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79 hesitation

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Lefty:
Hi,

I recently bought a 79 corvette which was on Historic plates in the NSW club. Some of you most likely have sen it around. The car is fantastic and is too much fun.

I have noticed-the car hesitates, it's not obvious when at idle, but bulks under acceleration, sometimes.
It's a 350, rochester carburettor, and i assume a vertex magneto.

I read the carburettor can suck air through the pump plunger (?) and a bit of oil on this can seal this, albeit temporarily. On this basis I am thinking the carburettor is up for an overhaul. But looking at forums on magnetos there seems to be some opinions these loose their reliability over time and need overhaul.

Any definitive opinions?

Cheers,

Lefty

anychevy:

--- Quote from: Lefty on July 28, 2013, 07:47:36 PM ---Hi,
I have noticed-the car hesitates, it's not obvious when at idle, but bulks under acceleration, sometimes.
It's a 350, rochester carburettor, and i assume a vertex magneto.
--- End quote ---

Hi Lefty
Magneto's are pretty rare on street cars, it's probably an HEI (coil in the cap) but you're not sure, post a photo of it.

Q-jet carbs are excellent, but misunderstood and can suffer from "bog" if the air door opens too fast, the accelerator pump is not squirting enough fuel, or wrong secondary metering rods etc. etc.
It could also be retarded timing, a poor advance curve and many other issues.

Take the car to a knowledgeable mechanic and get it tuned.
This place is also good with Q-jets http://www.carburettorservice.com.au/ if that's the problem.
Don't "throw a Holley on it" it could be something simple and a "properly" functioning Q-jet, is music to the ears.

Lefty:
Thanks Dave.

I did some investigations and its appears to be a vertex magneto, it does not have normal looking ht leads (silicone) coming out of it to the spark plugs. I went to Taylor's web site who have the magentos on it. http://www.taylorvertex.com/Vertex. I have a photo of the engine, but have difficulty uploading. I'll give this another go.


I did call the carburetor place a few weeks ago, they are close by. They have done work on previous cars and always were well priced and did great work. Good call.

I'll book it in to them in the first place and see if this resolves it, and advise back.

Cheers.

Lefty

sirfixalot:
Contact Steve at SR Performance Arncliffe

Lefty:
Sirfixalot,

Many thanks,

Lefty

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