383 tune up advice needed

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Swede123

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Hi i need some advice about engine tune up. Hard to start when cold and a horrible bog when giving it WOT. I can get it to WOT by easing it up there but can't be to fast. Pulled the plugs today and not quite sure what to make of it, some of Them were a little oily but not terrible.

Not sure of its a timing issue or carb. It has an brand new edelbrock 750 on it straight out of the box other than idle mixture adjustment. The plugs are Autolite 85s. Here are some pictures of the plugs.

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First thing needed is timing for a given rpm.

For a 100% factory setup, go with the factory.
Assuming its not 100% factory (incuding distributor) then this chart is helpful, especially if the engine is hot rodded.
Distributor starting point for a curve

This explanation from Chrysler on the purpose of timing is very helpful. See them here total timing reading accurate with no load?

If you don't have a factroy distributor, or if its a replacement my suggestion is to get some timing tape and measure the timing from as slow as the engine will run, then every 200 or 250 rpm up until it stops advancing or you don't feel safe. Then you can plot the advance curve and see what needs to be done, if anything to the advance.

You can use the pre-emmissions era 383 and 440 factory timing as a baseline.
See this thread: Total advance question
Notice the initial timing on those e ngines was 12.5* BTDC at 550 - 600 rpm. At least a couple degrees more initial was acceptable if the fuel allowed. With a cam that has more overlap, higher initial may be needed. See the first link. It also may have to idle higher, maybe 700 or 750 rpm.
Be alert to the fact that the distributor intended for a 600 rpm idle may already be advancing at 700 or 750 rpm.
 
14 BTDC initial timing is a good starting point for a 383, most end up around 18- 20.
I'm taking for granted that the engine has a performance cam and aftermarket intake. Headers ?
 
fishmens67 said:
14 BTDC initial timing is a good starting point for a 383, most end up around 18- 20.
I'm taking for granted that the engine has a performance cam and aftermarket intake. Headers ?
Click to expand...
Yes, not sure what cam it is, "hotter" cam according to previous owner. Edelbrock torker single plane intake and longtube headers.
 
Swede123 said:
Yes, not sure what cam it is, "hotter" cam according to previous owner. Edelbrock torker single plane intake and longtube headers.
Click to expand...
That combo will probably end up liking about 20 initial to run clean and provide the highest vacuum signal.
 
That is PIG rich at idle is my guess.

Ede carbs are VERY sensitive to fuel pressure. Make sure teh pressure isn't more than about 5-5.5 psi. When the engine is running look at the booster to see if you have raw fuel dripping into your engine

Might require a set of lighter springs on metering rods based on idle vacuum.

Timing FIRST... You'll have to find the spot your engine likes.
 
Back to basics.
That carb had a looooooong trip getting to Sweden. Bounced around.
- You need to check float level, which should be 7/16". You will NOT need gaskets if you are careful. With the top still off: [1] Remove a secondary booster [ 2 screws ] & turn it upside. It will have one or two brass tubes sticking out. Look at the end of thicker tube. Is it cut off flat or bullet shaped? If bullet shaped, measure the hole in it. Post a pic if you can. [2] Flick the velocity valves under the boosters to make sure they are not binding.
- Make sure the acc pump squirts fuel into each pri bore when you move the throttle lever.
- Take a vacuum reading at idle, in gear if auto.
- I would get new plugs, NGK BP5S.
- The Torker is a single plane manifold which typically needs richer jetting, but before that...
- There are little covers over metering rod pistons. Loosen these, swivel slightly then lock in place so that piston is retained but you can see it. Warm up engine, idle, in gear if auto. The pistons should stat DOWN & not move. If they move, you need softer piston springs [ Edel sell them ].
 
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