Carb question.

Read my post I just left on your previous thread. You just need to spend some effort with what you've got. I'd say more but have to get to work.

tylerdru said:

I started a new thread because everyone was fighting in my other thread. Which is sad. Okay I have a holley 4160 600 cfm carb sitting on my stock 289.It is too much carb for my engine.
Could i rejet the carb with smaller jets? Would this help any. I am getting gas in the oil and backfires through the carb. I am also running lean.The timing is right. too.

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that carb will work great on a 289 or 302. You just need to tune it. I have no idea how much you know about Holley tuning, so I don't really know where to start. A 4160 should have vacuum secondaries, this isn't a concern at this point however. You also didn't say to whaty extent your engine is modified, if at all. For a mild 289, start out with 65 jets in front, your rear jets will probably need to be in the 72-74 range. I'm not gonna go into accelerator pump system tuning at this point, thats a whole 'story. To tune the idle, start with ignition timing. Use a timing light to set the initial timing at 12 degrees BTDC, do this with the vacuum advance hose disconnected from the distributor and plugged and the engine at warm idle at 700-800 rpm. Once that is done, hook a vacuum gauge to the full vaccum port on the carb, or the vacuum fitting on the intake if you have one. Locate the idle mxture screws on the front metering plate of the carb (sandwiched between fuel bowls and main body). Turn the screws in all the way (turn clockwise) just so they seat, but not tight, now back off the screws 1.5 full turns. Hook a vacuum gauge to a full vacuum source, either on the carb or on the intake. Watch the vacuum gauge, if its a fairly stock cam in the engine, it should be showing a steady reading around 18-20. Now adjust the idle mixture screws one at a time, in slight increments (maybe 1/4 turn at a time) until you obtain maximum vacuum. If making these adjustments increases idle speed, lower the idle speed using the adjustment screw located near the throttle linkage. Then start over with the mixture screws and adjust until max vacuum. I have yet to tune a car that did not respond well to this procedure. Now that you have the timing and idle tune dialed in, you can proceed to tuning across the rpm range. Let us know if/when you make it this far.

Also, if you have gas in the oil you might have a busted fuel pump diaphragm, this will cause the pump to leak fuel down into the crankcase. Other possible solution would be the carb leaking fuel down into the engine while the engine isn't running, or excessively worn rings which would also result in oil consumption and a nice blue smoke screen.

Another reason for fuel in the oil would be dirt in the needle valves, them sticking open, or to much fuel pressure. With the car idling, look into the venturi area, there shouldnt be any fuel dripping... if there is, or it's comming out the vent tube, it's a needle valve or float level prob..

600cfm is fine on a 289..

tylerdru said:

I started a new thread because everyone was fighting in my other thread. Which is sad. Okay I have a holley 4160 600 cfm carb sitting on my stock 289.It is too much carb for my engine.
Could i rejet the carb with smaller jets? Would this help any. I am getting gas in the oil and backfires through the carb. I am also running lean.The timing is right. too.

Click to expand...

Sorry if I lit the fuse for the squable, but it looks like things are on the right track now. So other than the apology, I'll bow out.