Discussion in 'Hangar Flying' started by Little Scrapper, Aug 13, 2019.
thanks for going for it L.S.er
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.
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!
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.
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?
The early Bus/Transporter that used the Type 1 engine used the same cam as the Beetle, VW part # 113 109 021.
Did you ask for an opinion on doing the HVX mods to the cases?
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.
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.
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".
Interesting. We should just start discussing the oil mods. Consider your post the beginning of this journey.
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?
Bob Hoovers blog: http://bobhooversblog.blogspot.com/
May of 2007 has info on the oiling mods, there are a lot of gems throughout all his postings, some ramblings too.
If anyone has an index that describes what is in his individual postings that would be extremely helpful.
Also a PDF book written by him about building a VW aircraft engine ( something like 119 pages of general VW and specific A/C stuff).
No log on or hack needed:
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?
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
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
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.
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.
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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