I have a 66 289 'A' code with P/S and A/C. The PO had replaced the 4 brl manifold and carb with a 2 brl sometime ago. He said back in the 70's. I've since have put the 4 brl manifold and carb back to what it should have been and then had some over heating problems. The car isn't driven daily, just weekends and to shows. I solved the over heat problem with a fan shroud. But now after the car has been running for 20 to 30 min or so, then sits. It becomes really hard to get it to start and then keep it running. It keeps stalling. I also noticed the temp gauge is showing that the engine is really hot. The car seems to run smooth during that first 20 min or so. It's a real pain when I have to stop for gas. Really have a hard time getting it going again. Could it be my timing? I put a light on it and I'm at about 6 TDC. any thoughts?? ::
jfairbank
The vapor lock does sound like it is the hard start cause. The issue now becomes "why did this issue pop up after changing the intake and carb?". I assume it did not before. Not likely the intake unless it has a leak in it somewhere allowing extra air in, sooooo....carb may be too lean, allowing it to run hotter and causing this problem. Need to check it out. Good luck, John.
With your car running at night pop the hood with no lights...see if your headers are glowing.
Your air-fuel might be a little off on the carb and to compensate you adjusted the timing to a less than optimal location and/or upped the idle mixture on the carb.
Either way it is as the others have said, a heat sink and/or vapor lock condition. The way around it is to install the phenolic spacer already mentioned but you should also look at your fuel line routing. It should not be laying on the manifold or block. It should be held a few inches up above the motor and if it is all rubber hose you should replace it with hard line from the pump to the fuel bar for the carb.
When it is hard to start is it hard to crank? If so then you need to install a heat shield around the starter if it doesn't go away after you get your carb settings correct. If it cranks just fine and just won't fire, it is just vapor lock (gas boiling off in the carb leaving the car out of fuel until the pump can pull fresh up from the tank and fill the bowls) and the spacer combined with adjusted timing/carb should cure it.
Your air-fuel might be a little off on the carb and to compensate you adjusted the timing to a less than optimal location and/or upped the idle mixture on the carb.
Either way it is as the others have said, a heat sink and/or vapor lock condition. The way around it is to install the phenolic spacer already mentioned but you should also look at your fuel line routing. It should not be laying on the manifold or block. It should be held a few inches up above the motor and if it is all rubber hose you should replace it with hard line from the pump to the fuel bar for the carb.
When it is hard to start is it hard to crank? If so then you need to install a heat shield around the starter if it doesn't go away after you get your carb settings correct. If it cranks just fine and just won't fire, it is just vapor lock (gas boiling off in the carb leaving the car out of fuel until the pump can pull fresh up from the tank and fill the bowls) and the spacer combined with adjusted timing/carb should cure it.
Thanks, a little more info. I do have the stock 4 brl carb spacer. I purchased a 66 4 brl manifold, Autolite 4100 and spacer from Pony Carbs. The fuel line from the fuel pump up to abut 2" from the carb is hard lined. When I replaced the manifold I also replaced the T'stat with a 160 deg stat. The car cranks just fine, just won't fire. Didn't think about Hormonic balancer. When I did the manifold I replaced the timing chain and water pump. I inspected the balancer. Looked to be original, but seemed to be in good shape. Anyway to test the balancer? I will look to see if the headers are glowing tonight. I was thinking the carb maybe running a little rich. I'll try ajusting that as well. I was afraid to mess with the carb setting since the car seemed to be running so well at first.
I have had a problem with my spark plugs and carbon buildup/wet from too rich of a fuel mixture. I would run the engine for a while to warm it up, but not being ready for the street, it didn't get to really run. I had problems starting. I took out a plug and found it to be soot black and really wet. I cleaned them up, leaned out the carb a little and it now runs fine( and starts right up) Check spark plugs, they tell alot about lean/rich conditions. BTW, too rich is probably NOT why your running hot, but the shroud will help.
Get a "read" on your plugs. If they are black and sooty, you're probably a little rich. If they're too white, this indicates a lean condition, and that is what usually causes a heating problem or hot spots on the exhaust.
Be aware, you don't "adjust" the carb to richen or lean it out. That requires a change of jets. The adjustment using the air/fuel mixture screws affects ONLY the idle. Once the engine comes off idle, those screws have no bearing on the fuel mixture. Good Luck!
I had the same symptoms on a Chevy 350 I put in an 86 Monte Carlo. The carb was vapor locking. When I shut the car off, the heat from the engine would transfer into the carb. I installed a phenolic spacer and never had another problem.
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