timing question

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73-340

73-340

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i have a 73 340 comp cams 470-270 eddy rpm heads 600 vac holley eddy intake . the question is in order for the engine to run without getting hot ( hotter than normal ) at 20 deg. i have to have initial timing at 30 deg. that seems high to me. it starts fine hot or cold . i do have bounce in the timing when checking it . over all the engine run pretty good . i have not got into the dist yet .thanks
 
Are you checking it with the vacume on hooked and plugged? Sounds like maybe you need a good distributor curve.
 
With the vacuum line unhooked and plugged, initial should be a good bit lower than 30*. Total without vacuum should start at 32* unless a closed chambered head is being used. -2* for that.

Try initial @ 15* and play with it.

You have a new damper? Old ones slip from there set marks often. This will throw you off.
 
yes , total of 40 deg of advance at 2000 rpm with no bounce in timing , at 1000 rpm(idle) 30 deg timing bonces :wack:
 
OOOooofffff.

*I think* you may need a damper.........Check it. If possible.
 
for some reason when i back timing down the engine starts to run hot .
 
I would get a piston stop and verify your top dead center mark on your balancer. Your not too far off at 40* total timing. I would set it to 36* total and then check your initial again. Depending on what dizzy you have a recurve may help too.
 
i'm running MP dist , msd . after another timing i still get some bounce in timing at 2000 rpm , will have to check dampner later. i have checked tdc and i'm good there.
 
You need to determine what the advance in the dist. is doing. Maybe stuck, dont know the history, may be a very short curve or even locked, IE "no" advance
 
Update: Took dist apart found the advance is free with two light springs . The vac advance is an 8.5 . The reluctor plate was a little dirty underneath it . Regapped reluctor , put it back in car got 20 deg initial with no bounce and max of 25 at 2000 with no bounce in timing which seems low . Car runs real good.
 
I would think your Balancer has slipped and your timing is not where you think it is. At 30* initial I don't believe the car would start easy at all. It would be doing the Waaa,Waaa, Waaa sound kicking back on the starter for sure especially when it is warmed up.
 
Mad Dart said:
I would think your Balancer has slipped and your timing is not where you think it is. At 30* initial I don't believe the car would start easy at all. It would be doing the Waaa,Waaa, Waaa sound kicking back on the starter for sure especially when it is warmed up.
Click to expand...


would agree the outer ring has slipped..
 
73-340 said:
My timing marks line up with dist and 1 piston
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Distributer has nothing to do with TDC, the piston Yes. If all is correct then you must have had the car idling very high with the vac line hooked up to get 30* on the light when you were checking timing. That is the only other thing that i can think of if it was starting easily @ 30* initial from what you posted.
 
73-340 said:
My timing marks line up with dist and 1 piston
Click to expand...

do you mean you put the #1 piston at TDC with a piston stop on then look to see if the timng mark is lined up correctly.

how to make a piston stop
take a spark plug and bust the ground electrode off. drill the insulator out. tap the hole. cut the head off a bolt. round off the bolt with a grinder. you want about a 1/2" of the bolt sticking out of the plug. or what ever it takes so the piston will hit the bolt

make sure the piston is down far enough so that when you screw the piston stop in you don't hit the piston

turn engine over with a socket on the balancer bolt until the piston hits the bolt. mark you balancer. turn the other direction until the piston hits the bolt. mark the balancer. half way between the marks will be your TDC mark. if your mark is not there your balancer has spun.
 
Or maybe your light is broken, mine was showing a ton of initial then I remember dropping my light 15 years ago and the dial coming apart on the back and me snapping it back together and putting it in a drawer for 15 years until I tried to time my 360 and was showing 30 degrees initial...
 
You can use a vacuum gauge also.
At idle bring your timing up to max vacuum on the gauge and then back it down 2 to 3 from the highest reading on the gauge at idle.
This is a fast way of getting you in the ball park for advancing your timing past the stock setting.
As far as the timing mark moving,your distributor could be a little worn or the bushing in the block that the distributor sits in could be worn also.
It's very common for the mark to bounce around a little with a stock distributor.
How much the mark moves around ---being to much or the normal amount a stock distributor moves around----is hard to say without seeing it in person.
Always time the car with the vacuum hose off the distributor and plug the end of the hose that's still connected to the engine.
Check the plugs after a test drive and make sure to adjust the carb idle screws also after readjusting your timing so it isn't lean or rich.

I never use my vacuum advance because it's drag raced ----but if it's just a cruiser ,you will save some gas keeping the vacuum advance hooked up.
Keep a ear out for detonation. GOOD LUCK.:burnout:
 
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