How do engines die?
You put a 3.4" on all of them.
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09-15-2017
How do engines die?
You put a 3.4" on all of them.
09-17-2017
I'm going to hit 300k miles next month. Here are my thoughts:
1) I use Mobil-1 high mileage, changed every 5k. AC Delco PF-52 filter.
2) Occasionally (every 50k miles or so) I use an engine oil flush when I change oil.
3) I avoid knock like the plague - I listen for it an increase my octane if required. Knock hammers the crap outta your bearings.
4) Stay on top of your antifreeze too- change it every few years. And I assume everyone has installed metal intake gaskets by now. I'm in the minority and still use Propylene Glycol.
5) Don't bother with fuel injector cleaner.
Other than that - just keep driving. Your mileage may vary.
-Bob C.
09-17-2017
do tell how you listen for knock and avoid it and adjust your octane ???????
this is what kr aka knock does to a engine. and you cant hear it till it eats a spark plug and causes a misfire.
09-18-2017
How to listen for knock? Not sure what you mean. Sounds like you are shaking rocks in a coffee can. And you certainly CAN hear it, so I'm not sure why you would say something like that. At least I can, but my hearing isn't all that great (been struggling with tinnitus for a decade or so now). In the "old days" the way to adjust your distributor and advance curve was to listen for pinging and change your initial timing and springs until you eliminated the ping - so maybe it's something people just don't know how to listen for any more.
Adjusting octane is done at the pump. In MA (and I think 37 states) we have different formulations for winter gas vs. summer gas, and you can also use lower octane when the temperature is colder. Right now I'm running 87, but in the hottest of the summer I was using 89. I think we switch to winter formulation around October 1, so I will be listening for knock and might have to adjust to the winter fuel until it gets really cold again.
Knock retard is a reactive function, the key is to avoid knock in the first place. But most people think of knock retard at full throttle (which is what will cause you to break a piston) - knock at light throttle (especially transitional knock), accumulated over 100's of 1000's of miles, is what will kill your bearings.
One of the things I've done to reduce knock is to get rid of the function that reduces acceleration enrichment as a function of MPH. Not sure why that parameter even exists, except maybe as some kind of emissions thing perhaps. But I have full AE regardless of MPH. I've also set the target A/F ratio to 13.9 instead of 14.7 to compensate for the E-15 that we have in MA (and this helped gas mileage as well).
I also change to a 180 thermostat in the summertime, and a 195 in the winter. Obviously engine temperature can affect your octane requirement as well.
-BC
09-18-2017
i cant read all that. your talking pre ignition knock or pinging. your 3800 engine dont do that. and never will.
09-18-2017
Sure it does, they all do. Although if you didn't read "all that" I'm not sure which part(s) you are referring to. GM programs timing right on the edge which gives great performance in a lab, then relies on the knock sensor to band-aid the rest. Better to just prevent it the best we can.Originally Posted by Scottydoggs
And I apologize for the terminology, when you said "kr aka knock" I assumed you didn't think terminology was all that important. All of the above do happen and are bad for your engine - and minimizing them will help these engines last a long time, which is what the OP was asking about.
-BC
09-18-2017
It's not 1965.
These things don't octane ping.
And if they do; it's been replaced with Knock Retard in the PCM. Very RARELY audible. And if it is; you've got many other issues, one of which isn't what oil you use or what octane you've tossed in a car that hasn't been modified.
09-18-2017
Mahhnnn. LOL'z all over. "Listen for Knock"...? maybe with some sort of bionic hearing apparatus. Knock sensors recognize knock by feeding voltage signals to the PCM based of vibrations within the engine block. Knock sensors are high precision electronic components that utilize ceramic materials to pick up on these vibrations. You are not able to hear those vibrations with the human ear. We are talking vibrations, the human ear cannot recognize a knock vibration from regular engine vibration. It cannot be done. Period. End of story.
And like blueguy said, if you can hear knock, you're absolutely F'd.
Rocks shaking in a coffee can sounds like a bad coupler to me.
09-18-2017
exactly, since you dont have points, rotors or caps or a distributor, none of that crap can be heard. if you do hear that, park the car and set it on fire, its past repair lol
09-19-2017
Interesting set of opinions. I suggest you all educate yourselves, and for the OP you would be smart to not listen to people who don't know what they are talking about. Protect your engine and it will last a long time for you.
-BC
09-19-2017
Bob, you'll never hear pinging on a 3800 unless something is mechanically wrong with the knock sensor system. The knock sensors pull timing well before the human ear can hear any sound of detonation or preignition. A good amount of modern engines have these systems in place.
09-19-2017
see now this is one time you dont know what "you" are talking about. like blue guy said, its not the 70's no more, or the 80's even when pre ignition is or was heard. so lets talk about that Tinnitus you got? maybe its not helping you at this point. aka you hear things.
09-19-2017
09-20-2017
I have definitely heard knock in my NA 3800 a few times - gentle driving lets the ecu up the timing for best mileage, then stab it at low speed - jumps hard but pings like crazy for just a moment.
It was a rare thing, but it sure could and did happen.
09-20-2017
I've been on this forum for a few years, and there's a few members that have shown me that they are the true experts with these engines... They've been through more 3800's than you could ever find in any junkyard.
They've pushed these engines to well over 600+ horsepower...AT THE WHEEL.
That's through the made-of-glass 4T65E. A transmission that is known to break with less than 180hp at the crank.
They have the experience and knowledge that comes from many years of working on, building, modifying, tuning, and racing these engines.
Three of them have posted in this thread: Billboost, Blueguy, and Scottydoggs. It would be a good idea to listen to these guys, they have saved my bacon more than a few times, and many others as well.
And if you could sense when your 3800 was just starting to knock without any electronic sensors, you would feel the KR, not hear it. I've felt it in my NA turd, and every time the engine didn't make any kind of appreciably different noise. It was always an almost-kinda-shudder, and the engine seemed to struggle slightly right before the shift.
And after some tuning help from Scotty, I haven't felt it since, regardless of how hard I hammer on the bish. I will admit, however, that I have gotten what someone could possibly mistake for knock or pinging, but it turned out to be the mounts squishing enough to allow metal-on-metal contact. Because 3800's are little torque monsters compared to other, similar engines in the same time frame.
09-21-2017
You are hearing something else, or you have mechanical problems.
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