet to support that. And upon start up right after completion of the new intercooler there was several degree's differential temp from the inlet and outlet of the aftercooler and of course i checked for air in the system and nil with that being said tomorrow i am going to do several things 1 check the temp to the inlet of the tower and compare it to temps taken from a log from months of operator walkthroughs as well as the actual fan speed on the tower ran from an electric motor and recheck intercooler pressures and temps. Thanks for the help guys i'll give you an update tomorrow

 

[Danger]

Duraga, now that Brewski has weighed in, I'm pretty much supurfluous. The dude absolutely knows his stuff. Still, I'm going to hang around and make a pest of myself just because I find this very interesting. As such, I'm going to continue asking questions that probably have nothing to do with your problem but intrigue me.
One of those is, are your other operating temperatures within design parameters, such as cylinder heads, oil, and exhaust? Also, do you have valves in your coolant stream which might be misbehaving?

 

[brewnog]

If you struggle to find your blockage, just measure coolant pressures at various points around the system. The blockage will be between the two points with the unexplainable pressure drop. Sounds like you've got the other stuff sorted though. Let us know how you get on.

 

[Duraga]

First off thanks for all your ideas they where extremely helpful.Turns out the rebuilt aftercooler did not have a baffle plate that is required on the very inside of the inlet it is designed to do two things 1 spread the water across the whole aftercooler and 2 slow water flow down enough to allow heat transfer.i have since pulled the cooler and sent it back to the overhaul company and they are hot shoting me a newly done unit that they swear is correct thanks again .
Duraga

 

[brewnog]

That would do it. Glad to help.