Briggs vanguard conversions

Discussion in 'Firewall Forward / Props / Fuel system' started by Hephaestus, May 12, 2019.

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  1. Sep 28, 2019 #1001

    pictsidhe

    pictsidhe

    pictsidhe

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    I think the ports need fixing. I'm dubious about a P trap. I'm having fun determining the optimum port shapes.
     
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  2. Sep 28, 2019 #1002

    Hephaestus

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    Lol it snowed here last night.
     
  3. Sep 29, 2019 #1003

    TiPi

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    some more details on the oil pickup and outlets. The camshaft bearing in the cover is lubricated with oil from the pump outlet (unfiltered). There is an adaptor berween the cover and oil fiter to direct the oil to the oil cooler, it doesn't contain a thermal or pressure by-pass valve. I have added the oil temp and oil pressure sensors to this adaptor.
    upload_2019-9-29_9-19-7.jpeg

    upload_2019-9-29_9-23-19.jpeg
     
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  4. Sep 29, 2019 #1004

    pictsidhe

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    Is the oil cooler adaptor Briggs? How thick is it? What does it weigh? My 656 has no cooler, or adaptor...
     
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  5. Sep 29, 2019 #1005

    TiPi

    TiPi

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    Briggs, listed in the 49-series parts manuals, is about 25mm thick and needs the longer filter adaptor, not sure about weight (100-150g).
     
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  6. Sep 29, 2019 #1006

    pictsidhe

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    That adaptor looks like it could be modified with a VW type oil cooler pressure bypass valve.
     
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  7. Sep 29, 2019 #1007

    Vigilant1

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    That oil filter mount is coming in very handy as a general purpose high pressure oil manifold. Need another line? Just tap right in!
     
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  8. Sep 29, 2019 #1008

    pictsidhe

    pictsidhe

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    Unfortunately, it's unfiltered there. A tee into the cooler return would be fine for piston oil squirters, though
     
  9. Sep 30, 2019 #1009

    Vigilant1

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    FWIW, here are some pictures of the oil cooler fitted to the 810cc engines. As you can tell, they are fed directly by air from the fan shroud, it might take some experimenting to assure that another air source (maybe with less static pressure) will push enough air through it.
    If I've got this right, TiPi is doing a lot of analysis of the 810cc engine in its "natural state" before he starts his modifications. If he measures the in/out temp of the oil at the cooler at some power setting (?Good enough? IR thermometer aimed at a suitable target plate on the in and out lines?), he'll later know if whatever baffling/airflow setup he sets up for the oil cooler is as good as the stock one.


    [​IMG]




    [​IMG]



    [​IMG]

    It would be optimum if the oil had recently been through the filter, but I'm not sure it makes a big difference. If we grab some before it goes through, now we have a 90% of full flow filter vs 100% filtered. Regardless, every drop of oil in the engine will have passed through the filter within a minute or two.
     
  10. Sep 30, 2019 #1010

    TiPi

    TiPi

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    Thank you for these drawings, great work:)
     
  11. Sep 30, 2019 #1011

    TiPi

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    the numbers that I have for cooling airflow (at 3,690rpm, no external load)):
    total flow into the engine (fan intake): 920cfm
    airflow through the oil cooler: 72cfm
    airflow for intake air and air filter flushing: ~20% (180cfm)
    cooling air flow through cylinder heads: ~670cfm
    Temp drop at oil cooler: 10deg C (80 to 70)
    Cooling power: 3.3kW
    Oil pump volume: 12 lpm (the 2lt oil content circulates completely every 10s), I wouldn't worry about filtered or not

    Cooling air intake area SE-33: 73cm2 per cylinder head
     
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  12. Sep 30, 2019 #1012

    blane.c

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    I have issue with un-filtered oil. Kinda' like being a little bit pregnant. It just doesn't make sense.

    My recent and brief introduction to gerotor included language that it does not like solids. No oil pump does I suppose but since they are generally only protected by a screen any oil pump is likely to have to ingest some grime of some kind IC engines are not that sanitary. But downstream the oil pump it all should go thru a filter before being distributed to the rest of the engine. With the design of the 810cc the cam bearing at the end of the oil pump being an exception because it is an extension of the oil pump in a way. But also because unfiltered oil is going directly from the pump to that bearing it is even more reason to force all of the oil downstream of that point thru a filter before being tapped off for anything else. I can see the attraction of a off the shelf ready made part that is so easy to use (the adapter before the filter), personally I think it is an Albatross.
     
  13. Sep 30, 2019 #1013

    blane.c

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    Perhaps the adapter could have a in/out cover screwed onto it instead of the filter, then the filter could be remoted directly downstream from were the oil is tapped off using the adapter run thru the cooler and into the in/out cover. A bit more work but letting the oil decide if it's filtered or not is chaos.
     
  14. Sep 30, 2019 #1014

    Hot Wings

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    Oil filters aren't there to filter out the big chunks. There isn't really a need to filter 100% of the oil.

    The main purpose of the filter is to trap the small particles that are abrasive in nature. These small particles come from normal engine wear and from degradation of the oil. It is these abrasive particles that do most of the wear damage. Once things get to the point of metal to metal contact and start producing chunks then no amount of clean oil is going to slow down the damage much.

    The screen is sized to keep particles large enough to jam the pump from entering and is a last, rather futile, attempt to keep the engine operating.
     
  15. Sep 30, 2019 #1015

    pictsidhe

    pictsidhe

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    Useful numbers. I had taken a first guess at 120cm2 intake area for my 103. Looks like it needs to be bigger, which is easy for me. Or maybe new baffles will give enough of an efficiency boost... The oil pump has a relief valve between inlet and outlet ports. I still want to check its flow. The standard oil filter is rated 7 to 9 gpm by Wix. It has a 3/4 - 16 thread, so there are a lot of alternatives. Almost all larger.
     
  16. Sep 30, 2019 #1016

    blane.c

    blane.c

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    An engine is supposed to operate in the normal flight envelope of the aircraft with 1/2 of its maximum oil remaining ( https://www.risingup.com/fars/info/part33-39-FAR.shtml ). I imagine this is why some aircraft if you fill to the top of the oil level fill line about a quart blows out during the first take-off after. Some of these aircraft have a 7 quart fill line and it probably takes around 3 1/2 quarts minimum for the engine to operate normally. Most owners operators learn to fill to 6 quarts or as appropriate. Anyway some may want to know what the minimum operational oil level is so they can accommodate double somehow. If you want to … I guess.

    https://www.risingup.com/fars/info/part23-1011-FAR.shtml

    https://www.risingup.com/fars/info/33-index.shtml
     
  17. Sep 30, 2019 #1017

    Vigilant1

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    I wonder why they wrote the guidance like that, it seems pretty arbitrary to me. Maybe so there'd be some uniformity across certified engines ("Every engine on this ramp will keep running okay with the oil half full.").

    It would be good to know what type of oil consumption fleet operators are experiencing with these engines in mowers, or how much the ones already in airplanes are burning.

    I'm in favor of a generous amount of the slippery stuff on board (though we can't go crazy at 1 lb for an extra 3/4 quart). It's some insurance against a clamp/seal that allows a leak, it allows a (small) "heat buffer" for short ops at max power, it lowers average oil temps (a little), and the increased amount of the "additive package" goodies helps the oil perform better for longer.

    It would be a bonus if we could turn the filter so it mounts with the threads up. That's effectively an extra bit of oil on board (8 oz?) and it will get oil to the bearings a little faster on startup if the pump doesn't have to first fill the filter. Plus, it makes oil filter changes less messy. It's probably not practical to do that.
     
  18. Sep 30, 2019 #1018

    Hephaestus

    Hephaestus

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    Remote oil filter adapters exist - using them to travel through cooler, upgraded filtration and possibly storage might not be awful.
     
  19. Sep 30, 2019 #1019

    blane.c

    blane.c

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    I am thinking oil sucked thru screen goes thru pump and cam end bearing (on the 810cc barring a fix) then it gets a choice it either goes thru pressure bypass or thru the filter. At that point were does the bypass oil go because if it is bypassed because the filter is jammed then? But normally it will go thru the filter thru the bearings and thru the cooler to the reservoir.

    I can see that isn't were most are thinking, I am not a Lemming.
     
  20. Sep 30, 2019 #1020

    blane.c

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    What many forget is that though often uncomfortable, regulations are written in the blood of those that went before.
     

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