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  #1  
Old 05-05-2004, 12:49 AM
bad-bird-69 bad-bird-69 is offline
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Default 440 timing advance

The 440 in my car has never ran the way I think it should. I bought the car in 1989 w/ a noisy #matching 383. By 92 I was tiried of changing things on 440 to make it faster so I had a roller motor built. Started family and car went unfinished until now. I'm trying to get the timing set but something seems wrong. The gun shows 36 deg. at idle! (1000 rpm) Mech. adv. starts at 1200 and is all in by 2000 rpm. The guy that built the motor put a white mark on the damper at 36 deg. Would someone install the cam that far advanced? Car runs good at low rpm(1000-3500) but breaks up above that. I'm using a mallory unilite. This motor was built from oil pan to carb ready to run. The only thing I'm not sure of is the cam spec. It's a crower street roller (w/ .624 lift and between 280 - 290 dur. I think ?) Do I need to tear it down and slap a deg. wheel on it or does this make sense to someone?
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  #2  
Old 05-05-2004, 03:42 AM
Mr. Trans Am Mr. Trans Am is offline
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Default

Are you checking with the vac line hooked up? With a big cam you might be over on the main circuit and pulling vaccum.

If it has been sitting 10 year that might have caused the valve springs to go weak. That would explain the problems at 3500+
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  #3  
Old 05-05-2004, 05:14 AM
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MoparMarcIdaho MoparMarcIdaho is offline
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Arrow you can degree it

with the front cover on,just mount it to dampener and check vale events at the rocker arms.just unplug the vaccum advance and try it once.Might just need to recurve the distributor.
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  #4  
Old 05-05-2004, 10:40 AM
bad-bird-69 bad-bird-69 is offline
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The dist. has no vac. adv. The car was driven and moved several times during it's down time. Always inside and spotless!! I just never had enough time to really get into it until now. Motor idles at 14 in. of vac. w/ a steady needle. When I rev the motor to the point where it starts to stumble, I can retard the timing 16 deg. and it goes away. My dist. is set at 18 deg. If I take out the 16 deg. that only leaves 2 deg. The car runs with this setting but seems lazy at low rpm. The car will go through all the gears nice and rev to 6500 rmp w/ no stumble. I have a stock dist. that I set on my dads sun machine w/ vac. adv. but that won't fix the 36 deg. of adv. at idle. Can anyone share thier settings just to give me some ideas before it comes apart? Everyone swears by more than 10 less than 20 but the chrysler book says they were set between TDC. and 7 deg. BTDC. I have read that R/RB motors could take as much as 56 deg total??? Can anyone tell me if I can use my unilite on an old sun machine so I can set the curve. Machine works great w/ points. Does anyone think a dist w/ vac. adv. would work better for me? Thanks to everyone!!!
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  #5  
Old 05-05-2004, 12:05 PM
MitchB MitchB is offline
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Default

Let's understand this:

What is your current initial timing set at?

How much mechanical advance do you have in the distributor?

At what RPM is the spark advance all in?

Your current distributor does not have vacuum advance, correct?

What is the engine's compression ratio?

When the engine stumbles and you pull out timing, at this point, what is you spark timing and at what RPM?

I don't see how there is any correlation between the mark on the balancer and how your cam was installed.

Mitch
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  #6  
Old 05-05-2004, 01:46 PM
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MoparMarcIdaho MoparMarcIdaho is offline
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Exclamation worth a try

you have pretty much proved that its not valve springs,what carb do you run?If it was mine I would scrounge a decent stock electronic distributor and put that on dads sun machine and set it up to give less mechanical and just experiment with different vaccum diaphrams to match that roller cam for street use.At WOT you dont get any vaccum so that should work good.
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  #7  
Old 05-05-2004, 05:49 PM
sixpackgut sixpackgut is offline
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Default

at 3500 rpm, what is the timming at then? 50?

the unilite will work fine but that little optisensor thingy diod will drop dead from voltage spikes without warning. they sell some kind of voltage spike filter for this now.

i dont think anyone is getting a clear understanding of your dist right now though. is the vac advance hooked up? cam timming and ignition timming are two different things. are you useing a dail back light or just a regular one? is you marks on your balancer correct? if its a stock balancer, outer ring could have slipped. but i think you just need to turn your dist back so that you have around 15 btc at idle. and no vac advance.
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  #8  
Old 05-05-2004, 06:12 PM
warlockpowerwagon warlockpowerwagon is offline
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timing chain is off 1 tooth.
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  #9  
Old 05-05-2004, 10:48 PM
bad-bird-69 bad-bird-69 is offline
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Exclamation Dist. has no vac adv.

Mitch, the current initial timing is 36 deg. I have tried from 14 to 22 deg. mech. adv. inside the dist. The comp. is 10:1. When timing is pulled out total adv. at 3500 rpm is 38 deg. If I can remember right I thought the motor builder said rev it up to 3000,set the line at 0 deg. on the timing cover and go. But that is correct. That would give 36 deg. total adv. initial+mech.

Marc, I'm using a HOLLEY 850 DP. I have changed jets, power valves, nozzels and pump cams. Car runs best w/ 81 front jets, 90 rear, 10.5 power valve in front. 31 nozzles front and rear.Still playing with rear p.v. Don't have a problem w/ the carb. I can tune Holleys!!

SixPack, A dial gun is being used. I'm not sure about the timing marks. At TDC the rotor is just past the #1 by maybe 1/8 inch but don't forget initial shows 36 deg adv. If I try to lower initial timing, at 30 deg on the gun the car will start to miss and loses vac.

Warlock, have you seen this before. I have a 3 position crank gear but I think they are - or + 4 deg.

I'm getting ready to put the degree wheel on and go from there. When I pull the cover off and get the cam number where can look or call to get the specs? I know this doesn't make sense. Is it as simple as being off one tooth on the chain? Again Thanks to Everyone.
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  #10  
Old 05-05-2004, 11:33 PM
MitchB MitchB is offline
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Default Re: Dist. has no vac adv.

You can check the cam timing, but I would not worry about that right now. I still have some confusion about your spark timing and it appears you might too.

Get a piston stop that threads into the spark plug hole and find #1 TDC. Use this to index your balancer as true TDC. If you are not sure of the intricies of doing this, get back to us with questions.

Rework you distributor to give 14 degrees total mechanical advance. This is 7 degrees distributor advance.

Using either a timing tape on your balancer or a set back timing light, set your total timing (initial + mechanical) to 34 degrees. You will need to bring your engine up to 3000 RPM or so, wherever your mechanical advance all comes in, to do this. You will now have 20 degrees initial timing and 34 degrees total.

Go back over your carb idle RPM and mixture settings.

How does your car run now?

Mitch

Mitch, the current initial timing is 36 deg. I have tried from 14 to 22 deg. mech. adv. inside the dist. The comp. is 10:1. When timing is pulled out total adv. at 3500 rpm is 38 deg. If I can remember right I thought the motor builder said rev it up to 3000,set the line at 0 deg. on the timing cover and go. But that is correct. That would give 36 deg. total adv. initial+mech
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  #11  
Old 05-05-2004, 11:37 PM
MitchB MitchB is offline
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Default Re: Dist. has no vac adv.

I'm getting ready to put the degree wheel on and go from there. When I pull the cover off and get the cam number where can look or call to get the specs? I know this doesn't make sense. Is it as simple as being off one tooth on the chain?

If you get to the point where you are going to degree-in the cam, you will find the intake & exhaust opening and closing events. This is all the information you will need. From this, you will know everything about your cam and how to set it up.

Mitch

Last edited by MitchB : 05-05-2004 at 11:38 PM.
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  #12  
Old 05-06-2004, 12:11 AM
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MoparMarcIdaho MoparMarcIdaho is offline
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Arrow vaccum advance

I didnt think you had carb problems,I just wondered if it had a timing port on it and it does.Still think the right recurve could solve some issues here.strong springs and a quick vaccum pull could dial it in,keeping in mind that there is 0 vaccum at idle until the throttle plates come past timing orifice and you lose it again a WOT.Worth a try before you go ripping it all down.And you can check the open and close events at the rocker arms without pulling the front cover.
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