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vhhjr

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At least with an aircraft application there's lots of high speed air compared to an ATV. This problem of cooling capacity is very real. Many Himax builders use 4A084 generator engines and I have read several accounts of attempts to increase the HP output that immediately ran into CHT problems.

Now, if someone was offering water cooled heads for the V-twins like Rotec does for jabiru engines.......

Vince Homer
 

blane.c

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The real advantage to a blown aviation engine is to compensate for altitude. Only a small amount of the available extra boost/hp is used at sea level / low altitude and the rest is realized as you go up in altitude to maintain hp in climb / cruise. This way the engine is not over stressed and you can realize the benefit of the blower in higher cruise speeds developed at altitude because of maintaining a higher hp for cruise while at a higher altitude for better true airspeed.
 

Hot Wings

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Now, if someone was offering water cooled heads for the V-twins like Rotec does for jabiru engines.......
A water-cooled head conversion would actually be pretty easy - compared to inverting these as I'm wanting to do. But.............
You then run into the problem that a lot of auto conversions have. Most air-frames are designed for air-cooled engines and finding a good place for the radiator becomes a challenge.
 

Tallyho

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I've recently been thinking about oil cooled heads for these. Might not offer as much cooling as water and need the use of a second oil cooler radiator. Anyone have any thoughts on whether the stock pump would be able to supply the extra volume and maintain pressure?
 

pictsidhe

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I've recently been thinking about oil cooled heads for these. Might not offer as much cooling as water and need the use of a second oil cooler radiator. Anyone have any thoughts on whether the stock pump would be able to supply the extra volume and maintain pressure?
I am thinking the same.
Two options.
1, hose oil into the rocker cover. This is by far the easiest. Not as good as option 2, weld up the vent hole under the rocker cover and run oil through it. I am going to try the easy way first. I am doubling up the stock oil pump and making the pressure relief do double duty for diverting oil to parts that need cooling. Full oil flow through a non stock cooler, bearing oil only through the filter.
Piston squirters are also on my want list.
 

Hot Wings

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Full oil flow through a non stock cooler, bearing oil only through the filter.
Piston squirters are also on my want list.
You may need to use the late model VW bug dual oil pressure relief setup to make this work well. This is part of my plans - if - required. An external oil thermostat is the other option.
I'm not seeing an elegant way* to add piston squirters to the 810. I think your other idea of using water/alcohol as a temp supplement may be the best option.


* could just be lack of vision.
 

blane.c

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If as I understand it, these engines require two carburetors each or if one carburetor it is essentially two venturis Siamese'd to a single float bowl then you have to lean each cylinder independently. This isn't much of a deal with a single engine just having 2 mixtures to adjust instead of 1 but those wanting two engines it becomes more of a deal and for the real nut cases wanting three or more engines well having 6 mixture controls or more it really starts becoming problematic. You can imagine that it will take twice the time to lean a two engine plane as a single engine plane and three times as long to lean a three engine plane, actually longer because of the time involved getting rpm's and manifold pressures to match. So I am interested if there are those out there experimenting with the fuel injected models and if they have anything to add to the commentary, it would be appreciated.
 

blane.c

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Using the rocker covers to house a volume of oil ... well I've never seen a rocker cover that wouldn't leak. Something would need to be done?
 

Hot Wings

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So I am interested if there are those out there experimenting with the fuel injected models and if they have anything to add to the commentary, it would be appreciated.
Even with port FI the mixture between cylinders can vary if using a common throttle plate and a shared timing for the injectors on these syncopated engines. None of us know how much of a real problem this will be. I suspect (SWAG) that for moderate states of tune it won't be a problem. There are solutions. Using 2 different maps for each cylinder or real time adjustment using an oxygen sensor dedicated to each cylinder being a couple.
 

Vigilant1

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Using the rocker covers to house a volume of oil ... well I've never seen a rocker cover that wouldn't leak. Something would need to be done?
I recall seeing some pictures taken by a guy who had fitted windows into the valve covers of his VW Type 1. When running at speed, one was about 3/4 full of oil all the time. So, apparently things might not be much worse if we pumped more oil through the rocker arm gallery, at least if the oil isn't under significant pressure.
 

Vigilant1

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Using 2 different maps for each cylinder ...
?? 2 maps for each cylinder?? I'm not following that. Or do you mean one independent fuel map for each cylinder, presumably with a separate MAP sensor for each?
 

blane.c

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Yes, I "think" that these engines are like archipelagos reefed together by a common crankshaft. Each cylinder will have to be adjusted independently. Therefore multiport fuel injection and inputs for the computer off of each cylinder. Even carbureted you will need sensors for each cylinder and will need to adjust each cylinder independently, likely a procedure to get a "crude but safe" adjustment quickly and then when appropriate to spend a little more time on each with the fine adjustment. At some number of engines an inappropriate amount of time is going to be involved and "a crew member needs assigned to the duty" I vote the computer be that crew member and ergo EFI.
 

blane.c

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Having flown aircraft with 144 valve covers and a myriad number of other places to leak oil, I have seen a lot of leaking oil (we all wore black). In my opinion, if you are going to toss extra oil in to the area covered by the valve covers then some thought and a good plan for keeping it from leaking is necessary. Permatex form a gasket will work for a little while but it develops leaks too. Something like oversizing the rocker bolt holes Heli-coiling or inserts and studs with over-reaching clamp arms. Or some really good glue, but then how do you get them off? Maybe I am over compensating but I just don't think the stock retention is adequate especially if you start talking about flow.
 

Protech Racing

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Run one with the rocker cover off and see how much oil it gets . Direct sprayers onto the rockers may help the wear and add a tiny bit of cooling , if you can cool the oil.
If the intakes are separated , one EFI can run both jugs just fine from one wideband sensor . If you're gunna fly over 8000AGL then a leaning method will be usefull. The EFI has a map sensor to do it by it's own schedule .
There may be billit valve covers available .
 
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