11-06-2021, 12:36 AM | #41 |
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Join Date: Aug 2017
Location: Roseville, Ca
Posts: 84
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Re: Lean MisFire
Hello Crankster,
Good point on all the carb circuits. Lets not ignore the choke circuit. I get choked up about that one. Just keeping it light. :-) Unfortunately I do not have access to a Wideband and yes that would take some of the guess work out of AFR numbers. Elevation of Roseville Ca is 161 ft above sea level. Camshaft is a 274 lift and duration. I will install Charlie ny distributor when it arrives and keep everyone posted on the electrical side of things. Then turn to the carb questions once again. Solve or eliminate one thing at time. As mentioned before, I have run two electronic distributors and one ford load a matic with absolutely no change in driving performance on this engine. With the engine being new from H&H I am not going to second guess Mikes work. Under load the engine runs strong, and the engine idles with a slight attitude per Mikes original set up with these carbs. The lean misfire surfaced once the engine was in the car and driveable. Please stay tuned Respectfully Marc |
11-06-2021, 07:27 AM | #42 | |||
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Join Date: Oct 2017
Posts: 563
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Re: Lean MisFire
Quote:
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11-06-2021, 11:40 AM | #43 |
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Join Date: May 2010
Posts: 435
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Re: Lean MisFire
Some thoughts: How about plugging the windshield wiper port on the intake or has the connection for the vacuum gauge accomplished this? Does your intake have defects in the exhaust heat cross over? You can remedy that with core plugs in the block cross over ports within the block. Your manifold new or used? If all of the foregoing proves satisfactory and Charlie’s GM distributor does not correct the problem, which I hope it does, then pull the carbs and have them rebuilt by Charley NY or install Stromberg 48s with 48 jets and perhaps lean the power valve and send the existing carbs back to the vendor. Holleys are not top rung for me. I have used 48 carbs and they performed very well. You have the displacement and cam to take advantage of 48s. Another thought: Use a bored out Merc manifold mounting a Rochester 2GC!!! Your call!!!
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11-06-2021, 07:48 PM | #44 |
Member
Join Date: Aug 2017
Location: Roseville, Ca
Posts: 84
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Re: Lean MisFire
Hello Crankster and Bill OH,
That was a good one Crankster, :-) I took the plunge and ordered an Autometer analog face AFR meter along with a SS tail pipe clamp for holding the O2 sensor. Let the fun begin when the tools arrive. I apologize for my poor choice of words regarding second guessing Mikes work. I was really just trying to express my complete confidence in Mikes work and therefore invest alll our efforts in the ancillary items. I am very grateful for the continued dialog with everyone while working through this mystery. Hello Bill OH, Yes the vacuum port is currently occupied by a vacuum gauge. (Wipers are now electric) The manifold is a new aluminum one with no name on it. I am using one inch aluminum risers below the carbs. No difference when removed, they have been reinstalled. Mike of H&H recommends Strombergs for his engines, but I am not certain which series he is selling 48’s or 97’s. He did say he would rejett the carbs with 48 jets if I ordered some from him. I am partial to the look of the dual carbs, but the 2GC carb is certainly an option. I have invested a bit of time and effort redoing the throttle linkage and associated mounts for these 94’s after my wife requested AC and a heater. But If I cannot make them work then Strombergs it will be. Respectfully Marc |
11-16-2021, 11:59 PM | #45 |
Member
Join Date: Aug 2017
Location: Roseville, Ca
Posts: 84
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Re: Lean MisFire
Hello All,
Update on lean misfire (stumble) just off idle (850 to 1500 rpm) Final solution: GM distributor from Charlie ny, works great. 52 Main jets for the new Dennis Carpenter model 94's 7.5 power valves Rich idle mixture screw settings Car is very drivable from a dead stop on a slight incline and all through the gears with no stumble and no excessive clutch slipping or RPM revving. Realtime AFR readings from each tail pipe to follow in the near future. Many thanks to all for everyones interest and input. Respectfully Marc |
11-17-2021, 10:50 AM | #46 |
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Location: Minnesota, Florida Keys
Posts: 10,450
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Re: Lean MisFire
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11-18-2021, 01:27 PM | #47 |
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Join Date: Aug 2017
Location: Roseville, Ca
Posts: 84
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Re: Lean MisFire
:-)
YEAH Ford Barn |
11-18-2021, 02:41 PM | #48 |
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Join Date: Oct 2017
Posts: 563
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Lean MisFire
The old mechanic saying went "90% of the carburetor problems are ignition related."
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