'64 Corvair Turbo not "hitting boost"

[VincentLuong24]

Hi guys,
New to the forums and this is my first post. After doing research and finding no answer, I've decided to start my own thread in search of help. The car that I am working on is a '64 Monza Spyder 150hp. We first bought the car with a blown trans so right since day one we had the car on the lift to drop the motor to replace the transmission. We finished the car yesterday so I was excited to hop in to see how much power this baby can put down! To my surprise, I was very disappoint. The car didn't boost! I watched the manifold pressure gauge to see if pressures went positive but it never happened. It would blip to near zero but never passed the zero mark. I tried removing the mufflers as some board members suggested but it didn't help the boosting issues. I tried checking for exhaust leaks but I couldn't find any. I am stumped... Do you guys have any ideas?

P.S. I also realized that the somewhere along the timeline of the life of the car, someone changed the pressure retard solenoid to a vacuum advance. Don't think this is related to my issue? But I do know I need to change that ASAP.

[junkman]

Time to remove the turbocharger, and see if it is frozen. I have one Spyder that has fantastic boost, and the other one, barely gives any boost. One is like driving a rabbit, and the other is like a snail. Not all turbo's are equal, and many times, it will take a complete rebuild to bring the turbo back to its original potential. Since rebuilding turbo's isn't an easy job, I suggest that you leave this to someone with experience, since if you damage any part of it, it is going to get very expensive quickly for replacement parts. The impellers alone can be a couple hundred dollars if you damage them.

[VincentLuong24]

Time to remove the turbocharger, and see if it is frozen. I have one Spyder that has fantastic boost, and the other one, barely gives any boost. One is like driving a rabbit, and the other is like a snail. Not all turbo's are equal, and many times, it will take a complete rebuild to bring the turbo back to its original potential. Since rebuilding turbo's isn't an easy job, I suggest that you leave this to someone with experience, since if you damage any part of it, it is going to get very expensive quickly for replacement parts. The impellers alone can be a couple hundred dollars if you damage them.

Thanks for the reply! When pulling the turbo, what should I be looking for exactly in terms of the turbo. Shaft play? Free spinning? If both of those are good should I be okay or should I get a rebuild on the carb/turbo anyway?

[bbodie52]

Welcome to the Corvair Forum!

Without knowing the history of your engine and turbocharger, the cause of a frozen turbine and impeller could be a number of things. I have attached the 1964 Corvair Supplement to the 1961 Corvair Shop Manual. The section that covers the turbocharger starts on page 9-11. You will almost certainly have to tear down the turbocharger to discover why it is not functioning and producing boost. Your comments and perhaps pictures showing what you find when examining your turbocharger might produce some helpful comments and suggestions from members of the Corvair Forum.

P.S. I also realized that the somewhere along the timeline of the life of the car, someone changed the pressure retard solenoid to a vacuum advance. Don't think this is related to my issue? But I do know I need to change that ASAP.

Functional pressure retard units are becoming harder to find. The fact that someone installed a standard vacuum advance could be an ominous sign, as if they assumed that the turbocharger had failed and was unlikely to be repaired, so they installed a vacuum advance to effectively abandon the turbo with an attempt to continue driving the car anyway! Hopefully you will find the condition of the turbocharger to be repairable so that you can get it back in service and will then have a need for a pressure retard!

You can download a wide range of technical documents and Corvair shop manuals at no cost using the following link...

Common and Useful Corvair Websites

Corvair Forum viewtopic.php?f=225&t=6007

You may also find the attached two-part turbocharger primer to be helpful.

Effective communication on websites like the Corvair Forum can be difficult. I would like to encourage you to expand on your initial post and tell us more about yourself, your Corvair, and your goals for your Corvair. If you can describe your personal assessment of your mechanical skills and abilities, that would help a lot. Members of the Corvair Forum love to be helpful in assisting other Corvair owners with technical support and advice, but it helps a lot if we have some understanding of your technical background and mechanical abilities, Corvair-related knowledge, etc. Helping us to know more about you and your Corvair will help us to write comments to you that are tailored to your needs and experience. Pictures are great too, because pictures of your Corvair will help us to visualize where you are with your Corvair and its condition at the present time. Knowing your location is also useful, because knowing where you live can sometimes suggest possibilities to resolve some issues or problems.

[VincentLuong24]

Without knowing the history of your engine and turbocharger, the cause of a frozen turbine and impeller could be a number of things. I have attached the 1964 Corvair Supplement to the 1961 Corvair Shop Manual. The section that covers the turbocharger starts on page 9-11.

You can download a wide range of technical documents and Corvair shop manuals at no cost using the following link...

Common and Useful Corvair Websites

Corvair Forum viewtopic.php?f=225&t=6007

Thanks for the resources! I'll look into it.

[bbodie52]

I added a couple of additional documents that might prove helpful. Good luck!

[dudeinblue1]

Hey there!
Just wanted to make sure that when you pulled the trans you didn't change the flywheel? (assuming that it is a manual) The flywheel for the turbo motors are a lot heavier and actually help keep the motor up in the boost producing rpm range. If you by chance did change it i would make sure it is one specifically for the turbo model rather then a 110 or 120 horse. You mentioned that it did get near zero when throttled so my assumption is that it is just not gettin up their enough or there is a problem with the pressure retard like others have suggested. Just a guess!

[VincentLuong24]

Hey there!
Just wanted to make sure that when you pulled the trans you didn't change the flywheel? (assuming that it is a manual) The flywheel for the turbo motors are a lot heavier and actually help keep the motor up in the boost producing rpm range. If you by chance did change it i would make sure it is one specifically for the turbo model rather then a 110 or 120 horse. You mentioned that it did get near zero when throttled so my assumption is that it is just not gettin up their enough or there is a problem with the pressure retard like others have suggested. Just a guess!

I did not change the flywheel but then again I do not know the history of what has been done exactly to the car so if the previous owner has changed it, I hope they got it right. Thanks for the input!

[VincentLuong24]

So I pulled the turbo and it seems as if the PO recently rebuilt it right before he sold it to me. Although it looks new it feels as if the turbo was tightened up too tightly? The turbo almost stops instantly after I spin it by hand. From what I know from other turbo, arent they supposed to spin really freely and continue to spin even after force is applied? Is there a way I can loosen it myself? Any suggestions will be greatly be appreciated!

[junkman]

How tight is too tight is difficult to know. The turbo doesn't spin like a fan, and keep freewheeling. If it looks clean, and you believe it to be rebuilt, then I would assume that the problem is elsewhere. Also, check the part number that is stamped into the distributor housing to determine if it is the correct distributor. Playing detective is the only way that you will figure this out, and no one will ever say that it is easy. Just be diligent, and take small steps toward the end goal. Never change a lot of things, thinking that it will help. If you mess up one step in a group of 5 or 6, it makes it that much more difficult to retrace your steps to find the error.

[notched]

A stock Corvair turbo is not like a modern turbo. They have some resistance and will not continue spinning even when they are perfect. It should spin freely with minimal effort. If it does not spin easily (meaning you need a wrench to turn it) then check inside the turbine housing for carbon build up. If you are not getting boost I would look carefully at all of the exhaust pipes and make sure there are no holes or leaks ANYWHERE as this will reduce the exhaust pressure at the turbine side of the turbo. Corvair cross overs and inlet pipes are notorious for rusting through. Look at the exhaust manifolds and their donut gaskets. Make sure that you have good compression. Check the chrome cross over pipe and make sure you have no leaks where the turbo hose is and at the cross over to head gaskets.
The other things to check is the timing. Stock on most Corvair turbos is 24 degrees. You can artificially make it spool up faster by retarding the timing but the retarded timing will kill the power up top.

[Scott V]

you dont need to remove the turbo for quick inspection. just remove the exhaust pipe from the turbo & give the turbine a flick w/your finger. like others said it wont spin freely but it shouldnt bind - maybe 1 turn w/a strong finger flick.

-Scott V.

[VincentLuong24]

Thanks for the replies everyone. I will keep looking today and keep everyone posted!

[VincentLuong24]

Just checked out the distributor and it does look like its the correct one for a turbo from '64. Now to wait until Monday for the pressure retard to come in, adjust to stock timing and see where that takes me.

[notched]

It should still produce boost regardless of whether the pressure retard is hooked up or not.
Did you verify that the gauge works by removing the vacuum line from the left side intake port and blowing air into it?

[flat6_musik]

To give it a real check, take the car out for a drive and get it fully warmed up, then find a gradual hill you can floor the accelerator in 3rd gear for a good 10 seconds. These turbo engines aren't great at making boost in 1st and 2nd. It sounds like your turbo is able to spin freely enough to spool up and make boost. Give a good close listen for any exhaust leaks too. Those are a boost killer.

Also, if me, I'd check and double check your initial timing AND whether that boost retard on the distributor is NOT blown out and able to do its thing.