txnova
Feb 3rd, 03, 9:20 PM
Sorry guy's but I'm a Nova owner. Used to post here when I had my 69 Chevelle.
I need some input woth few problems I'm having with my engine. All input is very much appreciated.
Regards,
John
Here is a more accurate accounting of the problems I'm having with the Nova:
I bought the car about a year ago with no history about the engine. The engine has never felt right and I only drive it occasionally to car shows. I have started delving into it more since I want to drive the Hot Rod Power Tour this summer.
The engine is a 350 with a rather lopey idle. Not knowing any specs., I attributed the idle to narrow lobe centers. The intake is a dual plane Edlebrock with a 650 Holley DP with manual-secondaries sitting on top of a 1" spacer. The carb. Has been a problem area also. It is very sensitive to any adjustments. The previous owner had removed the power valve and blocked it off with a plug. I have since installed a 3.5 power valve based on vacuum readings of 6 to 7 inches. The floats on the carb. are a sore spot and cannot be adjusted properly using the standard trickle method. I must remove the bowl and adjust manually and it appears to work fine. I have opened the secondary throttle plates so that the idle transfer circuit is barely exposed figuring this would give me more control of the idle mixture screws. The carb. Is very sensitive to any adjustments.
The distributor is an Accel HEI unit with vacuum advance and has not been touched by me. The vacuum advance is connected to manifold vacuum at the base of the carb. Although the engine can be made to idle, as I mentioned it does not feel right. If I remove and plug the vacuum hose, the engine will not idle. With the vacuum hose connected the timing appears to be in the mid 20* range. I do not have a timing tape on the damper so I cannot be sure of the exact timing. The timing tab is a Mr. Gasket unit that measures from 16* BTDC to 8* ATDC. The mark on the damper appears to be about 25* or so BTDC. I have not tried to find TDC and look at where the mark on the damper is. I have not pulled the front of the engine yet to try and determine how the cam was installed.
Since I have got several gremlins, I am not sure that the logical steps I am trying to take to tune the engine are not causing more problems. Not knowing the history of the engine doesn't help either. For example, I have adjusted the valves based on the assumption they are hydraulic.
So, my comment about being at a loss still holds true. I am not sure which steps to take first.
Assume the distributor is faulty?
Assume the carb. problems are due to a vacuum leak?
Check how the cam was installed first?
I think there are multiple problems that are hurting my ability to diagnose and fix all the problems. I think the previous owner, I bought the car from a guy that was not the owner and did not know the particulars on the engine, passed along the problems to me and was evident by the lack of a power valve. Shame on me!
If anybody can suggest a starting point to try and resolve the issues mentioned, I will be very appreciative.
Regards,
John
I need some input woth few problems I'm having with my engine. All input is very much appreciated.
Regards,
John
Here is a more accurate accounting of the problems I'm having with the Nova:
I bought the car about a year ago with no history about the engine. The engine has never felt right and I only drive it occasionally to car shows. I have started delving into it more since I want to drive the Hot Rod Power Tour this summer.
The engine is a 350 with a rather lopey idle. Not knowing any specs., I attributed the idle to narrow lobe centers. The intake is a dual plane Edlebrock with a 650 Holley DP with manual-secondaries sitting on top of a 1" spacer. The carb. Has been a problem area also. It is very sensitive to any adjustments. The previous owner had removed the power valve and blocked it off with a plug. I have since installed a 3.5 power valve based on vacuum readings of 6 to 7 inches. The floats on the carb. are a sore spot and cannot be adjusted properly using the standard trickle method. I must remove the bowl and adjust manually and it appears to work fine. I have opened the secondary throttle plates so that the idle transfer circuit is barely exposed figuring this would give me more control of the idle mixture screws. The carb. Is very sensitive to any adjustments.
The distributor is an Accel HEI unit with vacuum advance and has not been touched by me. The vacuum advance is connected to manifold vacuum at the base of the carb. Although the engine can be made to idle, as I mentioned it does not feel right. If I remove and plug the vacuum hose, the engine will not idle. With the vacuum hose connected the timing appears to be in the mid 20* range. I do not have a timing tape on the damper so I cannot be sure of the exact timing. The timing tab is a Mr. Gasket unit that measures from 16* BTDC to 8* ATDC. The mark on the damper appears to be about 25* or so BTDC. I have not tried to find TDC and look at where the mark on the damper is. I have not pulled the front of the engine yet to try and determine how the cam was installed.
Since I have got several gremlins, I am not sure that the logical steps I am trying to take to tune the engine are not causing more problems. Not knowing the history of the engine doesn't help either. For example, I have adjusted the valves based on the assumption they are hydraulic.
So, my comment about being at a loss still holds true. I am not sure which steps to take first.
Assume the distributor is faulty?
Assume the carb. problems are due to a vacuum leak?
Check how the cam was installed first?
I think there are multiple problems that are hurting my ability to diagnose and fix all the problems. I think the previous owner, I bought the car from a guy that was not the owner and did not know the particulars on the engine, passed along the problems to me and was evident by the lack of a power valve. Shame on me!
If anybody can suggest a starting point to try and resolve the issues mentioned, I will be very appreciative.
Regards,
John