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#121
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I would first do a dry test to save some time and then if anything checks way out of normal do a wet test.
So you dropped a Carb on from another motor without adjusting the idle mixture again?!!
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Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
The Following User Says Thank You to steve25 For This Useful Post: | ||
#122
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I will check this again just to confirm. Sent from my iPhone using Tapatalk
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Three times the sound peaks, falls back, peaks again. A throttling back to cruising speed, a dwindling grumble of thunder and...gone. The frogs take up where they left off. |
#123
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Ok. I’ll grab a tester from HF this morning. Sent from my iPhone using Tapatalk
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Three times the sound peaks, falls back, peaks again. A throttling back to cruising speed, a dwindling grumble of thunder and...gone. The frogs take up where they left off. |
#124
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Since I am going to pull all the plugs to check compression, I could also look for slop in the distributor. I do have a BORO-scope that the wife bought me for Christmas. I’ve never used it (not even sure I know how) but I’m assuming that to check the TC, I would pull the fuel pump and snake the scope into the timing cover? Sent from my iPhone using Tapatalk
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Three times the sound peaks, falls back, peaks again. A throttling back to cruising speed, a dwindling grumble of thunder and...gone. The frogs take up where they left off. |
#125
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Don’t waste time with the scope unless !something with the compression test goes off the rails!
The correct firing order is on the intake manifold for reference.
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Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#126
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Rebuilt 400 HO suddenly runs rough
Quote:
The 4 and 6 plug wires were mixed up!. It definitely made a difference in the starting/idle. The timing also didn’t jump around. Total timing is at 35. Is that correct? Here it is with correct firing order: https://youtu.be/Hv_kIQ7ZHI4 https://youtu.be/Hv_kIQ7ZHI4 Sent from my iPhone using Tapatalk
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Three times the sound peaks, falls back, peaks again. A throttling back to cruising speed, a dwindling grumble of thunder and...gone. The frogs take up where they left off. |
#127
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Guess I missed the part you said all was well running till you filled up at a gas station, "then" things went bad gradually.
How does to run "ok" then after fueling went "bad" when you were driving? And now find plug wires mixed up? That I don't understand at all. Was running good, then fueled up, then degraded fairly rapidly, worsening seemingly, barely running. Put about a 1/2 gallon from the fuel pump supply side into a clean container and let settle and see what it looks like. Last edited by 1969400HO; 10-03-2021 at 12:13 PM. |
#128
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That sounds fine... Maybe you've solved your problem?
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1965 Pontiac GTO 455/469 w/ #48 Heads, '65 Tri-Power 9.25:1 CR Stump Puller Cam Muncie M22W 1st-2.56 2nd-1.75 3rd-1.37 4th-1.00 3.55 Rear Differential Front: 225/60R15 Height: 25.6" Rear: 275/60R15 Height: 28" |
#129
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It was running fine, and then it felt like it started to stumble. I thought maybe the gas gauge was incorrect, so I stopped to get gas. But it only took about 5-6 gallons, so the gas gauge was fine. However, the stumbling got markedly worse as I limped home (about 5 miles). No power, backfiring, sputtering, etc. The mixed up wires had to have happened when I pulled the cap to do the points. That one is completely on me. I'm going to take it out for a spin now. If it runs ok, then the issue I was having was either the points, which definitely looked a bit tired for only 300 miles or so, or all the grit in the carb. I will report back shortly!
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Three times the sound peaks, falls back, peaks again. A throttling back to cruising speed, a dwindling grumble of thunder and...gone. The frogs take up where they left off. |
#130
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Yes, 35 degrees is safe with those 670 closed chambered heads, but for the best around town drivability they may like 38 degrees total with the vacuum advance disconnected and then 8 degrees of vacuum advance coming in at 1800.
Ruining 38 degrees will Hinge on how the motor cranks when hot, if the motor pings at part throttle it knocks at full throttle which in terms of full throttle is to be avoided 100%!
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#131
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Rebuilt 400 HO suddenly runs rough
Car runs 1000x better! No stuttering or stalling accelerates great! Thanks so much for all the help! You guys rock!
The last annoying things are, when I come to a stop, it’s idling at 1200, but if I kick the throttle it goes back down to 800. It did not do this with the previous carb. To Steve’s point: I drive it for about 20 miles (local). When I shut it down, it dieseled a little. And once it was warmed up, it took a bit more cranking to get it started. Should I move the timing to 38 (with vacuum advance disconnected)?
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Three times the sound peaks, falls back, peaks again. A throttling back to cruising speed, a dwindling grumble of thunder and...gone. The frogs take up where they left off. |
#132
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Have you ever considered getting a 1967 pontiac service manual and following the service instructions in it?
It is difficult to fail if you´d start with this. If you follow some people's advice regarding the timing settings, it will soon be time to change the engine bearings. If you want your engine to live a healthy life, use the factory ignition settings. Especially with the inferior fuel we have today. FWIW |
#133
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Rebuilt 400 HO suddenly runs rough
Car also runs a bit hot now.
Kenth I have the service manual. It says to set initial timing at 6 degrees BTDC. I thought with today’s gas, that this wouldn’t necessarily be applicable anymore. Also, my balancer has two marks on it that are 6 degrees apart. I’m not sure, but I’m assuming that the engine builder added the second mark. I would think that the bottom mark is 0, and that the top one represents an additional 6 degrees BTDC. Sent from my iPhone using Tapatalk
__________________
Three times the sound peaks, falls back, peaks again. A throttling back to cruising speed, a dwindling grumble of thunder and...gone. The frogs take up where they left off. |
#134
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The conclusion was that your hub is a factory 1964-65 vintage for 1964-65 timing cover with just a pointer thus the two marks, first mark indicates 6° BTDC and the second mark 0°, instead of one mark on hub (0°? for the scale on 1966-67 vintage timing covers. Your engine builder simply mounted the wrong hub for your damper. And, the need for setting the timing out of the scale indicates a too lean F/A mixture. The carb needs to be recalibrated for todays fuel to let the engine give its full potential. This will not happen igniting a too lean mixture with timing set out of the scale. Also, a too lean F/A mixture will make your engine run hotter than necessary. |
#135
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Well yes, your carb needs to be set up right, but your also hitting on all 8 cylinders now which is putting more heat into the coolant!
Is your vacuum advance hooked up and working above 1600 rpm? No vacuum advance at road cruising speeds and part throttle will make the motor run hotter then it should !
__________________
Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#136
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Glad you found the firing order was off. If anything will cause poor running and popping through the carb, that is it. I would get someone who knows Quadrajets go over the carb. You had dirt in the gas and I think you said you ran the car with no filter which is never a good idea. Despite what others have said the stock brass sintered filter are actually very affective at removing debris. They are small and will clog quickly if you have a lot of debris in the tank. You may want to use an inline filter after the pump rather than the stock sintered filter. I wouldn’t use both. Properly setting up the carb will be important to getting your car running really well. Also if I were you I would replace the points with a Petronix unit. It will save you a lot of aggravation, for the $80 investment they are a no brainer, especially with a GM motor with the distributor at the back of the motor.
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#137
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Quote:
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Jeff |
#138
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You're welcome.
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Triple Black 1971 GTO |
The Following User Says Thank You to NeighborsComplaint For This Useful Post: | ||
#139
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My 69 RAIII std bore 400, 50K orig miles.
Was running a bit hot, a water pump rebuild and set the "Plate" to 0.050", gap, helped a little. Month later rebuilt Rad from a 3 core to 4 core. Now it Runs almost too cool now. Always been satisfied with New triple gauges set, they are More concise readout to monitor things. At the time was new to Rochester carburetors so I followed a Qualdrajet bible- PDF , set up the jets/rods for "total area" to near recommended 0.003xxxxx,. I never had any carb perform like it dd once I was done tuning setup it as per the manual!! Very impressive performance. See the link for resource. http://corvette-restoration.com/wp-c...arb_Tuning.pdf Last edited by 1969400HO; 10-03-2021 at 09:18 PM. |
#140
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Thank you! Sent from my iPhone using Tapatalk
__________________
Three times the sound peaks, falls back, peaks again. A throttling back to cruising speed, a dwindling grumble of thunder and...gone. The frogs take up where they left off. |
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