Knock on startup - 1998 Neon Twin Cam

When my daughter's car sits a few days, when it is started it has a fairly pronounced "rap" for about half a minute. I haven't had a listen to it yet - just her description. Is lifter noise common on
these 24 valve engines, or is it likely to be piston slap? Not sure of the mileage, but I think about 170,000km. I'm leaning towards lifters, because it is apparently intermittent - and doesn't USUALLY happen after just sitting all day or overnight (which would be cold enough for piston slap) - thinking lifter bleed-down if the particular lifter(s) in question stop with the valve open.
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That could be anything from a wrist pin,piston slap, or rod bearing. (all uncommon for this vehicle) Yes it could be lifter noise, also uncommon. Of course this all depends on how well the vehicle has been maintained. The noise could be excessive carbon build up on the head/piston. The noise could also be a cheap oil filter withe the check valve allowing all the oil to drain back to the oil pan. I would start off with doing an oil change and using a Mopar filter to see if the problem goes away. My thoughts only
Glenn Beasley Chrysler Tech
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On Thu, 18 May 2006 06:15:40 -0400, "damnnickname"

Vehicle has been well maintained - but it could very well have a cheap filter on it at this point (daughter's car - I didn't have time to do the oil change, so she had it done.) Carbon on the head would not gradually quiet down after starting and only show up after a long rest - and it gets driven hard enough I doubt there is any appreciable carbon build-up. I'm going to put some additive in the oil and see if it gets better (clean up the lifter hydraulics)
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With about 100,000 miles on the odometer I'd say lifter noise could easily be the problem. When he hears it he'll probably know for sure.

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clare at snyder.on.ca wrote:

If its ticking then its the lifters:goto Pep boys or autozone or somethin and get some Mystery Oil and put it in where u put the oil in!! this is comin wit these cars, but I still love them and I still have mine!! nothin to worry about with this problem just get some Mystery Oil and u will be good!!! If its Knockin and its real loud and annoying like someone is knockin on a door then that would be the Rod Bearing. Engine is bout gone!!! only reason why that would happen is no constent oil changes or no oil in motor!!!
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On Thu, 18 May 2006 18:16:38 GMT, "Rome97neon via CarKB.com"

You have given the only real answe I have recieved to my question - you claim valve lifter noise is common, and sinse I was leaning that way, that's what I'll attack first.
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Well, you have all the answers for everyone else. Why the hell can't you answer this one? Your the mechanical genious that has worked on a million cars, and dispense your diagnosis to everyone else, figure it out on your own!
-
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On Fri, 19 May 2006 00:53:13 GMT, snipped-for-privacy@hartless.com wrote:

OK Smartass. I have not seen/heard the noise yet - and was just asking if anyone has experienced it, and if it was common on this model. Chill out
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Lifter's ? 24 valve overhead cam motors don't have them. with out hearing the noise my guess is 1. timing belt system 2. exhaust heat riser 3. wrist pin
clare, at, snyder.on.ca wrote:

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Mike Perkins wrote:

Neons Only Have 16 valve motors not 24 valves!!!!! Keep that in mind!! where did u get 24 valves from?? the best Neon site for your Neon Needs!!!!! www.neons.org Check it out!!!
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Rome From ATL, GA

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On Sat, 20 May 2006 22:45:31 GMT, "Rome97neon via CarKB.com"

Sorry - my bad - 4 valve per cyl = 16 valve. The Wife's car is a 24 valve (V6 ford). I have put some MMO in and ran the car for a few hours. It was significantly quieter all round than it has been. We will see if the knock is gone in the morning. She's been running 87 octane fuel in it too - which is a no-no on this engine. On 89 it is marginal - it really likes 91 Octane fuel.
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On Sat, 20 May 2006 23:09:01 -0400, clare at snyder.on.ca wrote:

Well, I fired it up this afternoon, and it was MUCH quieter. The engine sounded like it had a piston slap before I put the MMO in - my STRONG suspicion is that the wrist pins were sticky, causing the pistons to tip in the bores, giving the classic double rap. When warmed up, the pistons expanded enough to free up the pin (assuming the pins are free to rotate(float) in the piston) and the engine quieted down. The MMO would disolve any varnish in the pin bush area, stopping the stiction. I'll have the car for a few more days as my daughter is spending some time travelling in Europe with her older sister. We'll see how it behaves.
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On Sun, 21 May 2006 17:45:47 -0400, clare at snyder.on.ca wrote:

Well, the engine is still quiet. Had a bit of a missfire when started cold - I had washed the engine and #1 plug well got some water in it- dried it up and it ran perfectly. I think the engine is quieter now than it was when my daughter bought it 50,000KM or more ago. For a 2 liter 4 cyl, it pulls pretty good, too.
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No lifters? Really?! Man my automotive knowledge must be waning badly. Although it'd be nice to see the day that lifters are somehow no longer needed. I've become convinced that regardless of maintenance you're eventually going to have at least one lifter start tapping. Just a matter of time.
But I see lifters for sale (turboneonstore.com) for the SRT4 to replace the "factory and aftermarket hydraulic units"
And on www.neons.org I see reference to lifters as well. "The 2.0L OEM lifters trap this aerated oil and fail to pump up properly negatively affecting engine performance at high RPM usage."

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cam followers aka hydraulic lash adjusters, but not lifters per se.......... http://home.bresnan.net/~spunbearing /
http://www.allpar.com/mopar/2dohc.html
http://www.allpar.com/mopar/2.html

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Yes, I see even the 4.7L V8 in my two Durangos refers to "hydraulic lash adjusters". I guess that's the term to use for OHC engines but it really looks like it's pretty close to the same thing? I imagine you still can get the same ticking noise when a lash adjuster eventually wears out, too.
I read somewhere that if the knock sensor picks up the ticking then you could lose some power and efficiency from the engine.

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Marcus wrote:

no the lifters will not go back knocking cause I had my car 4 more than five years after puttin Marvels Mystery Oil in it and its still runs strong!!!!

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Rome From ATL, GA

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clare wrote:

The problem may be the injectors when the engine is cold. I had the same problem on a couple of my vehicles and got a good injector cleaner(at the injectors themselves), changed the fuel filter and my troubles went away.
Steve
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