Airflow over engine - Max49, this is for you

[Joe Gilbert]

My W22 has 47,000 miles so I thought I would treat it to a set of new spark plugs (41-101 from Oemy's). I gaped these at .045" (I have the UltraPower mod). While I had the plugs & wires out I took photos of the plug wires and the side curtains which National RV installed on the Dolphin's. I'm not sure what the material is; perhaps carbon fiber cloth. Whatever, I expect it has a high heat rating. It is attached firmly at the top and with tie wraps at the bottom. It covers most of the opening to the wheel well. It works on the Dolphin as my plug wires and all other wiring look and feel like new. I'm sure it allows the air to move the entire length of the engine before exiting.

After leaking my share of blood on the engine I did get the old plugs out and the new in. The old plugs looked great.

Max49. I hope this helps.

The photos show

A) All of the plug wires (look like new)
B) #5 & 6 plug wires
c) Right side curtain (not too clear)
D) Left side curtain (nice clear photo)

JoeG

[max49]

That's amazing Joe. You would think covering the plugs like that would make them run hotter, and with mine wide open , I'd think they'd get enough air, but obviously not. So, if you have your air dam all sealed up, I can't figure out where your'e getting airflow over and beside the engine from. Are you just getting air, after it passes thru all the coolers and radiators up front? And then some more when the big fan kicks on?
I know this goes against the grain around here, but I really think the air dam, if too tight , has something to do with my wires melting. They always melt inside the heat shield; so I'm not sure if the shield is keeping the heat in, or just not keeping the heat out good enough.
On my first engine , it burnt # 5 wire 3 times I think in 30,000 miles. I don't think it burnt any more after I put the bilge blower and ducting in on that side of the engine.
On this engine, shortly before my last trip, I added more air dam material on the passenger side because , when I posted a pic here, for some reason, a couple of people said they thought I was missing some of my air dam. I had just put the 180* T Stat in and I wanted it to be right. Then I burnt 2 wires and all that air dam stuff I put in is gone now.
Anyway, it all seems to be trial & error. Trouble is , I make so many changes, if it does fix it, I won't know exactly what did it.
I put the 2nd blower in and ducting to the starboard side, changed my mind and put the heat shield back over # 6 wire ( may be a mistake, IDK), then I used some flashing material and made a 2nd heat shield over the 4 rear plugs.
I can't easily test my changes , pulling a trailer over the mountains, so I just have to wait for my next trip, and see what happens.
I'm going to get some free flowing mufflers , and hope that helps performance and getting the heat out of the manifold faster.
Thanks for posting those pics Joe.

[pkmesser]

Insulation, in a case like this, will help only if the high temperatures are there for a shorter period of time. Then the heat soaks through. (heat is energy, in order to cool, there has to be a place for that heat energy to go to) If you then do get cooler conditions, the insulation will then hold the heat in longer. With the very long grades being pulled, my opinion is that you need to do everything you can to remove the heat, you have the heat conditions for too long a time for the insulation to help. The heat shields are normally around the plug and wire, where it is closest to the manifold. If they are open to the outside, so that the heat can escape, then they would do some good. If you improve the airflow there, then they will do better.
I am interested in what Joe says about where his airflow is coming from, but I think you probably hit it on the head, it is the air from the coolpack. Even though that air is hot to you or I, it is cool in comparision to the conditions next to the manifolds. If that shielding keeps more of the air moving next to the manifold and engine, then I can see that it would help. There is so much in the photos, that it is hard for me to visualize the detail, but the concept makes sense. If you read my last posts in your thread about cooler plugs, that P-30 I had, allowed all of the ram air to escape w/o going through the radiator, unless the engine fan clutch engaged. (btw, when I boxed that in, I decreased the run time of the fan clutch by over 50%. It would only come on if on a grade, before, at ambient temps of over 105, it was on a great portion of the time on flat ground). Now, back to what Joe has, and we don't, about the only way to get air flow around the engine is what comes through the coolpack. If it can escape downward and out, it will take the path of least resistance. Keep in mind, that at road speed, the pressure underneath a vehicle is generally negative, so that's where the air will want to go, leaving somewhat stagnant air where we need the cooling.

I am wondering if the manufactuer of Joe's MH still has those shields available? That is something that will be a little more difficult to do, homemade. But they might not fit your P-32 so well even if available.

I know you are thinking about removing the airdam, you might, just might improve the air flow around the engine, but you will almost certainly cause a coolant heating problem, as well as decreaseing the efficiency of your dash air condensor.

On the headers, when I put the Banks system on the 460 we had, I believe it helped the heat, the doghouse on that MH was not insulated very well, it it got really hot, after the Banks was in place, there was a noticeable difference. If you have not looked into that yet, for the high weight condtions, you will get the most improvement in performance with long tube headers. They probably also do the best on extracting heat. (long tube for torque, short tube for horsepower gains is the general rule). On those Banks, for the 460, the collector was almost all the way at the back of the tranny.

[DriVer]

Quote:

Originally Posted by max49 I know this goes against the grain around here, but I really think the air dam, if too tight , has something to do with my wires melting. They always melt inside the heat shield; so I'm not sure if the shield is keeping the heat in, or just not keeping the heat out good enough.

Max, For the sake of clarity make no mistake that what you need to cool as best as you can is the coolant. The only way you can cool the coolant is by putting as much air through the cool pack as humanly possible.

Wasting your cooling air by allowing it to flow over the engine does NOTHING in preventing burnt out plug wires.

The vent kit on the other hand takes cool out side air and directs it to a specific location which apparently works in most cases where it is employed to prevent wire melt downs.

[Joe Gilbert]

My dog-house is still off (from changing my plugs) so I just inspected the air dam from both sides. The passenger side has a large opening with no attempt by the mfg. to stop air flow. Through that opening come the two dip sticks as well as the oil fill. From inside you see perhaps a sq. ft. of opening, looking right thru the grill. The driver's side has no real opening though when looking from within the dog-house forward you can see several areas of light looking towards the grill; perhaps 1/3 the opening the passenger side has.

So! looks like on my dolphin that you get a fair amount of air along the passenger side and some along the drivers side comming from the grill area, past any air dams. Also there would be a fair amount of air which has passed thru the radiator(s), and perhaps air entering from below the radiator(s). I think the important thing may be that the sum of all of the air sources flows in a laminar mode down the entire engine before exiting. I don't know if National RV knew how well this would work or if they just lucked out however, it does work very well.

JoeG

[Joe Gilbert]

I just took pictures from the front and inside the dog-house. I'll post these tonight when I get some free time.

JoeG

[max49]

It was the passenger side of mine that I had added material to, at some suggestions. That's when I. Burnt the wires and so far that's the only material I removed. None of the factory stuff.
The max. temp I saw was 214*, which is higher than I like, but not near as high as some here have posted, 228-230*. IDK if this could be apples & oranges or if we are both getting info from same place, the SG.
I am thinking about removing the tight fitting heat shields o.n 5 & 6 so wires and just using my homemade loose fitting flashing shield, which allows some air in and out. I have my twin blowers also if I try to always turn on at 200-204*. I hope my switch can handle the load of about 9 amps for both of them.

[max49]

I see we have another blown engine on Monarch pass. That's where I just crossed twice last week. It's not just Monarch but one after another down there. It's beautiful and my MH had better get used to it; but I really thought that I may blow my new motor up. I had just change #6 wire but I don't it lasted long, I was probably chugging on 7 cylinders.

[max49]

I wonder how the rear 8.1 , 26,000 lb. UFO gets air flow and what temps they see pulling a load thru the mtns.
That seems like a candidate for " Good Intentions"

[Joe Gilbert]

Here are the photos showing the openings in my Dolphin air dam. (This is factory stock from National RV). There is a passanger side and driver side both from the front and from within the dog-house. Note: The center opening is for the ECM, I think we all have that.

The photo showing the driver side from within the dog-house also shows the side curtain well.

I think you need to add a couple of side curtains Max and see if that doesn't solv e the problem.

JoeG

[max49]

I'm on my droid now So I can't blow the pictures up big enough for me to see. I'm starting to go around a and around . I have half metal walls or partitions that I drilled 1 inch holes in for more circulation. I think I have posted pictures of it before and they are on photobucket I think. when I get to a computer I may post a picture again .
At the time the general consensus was that I did good

[pkmesser]

Another issue that is not normally thought of, is that at 10,000 ft, the air density is only 69% of what it is at sea level. The mass (weight) of air, not volume, is what cools. This means that at 10,000 ft, you are only getting 69% of the cooling that you would at sea level. The only way around this is to increase the volume of air flow accordingly. That much increase is probably hard to get. Now, the engine will also burn less fuel at high altitude and full throttle , but you normally are not running full throttle at sea level for very long either.

The point I am making, is that what works at low altitude, may not do so at high altitude.

[txdutt]

just changed out my plugs after the fuel pump failed and had to be replaced, figured it was cheap insurance if the old pump really ran the engine lean before it crapped out...all of my plug wires looked like new & plugs looked fine (they had about 7k miles on them from when I changed them before but even the original plug wires looked good) but swapped them anyway...this summer we've been over Monarch, Kenosha, Wolf Creek, Eisenhauer, Vail passes-all towing our Jeep, I think I can finally relax & not worry about the the burnt plug & wire issues that plague other folks..I have noticed on my rig the air dam curtain up front is pretty thorough covering open space in there

[pkmesser]

Quote:

Originally Posted by txdutt just changed out my plugs after the fuel pump failed and had to be replaced, figured it was cheap insurance if the old pump really ran the engine lean before it crapped out...all of my plug wires looked like new & plugs looked fine (they had about 7k miles on them from when I changed them before but even the original plug wires looked good) but swapped them anyway...this summer we've been over Monarch, Kenosha, Wolf Creek, Eisenhauer, Vail passes-all towing our Jeep, I think I can finally relax & not worry about the the burnt plug & wire issues that plague other folks..I have noticed on my rig the air dam curtain up front is pretty thorough covering open space in there

Max49 has the P-32, with a severe problem, I think he needs to look at what is different about his P-32 vs the W series.

Also, this is the 2nd post I have seen where someone has been concerned about sparkplugs following a fuel pump issue, I understand being concerned about pistons but what is the issue with plugs? Not questioning it, other than what is the concern?