Has anyone seen this before!

[Dicer]

I just want to start out by saying “Hello” to everyone and I would like to say is the best forum I have ever had the pleasure to read and heed. Having bought an antiquated Benson last year I found this forum very useful in finding parts and the why things are the way they are. Now I am in the process in making the gyro complete again, having to replace the majority of hardware and frame tubes. Need some advice on the VW engine that I have, maybe someone can help me out. What I have is a VW 2180cc with the prop driven off the flywheel side of the engine. There is an extra bearing in place of the crank seal then the seal is located in its own housing bolted to the outside of the block. And a course the gland nut holds the prop hub to the crankshaft, as you seen in the pictures.
I don’t see any problems in doing this right? And also if you notice they shaved the engine /trans flange, maybe to let the prerotor ride a little close to the prop hub assembly, and to fit the engine to its mount? The bearing is the same outside diameter as the crank seal diameter. Maybe the roller bearing is used to help to keep the front main bearing from being wallowed out. I have sent these pictures to several VW companies including “GP’s” but only to get the same response,” We have never seen this before so we can’t help you”! Is there a better way or can this work is what I am asking?
I have one more question about the guide wire, or maybe it’s some sort of a strut that attached to the rotor head to the very front of the gyro itself. I have seen cables on older versions and a few gyros here and there are the cable used just for pull gliders? Thanks for any info.

[M. Pearce]

Hello,
All I can say about this is that someone knew what they were doing back then. Have you found any numbers on the bearing and seal? I'm wondering if the bearing is mainly used for/as a thrust bearing. As for using the gland nut for holding the prop hub on, I would do some modification here. I would find some way to safety wire that sucker in. The gland nuts usually torq to around 215lbs ft. Using some locktite on the gland nut might help hold it on better but the treads are fine and could be damaged later on if you remove it. I think this setup is a pretty darn good idea. That gland nut looks pretty special too. Maybe wireing isn't needed.

[Bob]

I agree ! I've seen them bolted right to the crank with nothing else added ! infact I had one like that a long time ago never realy messed with it though...
it looks like its ment for busness to me , clean'er up and use it dat way ! ....
I'm no expert at anything so take it with a grain of salt !
c ya !
Bob.........

[Butch S.]

This bearing is definatly for thrust & looks like a very good idea a new SCAT nut wouldnt b a bad investment so to a new bosch 009 distributor with electronic ign & an ego sensor to set up carby as this setup would have been tuned for super not ulp so will need biger main jet if properly tuned originaly
This is the opinion of a trained quaified mec who builds VW & SUBY motors for use in gyros for a living
Butch S.

[Doug Riley]

Dave, I had something similar on a Bensen way back when (well, about 1973, if you must know). The usual setup for VW's was to put the prop on the other end of the crank. That "other end" is designed only to carry the pulley that drives the fan and generator; no way it's strong enough for prop loads. The result was frequent crank failures and props departing aircraft. That's pretty hazardous on a pusher gyro!

One fix for using the fan end of the crank involved drilling deep into the shaft to the #3 bearing journal and using an extra-long prop hub bolt. That reinforced the shaft but dion't solve the related problem that the #4 bearing was too small. More elaborate fixes involve boring out the case and putting in a larger #4 bearing. Revmaster went even farther and installed a gigantic combined #3 and #4 bearing. They also extended the neck of the prop hub forward to the last crankshaft throw and used its outside surface as the journal for the big new bearing.

You setup is completely different. It's a refinement of Bensen's approach. The crankcase bore at the #1 bearing just happens to be the right diameter to take a standard bearing (90 mm, I think). An extra bearing in this area helps to take the large cyclic bending loads and thust loads imposed by a prop -- loads that the engine wasn't designed to take in its stock form.

What you have has the POTENTIAL to be a really good VW conversion, and 2180 cc is enough to make a gyo pretty lively (I had 1835cc, which was so-so with old, inefficient Bensen blades).

OTOH, there's a lot of rust visible. Might there be rust inside the engine, too? I'd take the engine apart or send it to a VW aircraft engine shop for overhaul. End play on the crank will be critical, since the tapered roller bearings produce reverse thrust under some loading conditions

Aside from age and corrosion, watch out for cast crankshafts. Even with your neat bearing setup, a cast crank will fail. I know of one gyro builder who had crank failure on a Revmaster conversion -- they installed their eleaborate bearing modification, but still used a cheap cast crank. You need a forged crankshaft. A forged unit will give off a bright metallic ring when tapped; a cast one will make a dull sound. If you have (or get) a forged crank, have it Magnafluxed.

There's lots more to do to make a good VW conversion; study up and good luck.

[Dicer]

Thanks Gentlemen for the input and encouragement, highly appreciated! You have given me soon insight on what the bearing was used for and why. I was hoping it was just there for the radial loads and nothing more. Yes the bearing and seal are the same outside diameter (90mm), and the seal they used in the seal cup is a stock 90mm VW crank seal also. I have torn the engine completely down and determined that the only usably parts are the crank and heads and nothing more. The crank is indeed a Scat and looks to be a forged unit, but will have it checked out anyway. So basically what I need to get hold of company or person(s) that would be so kind enough to install the crank, bearing, in a new case! Any takers, I will probably go through the list I tried before and elaborate just what exactly my needs are. Maybe I will have some takers, and again thanks everyone for the info. Dave

[Doug Riley]

Dave, you're likely to encounter resistance to your design because it's different. Great Plains and Revmaster (a couple of the good go-to outfits for VW aircraft engines) have put much effort into taking power from the other end of the crank, probably for ease of mounting. That bell housing flange does make a nice starting point for a firewall-type engine mount and crank-driven magneto(s). When taking power off the clutch end, you probably will use either a battery and distributor setup (pretty crude) or a Vertex magneto stuck in the distributor hole. The latter setup needs some add-on bracing if the magneto is not to fall off eventually.

It's typical to cut the bell housing flange back almost to the case when you run the prop on the clutch end. Coming up with adequate engine mounting points and geometry can be challenging if you go this route. The prop end of the engine should not be mounted rigidly, but should either be cantilevered or mounted softly.

One possibility if you're somewhat engine-savvy is to buy a pre-bored "super case" and assemble the engine yourself. "Super cases" are available from Claude's Buggies (I think they go by the name "CB Performance" now). They weld the case before boring it out, which can help avoid case cracking in the the thin metal that's left after boring. You might ask for a German-made case in lieu of a Mexican-made unit, as the former are rumored to be of better quality.

[M. Pearce]

Dicer,
Does the bearing and seal have any numbers on it? I'm building a VW right now and would love to try and implement this idea into my project. As for a good case, Empi makes one that they call a bouble top. It's clearanced for stroker cranks and larger bores already. It's close to $500.00 but it's a great case for HiPo engines. I order a lot of my parts from venders in the Hot VW's magazine. A google search for Empi case should bring you to some sources.

[Dicer]

Hi Mark, the seal is a typical VW crank seal a M90, bought two of them at local parts store for around $4.00 bucks apiece. The bearing had no number that I could see when I was dissecting the engine, but at the time everything was cold, dark, and dirty. But I will get back to you on the number, for I will be installing a new bearing. There’s a place down the street from where I work that specializes in bearings and seals, so they shouldn’t have any problems in getting the info to me.
I had a new seal housing made for the one that I took off, they had the holes going every which direction. There again I had the “new” housing made a little taller to accommodate not one but two crank seals. Over kill maybe but the seals are cheap, and the CNC lathe doesn’t care how long the piece is anyway. I am using six holes to mount the seal housing flange to the VW block with some good sealant. If you would like some dimensions to get you started just let me know and I will post them here.
The last couple of days I have email about dozen VW specialties shops, most said the extra bearing was an over kill, the stock engine configuration would work just fine. I have to disagree there is no way a lead/babbitt bearing would take a continuous load and not to be wallowed out in time?!? Remember there is no bearing on the outer prop hub for support just air.
And like what Doug said earlier in the thread it would be nothing to shave the flange off. Which is what I am gong to do; a lot can be done with a plasma torch, sawsall, and a good sharp hand file. But a word of caution DO NOT use a plasma torch on your new magnesium engine case you may end up with something as bright as the sun and just as hot glowing on your work bench!
But the greatest concern that I had was to try to figure out how to get the correct crank endplay. And that is because of the extra bearing and prop hub configuration that I was plagued with. Some old timers just hate to give up “their” secrets, finally I was enlightened! Thanks everyone! Dave

[Doug Riley]

Dave: I trimmed my case flange with a wood-cutting keyhole saw. No need for flames or any other high-tech tools.

You probably know by now that VW has main bearing shims of various thicknesses that you can use to set endplay. The #1 bearing is a thrust bearing that works in either direction. It'll need to, too, if your extra bearing is a tapered roller bearing. Large side laods on that type of bearing get turned into reverse thrust loads. The stock #1 bearing takes those loads, just as it does when clutching and de-clutching the car.

The reason for the external bearing near the prop hub is to support the crank against bending loads. During maneuvers, the spinning prop reacts like a gyroscope. With a 2-blade prop, these gyro loads come and go twice for each prop rev. The loads are steady for props with 3 or more blades. In either case, these bending loads are on the order of 200-300 ft.-lbs. The stock crank bearings weren't designed for this kind of loading.

Sincere thanks to Chuck Beaty for educating me about this stuff many years ago.

[Dicer]

FINALLY ! Got my engine I had built, took nearly 5 months, and few well placed phone calls and emails, but its here. 2180cc VW engine direct drive prop. If anyone is interested in the specifications I will be more then happy to post them, and the name of the creator of this fine looking engine.

I am thinking someone earlier in this post wanted the part number of the (radial/thrush) bearing that was use in prop end of the engine? 7012DU, I priced it at around $127.75 a bearing, Bearing & Industrial Sales bearing@srv.net

Again the bearing # 7012DU 60 x 90 mm

[M. Pearce]

Dicer,

Hey thanks for that part number on that bearing.

I'm very fond of that setup you have.

If you decide to not use the rear drive set-up I'd be interested in buying or trading.

I'd love to have that rear drive!

I am gathering parts for two projects right now.

I am building a Legal Eagle Ultralight and getting parts for a Air Command type gyro project.

I'm glad someone else here is planning to use VW power on their project.

You got a really nice engine there so keep us posted!

Some folk say they get hot in the heads.

I wonder how this would run with a nice center mounted alternator and aftermarket aluminum cooling shroud and fan on it?