Re: '65 300HP miss and bucking at steady speed
Just wanted to report back to everyone on what is apparently the resolution to the problem I was having with hesitation, roughness and bucking at steady speed after removing and reinstalling the intake manifold. Since my last post I verified again ignition did not seem to be a problem and disassembled & cleaned the carb without any improvement shown. I finally decided I had no choice but to remove and reinstall the intake manifold again. I felt I must have had multiple external vacuum leaks that I just had not been able to pin down using propane or carb cleaner. When I removed the intake I noticed the gaskets seemed to have been well compressed on the bottom but not on the top at the intake passages as if I just had not had the manifold seated properly on the first install. On the reinstall I decided to use permatex Ultra Copper RTV on the coolant passages and on the end seals in place of the end seal gaskets based on many recommendation I saw on the TDB for this technique. Although I know it's not recommended, I also used some Permatex #3 Aviation seal around the intake passages. The manifold seemed to torque down nicely and this afternoon I took the car for a run and it seems fine.
The end seals using a 1/4" bead of Permatex look good - appears to be a nice even seal but not bulging beyond the edge of the block. I tried to measure the final thickness of the end seal and it appears to only be about 1/16". This seems thinner than the end gaskets provided in the kit although I don't know how much they compress. At any rate, I'm thinking that my original seal was hampered by the intake not seating far enough due to the thickness of the end seals. I'm assuming the heads may have had some milling at one time that affected the original factory fit. Based on the recommendations on the TDB I also tapped and plugged the exhaust holes in the intake under the carb.
As with any project that has complications, you often windup learning things about the car and this was no exception. If I had not had the initial problem and had the responses from members to my post, I would not have learned some of the things I did about the distributor. I never knew about the rotor alignment to the dimple or what "walking the distributor entailed (nothing to it now!). I feel up close and personal with the AFB carb which I didn't expect would happen at the outset.
So my thanks to all of you who posted responses and suggestions. Maybe at some point I can start making some contribution of my own on the TDB instead of always asking questions!
Thanks,
Dave Brown
Just wanted to report back to everyone on what is apparently the resolution to the problem I was having with hesitation, roughness and bucking at steady speed after removing and reinstalling the intake manifold. Since my last post I verified again ignition did not seem to be a problem and disassembled & cleaned the carb without any improvement shown. I finally decided I had no choice but to remove and reinstall the intake manifold again. I felt I must have had multiple external vacuum leaks that I just had not been able to pin down using propane or carb cleaner. When I removed the intake I noticed the gaskets seemed to have been well compressed on the bottom but not on the top at the intake passages as if I just had not had the manifold seated properly on the first install. On the reinstall I decided to use permatex Ultra Copper RTV on the coolant passages and on the end seals in place of the end seal gaskets based on many recommendation I saw on the TDB for this technique. Although I know it's not recommended, I also used some Permatex #3 Aviation seal around the intake passages. The manifold seemed to torque down nicely and this afternoon I took the car for a run and it seems fine.
The end seals using a 1/4" bead of Permatex look good - appears to be a nice even seal but not bulging beyond the edge of the block. I tried to measure the final thickness of the end seal and it appears to only be about 1/16". This seems thinner than the end gaskets provided in the kit although I don't know how much they compress. At any rate, I'm thinking that my original seal was hampered by the intake not seating far enough due to the thickness of the end seals. I'm assuming the heads may have had some milling at one time that affected the original factory fit. Based on the recommendations on the TDB I also tapped and plugged the exhaust holes in the intake under the carb.
As with any project that has complications, you often windup learning things about the car and this was no exception. If I had not had the initial problem and had the responses from members to my post, I would not have learned some of the things I did about the distributor. I never knew about the rotor alignment to the dimple or what "walking the distributor entailed (nothing to it now!). I feel up close and personal with the AFB carb which I didn't expect would happen at the outset.
So my thanks to all of you who posted responses and suggestions. Maybe at some point I can start making some contribution of my own on the TDB instead of always asking questions!
Thanks,
Dave Brown
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