SOT: The truth about Corvair engines, Nothing but the facts and experience, please Options

[Dr Evil]

There has been lots of interest in the corvair power plant over the years as a possible source of cheap HP for many vehicles. There are used in experimental aviation, dune buggies, buses (such as mine), and in place of many other air cooled VW power plants. They are fairly cheap to buy and build, very easy to build and maintain, and plentiful with readily available parts from several suppliers.

The main divide in the corvair engine line took place in 1965 when the displacement of the engine was moved to 2.7L and was offered in a NA 110HP, NA140HP, turbo 150HP and turbo 180HP. The only differences in the long block between these engines are the nitrided crank found in all but the 110HP, and the heads: 110 had one single barrel on each head, the 140 had 2 with one acting as primary and one as secondary. The turbos had a single barrel blow through setup.

The heads are the major limiting factor in the design. They are not built in an intuitive way and rob much hp. The 140 head had bigger valves, but like its 2.0L TIV analog, would drop valve seats due to the limited amount of material between the seats in the head, and the inability of larger seats to shed heat as well as smaller seats. This can, and has been overcome by those who have been rebuilding these heads fro decades by making sure the crush tolerance on the seats are correct, and staking the seats in place.

Currently, you can get a set of rebuilt, 140hp larger valved heads, with new hardware and no core for about $1200 from Corvair Ranch in Gettysburg, PA. I bought a set that was rebuilt and had the plenums taken off for tri porting for $1500 shipped off of ebay from Starr Cooke in El Cajon, CA, another well known Corvair entity.

Modified with plenum removed for individual runners:


The above uses an adapter that allows the placement of Weber triples. My set came with this adapter.

Here is a head with a stock plenum, modified with bungs for FI. This is a 140 head as it has two carb bases on it:


Standard engine:


One of the cool things that many ACVW folks like is that the corvair engine has stock hydraulic lifters on it that use standard lifter, push rod, and rocker parts from Chevy. Easy and cheap to obtain.

Another great feature that I like over ACVW is the box design on the case. The top and bottom come off and allow for any maintenance. Swapping rods, bearings, what ever, is easy.

[Dr Evil]

I would think not, however, I have not done it so that is a specific install issue to overcome if is comes up. The engine has very good bottom clearance, better than the TIV with HEs, even.

[Spoke]

This is a friend's Corvair race car. The rear fender flares are off of one of the Chrysler K-cars. He's found that the front fenders have exactly the contour he wants not only for his Corvair but also for 914s.

The Corvair engine has been ported to accept the triple Webers as well as P/C and head work. The engine is immaculate and John estimates it puts out north of 250HP.

Brakes are still Corvair standard drum brakes.

[Don M]

something to consider regarding pushrods, the oem GM setup requires the use of a combination head bolt washer/stud plate /pushrod guide so there is a bit of limit to configuration of nonstock parts, not a real problem just something that needs to be addressed if other than stock units are employed.

[Spoke]

This is one nice Corvair. It has the 180HP turbo engine.

[Spoke]

This one might end up being a 914vair. He plans to put Corvair rear panel, Corvair engine, and Chrysler K-car wheel flares that he found match the contour of the 914.

[Spoke]

No Corvair collection is complete without a Corvair pickup.

[McMark]

Could you run a 911 transmission? (IMG:style_emoticons/default/idea.gif)

[Dr Evil]

Ya, but you would still have to reverse the engine rotation or it would spin the guts in the wrong direction.

[orange914]

Ya, but you would still have to reverse the engine rotation or it would spin the guts in the wrong direction.

couldn't you flip the ring&pinion, like when a vw trans is flipped to run a mid conversion?

[Tom_T]

We got a new 63 Greenbriar Van - Blue with White stripes & the vinyl houndstooth looking upholstery - which we drove to CA on old 66 (only small bits of I-40 were started then). I think it only had the base 95 hp motor & auto trans (it was ostensibly Mom's DD), but it fried the valves in TX 1/2 way there & we were stuck while the local dealer fixed it (Amarillo IIRC - I was only 10 then, so fuzzy on the details at 58.5! (IMG:style_emoticons/default/blink.gif) ).

Great car, we had 6 small kids (2 - 10 yrs), 2 parents & all slept in the car on the way & every summer trip up to 67 - back from San Diego to Pittsburgh - no AC either! (IMG:style_emoticons/default/blink.gif)

As kids grew, Dad added an Army Surplus stretcher across the 2 back bench seats that folded up against the wall for driving, & open for sleeping. When we grew to 4 teens, Dad moved up to a bigger rig.

Then Dad got a 67 Chevy 3/4 tom pick-up with 327 ci 2 bbl auto trans & towing pkg. with a cab over camper - ahhhh - the luxury, still no AC though!

[Dave_Darling]

couldn't you flip the ring&pinion, like when a vw trans is flipped to run a mid conversion?

That will get the output spinning the correct way, but the internal parts of the trans will still be spinning the opposite way of the one they're designed for. They won't be happy for very long, and they will let you know it with expen$ive noi$e$.

The Doc already answered this in the other Corvair thread, I believe. Or was it earlier in this thread?

--DD

[jk76.914]

We got a new 63 Greenbriar Van - Blue with White stripes & the vinyl houndstooth looking upholstery - which we drove to CA on old 66 (only small bits of I-40 were started then). I think it only had the base 95 hp motor & auto trans (it was ostensibly Mom's DD), but it fried the valves in TX 1/2 way there & we were stuck while the local dealer fixed it (Amarillo IIRC - I was only 10 then, so fuzzy on the details at 58.5! (IMG:style_emoticons/default/blink.gif) ).

Great car, we had 6 small kids (2 - 10 yrs), 2 parents & all slept in the car on the way & every summer trip up to 67 - back from San Diego to Pittsburgh - no AC either! (IMG:style_emoticons/default/blink.gif)

As kids grew, Dad added an Army Surplus stretcher across the 2 back bench seats that folded up against the wall for driving, & open for sleeping. When we grew to 4 teens, Dad moved up to a bigger rig.

Then Dad got a 67 Chevy 3/4 tom pick-up with 327 ci 2 bbl auto trans & towing pkg. with a cab over camper - ahhhh - the luxury, still no AC though!

Those are great memories. Which jogged mine for some more trivia- Corvair trucks had valve rotators to make them last longer (sounds like it didn't help on yours!) and they also had a transmission oil cooler on the powerglide...

[Dr Evil]

Ya, basically, the input shaft will always be spinning the wrong direction, so the gears will be spinning the wrong direction. Flipping the diff allows for the output to spin correctly, but not the internals of the trans.

When you flip the diff for a 901 to go 911 vs 914 the input shaft and internals all remain spinning in the correct direction as designed, you again change the out put direction only. The internals stay spinning as designed.

Clear as mud? (IMG:style_emoticons/default/confused24.gif)

[McMark]

I understand the internals would be spinning opposite of their designed intent. But just as a mental exercise:

If you install a 911 transmission in a 914 (type 4, etc) you get 5 'reverse' gears.
If you then install a Corvair motor and spin that transmission backwards, don't you get 5 'forward' gears?

It's still running on the 'backs' of the gears, but wouldn't flipping the diff be counter productive?

[Tom_T]

We got a new 63 Greenbriar Van - Blue with White stripes & the vinyl houndstooth looking upholstery - which we drove to CA on old 66 (only small bits of I-40 were started then). I think it only had the base 95 hp motor & auto trans (it was ostensibly Mom's DD), but it fried the valves in TX 1/2 way there & we were stuck while the local dealer fixed it (Amarillo IIRC - I was only 10 then, so fuzzy on the details at 58.5! (IMG:style_emoticons/default/blink.gif) ).

Great car, we had 6 small kids (2 - 10 yrs), 2 parents & all slept in the car on the way & every summer trip up to 67 - back from San Diego to Pittsburgh - no AC either! (IMG:style_emoticons/default/blink.gif)

As kids grew, Dad added an Army Surplus stretcher across the 2 back bench seats that folded up against the wall for driving, & open for sleeping. When we grew to 4 teens, Dad moved up to a bigger rig.

Then Dad got a 67 Chevy 3/4 tom pick-up with 327 ci 2 bbl auto trans & towing pkg. with a cab over camper - ahhhh - the luxury, still no AC though!

Those are great memories. Which jogged mine for some more trivia- Corvair trucks had valve rotators to make them last longer (sounds like it didn't help on yours!) and they also had a transmission oil cooler on the powerglide...

Jim - at about 13 my first aircooled mechanical experience was helping my Dad change out that tranny oil cooler! (IMG:style_emoticons/default/biggrin.gif)

[Dr Evil]

We got a new 63 Greenbriar Van - Blue with White stripes & the vinyl houndstooth looking upholstery - which we drove to CA on old 66 (only small bits of I-40 were started then). I think it only had the base 95 hp motor & auto trans (it was ostensibly Mom's DD), but it fried the valves in TX 1/2 way there & we were stuck while the local dealer fixed it (Amarillo IIRC - I was only 10 then, so fuzzy on the details at 58.5! (IMG:style_emoticons/default/blink.gif) ).

Great car, we had 6 small kids (2 - 10 yrs), 2 parents & all slept in the car on the way & every summer trip up to 67 - back from San Diego to Pittsburgh - no AC either! (IMG:style_emoticons/default/blink.gif)

As kids grew, Dad added an Army Surplus stretcher across the 2 back bench seats that folded up against the wall for driving, & open for sleeping. When we grew to 4 teens, Dad moved up to a bigger rig.

Then Dad got a 67 Chevy 3/4 tom pick-up with 327 ci 2 bbl auto trans & towing pkg. with a cab over camper - ahhhh - the luxury, still no AC though!

Those are great memories. Which jogged mine for some more trivia- Corvair trucks had valve rotators to make them last longer (sounds like it didn't help on yours!) and they also had a transmission oil cooler on the powerglide...

Valve rotators??? (IMG:style_emoticons/default/confused24.gif) I have not seen these, any pics?

I installed the tranz cooler on my PG. It was probably over kill, but I figure I like to floor it over mountain passes, in a bread box, in summer so it couldnt hurt. It was hard to find info on the cooler, it is not common and no pics could be found. I had to consult a guru about how to install and such and still no one could tell me which port is in and which is out.

[Dr Evil]

I understand the internals would be spinning opposite of their designed intent. But just as a mental exercise:

If you install a 911 transmission in a 914 (type 4, etc) you get 5 'reverse' gears.
If you then install a Corvair motor and spin that transmission backwards, don't you get 5 'forward' gears?

It's still running on the 'backs' of the gears, but wouldn't flipping the diff be counter productive?

(IMG:style_emoticons/default/headbang.gif)

You are focusing on the OUTPUT only. The helical cut gears would be spun so that their coasting side would then be the power-on side. Not good. You can switch the output of any differential by flipping the diff (if the design allows such), but the ring is being driven by the coast side of the pinion, because the INPUT shaft is spinning backwards of the tranny design no matter what side the diff is on.

[Tom_T]

I installed the tranz cooler on my PG. It was probably over kill, but I figure I like to floor it over mountain passes, in a bread box, in summer so it couldnt hurt. It was hard to find info on the cooler, it is not common and no pics could be found. I had to consult a guru about how to install and such and still no one could tell me which port is in and which is out.

IIRC that was an extra cost pick-up & Van heavy duty option with the auto trans (powerglide), and IIRC it had inlet higher than outlet - so you had gravity flow through the fin-box. If that's how you did yours, then it should be okay, so long as the "bread box" isn't so low it gets whacked off on the road.

Is there any other way to drive either a Greenbriar or a VW Bus/Van in the hills/mountains, than to the floor!!?? (IMG:style_emoticons/default/biggrin.gif)

BTW - the dealer we got it from was out by you Doc - in or near Bridgeville/Upper St. Clair Twp., but don't know if they're still there.

[McMark]

No, I'm not getting that involved. It would blow up, no doubt. But it would drive forward with a 911 transmission. For a few miles anyway.

[Dr Evil]

I installed the tranz cooler on my PG. It was probably over kill, but I figure I like to floor it over mountain passes, in a bread box, in summer so it couldnt hurt. It was hard to find info on the cooler, it is not common and no pics could be found. I had to consult a guru about how to install and such and still no one could tell me which port is in and which is out.

IIRC that was an extra cost pick-up & Van heavy duty option with the auto trans (powerglide), and IIRC it had inlet higher than outlet - so you had gravity flow through the fin-box. If that's how you did yours, then it should be okay, so long as the "bread box" isn't so low it gets whacked off on the road.

Is there any other way to drive either a Greenbriar or a VW Bus/Van in the hills/mountains, than to the floor!!?? (IMG:style_emoticons/default/biggrin.gif)

BTW - the dealer we got it from was out by you Doc - in or near Bridgeville/Upper St. Clair Twp., but don't know if they're still there.

Small world (IMG:style_emoticons/default/smile.gif)

I cant remember off hand how I have it plumbed. I have the cooler in the left rear behind the wheel. It is in its own little spot and protected by a mud flap from road debris. If I hit that, something went very wrong. Thanks for the info, no one on the corvair forum could answer it.

When I say that I was flooring it going over the mountains, I mean that I was doing 80mph, up hill (IMG:style_emoticons/default/wink.gif) Not that I had to do it to make it, just that I could. And that was in a pig-rich running, not quite tuned setup.

I cant wait to see how it does now.