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Proper Piston/Valves timing after timing chain slippage

Old Apr 17, 2018 | 11:36 PM
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Originally Posted by volaredon
there are "good" timing chain sets and "cheap" low quality" ones.... I always spend a few bucks extra for the "good stuff". but with 330K miles on it how long do you expect this engine to last? I see lots of relatively low mile 3.9s on Craigslist. buy one, regasket it, put your new chain and gears onto that engine and swap. be cheaper thana valve job and all new intake valves which is what will be needed if the valves and pistons made contact.
What's a good brand TC set to go with? Should I add the tensioner also or just a good TC set?
Well if all is well with the valves, maybe another 200-300K miles. JK, it's not a daily driver. It was in such good condition and I got it fairly cheap from the original owner so I bought it.
I shouldav changed it out sooner. Did the research and all on it but put it off to long.

I don't think I could handle a motor swap, or wouldn't want to. Lotta work and don't have all the tools or help.
 
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Old Apr 17, 2018 | 11:53 PM
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ragged89, that's along the lines of how I thought I should be going about it but wasn't 100% sure. Thanks
So is it ok to turn either of them (cam or crank) counter clockwise? You mentioned getting the dots to line up, taking the shortest distance to the meeting points?

Question, one complete 360* turn of the crank shaft causes all 6 pistons to go through a complete cycle? What does one 360* turn of the cam shaft cause the valves to cycle?

Appreciate everyone"s patience and helpful advice.
 
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Old Apr 18, 2018 | 07:57 AM
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Yeah, turn them the shortest distance. If you feel resistance, stop, and turn the other one a bit.
 
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Old Apr 18, 2018 | 08:01 AM
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Originally Posted by 93DAKV6
ragged89, that's along the lines of how I thought I should be going about it but wasn't 100% sure. Thanks
So is it ok to turn either of them (cam or crank) counter clockwise? You mentioned getting the dots to line up, taking the shortest distance to the meeting points?

Question, one complete 360* turn of the crank shaft causes all 6 pistons to go through a complete cycle? What does one 360* turn of the cam shaft cause the valves to cycle?

Appreciate everyone"s patience and helpful advice.
One 360* turn of the camshaft causes all twelve (V6) valves to cycle completely. What else would it do?

RwP
 
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Old Apr 18, 2018 | 11:06 AM
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Originally Posted by RalphP
One 360* turn of the camshaft causes all twelve (V6) valves to cycle completely. What else would it do?

RwP
I read about it being a 2 to 1 ratio, wasn't sure...

Anyways, it has a broken off valve in the #3 cylinder, cylinder wall scored up also. Good call on the bore scope camera HeyYou.
Looks like it'll be a motor swap if I wanna get it going again. Shoulda changed that timing chain sooner...

Thanks to All for the help/advice/info.
 
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Old Apr 18, 2018 | 12:26 PM
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Originally Posted by 93DAKV6
I read about it being a 2 to 1 ratio, wasn't sure...

Anyways, it has a broken off valve in the #3 cylinder, cylinder wall scored up also. Good call on the bore scope camera HeyYou.
Looks like it'll be a motor swap if I wanna get it going again. Shoulda changed that timing chain sooner...

Thanks to All for the help/advice/info.
Well, 360* of cam rotation is 720* of crank rotation; but that wasn't your question.

Sorry to hear about the #3 valve; that sucks. Or blows, if on a compression stroke *grins*

RwP
 
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Old Apr 18, 2018 | 01:38 PM
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Originally Posted by RalphP
Well, 360* of cam rotation is 720* of crank rotation; but that wasn't your question.

Sorry to hear about the #3 valve; that sucks. Or blows, if on a compression stroke *grins*

RwP
Thanks for the info. In post 9 I mentioned I don't have a complete understanding of the valve system.

Think I'll get a used head and a cheap TC set and put it back together and see how long it last...
 
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Old Apr 18, 2018 | 03:30 PM
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If the cylinder wall and piston are scored, I would expect that cylinder to be pretty stupid in relatively short order..... things like broken rings, and jammed pistons are a common result. You don't wanna go there. Just find a decent, low-mileage, used motor, and toss it in. Or, if you are feelin' froggy, upgrade to the 5.2 liter.
 
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Old Apr 18, 2018 | 07:19 PM
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Originally Posted by HeyYou
If the cylinder wall and piston are scored, I would expect that cylinder to be pretty stupid in relatively short order..... things like broken rings, and jammed pistons are a common result. You don't wanna go there. Just find a decent, low-mileage, used motor, and toss it in. Or, if you are feelin' froggy, upgrade to the 5.2 liter.
Yeah probably not a good idea to put money into it the way it is.

Any info or leads on where to locate a decent, low-milage used 3.9 motor? Checking all the avenues I know of (Craigslist, ebay, junk yards...)

Thanks
 
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Old Apr 18, 2018 | 08:27 PM
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Car-Part.com as well. You can search all participating yards in a given range. Pretty nice service.
 
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