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distributor position

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levicah

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Can somebody educate me. TDC is when #1 piston is at the very top of it's compression stroke, is that correct? Shouldnt this place the notch on my crank pulley at zero on the degree marks on my block? or at least near it? So, the distributor rotor, should also be facing the #1 terminal on the cap?

When #1 piston is as high as it can go...pushing out air, as in "compression", the rotor is 1 inch short of pointing to #1 cap wire. Also, the tds notch on my pulley is nearly 1/3 away from the timing marks.

So what is happening here? Is it only the distributor position?

I thought that notch in my pulley was set in stone??? I dont understand. Do I follow the notch, or the up position of my #1 piston as TDC??
 
A loose dampner will throw timing mark off. The best and most acurate way to check cylinder tdc is with a piston or cylinder stop and degree wheel.
Before just moving plug wires check also timing chain stretch.
 
A little history would help. Has the car not run in years? Been running every day?
1. The marks on your timing chain are set in stone (basically) & therefore, the timing mark on the harmonic balancer should be in stone too, but as mopar 3B mentioned, that harmonic balancer mark can move if the balancer goes bad.
2. The distributor rotor should point at #1 plug wire when piston #1 is on the firing stroke (basically). There should be no "air pushing out" since both valves will be closed (air pushing out would be the exhaust stroke). The crank notch should line up at top dead center too. And remember.....the TDC mark will line up TWICE for every time cylinder #1 fires ONCE.

a. make POSITIVE you have #1 piston at TDC on the FIRING stroke
b. line up the rotor to the #1 wire
This should make it start, or you have a bad timing chain, balancer or something like that (assuming fuel & spark are both good)
 
levicah said:
Can somebody educate me. TDC is when #1 piston is at the very top of it's compression stroke, is that correct?
Click to expand...
Correct

Shouldnt this place the notch on my crank pulley at zero on the degree marks on my block? or at least near it? So, the distributor rotor, should also be facing the #1 terminal on the cap?
Click to expand...
Correct

Has the distributor ever been pulled?
Any play in the distributor shaft?
Have the timing gears ever been pulled?
Has the timing mark tab ever been replaced?
 
What engine ? My cast crank motor home 440 has a larger balancer with 3 cut notchs all aprox 1/3 of the dia from the next one.
I had to locate the TDC one with the valve cover off and plug out, then mark it with a paint pen.
When I first tore the engine apart someone had stuck the dist in with #1 on the exhaust stroke so they had wired the cap using #6 as #1 instead of just rotating the dist 180
Pull the dist if its a big block and look down the hole & make sure the oil pump/cam gear rod notch is pointed front to back when your balancer is on the TDC mark, make sure #1 is up to the top. drop the dist in rotor pointed to #1, if its 180 out when cranked { back fire through carb} just pull the dist up a inch and rotate 180* and drop it back in.
 
………
DistAlign.jpg


Verify #1 TDC compression stroke. With the outer ring on the zero mark, extend the mark to the inner ring for visual reference if future of outer ring slip.
Aftermarket distributors may not have the shaft lug indexed the same as stock.
You can move the plug wires around the cap to compensate or re-index the oil pump drive slot to suit.
 
PurpleBeeper said:
A little history would help. Has the car not run in years? Been running every day?
1. The marks on your timing chain are set in stone (basically) & therefore, the timing mark on the harmonic balancer should be in stone too, but as mopar 3B mentioned, that harmonic balancer mark can move if the balancer goes bad.
2. The distributor rotor should point at #1 plug wire when piston #1 is on the firing stroke (basically). There should be no "air pushing out" since both valves will be closed (air pushing out would be the exhaust stroke). The crank notch should line up at top dead center too. And remember.....the TDC mark will line up TWICE for every time cylinder #1 fires ONCE.

a. make POSITIVE you have #1 piston at TDC on the FIRING stroke
b. line up the rotor to the #1 wire
This should make it start, or you have a bad timing chain, balancer or something like that (assuming fuel & spark are both good)
Click to expand...

So JohnPat....what's wrong with what I wrote? Is it that I said "firing stroke"? I guess I should have said exactly between the compression & the firing stroke?

When the original poster said, When #1 piston is as high as it can go...pushing out air, as in "compression" it made me think the distributor might be 180-degrees off. When the spark plug fires, both intake & exhaust valves should be closed and the gas/fuel in the cylinder fully compressed (TDC firing). If you are "pushing air out", that would be the exhaust stroke...180-degrees off. Am I missing something?
 
If your measuring TDC you DO get air pushed out from the spark plug hole (plug removed). So it is miss leading.
 
Dave's post is very helpful to your issue. Why your harmonic balance does not align to zero timing mark is unknown and you need to provide more history as requested.

Once that is fixed you have to merge two things after you ensure your oil drive slot is as pictured above. You need to see where your distributor vacuum canister aligns to not interfere with any engine items like fuel lines etc... and then the rotor position is adjusted to be just before a plug terminal, or for points just opening. Where the rotor points has to be the #1 plug wire and you install based on that. You rotate the distributor to get it right. Then once started actually set timing.

If oil drive is not right the #1 plug location will be different. If the shaft is not OEM correct and the tip is clocked different, the position will also be different and lastly if the cam stop slot for rotor is not right, the position of #1 will also be off from a typical OEM position. Knowing what distributor you are working on helps here. For example a Prestolite type can have lots of variations with mix and matched parts. Shafts and cam stops where clocked very differently between models despite the fact that they could work in other distributors.
 
Purple beeper,I didn't post an answer to your
post.
I don't know where that came from???
That's a definite mystery to me
 
PurpleBeeper said:
A little history would help. Has the car not run in years? Been running every day?
1. The marks on your timing chain are set in stone (basically) & therefore, the timing mark on the harmonic balancer should be in stone too, but as mopar 3B mentioned, that harmonic balancer mark can move if the balancer goes bad.
2. The distributor rotor should point at #1 plug wire when piston #1 is on the firing stroke (basically). There should be no "air pushing out" since both valves will be closed (air pushing out would be the exhaust stroke). The crank notch should line up at top dead center too. And remember.....the TDC mark will line up TWICE for every time cylinder #1 fires ONCE.

a. make POSITIVE you have #1 piston at TDC on the FIRING stroke
b. line up the rotor to the #1 wire
This should make it start, or you have a bad timing chain, balancer or something like that (assuming fuel & spark are both good)
Click to expand...
Purple Beeper, don't know how disagree got on there?
As a matter of fact I agree with your post.
Sorry for misunderstanding
 
Johnpat said:
Purple Beeper, don't know how disagree got on there?
As a matter of fact I agree with your post.
Sorry for misunderstanding
Click to expand...
Heck JohnPat..... I don't care if anyone disagrees, maybe they're just catching a mistake I made, you know? We're all here to help.
 
Something simple to check, make sure your rotor is engaged in the distributor shaft correctly.

Has your timing cover or dampener ever been changed? How about the timing chain, has it been replaced recently ?
 
Might help a little...

Piston up to top twice, once for compression stroke, once for exhaust stroke. Depending on the cam, finger over plug hole can blow air on either one. Yeah, more on compression stroke, though not all can tell the difference.

IF this is a BB, distributor up front...pull all the plugs, pull the distributor, and look in the distributor hole. Turning the motor by hand, you can watch the tappets for #1. #1 piston up, compression stroke, both the tappets (and valves) will be closed. If it's on exhaust stroke, only one will be closed, the other slightly open. Easy to tell, by 'rocking' the crank a little, back and forth.
If on exhaust stroke the tappets will alternately open and close, not much, but easily seen.

But, you've got to get your timing mark squared away, first. The outer shell on the dampners can slip, moving the timing mark.
Timing mark should be 90 degrees from the key slot.
 
Miller has a good idea so you don't have to pull the valve covers. It's rare, but I have had one SFI harmonic balancer "slip" on a Ferd (trying not to use bad language on a Mopar site).
 
mopar 3 B said:
A loose dampner will throw timing mark off
Click to expand...
A word of caution...if the outer ring on the dampner has 'slipped', it's up to you whether you use it, or not. At least look it over, the best you can. There have been a few, that have come apart...not a good thing.
Main thing to look at is the condition of the rubber, in between the inner/outer pieces.
 
FWIW, If you hear a screech as you rev your engine and you've determined it's not the fan belt or WP, you might want to check that old stock balancer. A couple years ago my neighbor had a screech coming from the front of his car. He changed belts, tightened this, that, and the other thing. He started thinking WP and was going to change it soon. A week or so later the screech turned into a clunking racket as the outer ring came off the balancer. It was Lexus, maybe a '92 or 3.
 
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