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| vacuum gauge https://www.slantsix.org/forum/viewtopic.php?t=39588 |
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| Author: | Tadams [ Sat Mar 27, 2010 1:26 pm ] |
| Post subject: | vacuum gauge |
I have a 65 Barracuda that has set for quite a while. I've been on workmens comp for 2 years so can't do a lot to finish my project. Well today is just to nice so I started the car and let her run for a while. Idles OK but a slight miss. I hooked up a vacuum gauge and it reads fairly steady around 17 at idle and goes up to around 27 at 2500 rpm. It varies just a little at idle, maybe a half point or so. I know the valves need adjusting but do those numbers seem To indicate the motors in pretty good shape or not. I think I need to have the valve seals replaced. After running 15 minutes at idle a do have a small amount of smoke from the exhaust. Any advice, I would be most thankful. |
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| Author: | 4speed [ Sat Mar 27, 2010 3:17 pm ] |
| Post subject: | |
How old is the gas and oil? How many miles on the engine? I would change the oil/filter and run out the old gas and try fresh. |
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| Author: | Tadams [ Sat Mar 27, 2010 4:43 pm ] |
| Post subject: | vacuum gauge |
Gas is old, was in car 2 years ago when I bought it. I added a couple of gallons, Car was last titled in 1986 so I don't know how long it was driven before it was parked. Has new oil and filter, plugs and pvc valve. I have to pour gas in carb to start it after it sits for awhile. I know the tank needs to be cleaned. The carb has been rebuilt. I bought the car in Virginia but it came from Florida. The bodies good and straight but the floors are bad. Thanks for the feedback. I do appreciate any help. |
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| Author: | Tadams [ Sat Mar 27, 2010 4:45 pm ] |
| Post subject: | vacuum gauge |
The car shows 57000 miles. I was told that was correct, but who knows. The numbers do line up perfect and the brake and gas pedal look good. |
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| Author: | Reed [ Sat Mar 27, 2010 5:01 pm ] |
| Post subject: | |
17 at idle is in the low-normal range for a slant six. I would adjust the valves, replace the valve stem seals, and then see what that does for you. I would also check the choke pull-off diaphragm and the vacuum advance on the distributor, for vacuum leaks. That car has been sitting a long time and the diaphragms can dry out and crack. |
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| Author: | Aggressive Ted [ Fri Apr 02, 2010 10:34 am ] |
| Post subject: | |
Quote: it reads fairly steady around 17 at idle
That is a fine number if your in gear and idling at 600 rpm. If your out of gear then that is a low number. You should be at least 19" or more depending on age of the engine. Like Ceej says, do a valve lash and see if it will go up. The stock lash at .010 and .020 should net you at least 19" out of gear @ 750 rpm with 6 degrees initial timing. You can squeak another inch of you go up to 10 degrees initial timing.Some of the valves may have a little carbon or rust or may not be closing all the way or long enough to provide a higher vacuum number. Re-gaping the valves and few days of driving should improve your idle vacuum unless there is a intake gasket leak. Sometimes that will cause a low reading. |
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