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post #1 of 97 Old 05-19-2021, 06:22 AM Thread Starter
Anotherusername
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Explain this

Working on a 258 inline six engine. It quit running and I go to check it out and find the rotor on the distributor is 180 degrees off. OK so I put the blame on the timing chain even though it's only got about 50,000 miles on it. I get into it and while the chain had an inch of slack in it the dots on the gears still line up. I then change the timing chain and gears, re-install the distributor and put it all back together and everything seems to be back where it belongs except it won't start. Worked on it a couple hours yesterday until I was worried I was over tasking the starter so I quit. This morning I go to work on it and convinced the problem is with the points, cap or rotor so I rotate the engine to TDC to set the points and when I take the cap off I find the rotor is 180 degrees off again. I then rearrange the plug wires to match and it runs. When I had the distributor out I checked it out to make sure it was in good condition as well as the gear on the cam shaft. I don't understand how it keeps jumping 180 degrees.

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post #2 of 97 Old 05-19-2021, 06:37 AM
ranger83
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Are you at TDC on COMPRESSION STROKE? sheared roll pin on cam gear? damaged cam gear?

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post #3 of 97 Old 05-19-2021, 06:38 AM
OrangeCJ-5
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I don’t see how the chain, especially the new one, could jump that many teeth when cranking. My swag is that you are not on the compression stroke.
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post #4 of 97 Old 05-19-2021, 07:22 AM Thread Starter
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Originally Posted by ranger83 View Post
Are you at TDC on COMPRESSION STROKE? sheared roll pin on cam gear? damaged cam gear?
Yes it is a TDC. I pulled the #1 plug to verify that it was. I wondered about the cam gear too but I put a wooden dowel in the hole for the distributor and and couldn't rotate it taping it with a hammer. Without tearing into the engine I don't know how I could really check it. I know there is no broken teeth on the gear. I rotated the engine over several times and inspected it.
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post #5 of 97 Old 05-19-2021, 07:27 AM Thread Starter
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Quote:
Originally Posted by OrangeCJ-5 View Post
I don’t see how the chain, especially the new one, could jump that many teeth when cranking. My swag is that you are not on the compression stroke.
It was questionable whether the old chain had jumped time. I had written that off when I got in there and saw the gears were still in alignment. I think the chain was right on the verge of jumping time and certainly needed changing but I don't think was the cause of my problem. The #1 cylinder was on compression stroke when I manually set the timing.
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post #6 of 97 Old 05-19-2021, 07:47 AM
Axhammer
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Was it on the compression stroke when you initially found it to be 180 out, when it first quit running?
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post #7 of 97 Old 05-19-2021, 07:48 AM
pedal2themetai
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Hi
You may be fighting the Point that TDC comes up twice per cycle of the motor..
TDC on the crank and the piston being to the top Comes up twice once on the compression stroke and once on the exhaust stroke... To set the timing you need to have it on the compression stroke..

The motor is 4 Stroke
1) TDC = compression
2) = power (piston going down after firing)
3) = exhaust (piston going up again and would be at TDC again when it reaches the top of the exhaust stroke)
4) = intake stroke (piston going down intaking fuel/air)
then it starts all over again..

It is easy to confuse the two as the piston would be at the top of both the TDC of compression and exhaust..
Hold you finger over the #1 spark plug hole and rotate the motor by HAND when you feel air coming out you are on the start of the compression stroke finish rotating the motor untill the TDC mark comes up.. That would be the TDC you need for timing ...

good luck
tim
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post #8 of 97 Old 05-19-2021, 08:34 AM
katwalk27
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Was it running and driving fine before it just quit? If so, I cant see how it was 180 degrees out. Is it possible it was correct and there was another issue going on and when you put the new chain and gear on.
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post #9 of 97 Old 05-19-2021, 08:55 AM
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You mention setting the points, so I am going to assume that this is an early distributor with the metal clips to hold the cap down. What kind of shape is the alignment tab on the bottom of the cap in? Sounds like tab is missing and somehow the cap is getting put back on 180 out after it has been taken off to make an adjustment.

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post #10 of 97 Old 05-19-2021, 01:02 PM Thread Starter
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It's a 1975 CJ5. The distributor cap is screwed down on this one. It had been running before it quit. I put a factory remanufactured engine in it in 1998 and have driven it 530000 miles. Right now I'm thinking they probably put the junkiest parts in the engine they could. I determined the original timing chain was an Engine Tech brand.

All of the pistons are in working order and getting 130lbs compression on each so I know the valves are working. I did check to see that the piston was on the compression stroke when I set the timing and after starting it adjusted the timing with a timing light and it ran real good. Then I drove it a quarter mile from my house and didn't make it all the way back. The timing had reversed again 180 degrees. It was difficult to get running but with a timing light the indicator line on the harmonic balancer was on the opposite side of where it was before and the rotor was pointed away from the #1 plug wire.

Right now I'm leaning toward the gear on the camshaft slipping. I would just like to make sure it's not something else before I pull the engine.
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post #11 of 97 Old 05-19-2021, 01:06 PM
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As said before, I find it very unlikely that the timing chain slipped exactly 180 degrees. Does the gear on the distributor have the roll pin in it? Can you grab the rotor and rotate it by hand?

Another thought...
Do you have a neighbor who is a competent mechanic and for some reason does not like you? Maybe someone is messing with you.
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post #12 of 97 Old 05-19-2021, 01:16 PM
devildog80
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It does sound like the distributor gear.
Had a Ford 300 I6 years back in an 84 F150, and scootin' down the Interstate 70 mph it just died. Rolled down the off ramp and found the dist gear roll pin had sheared off. Did a 3 hr roadside repair with an old allen wrench, side cutter, and a file to get back rolling again. As the allen wrench was much stronger than the roll pin, never touched it again.
Double check as the gear can't jump, unless it is not attached, with that roll pin.
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post #13 of 97 Old 05-19-2021, 02:56 PM
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Someone playing jokes on you?

Just for giggles, pull your cap

This is a hard call

WITHOUT BREAKING YOUR ROTOR BUTTON

See if you can forcibly turn the button to another position (and it stay there)--a little cw-ccw slop is normal. Many times it is really hard to make the (now loose) gear spin in the shaft.

We're looking to see if the roll pin in the distributor gear is sheared

Note--if you pull it out and look, the pin may look normal, seen in the hole on either end, the middle part (where it goes through the shaft) is where it's actually sheared---you have 3 pieces now, one you cannot see!

If you pull it, it may require a couple of pairs of pliers to turn the gear on the shaft. Don't go as far as SHEARING IT YOURSELF!

Normally, in any case do you not see a FULL 180 turn, maybe 10/ 30/ 90 degrees---something "Random"

If you need to know a super way to get back to "TDC" EZ and accurately let me know. The only way that will work is if you installed the timing set correctly.

Let me know,

----JEEPFELLER
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post #14 of 97 Old 05-19-2021, 03:02 PM
pedal2themetai
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HI just to let you know ... the crank turns twice to one turn of the distributor.. so it takes two turns of the crank to bring the distributor back to #1. Just an FYI..

the distributor well not point to #1 every time the crank is a TDC only every other time..
good luck
tim
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post #15 of 97 Old 05-19-2021, 04:49 PM Thread Starter
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Quote:
Originally Posted by StoneTower View Post
As said before, I find it very unlikely that the timing chain slipped exactly 180 degrees. Does the gear on the distributor have the roll pin in it? Can you grab the rotor and rotate it by hand?

Another thought...
Do you have a neighbor who is a competent mechanic and for some reason does not like you? Maybe someone is messing with you.
The timing chain certainly didn't slip after putting a new one on. The gear on the distributor just has a spiral gear. I haven't been able to rotate the rotor when installed. I checked to see how tight the gear was when I had the distributor off and just holding the spiral gear in one hand I couldn't turn the rotor with the other hand. I didn't try that today though. It's not much trouble to remove the distributor, I will have to give it another try. I certainly would rather find a problem with the distributor rather than the cam shaft. It's something I've never heard of before a gear coming loose on a cam shaft.

There wouldn't be a problem with a neighbor, I live in the country and my nearest neighbor is about 150 yards away. Anyway the Jeep is kept inside of a locked building at night.

Last edited by Anotherusername; 05-19-2021 at 04:55 PM. Reason: add more info
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