1962 olds 98

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  #1  
Old 03-09-05, 07:19 PM
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1962 olds 98

hi got a 1962 olds 98 394 4 bar. carb engine runs great at idle choke is set right ....new plugs points coil dist. cap... rebuilt carb.. in the mornings when i drive the car it runs smooth starts up great when it is cold the warmer it gets the more it starts to cut back ....the engine has only 44,000 miles on it there is no play in the timing chain or dist...... running 93 ouctan fuel had it tuned up... points at 18 th. dwell at 30' an timing 5 deg.... ran worse at that setting ..... before i had tuned up points where at 20 th. dwell 18............ timing 15 be for top dead center .......the guy said this is what the book called for .......my way ran better but why is is still cutting back.... no air leaks .......sitting still the engine revs up great an runs smooth ........is it fuel or fire .........it's a nice car but it needs to take off when i mash the gas with out cutting back....... someone out there knows about this kind of car ......please help thanks; mike ray
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Old 03-09-05, 08:53 PM
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The manual I have says 30 degrees dwell and timing 5 degrees BTDC @ 550 rpm in drive. Did you remove the hose from the vacuum advance and plug it when setting the timing? That engine probably required 95 octane with leaded fuel. If it pings when hot and under a load you may need to back the timing off until the pinging just stops. This will be trial & error.

Is the fuel filter clean?

If it is cutting out (missing) carefully inspect the distributor cap & rotor for cracks. (not common but new parts can be defective) Check the coil tower for cracks. Check the plug wires & coil wire for resistance. About 10,000 ohms per foot is a guideline. With someone holding the test leads securly on the ends wiggle & bend the wires. If the resistance changes the wire is bad. If you get 0 ohms the conductor in the wire is broken.

Also take a spray bottle and spray the wires from plug to cap and spray the coil wire with water. If it misses the insulation or boots are bad. Any of the above can leak spark voltage under load but the car may idle fine.

Were the plugs gapped at .030"? Spark plugs should ba an AC 44 or equivalent. If all the above checks out put a vacuum gage on the engine. See what vacuum you have. The needle should be pretty steady. I would guess you should see somewhere around 13-16 inches of vacuum.

Check to see if the advance weights under the rotor rotate and spring back freely. The next item will not cause a driveability problem but will cause poor gas mileage. Take the hose from the vacuum advance and suck on it. You should be able to rotate the plate the points are on. Then quickly stick your tounge on the end of the hose. The plate should stay rotated. If it goes back or you can't get it to rotate the diaphram has a hole in it and you need to replace the vacuum advance unit. With the engine running see if you get suction at the hose if you pull the hose off the vaccum advance unit. If you do not get suction at idle rev the engine up and see if you get vacuum. (this is called ported vacuum because the vacuum passage is above the throttle plates). If you can't get vacuum either way make sure the hose is not plugged or so soft it will collapse. Then see if you have vacuum at the nipple the hose connects to. If the hose goes to the intake manifold you have regular vacuum and it willl be present anytime the engine is running. If the hose goes to the carbeurator you may have ported or regular vacuum. Make sure the nipple is not plugged with carbon if you are not getting vacuum.

If all else fails you may need to run a compression test. The manual calls for 180 psi. Don't worry if it is not that high. The main thing is you prefer to see not more than a 10% difference between any of the cylinders. If you get a low reading on 1 or more cylinders squirt some oil in the low cylinder(s). If the compression comes up the rings are leaking. If it does not you probably have a bad valve which should give an unsteady vacuum reading.

If all else fails I can get the fuel pressure specification and you can check that.

Let us know what you find.
 
  #3  
Old 03-09-05, 08:53 PM
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Mikeray, I don't know where you live, but if it's cool & damp, the carb may be icing up. Is there a "heat stove" around an exhaust manifold missing, or the paper tube from the stove to the air cleaner snorkel missing, or the heat control valve in the exhaust manifold siezed or spring broken?? With only 44,000 miles, the crossover in the intake or ports in the heads may be blocked. Please tell me you DO NOT have a performance intake or a aftermarket open air filter or headers becaues they all lack pre-heat some of our climates need
 
  #4  
Old 03-09-05, 09:07 PM
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Originally Posted by hopkinsr2
Mikeray, I don't know where you live, but if it's cool & damp, the carb may be icing up. Is there a "heat stove" around an exhaust manifold missing, or the paper tube from the stove to the air cleaner snorkel missing, or the heat control valve in the exhaust manifold siezed or spring broken?? With only 44,000 miles, the crossover in the intake or ports in the heads may be blocked. Please tell me you DO NOT have a performance intake or a aftermarket open air filter or headers becaues they all lack pre-heat some of our climates need
Not sure if a 62 had the heat tube from the exhaust manifold to the snout on the air cleaner or not. If it does check what mikeray said and check the vacuum operated valve in the air cleaner snout. The flapper should allow the hot air from the exhaust manifold to enter the air cleaner while blocking outside air from entering the air cleaner when the engine is cold. You can check the valve operation by sucking on the hose just like I said for the vacuum advance and it should stay in position when you put your tounge on the end of the hose. There is a bi-metalic spring in the valve in the air cleaner snout that will cause the heat from the exhaust manifold to be cut off and outside air to enter when the air entering the air cleaner is hot enough. Also check to see if the hose has vacuum when the engine is running.
 
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