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 Post subject: How to be at TDC?
PostPosted: Thu Sep 01, 2005 2:14 pm 
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TBI Slant 6

Joined: Wed Aug 17, 2005 9:20 am
Posts: 208
Location: Lyon, France
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Hello everybody, i'm back in slanted business, i'm about to put my distributor back on the engine but i just don't know how to set the engine at TDC...
On the top of the bottom pulley i have some kind of piece of metal that has a hole and one or two marks. On my pulley i think i saw two marks.
What should i align with what? Could anyone put a picture so i see really what i should do.
Thanks a lot for your help!

Marc

P.S : Dan i know you're gonna answer first! :wink:


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 Post subject:
PostPosted: Thu Sep 01, 2005 2:57 pm 
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Remove the frontmost spark plug. Get a long straight wire (like the bottom straight section of a wire coat hanger). Make sure the wire is longer than 8", and place it into the spark plug hole. Jiggle it around so you are sure it is touching the top of the piston. Rotate the engine by hand (using the fan and belt) or by bumping the starter motor. You will see the wire follow the piston down and up. When the wire reaches the top of its travel, the piston has also reached the top of its travel. There are two TDCs for each cylinder -- find the one that has the transverse notch in the crankshaft pulley is right at (or at least near) the "0" mark on your timing tab (that "piece of metal with a hole and one or two marks" you found).

That said, the only reason you should have to worry about finding TDC before you put the distributor in, is if you rotated the engine while the distributor was out. If you didn't do that, then just put the distributor back in the engine so that the rotor is pointing the same way it was before you took out the distributor.

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 Post subject:
PostPosted: Thu Sep 01, 2005 3:11 pm 
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What was i saying about you answering? :lol:
Thanks one more time Dan!
Quote:
That said, the only reason you should have to worry about finding TDC before you put the distributor in, is if you rotated the engine while the distributor was out. If you didn't do that, then just put the distributor back in the engine so that the rotor is pointing the same way it was before you took out the distributor.
Well i actually did rotate the engine and not just a bit! I also have to say the distributor wasn't bolted on when i got the car...
By the way, is that normal that my distributor bottom plate (well i don't know the name, the plate you screw the bolt through, the same thing you loosen to set the timing) is slanted to the top?

One more thing, does the engine have to be very very precisely at TDC? How precise should i go? Also, I don't really see how to put the rotor on the N°1 ignition position very precisely... Actually my distributor cap doesn't really make contact through the rotor (judging by the ohmmeter) but the high voltage makes it through this little gap, i tried... I'm wondering if that lack of contact is normal.

Lots of questions not really organized, sorry!

Marc


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 Post subject:
PostPosted: Thu Sep 01, 2005 3:46 pm 
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Quote:
What was i saying about you answering?
I would hate to disappoint.
Quote:
Well i actually did rotate the engine and not just a bit! I also have to say the distributor wasn't bolted on when i got the car
Oh! OK, that makes sense, then.
Quote:
By the way, is that normal that my distributor bottom plate is slanted to the top?
More information please. What do you mean slanted to the top? Can you show us a picture?
Quote:
One more thing, does the engine have to be very very precisely at TDC?
Not really, because you can do the fine adjusting later, using the slotted hole in the distributor hold-down plate. The closer you can get, the easier it will be for you, though.
Quote:
I don't really see how to put the rotor on the N°1 ignition position very precisely
Put the rotor to 4:00 position with the #1 cylinder at TDC and the distributor fully seated in the block, and that should get you close enough. Make sure you're on the correct TDC point, or the engine won't even try to start.
Quote:
Actually my distributor cap doesn't really make contact through the rotor (judging by the ohmmeter) but the high voltage makes it through this little gap, i tried... I'm wondering if that lack of contact is normal.
Yes.

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 Post subject:
PostPosted: Fri Sep 02, 2005 10:47 am 
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TBI Slant 6

Joined: Wed Aug 17, 2005 9:20 am
Posts: 208
Location: Lyon, France
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Quote:
More information please. What do you mean slanted to the top? Can you show us a picture?
Well, i've got one but i don't know how to put it since it isn't online...
Quote:
Put the rotor to 4:00 position with the #1 cylinder at TDC and the distributor fully seated in the block
So that means about 2:30 - 3:00 before putting it (since it turns)?


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 Post subject: Maybe 2 o'clock
PostPosted: Fri Sep 02, 2005 3:51 pm 
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Quote:
So that means about 2:30 - 3:00 before putting it (since it turns)?
Yep, 2:30 sounds about right to start.

Once you are close enough to get it started, you may have to pull it out and reinstall it 1 tooth in either direction to get the range of adjustment that you require. Sounds like a pain, but once you are familiar with the process, it's no big deal. :wink:

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 Post subject:
PostPosted: Sat Sep 03, 2005 12:53 am 
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Location: Lyon, France
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Ok, thanks. I'll try to start with 2:30.
Once i have my engine at TDC, what should i do to set my ignition timing?
I mean, once the distributor is seated in the block, i have to rotate it counter clockwise (or am i wrong?) until what? The contacts open? On my repair manual they talk about 5°BTDC but i don't have anything to set that!... :?:


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 Post subject:
PostPosted: Sat Sep 03, 2005 11:19 am 
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Joined: Wed Aug 17, 2005 9:20 am
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Location: Lyon, France
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:?: :?: :?: :?:
Am I going crazy or what? My intake valve opens when the piston goes up and the exhaust valve when the piston goes down!!! I assume valves are in front of the exhaust and intake manifolds (know what i mean?)
And the exhaust valve opens just after the intake has opened!!
!!!! I don't understand anything!!!


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 Post subject:
PostPosted: Sat Sep 03, 2005 12:06 pm 
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When a cylinder is at tdc compression which is what you need to set 0deg timing, (vs tdc exhaust) both intake and exhaust valves will be closed. Take off the valve cover ( or the oil fill cap if you have one) and you should be able to wiggle both rocker arms back and forth on #1 if your at tdc compression.

If you can't, two possibilities - either the valve adjustment is too tight, or, your at tdc exhaust (180 deg. out) and the exhaust valve is open.

To set 0 degrees advance, yes, the points should just be closed while the rotor is pointing at #1. (Assemble everything, cap/rotor/wires, and get the distributor as close as possible to 0deg tdc. and put the key in the run position. then turn the distributor either way until you hear the loud crack of the spark firing, your at 0deg now). From there, you will need a timing light, preferably the dial back kind, to get a more precise setting.

Play around the timing, 5 degrees is fine to start.


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 Post subject:
PostPosted: Sat Sep 03, 2005 1:32 pm 
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Quote:
:?: :?: :?: :?:
Am I going crazy or what? My intake valve opens when the piston goes up and the exhaust valve when the piston goes down!!!
You are probably turning the engine the wrong direction. WHen it is running, the engine rotates *clockwise* as you look at it from the front of the car.

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 Post subject:
PostPosted: Sat Sep 03, 2005 1:52 pm 
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TBI Slant 6

Joined: Wed Aug 17, 2005 9:20 am
Posts: 208
Location: Lyon, France
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Actually, by seeing the exahust valve open just after the intake one, that's what i thought! I am sure now (i was rotating it anti clockwise).
The problem is : i turned it by the fan but when i try to turn it in the right way, the belt slips under the torque needed... I also don't see any bolt on my pulley at the bottom (harmonic balancer?) i only see three bolts that are keeping the pulley together but they're not on the crankshaft, anyway you slanted people know what i mean! So what should i use to turn it?


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 Post subject:
PostPosted: Sat Sep 03, 2005 2:10 pm 
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Put tension on the fan belt with one hand then work the fan with the other.

All cranks come threaded for a 3/4" fine thread bolt but not all slants got them. You can go to a hardware store and get a 2" long fine thread bolt or grab one off a small block next time your at a junkyard. You may need a washer underneath it - can't rmemeber if I put one behind mine or not.

Also - disconnect the coil and you can crank the motor over with the starter little by little so you don't have to butcher your hands on the fan. Then you can make fine movments with the fan.


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 Post subject:
PostPosted: Sun Sep 04, 2005 11:05 am 
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Joined: Wed Jun 29, 2005 7:34 am
Posts: 222
Location: Boulder Colorado
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i needed to turn my engine to get her back to the first cylinder after i had done some work on the distributor. everyone kept telling me, yeah just use the bolt on the pulley. all i found was a hole in the center of it. but there are also 6 holes around the edge so i made my own tool to turn the engine. i got some black pipe, 1/2' in diameter. run a 90 to a 2 1/2" nipple to a tee to a 12" section of pipe. put close nipples in the 90 and the tee. the close nipples fit in the holes around the perimeter of the pulley and the 12" pipe is your lever. i didn't need any extra leverage but if you do just grab a longer section of 1" pipe. its custom man, and very cheap.

i found when i bumped the starter the pulley only stopped at 1 5 and 9 on the clock.

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