Carburetion issues

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stevevancour
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Carburetion issues

Post by stevevancour »

I have a 64 Monza. I recently rebuilt both carbs. The car starts ok. It is timed to 10 degrees before TDC. The compression is high approximately 155psi each cylinder it doesn’t burn oil, new plugs, new wires, and a new coil. The problem is a flutter at lower rpms in both 1st and 2nd gears. I suspect that the throttle shafts are leaking. I did a vacuum check and the gauge fluttered rapidly between 12 and 16 inches indicating worn valve guides. I am considering replacing both carbs and put off the valve guides for now. Will replacing the carbs with carbs having reworked throttle shafts correct the low rpm flutter issue? Or do the worn guides have to be addressed first. I am in no position to tackle a head job. Thanks Steve

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terribleted
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Re: Carburetion issues

Post by terribleted »

If the vacuum flux is caused by worn guide changing the carbs will not fix it. If the guides are worn enough to cause this type issue they are on their last legs and approaching possible catastrophic failure which could cost more than a simple valve guide replacement and head recon. Why replace both carbs? Get new throttle shafts, install them and recheck all the internal adjustments on the carbs you rebuilt . No need for different carbs just to get new throttle shafts. The carb bodies do not wear much, the shafts are the item that wears for the most part, so changing the shafts usually fixes any issue at this spot. How does it idle? Smooth or a bit of flutter there as well? Could be valve adjusted a little tight perhaps. What engine is it? Is it timed to factory spec? What ignition is it using? What is the transmission?
Corvair guy since 1982. I have personally restored at least 20 Vairs, many of them restored ground up.
Currently working full time repairing Corvairs and restoring old cars.
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Located in Snellville, Georgia

stevevancour
Posts: 9
Joined: Sat Jan 04, 2014 12:02 pm

Re: Carburetion issues

Post by stevevancour »

Thanks for your it is greatly appreciated. The car has a 110HP engine and is attached to a 4 speed manual transmission. It came with an old style electronic ignition, not a pertronix, it has a disc mounted to the rotor shaft. The coil was a red aftermarket coil. A check of the coil’s resistance was way out of wack. I replaced it with a blue Bosch coil that met the correct resistance. The engine turns over and fires up quickly. I believe it is timed correctly at 10 DBTDC. Steve

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bbodie52
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Re: Carburetion issues

Post by bbodie52 »

Timing specifications for a 110 HP engine are 12 - 16° BTDC...
1962-1963 Corvair Manual Supplement - Tune-Up Specs
1962-1963 Corvair Manual Supplement - Tune-Up Specs
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1964 Corvair Tune-Up Specifications
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1965 Corvair Chassis Shop Manual Distributor Specifications
1965 Engine Tune Up Chart
1965 Engine Tune Up Chart
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terribleted
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Re: Carburetion issues

Post by terribleted »

stevevancour wrote:
Mon Sep 14, 2020 11:08 am
Thanks for your it is greatly appreciated. The car has a 110HP engine and is attached to a 4 speed manual transmission. It came with an old style electronic ignition, not a pertronix, it has a disc mounted to the rotor shaft. The coil was a red aftermarket coil. A check of the coil’s resistance was way out of wack. I replaced it with a blue Bosch coil that met the correct resistance. The engine turns over and fires up quickly. I believe it is timed correctly at 10 DBTDC. Steve
If you think it is timed correctly at 10BTDC you apparently need a GM shop Manual! Get one from Clark's or at least access one here: https://www.corvair.org/chapters/corvan ... .php#C95RP
Corvair guy since 1982. I have personally restored at least 20 Vairs, many of them restored ground up.
Currently working full time repairing Corvairs and restoring old cars.
https://www.facebook.com/tedsautorestoration/

Located in Snellville, Georgia

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