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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: belfert on September 28, 2016, 01:46:42 PM

Title: Will vents in engine hatch help with heat from engine?
Post by: belfert on September 28, 2016, 01:46:42 PM
My engine doesn't overheat, but heat gets into the passenger compartment and warms up the back area so bad I need to run the A/C unit or open the vent even at 50 degrees outside.

Will vents in the rear engine hatch help with this?  I find it hard to imagine this much heat coming into the passenger compartment when this was a passenger coach.
Title: Re: Will vents in engine hatch help with heat from engine?
Post by: lvmci on September 28, 2016, 01:53:31 PM
hi Brian, my MCI5A 8V71 was the same way, lvmci...
Title: Re: Will vents in engine hatch help with heat from engine?
Post by: Lin on September 28, 2016, 02:19:54 PM
Possibly vents will help a bit.  I do not know what your cooling setup is.  On my 5a, the cooling air is generally vented under the engine.  If the engine compartment had vents that could increase the flow, but there is a lot of air movement through the compartment anyway.  Our bed is over the engine with storage under the bed.  I fill that up with blankets and extra pillows but still the heat eventually come through.
Title: Re: Will vents in engine hatch help with heat from engine?
Post by: eagle19952 on September 28, 2016, 02:37:01 PM
Quote from: Lin on September 28, 2016, 02:19:54 PM
Possibly vents will help a bit.  I do not know what your cooling setup is.  On my 5a, the cooling air is generally vented under the engine.  If the engine compartment had vents that could increase the flow, but there is a lot of air movement through the compartment anyway.  Our bed is over the engine with storage under the bed.  I fill that up with blankets and extra pillows but still the heat eventually come through.

i just stop earlier in the day :)
Title: Re: Will vents in engine hatch help with heat from engine?
Post by: belfert on September 28, 2016, 04:26:56 PM
The radiator is mounted parallel to the rear next to the engine on the driver's side.  There is a large compartment on the driver's side that brings in air.  The hot air must exit under the bus somehow.

I have people who will sleep in the back while cruising down the road so the heat is an issue.
Title: Re: Will vents in engine hatch help with heat from engine?
Post by: Utahclaimjumper on September 28, 2016, 04:48:02 PM
 On the three different GMCs (4106) that I have helped to convert, it's been my observance that a lot of hot air is trapped high in the engine bay, unfortunately this is where the induction intake air is being drawn in and it gets heated during the process,,not good for power! or for the bedroom! Just above the rear access horizontal door hinge is a perfect place for ridding this area of heat by using polished stainless louvers from the marine industry, they do the job and look good to boot..>>>Dan
Title: Re: Will vents in engine hatch help with heat from engine?
Post by: DoubleEagle on September 28, 2016, 05:10:18 PM
Making sure that any access hatches in the floor are sealed well can help, and adding additional reflective insulation can help delay the transfer of heat. While parked with the engine off, consider opening up the back door to vent the heat, or have an electric fan running to do the same. Beyond that, while on the road, you need more A/C capacity in the rear to compensate.
Title: Re: Will vents in engine hatch help with heat from engine?
Post by: Scott & Heather on September 28, 2016, 07:50:48 PM
This is exactly why we insulated our floor and rear engine/bedroom area with pro spray foam inside a double 3/4" floor sand which topped with fire rock Sheetrock, then sound proofing mat then carpet. No more heat soak in the bedroom anymore even in the 90's. That being said, after I've been driving for a while, if I pull over and try to open the engine doors on our 102, the heat that washes over me is likened to opening up an oven door that's been baking something at 500 degrees F. So I can't imagine it would hurt to add vents back there on any model bus. I'm considering just removing the two lower doors altogether and installing a framed metal mesh similar to the generator bay (condenser) mesh


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Title: Re: Will vents in engine hatch help with heat from engine?
Post by: GM0406 on October 01, 2016, 01:14:29 AM
Well dealing with heat is best done by getting rid of it!  In the air conditioning industry, we give heat the bum's rush.  That means exhausting it wherever possible rather than trying to cool it with expensive refrigerated air.

My 4104 does not heat either in the rear bedroom area or on the temperature gauge.  George Thornhill did that coach and whatever he did keeps that engine temperature gauge at 180 degrees rock solid.  I don't care how hot it is out there or how hard we are pushing it.  It has for starters dual exhaust.  And it has the sign portion of the engine compartment door removed and wire mesh relief.  It also has large Donaldson intake air filter with large blower intake on a high block 4 valve engine.

Now here is the incredible truth about this engine.  It also has a Walker oil recovery unit on the engine and it doesn't leak oil.  Are you all listening to this?  Yes, it doesn't leak! 

Am very surprised that no one responded on the water injection that I suggested in another post.  Was hoping that someone here with positive or negative experience on that would chime in.

One more observation on my coach is the gen compartment where George also got the insulation bug!  I  had to use one of those helping hands grabbers to patiently pick all the foam off the walls of the gen compt. as the stuff all disintegrated.  So be careful of time and heat!  Best to get rid of heat as quickly as possible rather than trying to box it in!   

Lastly, a shame we aren't up to speed with future energy solutions which could replace our great Detroits with nice small Thorium reactors that would push these great coaches for the remainder of our lives with no refueling requirements.     
Title: Re: Will vents in engine hatch help with heat from engine?
Post by: dtcerrato on October 01, 2016, 02:28:41 AM
WOW!
Title: Re: Will vents in engine hatch help with heat from engine?
Post by: OneLapper on October 01, 2016, 08:28:10 PM
Quote from: GM0406 on October 01, 2016, 01:14:29 AM

Am very surprised that no one responded on the water injection that I suggested in another post.  Was hoping that someone here with positive or negative experience on that would chime in.



No one was ignoring you!

I'm confident that water/alcohol injection will improve the performance of our bus engines.  I have a 4106 and plan on installing propane and water injection on it, but like everything else, I'm always a few years behind on completing my bus projects.

I have quite a bit of experience with water injection on a 3.6 liter twin turbocharged car.   On the first dyno pull it would put down 580 to the wheels, then the next pull was 550, then 520, then high 400s.  I raced the car like this for a couple years and it was what it was.  By all records, I was the first one to put a water injection system on this type of car.  To do it right, the engine has to be pulled out.  The system I used measures boost and injection signals to adjust water flow.  After the system was installed, it put down over 600 to the wheels all the time.  No heat soak, no boost and ignition dial back to control detonation.  After word got out, everyone was installing them.  I don't feel a street car needs water injection, but on the race track, it made a huge difference, several seconds a race, which was the difference between winning and not.

Our bus engines run WOT most every time we hit a hill.  They run hot.  But diesels should run hot to run efficiently.  They shouldn't overheat, though.  I don't feel that water injection will prevent overheating on a long pull.  You'd need to inject too much water or alcohol in my opinion, but it will undoubtedly improve performance and reduce the heat load.  I think misting/spraying water on the radiator would be more effective on a long pull.