Corvair Forum

I have a 66 corvair monza, symptoms are no power, low compression on cyl 6, and engine overheats. Are these symptoms of dropping a valve?

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What is the compression reading? Did you do a leak down test after the compression test?

Quick trick...get a low compression reading. Squirt about a tablespoon of engine ppl in the plug hole and do another reading. If the compression goes up. It is a ring problem. If it stays low. It I a valve issue. I worked at a vair shop with about 20 unknown used engines. That test gave correct diagnosis about 95% of the time
Worth a try and does.not cost anything except a bit of oil.

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That was engine oil. Darned smart phone

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Robert 411 wrote:I have a 66 corvair monza, symptoms are no power, low compression on cyl 6, and engine overheats. Are these symptoms of dropping a valve?

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I thought I dropped a valve on mine about a month ago but it seems to be something else. I have a 65 Corsa turbo. I have a suspicion it’s a fuel/ turbo issue but I have had a dropped valve happen twice.


65 Corvair Corsa Turbo

slickclyde wrote:Wed Dec 27, 2017 2:48 am

Thanks for your reply. You guys seem to have way more knowledge than most shops that have tried their hand on my Corvair. As far as the fuel setup, I believe there is an electric fuel pump and mechanical as well with a bypass. I have to look at the build sheet again. I had the Holley fuel pressure regulator removed since the shop told me it wasn’t working and installed a stock OEM mechanical fuel pump instead. Unfortunately it’s still unclear why my engine died on me and what the root problem is. I keep spending money with these shops and they don’t know what the hell they’re doing because I keep having the same problem. Now they’re saying it’s not a dropped valve at all. I had the heads removed and was told the valves, cylinders, and crank are all intact and unscathed which leads me to believe that this may be a fuel/turbo issue...

... just want to be able to drive her before the end of the year.

I read the above response in your other thread. Unfortunately your comments seem to add more confusion and less focus on the original problem.

With regard to the possibility that an electric fuel pump exists in the system, and that the Holley fuel pressure regulator wasn't working, your fuel system should be using either an electric fuel pump or a mechanical fuel pump, but not both. The first illustration below shows a cross-section of a Corvair mechanical fuel pump. In an operational pump, the large spring at the top determines the output pressure of the pump that is fed to the Carter YH carburetor. These carburetors have a reputation for being very sensitive to fuel pressure, and need the correct specified fuel pressure of no more than 4 to 5 psi. If the pressure is higher it can overwhelm the carburetor and flood the float bowl with a high fuel level that will cause improper carburetor operation. Some aftermarket OEM-style mechanical fuel pumps have been known to produce excessively high fuel pressure, even when they are brand-new.

Holley manufactures several models of fuel pressure regulators. The model 12-803 regulates pressure ranges from 4-1/2 to 9 PSI, and the model 12-804 regulates pressures from 1 to 4 PSI. The latter model would be the correct one for your Corvair. To regulate pressure in the lower range, the pressure regulator would need to be installed between the fuel pump and the carburetor inlet. The original installation appeared to have the pressure regulator installed on the wrong side of the mechanical fuel pump. In any case, you should utilize a mechanic's vacuum/pressure gauge — as shown in the shop manual page below — to test the output pressure of the fuel pump that is being fed to the carburetor. It is important to have pressure and fuel volume delivery that meets the specifications outlined in the shop manual.





It might be helpful if you could recheck cylinder compression in each cylinder, and then list the results of your testing here on the Corvair Forum. The earlier descriptions of your engine describes multiple problems in the past with dropped valve seats, and apparently low compression in one cylinder. Yet you also indicate that the mechanics completely removed the cylinder heads and stated that there was no problem with the cylinders or valves! Did they retest the cylinder compression of each cylinder after reassembling the engine? How did they come to a conclusion that the seal in each cylinder was okay? Low compression in one cylinder might be caused by a poor seal between the piston and piston rings and the cylinder wall, or it could be caused by a problem with a poor seal of an intake or exhaust valve, or it could be a problem with a cylinder head gasket seal. A compression test would reveal the existence of a poorly sealed cylinder, and a leak down test would help to reveal the cause. The latter test accomplishes this by pressurizing the cylinder with air from an air compressor. If the leak down test equipment reveals that excessive air is bleeding out of the cylinder, a mechanic's stethoscope can be used to listen for the noise from the air leaking out. If the air is heard leaking into the crankcase, the problem is likely bad piston rings and a poor seal with the cylinder wall. If the air is hissing and heard to be leaking into the carburetor intake manifold, the problem is likely a poor seal with the intake valve. If the air is heard leaking into the exhaust system, the problem can be identified as a faulty exhaust valve seal. The final possibility may be a bad cylinder head gasket or mating surface between the cylinder and the cylinder head. But using a leak down test procedure it should have been possible for the mechanic to test for the cause of a low compression reading without having to physically remove the cylinder heads! For that matter, if the fault was a problem with the piston ring, the mechanic might not be able to determine that without further disassembly, removing the piston from the cylinder to allow examinations of the rings themselves.

So at this point, what are the compression readings in each cylinder at the present time? Do you still have a low reading in one of the cylinders?

If the compression test in all cylinders indicates a proper seal in each cylinder, then the mechanical condition of the cylinders with no longer be in question. If the engine will not start, your problem may be with the ignition system or the fuel system. A problem could also exist with the timing gear that drives the camshaft.

Where you physically located? Have you checked to see if there is a CORSA (Corvair Society of America) club chapter anywhere near you? If you lack some of the tools or experience needed to troubleshoot your Corvair, the existence of a local CORSA club chapter may be of help. The turbocharged Corvair engine is somewhat more difficult to troubleshoot than a standard engine. It would be unusual to find a local mechanic that would have the experience or knowledge to be of much help. So troubleshooting and fixing your engine will either be a DIY effort with assistance from the Corvair Forum, or might be more successful with the assistance of other experienced Corvair owners from the local area, if they exist. Your past experience with local mechanics sounds like an expensive and unsuccessful effort that is let you to nothing but frustration. Hopefully members of the Corvair Forum will be able to assist you in finding a successful solution to your problem. But if a local CORSA club chapter exists, reaching out to them could be very helpful as well.

bbodie52 wrote:

slickclyde wrote:Wed Dec 27, 2017 2:48 am

Thanks for your reply. You guys seem to have way more knowledge than most shops that have tried their hand on my Corvair. As far as the fuel setup, I believe there is an electric fuel pump and mechanical as well with a bypass. I have to look at the build sheet again. I had the Holley fuel pressure regulator removed since the shop told me it wasn’t working and installed a stock OEM mechanical fuel pump instead. Unfortunately it’s still unclear why my engine died on me and what the root problem is. I keep spending money with these shops and they don’t know what the hell they’re doing because I keep having the same problem. Now they’re saying it’s not a dropped valve at all. I had the heads removed and was told the valves, cylinders, and crank are all intact and unscathed which leads me to believe that this may be a fuel/turbo issue...

... just want to be able to drive her before the end of the year.

I read the above response in your other thread. Unfortunately your comments seem to add more confusion and less focus on the original problem.

With regard to the possibility that an electric fuel pump exists in the system, and that the Holley fuel pressure regulator wasn't working, your fuel system should be using either an electric fuel pump or a mechanical fuel pump, but not both. The first illustration below shows a cross-section of a Corvair mechanical fuel pump. In an operational pump, the large spring at the top determines the output pressure of the pump that is fed to the Carter YH carburetor. These carburetors have a reputation for being very sensitive to fuel pressure, and need the correct specified fuel pressure of no more than 4 to 5 psi. If the pressure is higher it can overwhelm the carburetor and flood the float bowl with a high fuel level that will cause improper carburetor operation. Some aftermarket OEM-style mechanical fuel pumps have been known to produce excessively high fuel pressure, even when they are brand-new.

Holley manufactures several models of fuel pressure regulators. The model 12-803 regulates pressure ranges from 4-1/2 to 9 PSI, and the model 12-804 regulates pressures from 1 to 4 PSI. The latter model would be the correct one for your Corvair. To regulate pressure in the lower range, the pressure regulator would need to be installed between the fuel pump and the carburetor inlet. The original installation appeared to have the pressure regulator installed on the wrong side of the mechanical fuel pump. In any case, you should utilize a mechanic's vacuum/pressure gauge — as shown in the shop manual page below — to test the output pressure of the fuel pump that is being fed to the carburetor. It is important to have pressure and fuel volume delivery that meets the specifications outlined in the shop manual.





It might be helpful if you could recheck cylinder compression in each cylinder, and then list the results of your testing here on the Corvair Forum. The earlier descriptions of your engine describes multiple problems in the past with dropped valve seats, and apparently low compression in one cylinder. Yet you also indicate that the mechanics completely removed the cylinder heads and stated that there was no problem with the cylinders or valves! Did they retest the cylinder compression of each cylinder after reassembling the engine? How did they come to a conclusion that the seal in each cylinder was okay? Low compression in one cylinder might be caused by a poor seal between the piston and piston rings and the cylinder wall, or it could be caused by a problem with a poor seal of an intake or exhaust valve, or it could be a problem with a cylinder head gasket seal. A compression test would reveal the existence of a poorly sealed cylinder, and a leak down test would help to reveal the cause. The latter test accomplishes this by pressurizing the cylinder with air from an air compressor. If the leak down test equipment reveals that excessive air is bleeding out of the cylinder, a mechanic's stethoscope can be used to listen for the noise from the air leaking out. If the air is heard leaking into the crankcase, the problem is likely bad piston rings and a poor seal with the cylinder wall. If the air is hissing and heard to be leaking into the carburetor intake manifold, the problem is likely a poor seal with the intake valve. If the air is heard leaking into the exhaust system, the problem can be identified as a faulty exhaust valve seal. The final possibility may be a bad cylinder head gasket or mating surface between the cylinder and the cylinder head. But using a leak down test procedure it should have been possible for the mechanic to test for the cause of a low compression reading without having to physically remove the cylinder heads! For that matter, if the fault was a problem with the piston ring, the mechanic might not be able to determine that without further disassembly, removing the piston from the cylinder to allow examinations of the rings themselves.

So at this point, what are the compression readings in each cylinder at the present time? Do you still have a low reading in one of the cylinders?

If the compression test in all cylinders indicates a proper seal in each cylinder, then the mechanical condition of the cylinders with no longer be in question. If the engine will not start, your problem may be with the ignition system or the fuel system. A problem could also exist with the timing gear that drives the camshaft.

Where you physically located? Have you checked to see if there is a CORSA (Corvair Society of America) club chapter anywhere near you? If you lack some of the tools or experience needed to troubleshoot your Corvair, the existence of a local CORSA club chapter may be of help. The turbocharged Corvair engine is somewhat more difficult to troubleshoot than a standard engine. It would be unusual to find a local mechanic that would have the experience or knowledge to be of much help. So troubleshooting and fixing your engine will either be a DIY effort with assistance from the Corvair Forum, or might be more successful with the assistance of other experienced Corvair owners from the local area, if they exist. Your past experience with local mechanics sounds like an expensive and unsuccessful effort that is let you to nothing but frustration. Hopefully members of the Corvair Forum will be able to assist you in finding a successful solution to your problem. But if a local CORSA club chapter exists, reaching out to them could be very helpful as well.

You are absolutely right it’s been a monumental waste of money because the root problem can’t be identified. 3 different shops have had their turn with it and none have been able to properly diagnose it 100%. I’m located in south Florida and yes there is a chapter in central Florida I believe. I’m literally taking everything you said on the last post and showing the shop and also asking them all these specific questions. I do not have the technical capability of fixing or diagnosing this. So a diy is not an avenue for me unfortunately. Thank you for all your feedback as it’s vital to me because it seems like you guys are more able to diagnose it without even looking at it then these shops down here. As soon as I get all the answers i will respond with them. Hopefully that can narrow it down.


65 Corvair Corsa Turbo

Owning a classic car like a Corvair without being able to do your own mechanical work can be a real challenge, since it can be difficult to find a professional mechanic who has the knowledge and experience to work effectively on an older classic car. The turbocharged Corvair is unique and sometimes a challenge for even experienced Corvair owners. There are several Corvair owner's clubs (CORSA) in Florida, and they might be the key to helping you with possibly learning to work (to some extent) on your own Corvair, or with finding a local mechanic who can be effective in helping you to troubleshoot and fix, and then maintain your turbocharged Corvair.

I don't know if this will be of use to you, but if you ever need a mechanic to work on your Corvair in central Florida, I contacted a person that I know who lives in the Tampa/St. Petersburg Florida area. He drove a Corvair convertible regularly in that area, but considered his own mechanical skills to be inadequate. He has been quite happy with the shop identified below.

Since he was able to find a Corvair-qualified mechanic in his area, I sent him an e-mail and asked him for the contact information. Here is some information that might prove useful:

All my service is done at JB Import Automotive Service at 387 16th St. N., St. Petersburg FL 33705 phone# is (727) 823-5951 Talk to Jeff. He and his brother Mike are the owners and are extremely knowledgeable of Corvairs (and do the work themselves).

https://www.jbimportauto.com/


JB Import Automotive Repair is located at the corner of Fourth Avenue and 16th Street near I-375 entrance and exit ramps. This full-service repair shop specializes in both imported and antique vehicle performance and maintenance. JB Import Automotive employs experienced and certified technicians with knowledge of foreign vehicles: Toyota, Nissan, Audi, Fiat, Alfa Romeo, Aston Martin and more. Services provided include A/C installation and repair, engine diagnostics, tune-ups and wheel alignments. Customers may schedule an appointment in person, online or by phone.

Hours: Mon - Fri, 7:30am - 5pm; Sat, Sun, closed
Handicap Accessible: Yes
Payments accepted: American Express, Cash, Discover, MasterCard, Visa
Associations/certifications: Automotive Service Excellence, Bosch Service
Parking: On-street: free
Auto repair services: Belts, Brakes, Engine performance & diagnostics, Exhaust, Fuel injection, Heating & Cooling, Inspections, Oil/lube/filter changes, Steering system, Suspension, Transmissions

There are seven CORSA chapters listed in Florida. The one below appears to be the closest to your location.



South Florida Corvairs (About 50 Miles), c/o Rodger Dill, 8951 S Kendale Circle, Lake Worth, FL 33467
http://www.corvair.org/chapters/chapter333/

Welcome to South Florida Corvairs

South Florida Corvairs is a local chapter of the national organization CORSA. We were founded in 1981 in Fort Lauderdale, Florida. Club members live between Key West and Port St. Lucie. As a club we participate in cruise-ins, car shows, tech sessions, social dinners, and drive-ins.

Our members cars range from show quality to daily drivers. Ownership of a Corvair is not required to become a member, just an interest in the vehicle.

The monthly meetings of South Florida Corvairs (SFC) are held on the 1st Tuesday of each month at Autonation Chevrolet of Delray, located at 1111 Linton Blvd. Delray Beach, FL 33444. Meetings begin at 7:00 PM. Following the meetings, you are invited to join other members for dinner at local restaurants.

Email: southfloridacorvairs@gmail.com
Phone: 754-800-1353

West Florida Corvair Club 5670 San Vair Street, Milton, FL 32583 Email: wfcc@mediacombb.net, Phone number: (850) 797-3565

Central Florida Corvair Club http://www.motortopia.com/car-clubs/cen ... r-club-683
12 Pine Trail, Ormond Beach, Florida 32174

Suncoast Corvairs PO Box 530463, St Petersburg, FL, 33747, https://www.suncoastcorvairclub.com/
Our current Meeting Location (2nd Saturday of the month @ 900A): Biff Burger, 3939 49th St N, St. Petersburg, FL 33709

Gulfcoast Corvairs 5549 Tewkesbury Place, Sarasota, FL, Email: tonycorsa@juno.com

Nature Coast Corvairs 1490 Druid Road, Inverness, FL http://www.motortopia.com/car-clubs/nat ... r-club-601

Greater Orlando Corvair Assn. http://govairs.net/Home_Page.html
For Information on the club events and activities Contact Titus Stewart (Club President) at 407-892-5999 or Craig Schielke (Club Vice-President) at
cschielke@cfl.rr.com

Finally, the following Corvair Forum link can provide you with a list of useful websites that should be helpful as a Corvair owner...

Common and Useful Corvair Websites
Corvair Forum viewtopic.php?f=225&t=6007

bbodie52 wrote:Owning a classic car like a Corvair without being able to do your own mechanical work can be a real challenge, since it can be difficult to find a professional mechanic who has the knowledge and experience to work effectively on an older classic car. The turbocharged Corvair is unique and sometimes a challenge for even experienced Corvair owners. There are several Corvair owner's clubs (CORSA) in Florida, and they might be the key to helping you with possibly learning to work (to some extent) on your own Corvair, or with finding a local mechanic who can be effective in helping you to troubleshoot and fix, and then maintain your turbocharged Corvair.

I don't know if this will be of use to you, but if you ever need a mechanic to work on your Corvair in central Florida, I contacted a person that I know who lives in the Tampa/St. Petersburg Florida area. He drove a Corvair convertible regularly in that area, but considered his own mechanical skills to be inadequate. He has been quite happy with the shop identified below.

Since he was able to find a Corvair-qualified mechanic in his area, I sent him an e-mail and asked him for the contact information. Here is some information that might prove useful:

All my service is done at JB Import Automotive Service at 387 16th St. N., St. Petersburg FL 33705 phone# is (727) 823-5951 Talk to Jeff. He and his brother Mike are the owners and are extremely knowledgeable of Corvairs (and do the work themselves).

https://www.jbimportauto.com/


JB Import Automotive Repair is located at the corner of Fourth Avenue and 16th Street near I-375 entrance and exit ramps. This full-service repair shop specializes in both imported and antique vehicle performance and maintenance. JB Import Automotive employs experienced and certified technicians with knowledge of foreign vehicles: Toyota, Nissan, Audi, Fiat, Alfa Romeo, Aston Martin and more. Services provided include A/C installation and repair, engine diagnostics, tune-ups and wheel alignments. Customers may schedule an appointment in person, online or by phone.

Hours: Mon - Fri, 7:30am - 5pm; Sat, Sun, closed
Handicap Accessible: Yes
Payments accepted: American Express, Cash, Discover, MasterCard, Visa
Associations/certifications: Automotive Service Excellence, Bosch Service
Parking: On-street: free
Auto repair services: Belts, Brakes, Engine performance & diagnostics, Exhaust, Fuel injection, Heating & Cooling, Inspections, Oil/lube/filter changes, Steering system, Suspension, Transmissions

There are seven CORSA chapters listed in Florida. The one below appears to be the closest to your location.



South Florida Corvairs (About 50 Miles), c/o Rodger Dill, 8951 S Kendale Circle, Lake Worth, FL 33467
http://www.corvair.org/chapters/chapter333/

Welcome to South Florida Corvairs

South Florida Corvairs is a local chapter of the national organization CORSA. We were founded in 1981 in Fort Lauderdale, Florida. Club members live between Key West and Port St. Lucie. As a club we participate in cruise-ins, car shows, tech sessions, social dinners, and drive-ins.

Our members cars range from show quality to daily drivers. Ownership of a Corvair is not required to become a member, just an interest in the vehicle.

The monthly meetings of South Florida Corvairs (SFC) are held on the 1st Tuesday of each month at Autonation Chevrolet of Delray, located at 1111 Linton Blvd. Delray Beach, FL 33444. Meetings begin at 7:00 PM. Following the meetings, you are invited to join other members for dinner at local restaurants.

Email: southfloridacorvairs@gmail.com
Phone: 754-800-1353

West Florida Corvair Club 5670 San Vair Street, Milton, FL 32583 Email: wfcc@mediacombb.net, Phone number: (850) 797-3565

Central Florida Corvair Club http://www.motortopia.com/car-clubs/cen ... r-club-683
12 Pine Trail, Ormond Beach, Florida 32174

Suncoast Corvairs PO Box 530463, St Petersburg, FL, 33747, https://www.suncoastcorvairclub.com/
Our current Meeting Location (2nd Saturday of the month @ 900A): Biff Burger, 3939 49th St N, St. Petersburg, FL 33709

Gulfcoast Corvairs 5549 Tewkesbury Place, Sarasota, FL, Email: tonycorsa@juno.com

Nature Coast Corvairs 1490 Druid Road, Inverness, FL http://www.motortopia.com/car-clubs/nat ... r-club-601

Greater Orlando Corvair Assn. http://govairs.net/Home_Page.html
For Information on the club events and activities Contact Titus Stewart (Club President) at 407-892-5999 or Craig Schielke (Club Vice-President) at
cschielke@cfl.rr.com

Finally, the following Corvair Forum link can provide you with a list of useful websites that should be helpful as a Corvair owner...

Common and Useful Corvair Websites
Corvair Forum viewtopic.php?f=225&t=6007

Hey thanks much appreciated on that shop info. Unfortunately, St. Petersburg is about 4 hours away from me. I occasionally run into guys from the Lake Worth Chapter. It doesn’t hurt to reach out to them anyways.


65 Corvair Corsa Turbo