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.

[ChrisFoley]

A note regarding the (upright blade) cooling fan: all the fins have a vertical rib cast onto the back side, which becomes the upwind side when rotation is reversed. These ribs are there to stiffen and strengthen the fins. If they're left in the airstream, the fan won't move enough air for effective cooling, as they create significant turbulence leading to cavitation. The difference in air movement is substantial based on our empirical research.
When we cut down the fans for T4 installation it's no biggie to remove the ribs, but I wonder what the effect on strength is with a full dia fan.

[Smitty911]

"A note regarding the (upright blade) cooling fan: all the fins have a vertical rib cast onto the back side, which becomes the upwind side when rotation is reversed. These ribs are there to stiffen and strengthen the fins. If they're left in the airstream, the fan won't move enough air for effective cooling, as they create significant turbulence leading to cavitation. The difference in air movement is substantial based on our empirical research.
When we cut down the fans for T4 installation it's no biggie to remove the ribs, but I wonder what the effect on strength is with a full dia fan."

The fan appears to be very lite in the first place, so is strength really an issue? Motor turning at less than 6,000 RPM? (IMG:style_emoticons/default/confused24.gif)

I'll be running up to a local Corvair place on Monday to take a look at some motors and see what they hold.

Possibly pickup a mostly complete motor to start playing with.

Smitty

[VaccaRabite]

Using a corvair transaxle would also neutralize the "spins the wrong way" issue.

Zach

[zymurgist]

Using a corvair transaxle would also neutralize the "spins the wrong way" issue.

Would it? Didn't the Corvair hang the engine out behind the transaxle a la the 911?

[gandalf_025]

I've only owned and driven turbo versions. I've always liked them. The turbo setup was "simple" probably because it was a production car and simple screwed up less.
There was no need for a waste gate since the size of the carb and the muffler limited boost.
The 215 V8 turbo of the same era had higher compression and needed some sort of Water Injection and Owners forgot to fill the injection fluid bottle and fried motors..
That = not simple enough.

Many ways to modify, as stated earlier.. The only issues I ever ran into were the valve seats and the cam gear needing to be bolted on because the gear was aluminum and tended to elongate the keyway otherwise. Never spun off a a fan belt myself though.

Last fall I sold a 64 Turbo Engine and Transmission as cores for 250.00. Engine was complete..and it turned over with a wrench on the pulley bolt.
It ran when I removed it from the car about 30 years ago. I posted it on Craigslist and only 1 guy came to look at it.

Hemming's featured Corvairs at their Concours last fall in Vermont. Here is a picture of a prototype Mechanical Injection Motor they has displayed there. Now that would have been interesting ??

[rascobo]

When I got My learners permit at 15 1/2, My dad bought Me a 62 turbo Spyder. Very cool car, especially liked the interior touches reserved for the turbo; seats, gauges, badges etc.. Saddly it never saw My 16th B-day (wish I hadn't smoked that fatty). Oh well, one more "Oh well'.

[ChrisFoley]

My older bro had 9 (mostly inoperable) of them in the yard at one time by the time he was 18. His dd was a turbo spyder.
I never drove one.

[Dr Evil]

The fans have been run in reverse on many engines in harsh conditions in the desert on sand rails and have done fine.

To install a corvair engine into a 914 should take ZERO modifications to the body. You will need to fab a mount that can use the stock mount points (this is very easy), and engine tin (also easy now that I have done it once). Thats it.


For those of you with more experience than me that have posted, and corrected my info, THANK YOU! I appreciate it (IMG:style_emoticons/default/smile.gif)

[KaptKaos]

All of this makes you wonder why VW & Porsche didn't make a 6 cylinder version of the type4.

[bfrymire]

The fans have been run in reverse on many engines in harsh conditions in the desert on sand rails and have done fine.

To install a corvair engine into a 914 should take ZERO modifications to the body. You will need to fab a mount that can use the stock mount points (this is very easy), and engine tin (also easy now that I have done it once). Thats it.


For those of you with more experience than me that have posted, and corrected my info, THANK YOU! I appreciate it (IMG:style_emoticons/default/smile.gif)

Pictures of the modifications to the engine tin would be useful, as well as the engine mounts. Even pictures of the existing (stock ) mounts and location would be good.

Used to want one of these when I was younger. (IMG:style_emoticons/default/smile.gif)

-- brett

[rick 918-S]

I can't find the resource infomation but I remember reading that the Corvair engine was originally designed for a tank project.

I have owned 5 corvairs a extremely low mileage 61 fawn beige auto coupe, a 62 white auto 4 dr, a 63 red 4 sp vert and a 65 4 sp coupe. as well as a cherry Greenbriar Van. The only photo I have is of my 65 coupe. The worse thing I ever had to fix were leaking push rod tubes. The smell of burning oil in the heaters were common.

This car was as bad as they get. Scraped down both sides, hit in the front, rusted out behind the rear wheels. I fab'd that air dam out of 18 ga. The paint is a custom mix laquer base red with wild rose pearl sprayed out over the base and the 8 coats of laquer clear cut and buffed. Oh, and this photo s probably close to 30 yrs old.

[Dr Evil]

The fans have been run in reverse on many engines in harsh conditions in the desert on sand rails and have done fine.

To install a corvair engine into a 914 should take ZERO modifications to the body. You will need to fab a mount that can use the stock mount points (this is very easy), and engine tin (also easy now that I have done it once). Thats it.


For those of you with more experience than me that have posted, and corrected my info, THANK YOU! I appreciate it (IMG:style_emoticons/default/smile.gif)

Pictures of the modifications to the engine tin would be useful, as well as the engine mounts. Even pictures of the existing (stock ) mounts and location would be good.

Used to want one of these when I was younger. (IMG:style_emoticons/default/smile.gif)

-- brett

There is no modification to engine tin. You just need to fab up some tins from 18ga. I made some for my bus starting with cardboard templates, copy-cut out on 18ga with tin snips (or other cutting implement, but I am addressing budget), paint and install. The engine is basically a square.

Mounts are easy to fab because the case is rectangular and has 2 mounting bosses on each side that are free and clear to mate a bar up to with shock mounts.

[Dr Evil]

Its weird how hard it is to find pics of one installed in an 914. In 2000-2002 or so I found one pic and posted on Pelican, can not find it. It has been done before with nice result, but I cant seem to find proof. (IMG:style_emoticons/default/confused24.gif)

[rick 918-S]

Its weird how hard it is to find pics of one installed in an 914. In 2000-2002 or so I found one pic and posted on Pelican, can not find it. It has been done before with nice result, but I cant seem to find proof. :confused

If you can't prove it, it's an Alien sighting. (IMG:style_emoticons/default/alien.gif)

[scotty b]

Its weird how hard it is to find pics of one installed in an 914. In 2000-2002 or so I found one pic and posted on Pelican, can not find it. It has been done before with nice result, but I cant seem to find proof. :confused

If you can't prove it, it's an Alien sighting. (IMG:style_emoticons/default/alien.gif)

Mike has a history of those (IMG:style_emoticons/default/av-943.gif)

[jk76.914]

Coupola more thoughts... The only issue with reversing rotation was with the belt life. The alternator (generator through '64) is fixed in place, and doesn't swivel to tighten the belt. This ensures that the belt geometry is fixed on the tension side: crank pulley-to-alternator-to-fan. The moveable pulley that adjusts belt tension is on the slack side: fan-to-pulley-back to crank. This was the case from day 1, obviously, and this is what you lose with a reverse rotation. Other changes over the years- belt guards on the adjustment pulley and just as the belt exits the fan pulley prevent the belt from flipping over. These came along in '64, along with the magnesium fan. The new fan was probably the biggest contribution to belt life, and it's the only fan that can be reversed. The earlier steel fans had curved blades to bite into the air as the fan turned, and they wouldn't work in reverse. All Corvair owners carried an extra fan belt, along with a 9/16" wrench to change it on the side of the road, but with all the improvements along the way, I personally never had one fail me.

Also, another comment about valve train and push rods- many firms offered performance cams for Corvair in the '60's, and all were hydros. It was generally accepted that hydros were necessary in the air cooled Corvair, and all 1.7 million Corvairs built used them. The only exception was an aftermarket cam by Edelbrock, which was for solid tappets. Interestingly, theirs was the only kit with aluminum pushrods. The theory was that though the push rods don't heat up as much as the cast iron cylinders, the aluminum expands more per degree and somewhat equalizes things. Sound familiar?

[TargaToy]

Any simple ideas for retaining your HEAT if the corvair motor were used in a year 'round dd?

[Dr Evil]

You can reverse the exhaust logs and retain the heater tins. They are easy to adapt since the design is straight forward.

I am working on a new way to get heat from headers.....stay tuned after I get my engine reassembled and installed.

[Lou W]

"Girls will be boys, and boys will be girls. It's a mixed up, muddled up, shook up world.............."




(IMG:style_emoticons/default/happy11.gif)

[TargaToy]

In a proposed 914 install, is there anything about the mounting that would interfere with shift linkage? (this is sounding better all the time).