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Old 04-10-2007, 02:09 AM
tdaver tdaver is offline
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Default Rebuilt 440 timing help?

Hi folks,

I am new to 440's and need some advice from the experts regarding timing and distributor settings.

I have just finished rebuilding a 440 and 727 to drop into my 72 Dodge Charger. The engine and tranny came from a 1966 Chrysler Imperial. It is mostly stock. Bored 0.30" over with stock 0.30" over pistons. 9.5:1 compression ratio. 516 heads rebuilt with 1.74" exhaust valves and seats. COMP CAMS XE274H cam/springs/lifters/timing set. Duration @ 0.050 is 230/236 and lift is 0.488/0.491. CAM was not degreed. TCI breakaway torque converter. 3.55, 8 3/4 rear end. Stock iron intake with Carter AFB 625 CFM carburetor. I know the carb isn't ideal but it is what I had to start with. Plan to upgrade to 750+ cfm soon. Heddman Hedders.

The good news is that the engine seems to have made it through the break-in and seems to be running reasonably, though still a little hard to start.

I have some timing questions. The car has the stock mopar electronic ignition and I installed a stock mopar rebuilt distributor. I set the timing so that at about 2300 rpm, it is 34 deg BTDC with the vacuum advance unplugged and capped. Then when I lower the idle to about 800 rpm, the timing is about 22 deg and the engine rpm surges. I have read that the initial timing should be set to about 10 deg BTDC. How do I check the initial timing and what should I expect to see for timing at idle?

Basically I am looking for advice on how to tune the distributor so that it sets the proper timing at idle and full mechanical advance. I don't really care about vacuum advance right now and will deal with that later. Can anyone help this newbie get another MOPAR on the road?

Thanks!
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Old 04-10-2007, 11:01 AM
BigBlockDude BigBlockDude is offline
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Your dist may not be getting full advance at 2300 rpm, thats why it would still be 22 degrees at 800 rpm.
Set it at 10 degrees at idle and see how it runs. Also check the full adavance at 3000 or more to see if what I stated above is true.
I've recurved a few stock distibutors by removing the heavy advance spring and welding the slots for the centrifugel wieghts to shorten the curve. This way you can have around 10-12 initial and full advance at about 2000 rpm. Works good for basically no $$.
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Old 04-10-2007, 05:33 PM
wilks3 wilks3 is offline
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Do you have lighter advance springs for the distributor? If so, put them in. Set your initial timing at 10* and then using a timing light, bring rpm up until you see where the advance stops. Might be as high 3000 rpm like BBD said, but now you will know how much mechanical advance you have. Set timing at 34* total. Then start playing with the different spring combos until any pinging goes away, if any. If pinging won't go away, back off timing 2* and start over with the different springs again. No car, engine, drive train is the same, each one wants different timing. Thats the fun finding out what it is! But in the end its nice knowing YOU did it when you stomp the loud pedal down and it smashes you in the seat!
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Old 04-10-2007, 07:00 PM
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dave571 dave571 is offline
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Rev it up a little higher to ensure the total timing is really 34.


All in at 2300 is fine. If you go with the lighter springs it will likely all be in by 1300, and ping like a bastard.

Unless the dist has been heavily modded there is no way the timing curve is only 12 degrees.
If it really is at 34, and only comes down to 22, then the weights are likely stuck, and you will ahve to take the pu plate off to get to them.

I would think a base of 16 would be nice with that cam (keeping the total at 34) if you are going to try and change the curve, when you have it apart.
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Old 04-11-2007, 11:47 PM
tdaver tdaver is offline
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Hi folks,

Thanks for the replies. OK, we set it to 35 degrees at 3000rpm and at 800 rpm it was reading about 14 degrees. However, it was pinging like crazy. We dropped it to 30 degrees at 3000 rpm and it was better, but finally ran best with even less than 30 degrees at 3000 rpm. Sounds like a lot less advance than what people expected. Not sure what this means.

Anyway, I opened up the distributor and it appears to be stock and working correctly. The weights are moving freely and there are two springs, one heavy and one light. I received only one spring from Summit for the dirtributor modification. Should I order another light spring from Summit and replace both? For now I will just keep the lighter stock spring and replace the heavier one with the (even lighter) spring I got from Summit.

Any more ideas on timing?
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Old 04-12-2007, 01:20 AM
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dave571 dave571 is offline
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If it's pinging now, the lighter spring(s) will only make it ping more. better to stick with what you have.

Perhaps there is an issue with the marks. Like the balancer has slipped etc.

There is a tool you can get (cheaply) to check that the tdc mark is correct. It may be worth it for you. my .02
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Old 04-12-2007, 11:33 AM
wilks3 wilks3 is offline
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See if you can buy a recurve spring kit for the distributor, if you can, try replacing the one light spring with one that is just alittle heavier and try again. If no pinging, add 2*,try again. Its all trial & error. Just change one thing at a time and keep a record of what you do. You seem to be real close. My car likes 12* at crank with 20* in the dist for a total of 32*, all advance in at 2800 rpm. Runs perfect on anybody's pump premium and will run on 87 catpee if thats all I can get while out driving, I just have to baby it. Keep going & good luck!
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