409 motor - Impala Tech
Engine General Engine Discussion.

  • 1 Post By Big Dave
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post #1 of 6 (permalink) Old 04-14-2020, 09:50 AM Thread Starter
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409 motor

Hey everyone....
I'm trying to help my Dad out with his 63 chevy. He just finished restoration and started her up and its pushing oil out the fill tube. It has the factory solid valve covers on it and no breathers like my small block.
Motor was rebuilt by a reputable local shop so I don't think its anything internal.
I'm not very familiar with this motor and any advice would be helpful.
Thanks !!
Ken Uhl is offline  
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post #2 of 6 (permalink) Old 04-14-2020, 10:17 AM
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409 used an oil fill tube in the front of the manifold with a vent on top of it. It also had a PCV system using the road draft tube in the back of the block with a hose attached to the rear most carb to suck in fumes and burn them. Without these two things your motor will pressurize the crank case from blow by (really prevalent with a 409 due to uneven weight distribution on the pistons) and pump oil out of any opening it can find. If it can't find a big enough opening it will blow out all of the seals in the engine (oil pan, rear main, front seal, valve cover, and china rails) to make an escape route for the blow by.

If you have these things on your motor it is time to call your reputable engine builder up and ask him why it has so much crankcase pressure. I would also ask for a leak down test to check ring seal in case he broke a few installing the pistons (409 requires a special ring installation tool due to the seventy four degree angle the deck makes with the ring pack, which is aggravated if you used a truck block with the holes cut into the block above the top of the ring pack to drop compression).

Big Dave
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post #3 of 6 (permalink) Old 04-14-2020, 10:46 AM Thread Starter
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well i'll have to see if he even has a pvc value setup..do you have a picture of the way it should hook up?
I'm a small block chevy guy...I know nothing of these 409 motors....strange setup for sure ! I also want to see if he has the correct fill tube..its not that much oil...just making a mess of a new restore....12 years in the making !!
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post #4 of 6 (permalink) Old 04-14-2020, 04:15 PM
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409 uses the same PCV system as the SBC did in 1963 (first year for PCV system, prior to that Chevy just dumped the oil on the road). You can see a picture with part numbers (good luck with those as they are all obsolete) in your 1963 Assembly manual.


Big Dave
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post #5 of 6 (permalink) Old 04-14-2020, 10:48 PM
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This is for the small block in 64, but should be similar with a 409. There were two variations, mine is the closed system that California required in 64. Crankcase fumes were drawn into the carb and burned.

The last photo is not my car and shows the 'non-California' breather cap (chormed).
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1964 Impala 4 door sedan

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post #6 of 6 (permalink) Old 04-15-2020, 07:54 AM
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I would check to see if you have a road draft tube, should be a tube at the dead center top of the engine at the rear, just below the intake manifold that comes out and does a 90 to go down and to the passenger side of the car. There are a lot of engine builders that can build standard SBC and BBC engines all day, but most never get enough exposure to W motors to build them well. Your builder may have only built 2-3 of these over the last 10 years if any at all.
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