Piston Slap

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engines could be designed like sockets. One designed with "impact" in mind and the other more regular. lol

In general , I think if you don't hear any noise (slap, tap, tick, bang, pop, etc.) when the car is new and then starts making noise after so many miles it could be a red flag.
with my Tundra it sounded like diesel/typewriter with 6 miles on it so I'm not as concerned ...
 
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I complained about engine noise when my Subaru was cold when it was new. Dealer told me is was piston slap, and harmless. He must've been correct. It never worsened.
 
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They dont machine engines at their operating temperature. It must be quite an engineering and testing process to have a hot engine especially aluminum keep clearances at temperature similar to when cold. Chrysler made the slant six in aluminum too, didnt work out either apparently, like the American Motors aluminum six. The Buick aluminum v8 was good though.

You are reminding me of when I used to ruminate on how an engine can work when the thermal rate of expansion of steel/metal/iron (your "iron block") is different than that of your aluminum head. My first Volkswagen had "iron block and heads" and sometimes it can get HOT HOT HOT and you can survive an overheat.

It was described to me that head gaskets are moving parts. It is no wonder they blow.
 
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Will Subaru ever abandon the Boxer engine?

The pistons are laying down flat.. seems like they want to slap. ?

I wonder how my new EJ20 will do.
 
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engines could be designed like sockets. One designed with "impact" in mind and the other more regular. lol

In general , I think if you don't hear any noise (slap, tap, tick, bang, pop, etc.) when the car is new and then starts making noise after so many miles it could be a red flag.
with my Tundra it sounded like diesel/typewriter with 6 miles on it so I'm not as concerned ...

100% spot on. The 1.8 and 2.0 Hyundai Nu engine family develops piston slap later on in their life and they end up failing.
 
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Some shouldn't have made like GM's attempt to take a gas engine block and make a diesel engine out of it for Cadillac back in the 1980s? (If I remember correctly.)
plenty of successful diesel engines have been made from gasoline designs. that engine wasn’t all that far off from being decent, the block was the least of its problems
 
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Ford enhanced the “truck” version of their already reliable 4.6L engines with full floating piston pins, a slightly different pin offset, different rods, high quality pistons and hard chrome faced rings. The result is a 900,000 mile lifespan with good maintenance.

Hyundai uses the lowest quality components, many designs are copied from others who also don’t make the longest lasting engines, and their metallurgy is known to be substandard or even non existent in some cases.

The difference between unbreakable and awful may simply be a few key cost saving items.

As stupidly obvious as it sounds, it’s probably best to purchase vehicles of known high quality and reliability.

There was a time a few years ago when a VW Passat was 1 order of magnitude less reliable than a Camry. In other words 10X worse. Why anybody would “knowingly” subject themselves to that kind of risk, for a clearly bland car, escapes me.

sports cars may be another matter and people will put up with all sorts of things to have fun. But when it comes to pedestrian transportation, I fail to see where a Hyundai saves any money over the long term.
 
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Will Subaru ever abandon the Boxer engine?

The pistons are laying down flat.. seems like they want to slap. ?

I wonder how my new EJ20 will do.
It’s not that they are flat. Pistons went skirtless sometimes in the 90s, which means basically they went from being a soup can to a hockey puck, so to speak. That allows them to deflect some tiny amount if the fit isn’t precise. Subaru also went to a low friction coating and a shallow top design where the rings were very close to the top of the piston, to reduce unspent gases from sneaking through the combustion cycl. I mentioned in another thread, it didn’t matter in my ej22.... sucker just ran. But apparently it can matter in other makes and models.

my buddy owns a land cruiser garage. It’s all he works on. We learned at some point that the iron from Toyota was far less porous than other makes of that vintage, a contributing factor to blocks still within tolerances after a couple hundred thousand miles. As another posted above, Japanese tech at that time was hard hitting with material quality.
 
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In GM groups I belong to the answer for piston slap is always the same. Lucas Oil Stabilizer!!!. When I first purchased the 06 Escalade the Lq9 engine had startup piston slap. I started using Mobil 1 5W30 regularly. It wasn't as bad but it was still there. I had a spare AC Delco hanging around so I hot swapped the high efficiency Ultra with the Acdelco and it was gone. Put the ultra back on, the "slap" came back. So I stopped using high efficiency filters on that engine. The other day I started her up after sitting in the garage for 6 months. Not a peep! My "slap" was actually a startup slow flow issue. So Lucas is the last thing these engines need. And it doesn't like high efficiency filters either.
 

BeerCan

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Is piston slap not an issue on the 3.8 or 5.0 Hyundai? I had those 2 and they were good running for me. The 5.0 had close to 100k and it was still a great runner.

The 3.8 was very abused by my son and it had over 130k when he sold it and to my surprise still ran great. I know this is only a small example, just wondering.
 
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In GM groups I belong to the answer for piston slap is always the same. Lucas Oil Stabilizer!!!. When I first purchased the 06 Escalade the Lq9 engine had startup piston slap. I started using Mobil 1 5W30 regularly. It wasn't as bad but it was still there. I had a spare AC Delco hanging around so I hot swapped the high efficiency Ultra with the Acdelco and it was gone. Put the ultra back on, the "slap" came back. So I stopped using high efficiency filters on that engine. The other day I started her up after sitting in the garage for 6 months. Not a peep! My "slap" was actually a startup slow flow issue. So Lucas is the last thing these engines need. And it doesn't like high efficiency filters either.

in case of engines with cold start slap, you would think if there is an initial contact, nothing can stop it but the contact/impact can be cushioned (or reduced?) till the engine warms up or parts expand, etc. No?

Does the filter material impact the oil flow? I keep reading with a PD pump, the volume is fixed but the pressure could obviously be different.
Maybe oil doesn't get there fast enough with older cars (sludge?) even if the same volume is moved. idk trying to figure out how filter material can impact lubrication with PD pump.

btw, is there a voa for Lucas oil? Curios what's in it? Moly? I read stuff that "cling"can reduce or cushion the impact things like ester, moly, intelligent molecules , etc.
I have experienced oils with more moly running smoother ... However they can't eliminate the contact maybe we just don't hear it as loud.

Anyway not arguing with you just trying to understand.
 
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btw, is there a voa for Lucas oil? Curios what's in it? Moly? I read stuff that "cling"can reduce or cushion the impact things like ester, moly, intelligent molecules , etc.
I have experienced oils with more moly running smoother ... However they can't eliminate the contact maybe we just don't hear it as loud.

Anyway not arguing with you just trying to understand.

that was easy
 
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My Tacoma 2.7 has piston slap on cold start when ambients are below 30F. It goes away after about 90 seconds of idling. This is the only time I hear any unusual noises on cold start.
 
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