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Timing Chain replacement

8K views 10 replies 8 participants last post by  Bobsleddia 
#1 ·
So I've been collecting parts for a while, was going to let a guy go over my 2000 Safari, but then the waterpump started leaking and decided to go ahead and put a new timing chain while I was down that far. My mech is busy, so I started tearing into it. The pulley puller I used to get the harmonic balancer off separated the 2 pressed in pieces so wondering if there's some kind of alighnment process for the harmonic balancer or just go get another one.

Secondly, I have the timing chain cover off, and am looking at the crankshaft sensor plate covering the lower timing gear. What's the procedure for removing and reinstalling it? I do before I pull the timing chain and gear off, I need to align the 2 marks at 6 and 12 o'clock. Learning on the fly here, first one.

Also how big of a deal is it to change the front seal? I bought one mainly because it leaks at least at the timing cover, or is that that main seal. Dang I'm getting another headache....
 
#2 ·
I guess I'm just venting. I have done a lot of searching and have somewhat of an idea what's going on. As soon as I posted the above, more relevant threads popped up. I did get a Felpro oilpan gasket and timing seal kit along with a new timing chain cover, looks like I need to drop the oilpan to do it right. The van has 200K miles and the 4.3 with cast aluminum oilpan. Would it be prudent to put a new oilpump while it's down or just clean the intake. I have run full synthetic since it was new, every 5k with ACDelco filter.
 
#3 ·
I just went through that last week. If you start by aligning it with TDC compression stroke on #1, 3 more revolutions brings it to TDC on #4, which is where the marks line up at 6:00 and 12:00. If you get a new cover, you don't need the gasket kit because the cover has rubber gaskets built into it, as is a new seal. I was planning to drop the oil pan but after seeing all the work involved in disconnecting the oil and transmission cooling lines I said nuts to that. I took a rasp and beveled the corners of the lip that overlap the oil pan gasket and kept trying to dry fit from underneath, filing down a little more each time until I got it to slip in. Applied the usual amount of RTV at the corners and it's been leak free. I attached a picture, although I don't know how clearly it shows. Good luck!
 

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#5 ·
paulbot said:
The van has 200K miles and the 4.3 with cast aluminum oilpan. Would it be prudent to put a new oilpump while it's down or just clean the intake..
For someone who started out changing a water pump... you are really turning this into a major job! New timing chain (in the front)... new oil pump (in the bottom)... and cleaning the intake? Cleaning the intake???

Personally (my opinion), with 200K... I would have considered riding it out. Mine.. went 282K before a wrist-pin went bad. My timing chain and oil pump easily out-lived the engine. I ran cheap oil, and still feel like I got a good life-time out of my engine. To me, it seems like a lot of "preventative" work for an engine still running worn rings and bearings, in it's final years anyway. The average life seems to be about 200-300K... but certainly some have gone further. With good oil, you may get some good extra life out of it.

But if you've got the time, place, and know-how... then have at it! The preventative parts you are replacing don't last forever either... and it's all a race for time now as to how far it will go. A full rebuild would be a good option (and is eventually inevitable)... but certainly much more work.

Not trying to be negative... just practical.

Changing a front pan gasket and seal without dropping the pan is doable. I've never had one leak. OIl pumps themselves typically go a LONG time. Like I said, mine outlasted the engine itself. But pulling the pan isn't impossible either... just a bit of a pain.

As far as the harmonic balancer, I agree with Maher... you will now need a new one. A proper harmonic puller would have prevented that.
 
#6 ·
Thanks for the replies. I meant cleaning the oil pump pickup if I need to drop the oil pan. And yes the right puller would have prevented the separation, but I live out in the boonies, it would mean a 40 mile round trip to get one, and I didn't realize the thing could come apart.

But now that you mention it, I do have a new updated spider injector set that needs to be installed :p
 
#9 ·
I've read this thread 10x...and guess what I found when I walked over to the bench after installing the timing cover and water pump? Dang. Round two.
 
#10 ·
Seems like a lot of work for very little benefit to me....
I remember the mopar timing gears of the past which were plastic over steel... they wore down pretty readily. (Sprockets looked like worn out motorcycle running gear).

Have not seen GM timing gear to do that... can you post a picture of the sprocket or the slack in the chain to show what you found when you got in there? Were they really all that worn?
 
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