Corvair - Not MG

I'm just in a foul mood tonight - sorry, Gary....shop got the heads off the Corsa today...they've been rebuilt not long before car was parked (a good thing) - by a DFPO (a bad thing)!! One of them had dropped an exhaust valve & they just put new seats in without resurfacing that combustion chamber....tomorrow they go to the machine shop...gotta clean up that chamber, reweld it & reshape...then all 6 cylinders have to be resurfaced inside valve area as well as outside where the jugs fit so each one has exact volume & so jugs fit the same......that means all new seats, guides, valves, springs....hell, that means I'll have about $800-$1000 in the 2 heads alone!

It ran but we wanted to freshen the engine because we didn't know its history....now we do & I can't restore it without fixing that engine correctly

....Gary, you & me & engines!

I'm a little lost!! Resurfacing a combustion chamber?? What does that mean?? (now I feel real stupid!!)

Resurfacing a combustion chamber keeps hot spots from forming. I don't really know what it means, but I think that's techincally the correct answer. Felt like typing....

Thanks Dave, but I thought they were still cast!! Maybe I should look before I speak!! I have never had it done, and I have done maybe 25 engines and 50 sets of (or single) heads!!

A Corvair is a whole different kind of animal. When it dropped the valve it beat the crap out of the aluminum combustion chamber and piston. The DFPO replaced the piston, but didn't fix the jug right, it's still beat up.

OH!!! Now I get it!! How do the re-finish (or whatever it was) them??

I don't know, they just clean them up and match the chamber volumes or something.

Tony, for that kind of dough, what's a new engine run? Or a new set of heads and jugs. May be one of those things that CAN be done, but it just ain't worth it.

Problem, guys, is that this is a 140hp engine, 2 carbs per head...those heads are hard animals to find & they had a reputation for dropping valves so any old one you buy will probably be the same....I can buy a new head for $800 plus shipping from one of the Corvair restorers, so $800 - $1000 to recondition both mine isn't that bad, I guess....

...I also have a set of 110hp, 1 carb heads I could put on the engine but then its not the 140hp engine - though I'm learning most Corsa guys do that when they drop a valve (if they weren't lucky enough to rebuild & correct problem before dropping it)

....when the valve dropped, it beat up the aluminum head taking 'divots' out of it so that its craggier than General Noreiga's face!....if a seat will fit (in this case, it did), the head will still work though that cylinder will be less efficient than the other 5....

...so, new metal has to be welded in & then cut to size then the combustion chamber reshaped then the volumes off all 6 matched...then, the outer part of the heads where the jugs fit recut so all of them sit on the newly reshaped combustion chambers the same....

...oh, JDW, it appears that he put a new jug/piston assembly on the engine when he redid valves - at least that's good!

...hell, its only $$$'s, as Gary says...&, we all do whatever it takes to keep the little ladies happy, don't we (well, Naomi & Kim do whatever it takes to keep the guys happy, right ladies?)....&, jerri's the one who bought the Corvair - its her car, not mine!

You are right!! it is only money and who knows what tomorrow will bring!! Do it right big guy!! :o)

Showing my ignorance of Corvair engines, how did they run the pushrods? I assume it is not OHC. Do the pushrods go through holes in the cylinder casting or external tubes? I know the external tubes on motorcycle engines can be a bitch to seal! (At least on a Royal Enfield!)

Sounds like you are having fun with this motor. When you say two carbs/head does that mean two/cylinder (12 carbs!) or two/three cylinders (4 carbs)? If it is 2 for 2 (6 carbs), how do they work the intakes?

Eric (&, I'm still learning about Corvairs myself)...the Corsa is a 6-cylinder 140hp engine that has 2 1-barrel Rochester carbs per cylinder head....1 carb is the primary, the second carb is the secondary.....regular Corvair engines are 110hp w/1 single barrel carb per head, no secondary....
...&, as I understand them, the pushrods are laid out much like the Volkswagen air-cooled engine

and that car will LEAP down the road. Got a ticket in a small town in South Carolina back in college in a buddy's Corsa. One of those that you just pay the officer and leave.

JTB

Tony, which models were turbocharged?

David....Of the second generation Corvairs (1965 - 1969), only the top-of-the-line 1965-66 Corvair Corsa was available stock w/4 carbs (140hp) or turbocharged (180hp); all other Corvairs were 110hp or less with only 2 carbs. Don't know much about the 1st generation cars (1960 - 1964; the ones Ralph Nader told lies about!) but the Monza 'Spyder' option of that generation (1962-1964) was a turbo car with 150hp. All other 1st generation cars were 95hp. I think.

UPDATE:

Just got back from dropping heads off at machine shop....as I was talking with owner, an old guy who works in back came in, took a look and said, "Corvair heads. You need deeper Porsche seats. Bring a 'jug' in before we do any work" as he walked past - I mean, he didn't even miss a stride as he walked off proclaiming what needed to be done!

So, they're tearing them down today to see what needs doing; they'll call me tomorrow with parts prices & labor prices (my deal with shop has always been that if I can get parts less expensive, they'll use my parts - they give me their parts prices so I can shop)....I'm guessing new seats all way around (yes, deeper Porsche seats; seems depth of seats was what caused these more powerful Corvairs to drop valves), definitely new springs & silicone/bronze guides...as for valves, we'll have to see how much meat they still have on them before deciding....

...more to come if anybody's interested...

Can't speak for everybody else - but I'm interested!

Hey, Eric....couldn't help but notice your 1971 Cherokee in your signature....I did my inital training in a Cherokee 140 up through solo & short/long cross-country! Really enjoy low wing flying!

WHEW! Final machine shop estimate after heads were disassembled, cleaned, inspected, & miced is only $500, parts included....lots less than we had expected...of course that's my price as a jobber who brings lots of stuff in for machine work! So, running it through as a 'theAutoist' job helped! &, I think he just cut me a deal...but, they're a good shop who I've used for 10 years now - innumerable MG heads have gone through him plus a few blocks!

That price includes all the normal machine work & combustion chamber reconstruction work, all new Porsche seats, all new valves, all new springs, all new guides, all new seals (did you know Corvairs only use seals on intake valves?)....basically the old heads with everything replaced! Parts will be in Friday, heads ready for pickup Monday!

so you don't have to sell your watch now?

Tony, Check out staking the valve seats, that my help. As you ay know by now, 140 heads are terrible about this. GM just didn't provide enough cooling fins for the higher HP head. (the 110 has more)

Make sure that you clean out all of the flashing, you should be able to see through the fins. If not get a very tin, but long screwdriver and open it up.

I have almost every Corvair book you could think of here, so email if you need any info.

Patton Dickson - Richmond, TX
1965 Corvair Monza 110/4sp 'vert (eventually CORSAfied w/140)
1967 MG MGB Mk. I Roadster

Website - http://carport.virtualave.net/

Oh Yeah! Read this site about head work....

http://autoxer.skiblack.com/heads.html

Patton

Thanks, Patton...I earmarked that site for reading...