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12 replies to this topic

#1 Scoobywagon

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Posted 25 August 2005 - 04:32 PM

Well, I went looking and couldn't find something definitive that says "This is how you find TDC on an EA81". So, barring that, I figure i'll set the crank to 0 as indicated by the timing marks on the flywheel. Then, I'll install the disty with the rotor pointed at #1. Then I'll try it. If it fires, great, if not, then one complete revolution at the crank pulley should do it, right?

Any thoughts?

#2 NorthWet

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Posted 25 August 2005 - 04:37 PM

Well, if you want to disturb the oil sealing on your valve cover, it is easy. Pull off the valve cover on the 1-3 side, crank the engine over to the "0" mark, and see if the rockers on the 1-3 cylinder are loose or depressing the valves. If they are loose, then you have TDC on the compression stroke for cylinder#1.

#3 Scoobywagon

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Posted 25 August 2005 - 04:41 PM

Yeah...um...about that. See, I was trying to do this without opening the engine at all...so there! Concordantly! Ergo! Vis a Vis!

Sorry...was just watching the Matrix Reloaded special features DVD...funny stuff. good times!

#4 ShawnW

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Posted 25 August 2005 - 04:42 PM

Compression tester into #1. Turn engine by hand until compression rises and then watch the flywheel for the 0 mark.

#5 NorthWet

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Posted 25 August 2005 - 05:07 PM

Compression tester into #1. Turn engine by hand until compression rises and then watch the flywheel for the 0 mark.

You can also use a digital compression tester, if you didn't want to take your fancy HF system out of its case. :-p You can use your finger, or a loved-ones finger, on the spark plug hole and turn the engine until you feel the pressure.

I guess you will go with ShawnW's excellent suggestion, though, eh?

#6 Scoobywagon

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Posted 25 August 2005 - 09:08 PM

Ya know....there's a digital expression just for people like you.....

:lol:

#7 NorthWet

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Posted 26 August 2005 - 12:03 PM

Ya know....there's a digital expression just for people like you.....

:lol:

I know it. I am very "up" on digital communication. :-p

#8 iamtheq

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Posted 26 August 2005 - 12:39 PM

Along the lines of the "digital" compression tester, take the spark plug out, crank to '0' and stick a screwdriver in the spark plug hole. If you feel the piston at the top, you've found TDC. If the screwdriver goes way in, either you're 180 out or you've got a hole in your number 1 piston.

#9 Scoobywagon

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Posted 26 August 2005 - 12:39 PM

I know it. I am very "up" on digital communication. :-p

Yes, but what about the "extended" set?

#10 NorthWet

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Posted 26 August 2005 - 01:04 PM

Along the lines of the "digital" compression tester, take the spark plug out, crank to '0' and stick a screwdriver in the spark plug hole. If you feel the piston at the top, you've found TDC. If the screwdriver goes way in, either you're 180 out or you've got a hole in your number 1 piston.

Well, first off, sticking a screwdriver into an engine is similar to sticking something sharper than an elbow into your ear: It is a really BAD idea.

Second, it is pointless, as he knows where TDC is; he just needs to determine which is compression-stroke.

And if you have a hole in your number-1 piston, it might be because somebody used a sharp, hard, foreign object to check for TDC. ;)

And scooby, I got your "extended" set right here! :lol:

#11 Caboobaroo

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Posted 27 August 2005 - 01:37 PM

I found the easiest way to find TDC without any special tools like a compression tester and blah blah blah. First off, pull the #1 sparkplug out and then thread it back in just a couple threads, just enough to let the pressure exscape from the chamber. Then put a ratchet with the correct size socket on it to turn the crank. Slowly listen for the hissing of the air rushing past the loose sparkplug and watch for the timing marks. If the hissing stops and you see no timing marks, keep turning and they might pop up. If they don't, keep turning until it starts hissing again and when it stops, the timing marks should appear. Then static time it by putting it on 8 deg. BTDC.

#12 washakie

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Posted 18 November 2006 - 08:13 PM

Well, if you want to disturb the oil sealing on your valve cover, it is easy. Pull off the valve cover on the 1-3 side, crank the engine over to the "0" mark, and see if the rockers on the 1-3 cylinder are loose or depressing the valves. If they are loose, then you have TDC on the compression stroke for cylinder#1.


Wanted to revive this thread...

So, if the springs are loose, then I'm at the top of the compression stroke for #1, however, shouldn't the rotor then be pointing to the #1 wire?? Mine is pointing to #2. Do you think I've been running around with it 180 degrees out! Man, this thing is going to be HAPPY when I'm done if that's the case


..oh wait, just thought this through a little further... at TDC #1 should be taking IN fuel/air, so it's not until the second stroke that the spark should fire, eh? Okay..

So, here's the question, if I get this orientation way off, will I be able to adjust it later when doing the timing?

#13 NorthWet

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Posted 18 November 2006 - 08:57 PM

Wanted to revive this thread...

So, if the springs are loose, then I'm at the top of the compression stroke for #1, however, shouldn't the rotor then be pointing to the #1 wire?? ...
...oh wait, just thought this through a little further... at TDC #1 should be taking IN fuel/air...
...So, here's the question, if I get this orientation way off, will I be able to adjust it later when doing the timing?

If the engine is at TDC, and if the cyl#1's valves are fully closed (rockers/followers are a little loose), then you are at TDC between the compression and power strokes for cylinder#1. The rotor should be pointing towards cyl#1's wire. Engine should not run with ignition 180 degrees out. Adjustment range is not great enough to compensate for being that far off. You would need to remove the distributor and insert it correctly... or swap the plug wires to match.




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