Steps to scratch build a VW

Discussion in 'Hangar Flying' started by Little Scrapper, Aug 13, 2019.

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  1. Aug 29, 2019 #441

    samyguy

    samyguy

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    thanks for going for it L.S.er
     
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  2. Aug 29, 2019 #442

    Pops

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    Different VW factory cam profiles for the transporter/bus, I don't know for sure, I have heard people say yes and no. Its also been said that they are all the same except for the VW GPU's and they had a different cam profile. I don't know.
    I always used the stock type 1 cam for the VW aero engines. I know the Kiddies in their hot rod VW streel cars usually puts high revving cams in their engines where they can't start off from a stop unless slipping the clutch. Also light weight flywheels makes it worse. Yep, if it works for the hi-torque iron block big V-8's it has to work for the VW's. Makes for a lot of money selling parts.
    I do know that the stock Type 1 cam works very well in the aero-VW engine. If I remember correctly the max torque is at about 2500 rpm, could be wrong.
     
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  3. Aug 29, 2019 #443

    ncmc47

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    Thanks from me as well Little Scrapper. I have recently been checking websites for Aero VW parts. Any recommendations on Scat cranks? Are they aviation friendly? Thanks!
     
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  4. Aug 29, 2019 #444

    dino

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    Nice to know there are stock German cranks still available, I remember a long time back reading ( I think in the HAPI manual) that both cast and forged cranks were produced by VW in Germany and that forged were preferable but cast were adequate for most uses. Forged would ring when tapped while hanging.

    Wonderful research. Thanks for sharing.
     
    Last edited: Aug 29, 2019
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  5. Aug 29, 2019 #445

    Little Scrapper

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    Keep in mind, I'm still learning and still absorbing all of this so I can't be trusted for specific. information. We did talk about cranks but briefly. My mission was cases.

    What he said about cranks was that they just don't experience hardly any any crank issues from ANYBODY. they've had great luck with Chinese cranks. Sonex and GPAS probably use Chinese cranks.

    I'm guessing here but that would indicate SCAT would be good but not necessary?
     
  6. Aug 29, 2019 #446

    fly2kads

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    The early Bus/Transporter that used the Type 1 engine used the same cam as the Beetle, VW part # 113 109 021.
     
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  7. Aug 29, 2019 #447

    samyguy

    samyguy

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    Did you ask for an opinion on doing the HVX mods to the cases?
     
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  8. Aug 29, 2019 #448

    Little Scrapper

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    I did not it, everything I wrote is everything I discussed except for testing, we did talk about testing.

    When I get my case, which will be soon, I'm going to go deep in to the case mods. That is my next adventure so to speak. I will publish everything here.
     
  9. Aug 29, 2019 #449

    Pops

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    That is what I was thinking, same cam in the Type 1 engine.
    I think VW went to the type 4 engine in the Bus/Transporter in August, 1971 with dual carbs. I would have to look it up to be sure. I had a type 4 engine FI in the 78 Bus Camper that I used to own.
     
  10. Aug 29, 2019 #450

    Pops

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    I know that the HVX does get more oil the the right side heads for more cooling. But there is a down side. More flow= less pressure. Mine was 10 lbs less. Larger capacity oil pump will take care of that or going to a 2.5 Thousands oil pump cover gasket over the stock .004".
     
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  11. Aug 29, 2019 #451

    Little Scrapper

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    Interesting. We should just start discussing the oil mods. Consider your post the beginning of this journey.
     
  12. Aug 29, 2019 #452

    Little Scrapper

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    Let's see if we can stay on the topic of "VW oil mods".

    Pops kicked us off with an interesting post above. That's information worth noting. I do do keep a notebook, do you? You should. Things that are important should be recorded.

    Question. Who is the "VW Bob Hoover" and what do we know about him? Sounds like he was quite the guy and knew VW's well. Why is this? What do we all know about him and what he did for VW builders?

    Also. What does the initials HVX even mean?
     
  13. Aug 29, 2019 #453

    lakeracer69

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  14. Aug 29, 2019 #454

    Hot Wings

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    No log on or hack needed:
     

    Attached Files:

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  15. Aug 29, 2019 #455

    Little Scrapper

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    Curious.

    I have to do a lot of reading but before no jump in to that, briefly what is the history of oil mods for VW airplanes.

    Did people modify oil for cooling prior to anything Hoover. Are Hoover mods included in GPAS or Aerovee? VW powered airplanes in the 70's and 80's, what oil.mods were common if any?
     
  16. Aug 29, 2019 #456

    samyguy

    samyguy

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    GPAS Aerovee Scott and the rest, I have not heard of them advertising that they do.
    Think this was Hoover's racing and magazine journalist writers bud's developing
    the HVX mods
     
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  17. Aug 29, 2019 #457

    Little Scrapper

    Little Scrapper

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    Maybe these mods aren't required?

    I'm interested in actual problems and issues associated with oil in VW Aircraft. I can't find anything searching Google
     
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  18. Aug 29, 2019 #458

    samyguy

    samyguy

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    Well, I have a factory built GPAS motor on my bench right now. 83 hoursTTSN
    Has had the right side head rebuilt by GPAS an installed. Run some more, died.
    I got the plane not running. Opened it up lifter bores shoot, 3# main bearing scored, needs 10th off
    I think the HVX mods may have saved it, don't know, speculation.
    Zenith CH600 with redrive.
     
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  19. Aug 29, 2019 #459

    Hot Wings

    Hot Wings

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    Not directly answering the question but offering a bit of history trivia:

    It's my understanding that the origin of the HVX oil mods was due to broken rocker arms on one side. I've never seen a broken rocker arm but I have tossed out a bunch due to galling of the shaft and bore.

    Way back in time the stock VW lifters were '2 piece'. The very old 36hp having a chunk of material in the aluminum tube that was free to slide back and forth. When VW introduced the 40 hp with the mushroom type lifters they also had a shuttle in them. I was told that the purpose was to act as small oil pumps to help oil the rocker arms. Standard practice back then was to shake each lifter to make sure the shuttle was free.
    Somewhere about the early 70's the one piece lifters started to show up - at least in my part of the world. They were originally rejected as being cheap aftermarket junk and only genuine VW 2 piece lifters were used. As time passed the single piece lifters became the only available type as they seemed to be working. Some of the hot rod shops even touted the one piece as being superior.

    I can't come to any conclusion based on this history - just presenting it. I do know that I have never seen a galled 40 hp rocker/shaft that used the 'shaker' lifters.
     
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  20. Aug 29, 2019 #460

    blane.c

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    Oil can only get to the right side valve train 8% of the time with stock oil system. Does that really sound ok to you? It does not sound ok to me. It was obviously fine or more likely good enough with 25hp and 36hp and the like and for the era, but that era was before oil filtration was considered a good idea as well. For reliability demanded of modern aviation engine getting oil to all the parts that need it 100% of the time seems prudent to me.
     
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