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Another timing chain question

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Old 07-10-2015, 07:54 PM   #1
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Another timing chain question

OK so I posted this is my build thread but that's about as active as a statue. Besides probably being in the wrong section for tech help. So here goes

OK so I found that the drivers side timing chain guide decided to break after 230k+ miles. Not bad for plastic :-) . So although I am close to doing my new motor I am not quite ready to get the block and crank work yet. So I pulled the oil pan and timing cover off to replace the chain set with a less than 5 miles use one I had.

I set it to tdc on compression and then started pulling it apart. AC, PS, oil & water pump, finally cover. Some how surfing the dissassembly the crank and cam got moved ever so slightly together before the chain was off. So slightly that I didn't notice until it was almost all back together.

After I put the oil pump back on I realized it was about a crank pully notch to the right of zero on the pump. I rolled it back to zero counterclockwise a smidge and noticed that the drivers side chain is not taught there I a little slack in it. Not a lot but more than none at all. So my question is do I need to do it again? Or can I roll it through a full compression and exhaust cycle slowly and listen for valve and piston contact with the plugs pulled?

What are your thoughts?
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Old 07-10-2015, 08:34 PM   #2
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You should not be able to hurt anything if you turn it over slowly with a breaker bar.

I don't think a tooth off would be enough to cause interference, in any case.

Turn it clockwise, the direction it runs, you'll have to turn the crank two revs to bring the cam back around.

If the cam and crank positions are good, you've got it made.
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Old 07-11-2015, 07:44 AM   #3
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Awesome thanks
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Old 07-11-2015, 09:43 AM   #4
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Rotating the engine two full revolutions by hand is always a good practice after changing a timing belt or chain. If all the marks, crank & cam gears line up you are good. If you are 1 tooth off, you need to fix it. The car will run and likely not crunch the valves but it will not run properly.
Also a couple of things that help. 1st be sure to leave the slack / loose side closest to the tensioner. This way when you release the tensioner the slack is taken up and it doesn't jump a tooth. 2nd start with the chain like half a tooth off on the cam and use a wrench to rotate the cam gear ever so slightly (clockwise) back to TDC this chain should fall into place and your marks should be perfect. Another trick I found before you start is to heat the cam , crank and chain in the oven at 200 F for about twenty minutes before you start the job. Just don't use your wife's favorite cookie sheet. This helps stretch the chain and things slip on a little easier. Good luck
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Old 07-11-2015, 05:41 PM   #5
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OK so I just went out turned it over by hand. All is silent. So that's good. It took 8 full rotations of the crank to get a bright link back up top on the dot. It was the opposite link each time. Is that normal?
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Old 07-12-2015, 05:41 AM   #6
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The crank to cam ratio is 2:1. The crank spins two full revolutions for every cam revolution. Note the small gear is on the crank and the large gear is on the cam.
So the fact that you had two rotate it a couple of times to get the link back is not a surprise. As long as the timing marks align when the crank is set to TDC on the no 1 cylinder u are all set. Check everything twice, reassemble, add some coolant, fire it up, burp the radiator and call it a job well done.
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Old 07-12-2015, 07:09 AM   #7
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Awesome. I will check to make sure it looks good at TDC on compression. Then clean the bottom of the block reinstall the oil pan. Finish the cooking system and fluids. And fire her up. Thanks all for the help.
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Old 07-17-2015, 03:21 PM   #8
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Ok so got her all buttoned up and she ran great! Then today I notice that I don't have the same oil pressure as when I first got it back together. I also notice I am down a quart. After she is cooled down tonight I am going to see if for some reason that one bolt in the oil pump you rtv some how didn't get a good seal and is leaking oil in to the coolant. That's the only thing I can think of. The engine looks dry to me. Any ideas would be great. Thanks all
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Old 07-18-2015, 12:40 PM   #9
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Low oil pressure does not sound good. It's normal for the pressure to drop a little after the car warms up but it should not be that significant. I would look for any external leaks around the oil pump and timing cover. Also check the coolant for the presence of oil and the oil for coolant.
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Old 07-20-2015, 07:40 PM   #10
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OK so I have been waiting for the problem to manifest and today when I checked my oil and coolent before going to the store it was good and clean. Checked the oil cap when I got home and milkshake. I know this could be a head gasket I will run a compression test tomorrow. But my question is could it be a bad RTV seal on the bolt that gets RTV on the oil pump. If compression checks out there that's what I'm going to check next
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Old 07-30-2015, 11:59 AM   #11
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Update

Ok so I ran a compression test. 175,175,175,160. The 160 was on number 4 and I could not get a good seal so I seriously doubt its a head gasket. I pulled the oil pump cleaned the bolts and reinstalled per FSM directions. Let the RTV cure 24hrs and still little to no oil pressure at idle, bring it up to 2000 rpms and its in-between the lines. This leads me to believe it's a bad oil pump. DNJ is normally good stuff. I guess I will order a OEM one when I get paid.

Am I over thinking this. Any other ideas?
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