ummmm......what?
Dyno run/ missing out maybe? Low hp/tq
- Thread starter ScampChamp
- Start date
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ummmm......what?
Scamp - Grinding this in my head, I would think your first issue is heat, carb heat and fuel heat.
From the balance of the build, your parts and pieces seem balanced, so my thought is the builder had a focus. I had a 68 GTO I built, well balanced too. In the summer or even on long drives what I noticed is mid-power or on passing the thing would choke, stumble and fight. What I discovered is the fuel was boiling and having issues. Once I cooled the fuel (spacer, moving and wrapping line) I did not have this issue any more.
Again, my thoughts -
From the balance of the build, your parts and pieces seem balanced, so my thought is the builder had a focus. I had a 68 GTO I built, well balanced too. In the summer or even on long drives what I noticed is mid-power or on passing the thing would choke, stumble and fight. What I discovered is the fuel was boiling and having issues. Once I cooled the fuel (spacer, moving and wrapping line) I did not have this issue any more.
Again, my thoughts -
ScampChamp
Active Member
Car runs consistently at 190 degrees all day long stays that temp all the time never any problem cooling car runs great besides it feeling rough or missing between 3-5000 rpm
ScampChamp
Active Member
Compression test sounds like a great idea and I will see about wrapping the fuel lines possibly too. What did you use to wrap it? All great ideas and tips guys thans so much!
Scamp - Please keep in mind these are ideas, may not be the problem. They are easy things to check - run for a while and then look, see and listen if the fuel is perculating in the bowls or excessively hot carb, lines etc.
One learning point from this site for me was "not to throw money at it", learn the cause.
GTO ran great at same temp and fought at the same RMP, why I bring this issue up. Long drivers is when I found the fuel boiling, after I parked and let sit for a few minutes. Wrapped with insulator wrap from Summit, used a phenolic 1" spacer. If you have a filter, make sure it and the line is not close to header or exhaust.
Also - RRR has a point, compression is a good starting point too, no cost just time.
Charles
One learning point from this site for me was "not to throw money at it", learn the cause.
GTO ran great at same temp and fought at the same RMP, why I bring this issue up. Long drivers is when I found the fuel boiling, after I parked and let sit for a few minutes. Wrapped with insulator wrap from Summit, used a phenolic 1" spacer. If you have a filter, make sure it and the line is not close to header or exhaust.
Also - RRR has a point, compression is a good starting point too, no cost just time.
Charles
ScampChamp
Active Member
Great stuff thanks
I'd focus on ignition timing FIRST! If you street drive the car, total timing method is a rotten way to set ignition.
That camshaft and low compression, get the car hot, slightly loosen dist clamp and twist dist body clockwise a bit. if it picked up RPM, reset to idle point say 800-850. Shut off and try to start, if it starts OK, do it again. Find point it strains or kicks back on the starter. Back it off from the strain level and put a timing light on it. Note the number.
Total timing, it may take 40+ if it's low compression. Maybe start at 36* total and feed 2* in at a time until you hear it ping. Find the point it pings and back it off a couple degrees. Depending on the distributor, it may take 4000rpm to find the point all the mechanical advance is applied. Reading plugs can be helpful, blackish speckles on the porcelain is not good.
Once you have those two timing numbers, initial and total, you can dial in the distributor so it works well with your engine. I wouldn't be surprised to see the engine wanting 20+* of initial/idle timing. The engine should idle in the 850ish range. DO NOT look at any old mopar factory service manuals because those idle timing numbers, usually TDC to 5BTDC, are garbage for a car that doesn't have to pass smog certifications.
Then tune up the carb idle settings. Use a vacuum gauge to set the idle mix screws.
That camshaft and low compression, get the car hot, slightly loosen dist clamp and twist dist body clockwise a bit. if it picked up RPM, reset to idle point say 800-850. Shut off and try to start, if it starts OK, do it again. Find point it strains or kicks back on the starter. Back it off from the strain level and put a timing light on it. Note the number.
Total timing, it may take 40+ if it's low compression. Maybe start at 36* total and feed 2* in at a time until you hear it ping. Find the point it pings and back it off a couple degrees. Depending on the distributor, it may take 4000rpm to find the point all the mechanical advance is applied. Reading plugs can be helpful, blackish speckles on the porcelain is not good.
Once you have those two timing numbers, initial and total, you can dial in the distributor so it works well with your engine. I wouldn't be surprised to see the engine wanting 20+* of initial/idle timing. The engine should idle in the 850ish range. DO NOT look at any old mopar factory service manuals because those idle timing numbers, usually TDC to 5BTDC, are garbage for a car that doesn't have to pass smog certifications.
Then tune up the carb idle settings. Use a vacuum gauge to set the idle mix screws.
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