what tips to liven them up? Costs? What about the manual transmissions? Are they reliable? I'm surprised how many i see on CL. Asking for a friend.
what tips to liven them up? Costs? What about the manual transmissions? Are they reliable? I'm surprised how many i see on CL. Asking for a friend.
I have a friend who built an engine using parts from other engines that were either stronger , like Rabbitt conecting rods, and pistons that better fit his needs. He uses Porche carbs on each bank. It is installed in a Monza body with race car mods. He used, I think he retired, to do track days with a Corvair club, Northeast Corvair Councel. The manual transmissions seem to be pretty reliable with the increased power. I know all this because I ran my ZX2SR with them.
Lots of tips, depends on your budget. Not a lot of off the shelf stuff. Electronic ignition is an obvious change. Carb mods help, but not super easy. For real gains: big bore, head work, exhaust, cams, none of which will be cheap. Probably the best easiest mod is flycutting down the heads (I think this only works with 140 heads) to remove the step. The ups the CR, but also increased turbulance a lot (reducing knock tendancy). This unfortunatly will mess with the valve geometry and the sheet metal so maybe not super easy.
My favorite mod: Having my 140 head welded up to remove the step. This gave the advantage of the compression and turbulance, but did not have the issue of the valve geometry and sheet metal (because the heads did not move closer together). Not super cheap of course.
The general answer would be: You can make small improvements pretty easy, bigger improvement will involve a good amount of effort (with likely more the typical V8 mod costs). Reliability is typical to any modified engine, go to far and it drops off, be conservative, no real issues.
There were two basic types of manual transmissions for Corvairs. The original (ignore what I think was a special on in 1960) 3 and 4 speeds should be plenty strong for most not over the top cars. In 1966 they went to the Saginaw transmission, which was essentiall the same parts as the big car trans, they are a bit heavier duty of course. The real concern is not the trans though, its the diff. The spider gears in the difff are a weak point in modified cars and shoudl be built up to a 4 spider gear setup if you plan on doing hard launches in a modified car.
Here is a site that has a number of performance tips:
P.S. A good Corvair engine rebuild will push $3000, and performance one can add thousands to that.
What about a subie swap? Had to have been done. I’ve often dreamt of a subie powered Corsair with WRX front suspension (no awd of course). It’d be a sweet set up, possibly a cheaper version of a restomod
Just saw a Subi in a Ghia last weekend.
I don't know if I have heard of one in a Corvair though. Certainly a possibility (you would clearly need a custom adaptor plate), but I suspect once you start thinking about adding a radiator, you thoughts go straight to a V8 ('murica').
I'm sorry, I'm again building a car on paper. I should have mentioned up front that this is within the context of Chumpcar. I'm thinking this thing would be pretty doggone close to stock and apparently there's a penalty for changing the carbs/induction. I haven't digested the rules yet. This would installed in a different car, but right now I'm just thinking about the engine.
Corvair engines rotate the opposite direction from Subaru stuff, so you would need to replace the transmission too.
Four cylinder Hondas rotate backwards though, and can make a lot of power too.
You can learn alot about these by getting a catalog from Clark’s Corvair Parts and thumbing thru it.
OK, different car then. Sounds like you will use the transaxle then. 64 and earlier are swing axle, 65 plus are independent but do use the driveshaft as the upper suspension component. Swing axles will be easier to swap since you can move the whole rear structure.
In that context, my only real suggestion would be under driving the cooling fan (it can use a lot of HP). That can cause belt alignment issues though, which can make throwing belts easier (you may have heard, that is already an issue). If you want to get fancy, figure out how to rig up an AC clutch to the pulley and have a "push to pass" button to disable it. At high RPM the fan draws almost 15 hp!
In reply to aircooled :
I was expecting to use some sort of electric fan... that serpentine belt looked like Trouble.
stroker said:In reply to aircooled :
I was expecting to use some sort of electric fan... that serpentine belt looked like Trouble.
The serpentine belt on my '64 was trouble. It would reliably flip off at 62 mph. This was during the 55 mph national speed limit days so the upside was that it helped me stay legal.
stroker said:In reply to aircooled :
I was expecting to use some sort of electric fan... that serpentine belt looked like Trouble.
They have been tried. Even very well done they will have issues keeping up with a motor under load. There is just too high of an airflow requirement. Belts are mostly a problem with modified motors and will tend to go during rapid RPM changes (e.g. shifting). Stock setup works pretty good if pulleys are in good condition and aligned and you put the belt on loose, allowing it to slip if possible.
The Porsche vertical style fan is the preferred performance option:
Couple of things to bear in mind:
Stock carbs tend to flood under hard cornering. There is a quick, easy and cheap fix that involves adding extension tubes to the vents. Get a copy of Bill Fisher's How to Hotrod Corvair Engines.
When the heads get hot, like in competition, the valve seats tend to fall out (steel/aluminum issue). They can be "staked" to prevent this, again detailed in Fisher's book (an oldie but a goodie).
AFtermarket oil pans and valve covers can help with oil starvation and cooling. A good open exhaust wakes the engine up. If tempted to go with a 4bbl carb, don't go overboard. A 390 cfm is plenty for most purposes.
If you're going to race, you probably want a late model (65 on), and the biggest performance improvements (other than reliability) are from removing weight. Those seats, etc, are HEAVY! Our 1966 SCCA pro rally car (boy the series name dates me) weighed in at 2100 with two seats and a full roll cage, alloy skid plates, lights and no fiberglass, just unbolting stuff, cutting away bracing under the hood and engine cover, etc. With a blueprinted, but nearly stock, turbo engine, it was plenty quick in a straight line for the day. We ran factory convertible HD springs and Bilstein HD shocks, and it handled great, got a top 10 finish at the Big Bend Bash national event back around 1980 (forget the exact year) through reliability and not crashing.
I've learned there's a kit to reverse the "wrong" rotation on the Corvair engine. Anyone have any experience with that?
On our D-Prod cars in the late 60's the Fix for the belt problem was to put a spring on the Idler pulley to keep it in Tension.
if I were to build a corvair, I would be tempted to get one of the more unloved Porsche 911 engines and a porsche 5 speed and stuff that in the back. Would make for a good looking, reliable, vintage, car with great power
Since you will be looking at clist specials, a good check on the motor is to pull out the oil dipstick with the engine running. If oil spits out of the dipstick tube you have blow by past worn rings. If I remember correctly.
In reply to mad_machine :
You'd be spending a lot for any Porsche 6 cylinder engine. Subaru would be the ticket. Get a salvage 2.0 turbo and either reverse the pinion or adapt it to a porsche/VW/audi transaxle.
edit: strike that. Go with an EZ30D for torquey 6-cylinder NA goodness. stock CPU can be adapted easily.
Actually, I'd like to go to work on a pair of Subaru heads someday. The biggest flaw in that engine seems to be lousy breathing. Fixing it is no picnic, but might be interesting nonetheless. Since it's air cooled, you can do stuff that would be much more difficult in a water-cooled head.
In reply to Joe Gearin :
Obviously people with Class given the E-body in the background....
Joe Gearin said:I'm just going to leave this here......so someone else buys it!
Look closer: Gonna take a lot of chemo to cure that cancer.
Kreb said:In reply to mad_machine :
You'd be spending a lot for any Porsche 6 cylinder engine. Subaru would be the ticket. Get a salvage 2.0 turbo and either reverse the pinion or adapt it to a porsche/VW/audi transaxle.
edit: strike that. Go with an EZ30D for torquey 6-cylinder NA goodness. stock CPU can be adapted easily.
If you went with the turbo though, you could just get an STI half cut and have a manual transmission available. With the 6 cyl, it would be another scavenger hunt for a manual trans and/or adapter. subagears in Australia may have a flip pinion kit but they definitely have the lockers for the transaxle.
If you are going water cooled anyway, why not get the STI half cut for a nice trans, fuel pump and a boost controller, and be right at 300 hp at the crank?
I don't think that they make the flip kit for the STI transmission. Are you talking about making the thing a middie? And have you priced a STI+transaxle lately?
Kreb said:I don't think that they make the flip kit for the STI transmission. Are you talking about making the thing a middie? And have you priced a STI+transaxle lately?
Sure. I've purchased 2 version VI halfcuts in the last few years. Out the door around $2700 bucks then after sell off the fenders, headlights, hood, front brakes, strut brace etc etc. I was in them around $400.
I'm just saying this is the path I'd look into before messing with a slow and expensive Porsche 2.7 or another Corvair engine.
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