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-   -   440 timing advance (http://www.moparchat.com/forums/showthread.php?t=82631)

bad-bird-69 05-05-2004 12:49 AM

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?

Mr. Trans Am 05-05-2004 03:42 AM

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+

MoparMarcIdaho 05-05-2004 05:14 AM

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.:confused:

bad-bird-69 05-05-2004 10:40 AM

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!!!

MitchB 05-05-2004 12:05 PM

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

MoparMarcIdaho 05-05-2004 01:46 PM

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.;) ;)

sixpackgut 05-05-2004 05:49 PM

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.

warlockpowerwagon 05-05-2004 06:12 PM

timing chain is off 1 tooth.

bad-bird-69 05-05-2004 10:48 PM

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.

MitchB 05-05-2004 11:33 PM

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

MitchB 05-05-2004 11:37 PM

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

MoparMarcIdaho 05-06-2004 12:11 AM

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.;)

bad-bird-69 05-06-2004 09:00 AM

Got my tires yesterday. I'm going install them today and I'll try what Mitch thinks might do some good. Who knows? Anything is better that a teardown!! I'll let you know.

sixpackgut 05-06-2004 05:28 PM

new tires?

i would try what mitch said first. degreeing a cam while its in your car will not be to much fun. plus you still need to get a piston stop to find TDC anyway to degree it. find TDC first.

also, i havent seen to many cams with numbers that really mean much of anything.

warlockpowerwagon 05-06-2004 06:40 PM

My jumped tooth came while I was experimenting with my nitrous plate. I had one wicked backfire at WOT and thought I would be picking up pieces. The car still ran ok at low RPMs, (under 3000) but if I got up to or over 3000 RPM the engine would sound like it was misfiring and not accelerate any further. Also, when I would start it on a colder morning, (under 40 degree F) I would get a backfire in my exhaust. Sort of like gasses collecting and then firing off. I Changed my timing chain and no problems. I was probably pretty lucky over the whole event. It was just my .02 for your problem and something to check out. If you have 3 settings on your crank gear, maybe it is in the wrong one. You are going to have to find your intake and exhaust closing events as has already been suggested.

6 packin 05-06-2004 10:47 PM

First things first. Its never goping to run right idling on the primary main circuit, to much transfer slot open, like idleing 1500+ rpm. The thing should idle fine at below 1000 rpm's if you have the correct intial timing. You want 14-18 deg intial timing with that cam to get a clean plug reading on the idle circuit. Then, limit it to 34-36 deg total which means 20 deg mech advance, remeber this is cam deg not crank deg there not directly related. Make sure you have no vacum leaks etc. start with these things, and if you cant seem to find the solution, borrow another distributor. run it without the vacum advance, with 12-14 deg intial 30-34 deg total is acheivable, and will run good, untill you can make a few changes.

bad-bird-69 05-06-2004 11:52 PM

Warlock, you might have a good point! A couple years ago I broke the driveshaft, trans and bellhousing. I know the engine red lined and backfired. Engine will be looked at this weekend. Weather says three days of rain.

bad-bird-69 05-06-2004 11:58 PM

Sixpack, I bought new yokohama avid s/t tires.

creative1 05-07-2004 02:37 AM

this may be waaaaayyyyyy out in left field, but i had similar problems about a year ago. i had just ruinedanother driver's cell phone call when BOOM... big backfire! then i could kind of idle along ok... but any attempt to accelerate resulted in numerous backfires... machine gun style. i limped the truck home. figuring jumped timing gears, i automatically called the parts store and ordered about $100 worth of timing gears and gaskets.

when i got the parts, i started removing the necessary things to get access to the timing gears. set engine to TDC, then proceded to remove the distributor. on removal of the cap, the magnetic pick-up looked crooked... and investigation revealed that the pin on the end of the vacuum advance arm had become disengaged from the timing plate in the distributor!!! completely! this would mean that the ignition timing was way off... in this case i think it was about 35 degrees advanced. popped that puppy back in place and everything was normal again! i have since replaced that dist with an FBO recurved unit... so that wont happen again. this seems to be something that CAN, but rarely DOES, happen to mopar distributors.

just might be something worth checking. if it is that, it will save you a lot of work and still have not cured the problem!

bad-bird-69 05-07-2004 05:44 PM

Timing Marks ??
 
Took off the timing cover today. Both timing marks are at 12 o'clock. Shouldn't the cam gear mark be at 6 o'clock like a stock set? I'm using a cloyes double roller 3 bolt w/ thrust button. I've seen some fords that line up like that but never a chrysler. If it's 180 the engine couldn't run, right?

MoparMarcIdaho 05-07-2004 06:00 PM

supposedly
 
The cam gets timed with the marks together and the distributor gets stabbed at both to 12 oclock.Anybody else?:help:

creative1 05-08-2004 01:16 AM

4 stroke/cycle engine 101:

ok... to make things simple, the camshaft (when the timing gears/chain are installed) rotates EXACTLY one-half turn for every EXACT whole turn the crankshaft makes.

every other time a given piston travels upwards, it is on the compression stroke... both valves on that cylinder are closed. at approximately the time the piston reaches TDC, the spark plug is supposed to fire and ignite the fuel/air mixture. this burning mix expands rapidly, forcing the piston back down the cylinder (power stroke).as the piston reaches the bottom of its travel, the exhaust valve opens and as the piston moves back upward, it pushes the burned gasses out the exhaust (exhaust stroke). as the piston again approaches TDC, the intake valve opens, overlapping the exhaust valve a little... the idea here is to allow the exiting exhaust gasses to "suck" in fresh air and fuel)... then by the time the piston starts its downward travel, the exhaust valve has closed. the downward motion of the piston draws more air/fuel into the cylinder (intake stroke). by the time the piston reaches BDC, the intake valve closes, and the piston begins the whole 'compression/power/exhaust/intake' thing all over again.

now... if you turn the engine over by hand and watch the camshaft/crankshaft/piston/valves, you will see these things happen. you will also see that the crankshaft MUST make 2 revolutions for the piston to do its thing, but the camshaft MUST only make ONE revolution during this same time.

when you put the cam/crank gears in a mopar engine with the marks at 6 and 12 o'clock, you are assembling the engine at TDC on the EXHAUST stroke, not the compression stroke! to get to TDC on the compression stroke, you MUST turn the crankshaft exactly ONE turn (after installing the timing gears). TDC on the compression stroke is where you want to install the distributor! if you install the distributor while the timing marks are lined up at 6 and 12 o'clock, the distributor will be 180 degrees out of phase. or, you can wire and time the ignition to #6 cylinder (the 4th cylinder in the firing order). or you can just leave things 180 degrees out of phase. it can cause headaches for anyone else that works on the car, though.

it really doesnt matter to the engine, except that #1 cylinder must be wired to what the camshaft thinks is #1 cylinder on the distributor WHEN #1 CYLINDER IS AT TDC ON THE COMPRESSION STROKE!!! then you just follow the firing order to wire the rest of the cylinders. they will be 4 holes out of phase (one rotation of the crankshaft, one-half rotation of the camshaft).

ease (and accuracy) is why you assemble the timing gears at 12 and 6 o'clock, then give the crankshaft EXACTLY one turn before installing the distributor. and while the timing marks are lined up this way, it also gives you the best chance you will ever have to verify that the timing marks on the damper are correct.

MoparMarcIdaho 05-08-2004 01:39 AM

this is right except in england
 
Believe it or not on a 650 triumph T110 tiger the timing gears aling only every 64th revolution of the crankshaft.Why is this?Because the british,in their infinite wisdom put odd number of teeth on the timing and cam gears.So when you are setting up the magneto on one and some dimwit decides to kick it over when the sidecover is off and the gears all come flying out on the floor,try to be cool.:crying:

creative1 05-08-2004 02:49 AM

wow... i never knew that!!! never worked on a triumph, but i did have a bout with an XKE jaguar once...

it won... lol... dohc and a timing chain about a mile long. set valve timing to #6 cylinder and the ignition was timed to #1 cyl... something like that anyway... 1972 was too many years and too many little orange pills ago...:rolleyes:

i think i would rather put a 440 in a 1980 subaru GL than try THAT again...

bad-bird-69 05-08-2004 05:42 PM

Timing marks line up if crank is rotated 1 full turn. I thought you found TDC by putting your finger over #1 spark plug hole. When air pressure builds and starts to blow by finger, slowly rotate till timing marks line up on the damper. Still doesn't explain why the engine shows 36 deg int. timing w/ no vac. or mech. advance.

Charger 1 05-09-2004 10:30 AM

I personally lock out the dist. at 39 total at idle works great. also i have experience breaking up at the top end due to lean condition. So I would try locking out the dist. and set it at 35 and see if that solves the problem? just my .02

bad-bird-69 05-09-2004 03:40 PM

Getting gaskets tomorrow. I think I'm going to take out the unilite and try one of my other dist. I have a mallory dual point w/ mech. adv. and a factory dist. w/ vac. adv. The shop that built the engine also built the dist. so I'm not sure what has been done to it. Changing the dist. should hopefuly give me some answers. What does it mean when the timing is locked out? My dist. seems like it is some how set or locked at 36 deg?

warlockpowerwagon 05-09-2004 04:38 PM

My .02 again. Throw a degree wheel on there and find out what the cam is doing with the valve events.

bad-bird-69 05-09-2004 08:25 PM

What effect does putting the bottom gear at + or - 4 deg. have on engine performance? Which is + 4 deg. the triangle or the rectangle? What am I looking for when I put the degree wheel on? Just trying to get as much info. as I can before I put it together.

MoparMarcIdaho 05-09-2004 11:16 PM

cam timing
 
advanced position gives more low end,retard position gives better top end.Changes your power curve.


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