# Steps to scratch build a VW

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

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1. Aug 13, 2019

### Hephaestus

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It was probably 2180 I was thinking of... Not 2.8... that probably makes more sense.

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2. Aug 13, 2019

### Pops

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All good advice from everyone. I do like the CR at about 7.5 to 1 or so. The last engine was 7.55. Engine is happy with 90 oct non ethanol or 100 aviation fuel. Can't tell the difference in running. IF you go to the 2180, don't, unless you use the Force One prop hub or flywheel drive. Like was said, parts or kits from GP's or Scott Casler. I have bought a lot of parts from both and was always happy. They save you from buying a lot of the VW parts on the market that is junk. Its a win/win. Aero-Vee's prop hub is not as good as the Force-One. Never been a failure of the Force-One prop hub.
The 1835 cc is the best bang for the buck and still is as reliable as the smaller engines. I have been building a flywheel drive 2180 cc engine and thinking of building another SSSC but trying to get lighter. If I build one its going to be an all out on saving weigh. I really miss the SSSC. JMR is at the paper work stage and I have to be building something or I'm hard to live with

The How to Keep your VW Alive book is a good view of all the VW engines and will get you laughing at the same time. I have had 2 or 3 and each time I loan one out I never get it back, its that good.

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3. Aug 13, 2019

### plncraze

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Was it on this website that somebody said all the VW car engines have been altered in ways that make them useless for putting in an aircraft. Heads were poorly machined, etc.

4. Aug 13, 2019

### Little Scrapper

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I don't have a budget. I can swing anything VW related but I'm not looking to freely blow money for the heck of it. I know what VW cost and it's all within my range I guess.

I'm really after the education but in a intentional and smart way if that makes sense

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5. Aug 13, 2019

### Little Scrapper

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I was just thinking, I have all the Sonerai newsletters on CD. I bet there's some good VW information inside those. I'll have to dig those up.

6. Aug 13, 2019

### TFF

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I would build the 1835 if it will do what you want. It seems to be the punched out size that is natural for stock VW parts. Not special when it comes to the machine work. Not fragile.

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7. Aug 13, 2019

### Hephaestus

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Curious, I see nobody really mentions revmaster or their aviation heads anymore... Is there a reason?

8. Aug 13, 2019

### plncraze

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I also encourage you to read rs hoover's blog. You will find a kinship with him that will carry you through this project and others. In a way you are already carrying on his work. It's great to watch!

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9. Aug 14, 2019

### Vigilant1

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I'm sure they are fine--Joe Horvath makes very good parts (and engines). But they aren't (really) optimized for VW aviation use (they'd have smaller valves if they were). They also aren't inexpensive--$1000 for 4 cylinders-worth of heads with valves springs, etc is dirt cheap by aviation standards, but not by penny-pinching VW standards (a pair of GPAS heads, drilled for the extra plug, would be bout$760). And they have a funky extra hatch/panel/gasket that must be removed IOT get a wrench onto the lower plugs. They may be a good choice if you are building a "bleeding edge" VW engine, but might be an unnecessary expense for a more hum-drum build.

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10. Aug 14, 2019

### Hephaestus

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Didn't the revmaster heads have larger fins? Wasn't that the whole claim to fame?

11. Aug 14, 2019

### Vigilant1

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"Larger?" The problem with all heads adapted from automobile use is that they can't be much larger (in footprint) than the cooling shroud in the VW auto. I suppose each fin could be thicker, and they could certainly have air passages free of flash, etc so the air goes through.
Some brands have an "extra fin" (I think the CB Performance 044 heads tout this attribute). I don't know how their fin count compares to Revmaster's.

Bob Hoover did pioneer the welding on of additional fin area using a then-new welding rod of some type, and I've heard this works.

I'm all for keeping CHTs down for better longevity, but it apparently doesn't require heroic measures if we have good baffling and stick with the proven HP capability for each displacement level. For those who aren't racing, that's the best approach. If someone needs more than about 75 HP for their fun flyer, IMO they should be looking at a different engine.

Last edited: Aug 14, 2019
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12. Aug 14, 2019

### robertl

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Wow Scrapper, I had that book, How to keep your Volkswagen alive for the complete idiot back in the 70's. It's a great book but someone borrowed it and I never saw it again. Also, I think Molt Taylor had a book about the VW.
Bob

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13. Aug 14, 2019

### Pops

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LOL, Don't let someone borrow that book because that will be the last time you see it.

This is all good. I like the 1835 cc engine and think its a good compromise in power, reliability, cost, etc. Friend of mine used to have a Sky-Rader, same empty weigh, same wing area, etc with a 60 HP HKS engine that has a redrive, of the 60HP 1835 cc VW powered SSSC. I'm about 40 lbs heaver than he is. They had the same cruise speed at 75% power, same ROC , same take-off distance. So the 1835cc VW engine has to put out an honest 60 HP.

The SSSC performs so good with the 1835 cc VW engine, I always wondered what it would be like with the 75 hp 2180 engine. The 1835 cc engine hauled my 230 lbs up at 1200+ rpm with a cruise of 80 mph. Good STOL airplane, maybe if I keep a new SSSC even lighter in weight it well be even better.

14. Aug 14, 2019

### Little Scrapper

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Pops, what would you do if you were me? I'm not sure of the HP of Steve Wittmans little V-Witt but I believe he ran it at a high rpm. I'm more interested in sport and reliability, not racing.

15. Aug 14, 2019

### TFF

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I believe the racers were limited to 1600.

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16. Aug 14, 2019

### Richard6

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Here is a PDF that I found some time ago. You may find it interesting.

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• ###### VW aircraft engine building.pdf
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17. Aug 14, 2019

### N804RV

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Another "must read" is Rex E. Taylor's "What about Volkswagen Conversions" series that ran in EAA Sport Aviation. I believe it can be found online in PDF format.

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18. Aug 14, 2019

### dmar836

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Building one now for the V-Witt. Just remember you are wanting a tractor motor - not a car engine. VW car guys will have a hard time giving good advice for your application... and even then. Also, revealing your application on a forum or two will put you on the black list at many parts places. Some already pry what you are using it for during the sales dance as if they have suspicions. It’s been a thing for a while.
If just for tooling around I would build stock late block 1600 and just make it bulletproof. The new blocks are humped for big stroker builds, are all aluminum, and are 15lbs heavier than a stock mg block. Line boring the mains is the main machining needed on any used block then the crank thrust surface and then decking of the cyl spigots. These are pretty much universal requirements on any used block. It’s hard to find new heads that cool better than stock without them including huge runners and valves. Anything more than a mild stroker crank is asking for more headaches. Same with anything but an “efficiency” cam.
Little benefit from turning it around like Wittman unless the airframe dictates it. His extension shaft and cone are no joke and no low-dollar solution nowadays. Running it backwards without that extension requires an even larger nose bowl! The Force one would be cheap insurance for the standard direction and minimize the bearing issue. Minimal massaging and careful parts selection along with balancing and blueprinting will make extra horses and better reliability and cooling.
\$7-8000+ for a converted engine might be most reliable for those who aren’t engine builders but 3 times the money. Not dynamically balanced either. Buying “balanced” parts is useless to me. Many of my already balanced parts are too far off for my liking. I’ve talked to a couple Aerovee engine “builders” and many of the parts are just drop shipped from suppliers. Nothing wrong with Aerovee but many of the customers don’t want to have to learn about engine building.
Just opinions I’ve formed likely to upset some. And like my offering at OSH, feel free to contact me offline.
Dave

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19. Aug 14, 2019

### Little Scrapper

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I'm not sure I totally understand this "force one" hub. It's discussed all the time and some people argue over it.

Anyone care to lay out that whole discussion for me? How is that a advantage?

20. Aug 14, 2019

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