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Unread 08-06-2013, 02:05 AM   #1
jayzcj5
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258 timing chain help

Guys,
I have read jeephammer's thread on the timing chain install and did exactly what he said. I found top dead center of #1 cylinder. Took off the timing chain and rotated the camshaft until the intake valve closed. Then rotated the camshaft an additional 90 degrees to set the cam at the correct point of the compression stroke. My question is; the position of the camshaft is the exact opposite of what my books are showing me. It looks like if I were to rotate the cam 180 degrees then I would have my marks lined up like the book shows? Are these marks wrong or am I wrong?

The whole reason I tore back into this thing is because I put a Howell kit on and can't get it started to save my life. I have fuel and spark but can't get this thing timed enough to fire? I replaced this chain months ago and I thought I put it in wrong but after doing everything I read in jeephammer's thread I didn't change anything...it's in the same position as when I started? I'm a loss as to why this thing won't fire and start? I need help or re-assurance as to what I'm doing, what do u guys think?

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Unread 08-06-2013, 02:07 AM   #2
jayzcj5
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I couldn't send the pics in the last post for some reason, here is what I got?
image-736457021.jpg

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Unread 08-06-2013, 09:35 AM   #3
jayzcj5
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No one has any input, someone has to help a stranded jeep member.
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Unread 08-06-2013, 10:04 AM   #4
MoC
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Did it run with the new chain before u installed the Howell?

Aren't both of the gears keyed so the only install one direction?

The Haynes instructions are pretty simple, but if the dots don't line up its wrong. The instructions also tell you how to count the teeth to make sure its lined up properly.
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Unread 08-06-2013, 10:08 AM   #5
Matt1981CJ7
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Why did you rotate the cam 90 degrees after finding TDC of the compression stroke?

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Unread 08-06-2013, 10:11 AM   #6
MoC
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It's been a while buy the crank gear is keyed for sure.
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Unread 08-06-2013, 10:19 AM   #7
jayzcj5
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Quote:
Originally Posted by MoC
Did it run with the new chain before u installed the Howell?

Aren't both of the gears keyed so the only install one direction?

The Haynes instructions are pretty simple, but if the dots don't line up its wrong. The instructions also tell you how to count the teeth to make sure its lined up properly.
No the engine hasn't ran since...well a long time ago. The the crank is keyed and the cam gear has a dowel rod sticking out so essentially yes they do. I just talked with my engine builder and he said that they tell you the cam gear could be on either way.
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Unread 08-06-2013, 10:22 AM   #8
jayzcj5
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Quote:
Originally Posted by Matt1981CJ7
Why did you rotate the cam 90 degrees after finding TDC of the compression stroke?

Matt
Keep in mind the timing chain was off at that point. Found top dead center of the #1 cylinder, then rotated the cam until the intake valve closed, and then you have to go 90 degrees past the so you are at perfect top dead center with the valve timing.
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Unread 08-06-2013, 10:33 AM   #9
MoC
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Sounds like if jeep hammer and the builder were correct it would be running now...

Ditch what the engine builder and jeep hammer say and install it per the factory installation instructions. Done.
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Unread 08-06-2013, 10:40 AM   #10
Matt1981CJ7
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The intake and exhaust valves should both be fully closed at TDC of the compression stroke.

I've never heard of rotating 90 degrees past that point.

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Unread 08-06-2013, 10:55 AM   #11
jayzcj5
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Quote:
Originally Posted by Matt1981CJ7
The intake and exhaust valves should both be fully closed at TDC of the compression stroke.

I've never heard of rotating 90 degrees past that point.

Matt
They are fully closed right now set up this way. Once the intake valve closes the reason you go another 90 degrees is because then the cam is in the right position to open the exhaust valve when the piston reaches the bottom of the cylinder. For every one revolution of the crank the cam turns 180 degrees. I have read up all last night and this seems to be all true. I was just Hoping someone else has been through this before?
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Unread 08-06-2013, 11:09 AM   #12
MoC
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Quote:
Originally Posted by jayzcj5

They are fully closed right now set up this way. Once the intake valve closes the reason you go another 90 degrees is because then the cam is in the right position to open the exhaust valve when the piston reaches the bottom of the cylinder. For every one revolution of the crank the cam turns 180 degrees. I have read up all last night and this seems to be all true. I was just Hoping someone else has been through this before?
Then why does the FSM, Haynes book, installation instructions from the company that makes the chain say to install it differently?

I would think it you installed it per then instructions and its till didn't run the problem lies elsewhere.
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Unread 08-06-2013, 11:16 AM   #13
Cj5Bob1952
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Matt and Moc are correct
I just looked this up in Haynes manual and Motors manual. They suggest a you use a straight edge from center to center of cam shaft and crankshaft. Lineup the dot on crank gear with dot cam gear directly across from each other along that line. Easiest way.
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Unread 08-06-2013, 11:27 AM   #14
lucdog
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I wouldn't crank the engine over until you have the timing correct.This is a good way to bend a valve if one makes contact with a piston.

And what MoC said about the dots, and Matt about the 90*.

The easier way to do this would have been to put the new parts on, so they matched up to the old ones.
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Unread 08-06-2013, 11:38 AM   #15
jayzcj5
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Yes I have been looking at the books too and I think we are both right. If I rotate the engine one full crank revolution the marks line up perfectly. I think it's just a matter of setting your TDC and making sure you got that part right.
image-3104187504.jpg

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