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stroker
stroker UltraDork
7/1/18 9:50 p.m.

Anyone with any experience or some idea of how complicated that process would be assuming the parts are available?  I'm told they are....

oldopelguy
oldopelguy UberDork
7/2/18 12:49 a.m.

Since all corvairs rotate reverse direction compared to almost everything else I don't know if you are asking about a regular one or a corvair somehow reversed so it turns the direction a regular engine does.  I have never heard of such a conversion,  and am kinda curious though. 

stroker
stroker UltraDork
7/2/18 7:17 a.m.

In reply to oldopelguy :

There are parts/kits available to make it do so.  I figured somebody here would have some sort of experience with them.

M2Pilot
M2Pilot Dork
7/2/18 8:03 a.m.

I think Crower and/or Crown used to make a cam for this purpose.

californiamilleghia
californiamilleghia New Reader
7/2/18 8:10 a.m.

Crown sold the cam etc in the 70s , maybe OTTO did after that , 

How to Hot Rod your Corvair from HP books  probably had that info , 

What are you going to put the Corvair motor in ?

stroker
stroker UltraDork
7/2/18 8:29 a.m.

In reply to californiamilleghia :

The idea (on paper at this point) is a 914.

AngryCorvair
AngryCorvair MegaDork
7/2/18 8:33 a.m.

Process is not complicated.  Consider this:  crank spins backwards, so cam is forced to spin backwards.  This requires the cam lobes to be reversed to coordinate the valve events to the piston movement.  Distributor drive and driven gears are cut in opposite direction for thrust wear and to spin the oil pump in the correct direction.  It's all figured out and robust.

Clark's Corvair Parts reverse rotation info page 1

californiamilleghia
californiamilleghia Reader
7/2/18 8:43 a.m.

In reply to stroker :

my friend is doing a 914 now with Corvair motor and Porsche trans and did not reverse it.......

if you get closer to doing it let me know.......

GTXVette
GTXVette SuperDork
7/2/18 8:48 a.m.

sadly the corvair ring gear cannot be flipped but the early VW can or the 914transaxle, the corvair isn't reverse rotation it's just installed from the rear. or subie?

aircooled
aircooled MegaDork
7/2/18 10:30 a.m.

As Angry said, basically cam and the distributor gears.  Of course, the cam is in the dead center of the engine and the case has to be split to change it, so it's a total disassemble (not a big deal if you are rebuilding anyway, but a bit of work if you want a quick conversion).

I have heard that they actually run a bit smoother.

BTW - not a reverse rotation engine normally if you look from the front of the car (which is the rumor as to why GM went that way, for consistency)

AngryCorvair
AngryCorvair MegaDork
7/2/18 11:41 a.m.
aircooled said:

BTW - not a reverse rotation engine normally if you look from the front of the car (which is the rumor as to why GM went that way, for consistency)

Because engine was "clean sheet of paper" design, it could be designed to spin either way.  By making it spin CCW (as viewed from harmonic balancer end), GM saved transmission tooling costs  since existing gear cutting tooling could be used for Corvair trans gears.

wearymicrobe
wearymicrobe UberDork
7/2/18 11:48 a.m.
stroker said:

Anyone with any experience or some idea of how complicated that process would be assuming the parts are available?  I'm told they are....

What transmission. It might be easier to simply swap the transmission rotation. 

Also if this is going into something like say a 914 or a bug or really anything else there are tons more options then Corvair motors now that are cheaper, make better power and actually hold together. 

stroker
stroker UltraDork
7/2/18 11:51 a.m.

Okay, let's get this clear--you take a Corvair engine and attempt to install it with the standard VW transaxle already installed in a 914--is it rotating the correct direction or not?  My understanding is that it is NOT rotating the correct direction for that application?

barefootskater
barefootskater HalfDork
7/2/18 11:59 a.m.

In reply to stroker :

That depends entirely on whether you want 4 forward gears and one reverse or if you want 4 reverse gears and one forward. I saw a small race series years ago where the racers would take old american iron and flip the axle over and race oval tracks in reverse at like 80mph.

Edit- Linky

wspohn
wspohn Dork
7/2/18 12:00 p.m.

Probably be a lot better of with a modern Subie engine.....

RossD
RossD MegaDork
7/2/18 12:12 p.m.

Just as a reference point, I just picked up a VW Type 1 transaxle with better gears for high way use for $150, a used Kennedy adapter and flywheel for a Zetec for $125, and I expect to pick up a Zetec for $250 or less. Of course the devils (or the dollars) are in the details.

 

stroker
stroker UltraDork
7/2/18 12:28 p.m.
barefootskater said:

In reply to stroker :

That depends entirely on whether you want 4 forward gears and one reverse or if you want 4 reverse gears and one forward. I saw a small race series years ago where the racers would take old american iron and flip the axle over and race oval tracks in reverse at like 80mph.

Edit- Linky

Let's assume 4 forward and 1 reverse.   Does it spin the right way?

oldopelguy
oldopelguy UberDork
7/2/18 12:57 p.m.

No. As you look at the belt pulley on the engine,  what is commonly referred to as the front of the engine opposite the bell housing end, the pulley will spin counter clockwise as the engine is running.  Just like 4-cylinder Honda engines used to. 

In the corvair, just like ACVWs and Porsches that end of the engine is in the rear of the car. 

Now if you mounted it to a regular ACVW transaxle and flipped it around to mid engine in a 914 you would actually get 4 forward gears and one reverse, but every shaft and bearing in the transaxle would be spinning opposite the direction it was supposed to spin.  I doubt it would lubricate or thrust load acceptably enough to last very long that way.

 

stroker
stroker UltraDork
7/2/18 2:05 p.m.

In reply to oldopelguy :

You're assuming a REAR engined transaxle being rotated 180 degrees.  What I'm talking about is using the OEM 914 transaxle in the original mounting position.  Does the Corvair engine rotate in the correct direction? 

oldopelguy
oldopelguy UberDork
7/2/18 2:11 p.m.

No, almost every engine in the world turns the crank pulley on the accessory drive end clockwise when looking at it,  including the Porsche engine.  The Corvair and 4-cylinder Hondas rotate the opposite direction. 

wearymicrobe
wearymicrobe UberDork
7/2/18 2:23 p.m.
stroker said:

Okay, let's get this clear--you take a Corvair engine and attempt to install it with the standard VW transaxle already installed in a 914--is it rotating the correct direction or not?  My understanding is that it is NOT rotating the correct direction for that application?

You swap one gear in the VW transaxle and it can spin any way you want. They do this all the time in the VW kit car world. heck you can buy a freeway flyer already built this way. 

spitfirebill
spitfirebill MegaDork
7/2/18 2:33 p.m.
AngryCorvair said:
aircooled said:

BTW - not a reverse rotation engine normally if you look from the front of the car (which is the rumor as to why GM went that way, for consistency)

Because engine was "clean sheet of paper" design, it could be designed to spin either way.  By making it spin CCW (as viewed from harmonic balancer end), GM saved transmission tooling costs  since existing gear cutting tooling could be used for Corvair trans gears.

I heard that the Corvair engine was derived from a stillborn aircraft engine.  Fact or fiction? 

californiamilleghia
californiamilleghia Reader
7/2/18 5:10 p.m.

simple , if you put a stock corvair motor in a stock 914 using the 914 gearbox you will have 4 reverse gears..........

if you put a stock corvair motor into a 914 body and use a stock VW 4 speed bug  IRS gearbox you will have 4 forward gears 

if you put a stock corvair motor into a 914 body and use a 911-912 gearbox  you will have 5 forwards gears........

a early 1965-71 Porsche 912-912 is internally  the same as a 914 gearbox BUT the ring gear is on the opposite sides 

 

Clear as MUD ??

 

 

stroker
stroker UltraDork
7/2/18 5:23 p.m.

In reply to californiamilleghia :

How much is the 911/912 gearbox to buy?

californiamilleghia
californiamilleghia Reader
7/2/18 5:33 p.m.

its a 901 box , they made 4 and 5 speeds....

like any used gearbox you do not know whats inside it.........

$1000-$2000

You can also use the later 930 gearbox  , but they are more , 

if you are really planning on doing a 914 you need to talk to my buddy , 

He has a Corvair powered 914 in his shop now and knows both Corvairs and Porsches

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