By Kellison Jim Date 2012-12-08 18:00
I'm seriously thinking of swapping out my 1641 for a 140hp Vair engine I have. What all do I need to know and be aware of. I am aware that I will need to flip the ring gear and the adapter itself but what else will I need to do and buy? Who do you guys recommend for these parts? Does anyone have step by step instructions? Thanks!!
By ManxRob Date 2012-12-09 07:48
Jim, that is a fine looking 140! I'm sure you will feel a power difference between that Corvair engine and your 1641. I bet it sounds great through the glass-packs too. Have you had it running yet?
I don't have any experience running the center-mount 4 barrel carburetor setup you have mounted (I do have a NOS one on the parts shelf), but I have heard that they can be sensitive to 'icing'.
There is a copy of the old 'Crown' conversion instructions posted here:
The engine adapters seem to come up on Ebay quite frequently. I would stay with the ones manufactured by Crown, Otto (Clarkes Corvair), or Kennedy. Flywheel & Starter selection gets a little more complicated. I'm assuming that your Corvair is running the 'standard' rotation:
I used a 127 tooth flywheel, a Corvair starter (modified with an adapter) and a off-center starter bushing installed. This setup has worked for me for several years, though I did replace the starter once, and had to pull the engine once to re-install the starter bushing when it slipped its stake. The proper flywheel with the Corvair ring-gear is only available on the used market, and I think the combination of adapters on modified (sawn-off) starter housings & reamed/bushed shaft supports leave opportunity for frequent maintenance. I used this option since I had all the parts at the time, and no extra $.
Use a 130 tooth flywheel and a 'reverse-wound heavy duty VW starter' available from Clarks Corvair. If I were dong my project again I would go this way. The only piece that would not be re-usable if in the future you were to reverse your engine would be the starter. I have also heard that a 'stock' Porsche 928 starter works for this setup, though I don't know of any documentation.
Other parts you will need include:
An output shaft/pinion bushing in the flywheel
A voltage regulator
Figure out the coil voltage resistor for your ignition
Throttle linkage adapter.
I would also suggest going on the lighter side when selecting your clutch/pressure plate. I used a stage 1 clutch on my 140 without any problems.
I have never been inside a VW gearbox to flip the ring-gear. I used a stock VW bus transmission with the reduction boxes removed for several hundred miles until it started complaining, then I had a 'Freeway Flyer' transmission built with all the normal internal upgrades, and a flipped ring-gear. It worked great for several years. I sold it last summer.
I do have some, (more than I need), engine adapters and flywheels, PM me if interested.
By Kellison Jim Date 2012-12-09 15:43
Thanks Rob! I heard it running when I bought it and it did sound great through the old chrome glass packs but haven't had it fired up since I cleaned it up. Is there a way I can test fire it on the engine stand without a starter? If so, how would I wire it?
The guy I bought it from converted it from a 4 carb setup to the current one. He also said the engine also had a larger cam put in it as well as other things (I'll take that with a grain of salt) when the original owner started the buggy project back in the early 70's but never completed it.
If I go forward with this idea, I think I wiould be leening toward Option 2.
Thanks again and I'll check the coversion instruction to see if it's something I could handle.
By ManxRob Date 2012-12-10 03:36
I test ran my turbo engine on the floor before putting the VW adapter on it. I just bolted the Corvair starter on the existing belhousing, ran the fuel pump line to a gas can, and hot wired the ignition. Not having a starter might be a challenge though.
By Leon R 2038 Date 2012-12-10 21:11
The starter is a standard Chevy starter I think the same as Chevy's straight 6. You can mount it by placing 2 lug nuts between the starter and the bell housing as spacers for a test start. then just hook up a small fuel supply and wire up a battery ,You'll need a hot wire to one of the small starter terminals and one to the coil along with the + battery cable to the starter. you can jump across the starter terminals from the small one to the battery cable once the smaller hot wires are inplace to kill it after just remove the hot wire to the coil.You dont even need an engine stand you can start it right on the floor. with everything I see on this motor it's easy to believe it got a hotter cam and maybe even bigger pistons and cylinders in the rebuild.
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