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Discussion Starter #1
or probably the cam even

hi guys,

Im about to install my distributor so I decide to take no1 to TDC so I can install it correctly. I use the big puff of air/ small puff of air to verify which is the correct stroke.

my understanding is there should be a puff of air when it reaches tdc on both strokes right? well the puff(S) of air where starting around 90 degree btdc and by the time I got to top dead center on the balancer, no puff. by now Im afraid maybe my timing chain has jumped because when I was putting the engine together I verified and reverified TDC with the heads off and a dial indicator.

so I pulled off the valve cover because I read that tdc should be when the intake starts to open. well................. my intake starts to move around 10degrees before TDC

so I dont think this is normal. first air puffs 90 before tdc, then intake starting to open 10 degrees before tdc. something doesnt smell right

could my timing chain have jumped? even though its a brand new, non walmart brand (big al) double roller, or could my cam be off.

need ideas PLEASE.
 

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I don't understand the 2 puffs of air your reffering to. How I have always done it is remove # 1 plug, put finger over hole and bump engine over till I feel air hiss out. Then I look down at the timing marks and using a breaker bar slowly rotate engine on around till the line on balancer lines up with the "0" on timing tab. Also to double check your at TDC with the valve cover off. Look at both valves, they should both be closed all the way, when balancer marks are lined up. A 4 stroke engine does not have 2 compression strokes, just 1.
 

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so I dont think this is normal. first air puffs 90 before tdc, then intake starting to open 10 degrees before tdc. something doesnt smell right THIS IS THE EXT STROKE

could my timing chain have jumped? even though its a brand new, non walmart brand (big al) double roller, or could my cam be off. MAYBE, DID YOU LINE UP THE DOTS?

need ideas PLEASE.

Put the dist in on TDC, if it cranks it's correct.

if not, rotate the dist 180° and reinstall!
 

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so both valves should be closed at tdc?
Yes............you can also put a straw or something into the spark plug hole to see if the piston is at the top.Most might disagree but I've done this before without any problems....You'll be able to tell if the cyl's at tdc....Then see if your balancer is at, or before tdc.on your timing tab...Then look at your rotor to see if it's pointing at number one cyl....If not...then your timing may have jumped...If it did...You'll have some work to do....
 

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The straw idea works.:d but if you get your motor to tdc and you timing marks are off the i would either look into you balancer or timing tab. The balancer could have spun giving you a false reading and if you have the wrong timing tab for your specific balancer it also would be off. Bring the piston to tdc with a (straw) or something to gauge it by in the cyl. Then check to see if both valves are closed, if they are then your cam timing is fine and i would look into the other options. Good luck
 

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Discussion Starter #7
Yes............you can also put a straw or something into the spark plug hole to see if the piston is at the top.Most might disagree but I've done this before without any problems....You'll be able to tell if the cyl's at tdc....Then see if your balancer is at, or before tdc.on your timing tab...Then look at your rotor to see if it's pointing at number one cyl....If not...then your timing may have jumped...If it did...You'll have some work to do....
ok, then its definitely 180 out right now like big al said. Im gonna redo it tomorrow and put a wire or something in there to be doubly sure. I'll be mad if my timing has jumped because it really is a whole lot of work I dont feel like doing right now.

also,
I couldnt get the rotor pointing exactly to number 1. is this close enough? or does it have to exactly point to the number 1 cylinder

 

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And make sure you're on TDC in the compression stroke. TDC with the intake valve starting to open is TDC between teh exhaust and intake stroke, not compression. The compression stroke is when both valves are closed and the piston is at TDC.
 

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Discussion Starter #9
thanks guys. Im going at it again tomorrow at 8 am . will update.

on the rotor issue in the pic above, does it have to be exactly pointing at number 1 or is it fine where its pointing right now.
 

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As long as you have enough room to move the distributor to adjust it doesn't matter where it is pointed. I would move it back a tooth. It looks like your vacuum advance can might hit the firewall where it is at.
 

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I always just watch the valves open and close and use the timing marks on the balancer. To me it's easier than the air in and air out thing. It always seems to me the engine rolls over faster than I get it stopped. Then the engine is past TDC and it needs to stop before TDC to get the initial advance close.
 

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"point the distributor towards #1 cylinder" is a phrase which is a bit misleading. It actually means to point the rotor to the cap terminal wich is WIRED to #1.

Or in other words, drop in the distributor, swing it around until you have optimal adjustment ( vacuum dapshot clearance ) and put the cap on. See which terminal the rotor points to, and make that one #1.
 

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Discussion Starter #13
"point the distributor towards #1 cylinder" is a phrase which is a bit misleading. It actually means to point the rotor to the cap terminal wich is WIRED to #1.

Or in other words, drop in the distributor, swing it around until you have optimal adjustment ( vacuum dapshot clearance ) and put the cap on. See which terminal the rotor points to, and make that one #1.
I dont have a vacuum advance. its locked out., so if its pointed where its at right now, just put the cap on and whichever terminal its pointed at is number 1?

how does this take into consideration the advance when you turn the distributor. I mean, the rotor stays in the same place, but the terminal can move.
 

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Discussion Starter #14
As long as you have enough room to move the distributor to adjust it doesn't matter where it is pointed. I would move it back a tooth. It looks like your vacuum advance can might hit the firewall where it is at.
Ive tried that, but back one tooth is pointing squarely at the number 2 cylinder. what am I missing?
 

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Ive tried that, but back one tooth is pointing squarely at the number 2 cylinder. what am I missing?
Then thats where you place the #1 plug wire and go around the cap with the firing order.



Al
 

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It doesn't have to be pointed at any particular cylinder. It is just easier to route wire and have vacuum can clearance it the rotor is pointed at the #1 cylinder. It doesn't look like you will have a problem. Put your cap on and start you firing order from where the rotor is pointing.
 

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how does this take into consideration the advance when you turn the distributor. I mean, the rotor stays in the same place, but the terminal can move.
When you turn the distributor you are turning the body. The rotor is connected to the shaft which is connected to the camshaft and can't be adjusted. When you turn the body of the distributor it will put the cap terminal in a different position in the timing of the engine making the spark plug fire at a diffent time in the stroke.
 

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When you turn the distributor you are turning the body. The rotor is connected to the shaft which is connected to the camshaft and can't be adjusted. When you turn the body of the distributor it will put the cap terminal in a different position in the timing of the engine making the spark plug fire at a diffent time in the stroke.
This statement is correct....Also...don't think of the rotor poing to the valve cover. think of the rotor pointing to the top of the piston itself...In your picture...The rotor looks to be pointing straight to the cam gear...If it was 180 off...it would be pointing at the firewall passenger side.....I doubt very much timing would jump 180 degrees...If it did you would have definatly known it at the time it happened..Without seeing the balancer and timing tab along with the rotor....It's hard to say....Take pics of the balancer and tab tomorrow too.......That will help..
 

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Ive tried that, but back one tooth is pointing squarely at the number 2 cylinder. what am I missing?
It can be a touchy situation droping the dist.. sense the gears are angled...You have to drop the dist. with the rotor point at the number 5-7 cyl....so when it drops completely down the rotor will turn to the number 1 cyl....
 

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The way I'm reading some of these posts is people are thinking the rotor has to point to a place on the engine or firewall or somewhere in space. Wrong!

The rotor just has to align with the #1 terminal on the distributor cap.

It's also better to move the damper back to 10 degrees BTDC after you find the compression stroke.
Why? because that's when the plug fires so that's when the rotor and cap terminal must align to transfer the spark energy.

Yes, the rotor will rotate while you drop it in because it has a helical drive gear. You just compensate for the amount of rotation. You may also need to align the pump shaft so the distributor drops down.
 
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