Whats the best VW conversion???

MDF1 · Post by **MDF1** » Sun Oct 05, 2008 4:08 pm

Thought this might be a good question to ask on a wet and windy Sunday afternoon!

I'm no engine expert and was wondering if there was a consensus on which were the best VW based engines. I know Barry Smiths engines are well regarded but are no longer available, so what are the pro's and con's for those that are available??

MikeGodsell · Post by **MikeGodsell** » Sun Oct 05, 2008 5:13 pm

Limbach of course.
Fully certified, or for permit aircraft. Run on Avgas or mogas. Versions with conventional single or double mags, & electronic ignition. Carburetter or injection fuel systems. Air cooled or liquid cooled. Full spares and service back up, exchange your servicable time expired engine for a new one and get a substantial rebate. Why risk your life with amateur built experimental lash ups. see: www.limflug.de
Limbach engines are fitted to certified aircraft, commercial airships, military UAVs, as well as the whole range of experimental, permit, and home built aeroplanes.

MDF1 · Post by **MDF1** » Sun Oct 05, 2008 6:12 pm

Haven't seen any prices for the Limbach. How do they compare to the Great Plains engines which seem to be the cheaper end of the VW market? Do you pay a premium for the 'Certified' heritage??

Nick Allen · Post by **Nick Allen** » Sun Oct 05, 2008 9:09 pm

From memory, as of three years ago when we replaced ours, a new Limbach is the thick end of £10,000. The decline in the value of the pound vs. the euro won't have helped this. Certification certainly costs: viz. the price difference between certified and uncertified versions of the Rotax 912. Limbach now list one of their models as "experimental", and it would be interesting to know the price differential for this.

rogcal · Post by **rogcal** » Mon Oct 06, 2008 5:59 am

Considering it's almost winter and there will be many more wet and windy Sunday afternoons coming your way, perhaps you should consider doing your own conversion.

I flown many an hour behind a Peacock conversion and I'm still here to tell the tale!

Whether it be belt drive or chain, Lucas or Slick, the choice is yours but personally, I would go for belt drive and impulse Slicks.

The Leburg electronic ignition option may still be open to you but what I've read on these pages leads me to believe that production has ceased.

If you have average engineering skills and an inspector with a good knowledge of VW conversions, you should have no difficulty in producing a unit that will give you many safe hours of use!

ColinC · Post by **ColinC** » Mon Oct 06, 2008 8:28 am

MDF - we seem to be thinking in parallel at the moment, I've been reading up on VWs too.

I just bought a set of Peacock drawings from the LAA. Great Planes seem to be a good supplier of parts and kits. I'm currently thinking of building an 1834/1915 vw. Weight is an issue so it will be relatively simple.

Rog, you mention slick mags and belt drive, I'm guessing that you have some experience of them. The Peacock plans use use chains. Can you point us to any material on belt drives on vws or pass on anything you know.

Also, what model Slick mags are used? Clearly LH (anti-cw) rotation are needed if the mags are mounted with the drive flange to the rear like the Peacock. Slick sell a 4316 for the VW but I have it in my head that it rotates at crank speed and mounts at the back in the Great Plains style. From memory a lag angle of about 30 degrees is necessary for the impulse coupling.

Any pointers would be appreciated here too.

Colin

cardiffrob · Post by **cardiffrob** » Mon Oct 06, 2008 9:51 am

I have an 1835 crankcase, crank, pistons and barrels, mags, pulleys etc here. Never used since case bored and crank crack-tested. I know I'm not meant to advertise here, but it would seem that the cheapest option is to buy a kit from someone who has already done the hard/expensive bits already?

If money was not tight then I'd go for the GPASC kit of parts with standard single-port 1835 heads with 2 extra plugs and Lucas SR4s or Leburg if there was cash to spare. Leburg is awesome. Fires first time and you'll never lose your fingers. Less than 1 lb weight difference (in my case; yours may differ) from the SR4s but it does add a 20 amp alternator.

Alloy pots will save 10 lbs, alloy crankcase will add 14 lbs.

cardiffrob · Post by **cardiffrob** » Mon Oct 06, 2008 9:55 am

I've posted this before. First run of rebuilt ACRO engine with Leburg ignition. I'd just had both hands released from plaster casts a few days before, so, was being a bit careful. Not even set the carb up but it fired after one gentle tug on the prop rather than the usual SR4 violent swing.
I'd recommend Leburg to anyone. I'm thinking of a similar system for my 1935 Austin 7 racer.

http://s82.photobucket.com/albums/j279/ ... ge0022.flv

Nigel Ramsay · Post by **Nigel Ramsay** » Mon Oct 06, 2008 11:19 am

I was thinking of a GtPlanes 1835 for my D9 but discovered to my great pleasure that it wasn't currently fitted with a 1200 (as I was told) but that it was in fact a 1600 on a Brazilian crankcase complete with case savers, dual pressure relief valves etc.

It also had a Peacock conversion but I've removed it to receive a Leburg system. I figure the 1600 will be powerful enough in the D9. Dave M WILL still supply Leburg systems if you ask him nicely and pay CASH by the way.

It's currently fitted with single port, small valve heads, but at 1600cc I don't think this is a problem, it ain't a racing engine! The carb is a Zenith 32 something or other which Barry Smith informs me one cannot get parts for. So I'm going to look at alternatives, one being a Stromberg CD125 (the current inlet is 1 1/4" dia).

I've read about VW conversions for months now and figure like a previous writer that one should be able to build up a unit quite successfully from UK sourced parts. The main problem seems to be getting the second plug drilling work done, but I know there are places that will do it well - does anyone know who does this sort of work here?

cardiffrob · Post by **cardiffrob** » Mon Oct 06, 2008 12:36 pm

I tried making the drilling jig via the peacock drawings. The back-drilling bit of the kit was a bu66er to make and not all that sucessful.
I later noticed that my scrap ACRO head had the extra plug seats cut at a different angle and could be forwards cut on a jig. Much better! Go for 10mm plugs if you can. Leaves max meat around the hole and the option for steping up if you knacker the thread later on.

If money is not too great a problem, get the exhaust ports ceramic coated to keep the heat transfer down. Will save cracking and will keep the CHT down. Stailess valves, too.

My opinions, for what they are worth.

CD150 and 175 carbs are still around brand new. LandRover used them since they are one of the few carbs that still work at 45 degree angles without flooding or rich-cutting.

ColinC · Post by **ColinC** » Mon Oct 06, 2008 1:00 pm

Rob,

that video looks like a good ad for the Leburg system! I know from our earlier discussions that Nigel had gone that direction too.

thanks for the info.

Colin

Nigel Ramsay · Post by **Nigel Ramsay** » Mon Oct 06, 2008 1:34 pm

I have a brand new CD150, but as the current inlet is 1 1/4" I'm after a CD125 (only reason really). Barry maintains that the 150 Stromberg is the ONLY carb for an 1835 and I bow to his experience. A mate of mine had a Reece Fish (Fish Reece?) unit on his 1600 and it seemed to serve him well but took a lot of fettling. I remember they used to use them on mini7 racers until someone went to the expense of cutting a twin choke webber in half!

At the end of the day, any fuel delivery device has a simple enough job to do on an aero engine in our world anyway, no rapid acceleration, overun etc. just a straight fuel delivery at full chat and a little less at cruise rpm.

Mike Mold · Post by **Mike Mold** » Mon Oct 06, 2008 2:47 pm

I considered replacing the Solex carb on my 1600VW / Jodel D9 with a CD150 having had good service out of one of these on an Limbach powered Fournier. However, the CD carbs are big blocks of metal and I couldn't physically incorporate one inside my D9 cowling. So I stayed with the Solex but if I was to go that way again I'd consider the Zenith carbs that Steve Bennett sells specifically for VWs.

And I agree that the Leburg EI system is the preferred option. I replaced the Lucas mags & chains with David Mickleburgh's kit and it was superb. If anyone's interested I still have drawings for a belt drive system.

MDF1 · Post by **MDF1** » Mon Oct 06, 2008 3:23 pm

So for an 1800 VW the view is a Stromberg 150 Carb and Leburg Ignition?

For those of us with limited skill and equipment, does the Leburg system come ready to fit or if not what's involved? Seem to remember an ignition system described in PF a while ago?? or was that a diferent system?

Anyone know who can do the mod for the extra plug? And does anyone currently do an inverted Oil System?

Nigel Ramsay · Post by **Nigel Ramsay** » Mon Oct 06, 2008 4:10 pm

MDF,
If you can persuade Dave M to sell you the metalwork kit for the Leburg then you are a long way to a 'limited skill' fit! Depends how limited i guess, but I'm sure there will be suitably skilled PF...er LAAer nearby who would help!