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Race Director
Joined: Oct 2000
Posts: 14,994
Likes: 79
From: central FL, near the beach.
Take it to a corvette shop and have them do a pre-purchase inspection. They will tell what they think is wrong and what it will cost to fix. Since you told them you haven't bought it yet, this should be helpful, and you wont get stuck with a large bill since nothing will be fixed, only an estimate given.
Myself, i took Auto Shop in HS. When i got my 61, I signed up at a community college to learn auto painting so i could paint it myself.
Most people either can't or don't want to fix a car. It is a major undertaking, but if you want to do it, sign up for classes and bring the vette and work on it there. That is what i did.
Myself, i took Auto Shop in HS. When i got my 61, I signed up at a community college to learn auto painting so i could paint it myself.
Most people either can't or don't want to fix a car. It is a major undertaking, but if you want to do it, sign up for classes and bring the vette and work on it there. That is what i did.
Thread Starter
Instructor
Joined: Jun 2012
Posts: 212
Likes: 0
It would make sense as im getting the same kinda reading as #3 in the video ...@ 1:35
Last edited by brady5885; Jan 22, 2013 at 08:38 AM.
Thread Starter
Instructor
Joined: Jun 2012
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Instructor
Joined: Apr 2012
Posts: 224
Likes: 2
From: St. Charles Missouri
Has the head on this motor been ported/polished recently? (hint: debris) .... I dunno. Timing, exhaust, electrical and everything on the outside of your motor seems to be correct which means it can only be a flaw in fuel delivery/combustion to #7.
Safety Car
Joined: Jan 2009
Posts: 4,000
Likes: 299
From: New York
Change the cap , your vac readings and all your posts show an ign issue on cyl 7 , Some may call plug 7 lean but i see a non-firing plug add to that your vac readings and the fact you have swapped wires from 5 and 7 or 1 and 7 and have same results just says to me it is the cap.
Plus a cap is cheap and it can not cause new issues , if you want snap a clear photo of the inside of the cap or look your self you may see signs of carbon tracking that indicate cross firing between 7 and another cylinder
Plus a cap is cheap and it can not cause new issues , if you want snap a clear photo of the inside of the cap or look your self you may see signs of carbon tracking that indicate cross firing between 7 and another cylinder
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Instructor
Joined: May 2012
Posts: 105
Likes: 12
From: Rockford, IL
I would recommend checking for any wear or deposits on the point for #7 in your cap. Also, you can test the spark strength for number 7 by removing the spark plug and reconnecting the wire. Hold the screw in portion of the plug to a ground and have someone crank the engine. The spark should be a bright blue. If it's orange, it's too weak and could indicate a problem with #7 on your cap.
I'm not an expert, just my $0.02.
I'm not an expert, just my $0.02.
Thread Starter
Instructor
Joined: Jun 2012
Posts: 212
Likes: 0
I have been out of action for a couple of weeks as i had a rear diff fail on its maiden voyage while driving it to see the color/condition of the plugs under real world conditions.
In the most part it has a new diff and nearly ready to hit the road when i get an hour to finish it.
Im going to try doing the rocker arm/valve adjustment with the engine running, if that doesnt fix the issue then i will look at mixture and rejetting it.
So i believe it has #68 jets in the holley carb.
I have crane blue racer 488 cams in, hydraulic lifters.
What would be the best adjustment? next jet size? main or secondary jets? ...... new to carb tuning
In the most part it has a new diff and nearly ready to hit the road when i get an hour to finish it.
Im going to try doing the rocker arm/valve adjustment with the engine running, if that doesnt fix the issue then i will look at mixture and rejetting it.
So i believe it has #68 jets in the holley carb.
I have crane blue racer 488 cams in, hydraulic lifters.
What would be the best adjustment? next jet size? main or secondary jets? ...... new to carb tuning
Thread Starter
Instructor
Joined: Jun 2012
Posts: 212
Likes: 0
I don't have the temp gauge working right now but using an IR thermometer I measure the elbow by the thermostat at 180* and a minute after shut off each primary at 2'' from the engine at 135* give or take 5 deg.
I pulled the plugs after about 2 miles drive and this is what they look like. #1,3,5,7 and 4 respectively.
Looks lean right??
I pulled the plugs after about 2 miles drive and this is what they look like. #1,3,5,7 and 4 respectively.
Looks lean right??
Advanced
Joined: Dec 2009
Posts: 83
Likes: 0
Wow thats almost three months of work taking plugs out putting them in checking vacum and compression taking valve covers off ect ect.
It looks like you are getting some great experience and advise.
I would suggest however that if you are still not driving it and have been working on it for three months and given the fact the spring is apon us it may be time to take it to a trusted shop.
It looks like you are getting some great experience and advise.
I would suggest however that if you are still not driving it and have been working on it for three months and given the fact the spring is apon us it may be time to take it to a trusted shop.
Drifting
Joined: Aug 2009
Posts: 1,346
Likes: 160
From: new iberia la
I don't have the temp gauge working right now but using an IR thermometer I measure the elbow by the thermostat at 180* and a minute after shut off each primary at 2'' from the engine at 135* give or take 5 deg.
I pulled the plugs after about 2 miles drive and this is what they look like. #1,3,5,7 and 4 respectively.
Looks lean right??
I pulled the plugs after about 2 miles drive and this is what they look like. #1,3,5,7 and 4 respectively.
Looks lean right??
Thread Starter
Instructor
Joined: Jun 2012
Posts: 212
Likes: 0
Brady, I see you are still at it ..I still think you have a fuel problem....those plugs look like a lean air/fuel condition, they should be a light tan , more like the one plug is... jets are cheap, go to parts store and get a set of 72 s .. remove your primary 68 s and install 72 s.. you can eliminate that cause for about $6 for jets ...if you need directions to swap, let me know...
I put #74 in the carb and ran it a couple of miles.
Pulled the plug out of cylinder #1 and one half was white and the other tan??
Drifting
Joined: Aug 2009
Posts: 1,346
Likes: 160
From: new iberia la
Thread Starter
Instructor
Joined: Jun 2012
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So i changed the jets to #74 and it seems to be better and want to put miles on it to get a true representstion of the way it is running.
But im having issues with the brakes and the power assist not working. I checked all is working, and lastly checked the vacuum. Im only reading 10 but it is fluctuating very quickly between 8-12.
i have a .488 cam installed if that matters
But im having issues with the brakes and the power assist not working. I checked all is working, and lastly checked the vacuum. Im only reading 10 but it is fluctuating very quickly between 8-12.
i have a .488 cam installed if that matters
Last edited by brady5885; May 5, 2013 at 07:21 PM.
Thread Starter
Instructor
Joined: Jun 2012
Posts: 212
Likes: 0
So i changed the jets to #74 and it seems to be better and want to put miles on it to get a true representstion of the way it is running.
But im having issues with the brakes and the power assist not working. I checked all is working, and lastly checked the vacuum. Im only reading 10 but it is fluctuating very quickly between 8-12.
i have a .488 cam installed if that matters
But im having issues with the brakes and the power assist not working. I checked all is working, and lastly checked the vacuum. Im only reading 10 but it is fluctuating very quickly between 8-12.
i have a .488 cam installed if that matters
Drifting
Joined: Aug 2009
Posts: 1,346
Likes: 160
From: new iberia la
Brady, you have insufficient vacuum for your booster to work properly..8-12 inhg is too low ..you need 12 or more ...are you sure about the cam? if your cam is only .488 lift, vacuum should be higher.. try advancing theignition timing by 4*... the position and fluctuation of the needle would indicate more cam than .488 lift with lots of duration.. or possibly the valve timing is off .. if you can t get more vacuum, you may need to go to an electric vacuum pump.. my motor only has 6-7 inches HG because of a huge .576lift 254* duration cam.. I had to use the electric pump to get brakes. they work great now