蒼之無行 wrote:
1000公里換太晚...(恕刪)
既然你有這疑問,我不確定你是否知道汽缸製造技術不同,磨合期內的機油所含的金屬屑會差異很大,我自己DIY 漏出兩部車與兩部汽車的機油,用手電筒,陽光下觀察,我都親眼看過了,不知道你是否有看過?
所以你的車都沒有金屬屑嗎?
到目前為止,我只有 2017 的 Golf R 我漏出的機油完全看不到金屬屑,我還刻意檢查了兩次,為了瞭解這樣的差異,我Google 不少文章,看到關鍵的文章與心得如下,你可以看看再來討論,文章滿長的:
http://www.stealth316.com/2-breakin.htm
http://www.aa1car.com/library/plateau_finish.htm
http://www.aa1car.com/library/oil_consumption.htm
文章太長,沒時間翻譯...內容主要提到,
1. 磨合期可以使用合成油 2.汽缸膛線是要含納機油,新引擎膛線表面有許多高山的尖凸,需要靠適當磨合,磨成高原狀,若尖端彎掉,磨得過平,都會吃機油,潤滑也不好.需要重新搪缸才可以改善.
磨合過程會使汽缸環磨掉一部分,所以活塞環壽命比較短,新的製程在磨出膛線後,增加細磨,使表面成為高原型,
而且有均勻的油溝,因此很接近引擎磨合後的結果,這種設計的汽缸環沒有初期耗損,所以壽命長,
更先進的技術適使用雷射製造油溝,此表面尖凸更少,更不需要磨合,賽車會用更深的油溝(膛線),但會因此耗機油,但潤滑比較好...
以上可以解釋,目前日系車沒有對汽缸細磨,因此磨合期機油仍是金屬屑很多,而我今年買的 VW Golf R 1250km漏出的機油卻完全看步道金屬屑.
也難怪一些歐系車車主,一拿到車就大腳油門,車也沒什麼太大問題(雖然車主手冊還是建議1000 km 裡面避免引擎超過 4000 rpm)
我看完以下連結的文章,比較能理解為什麼歐系車比較會吃機油,如果吃的量不大,而且沒有變嚴重,就比較能接受,我摘錄一些關鍵的句子:
http://www.aa1car.com/library/plateau_finish.htm
Scott Gabrielson, a ring engineer with Federal-Mogul, says he is very much in favor of plateau finishing because that is what a ring does to the bore finish when it breaks it in.
"The closer we can get the bore to what the ring likes to run on, the less the ring will wear during break-in and the longer the rings will last."
"What is more important than bore finish today," says Scott, "is bore geometry. With low tension oil rings, you can get into big trouble fast if you have bore distortion problems."
One change Meara said he has seen lately among some race engine builders is a desire to increase the "RVK" numbers (valley depth) in the crosshatch to improve oil retention.
Another issue is how to minimize bore distortion when the engine is running.
http://www.aa1car.com/library/oil_consumption.htm
HIGH OIL CONSUMPTION IN SOME NEW VEHICLES
Auto makers plateau hone the cylinders so the rings will seat quickly. Plateau honing shaves the sharp peaks off the scratches in the cylinder wall after the initial honing
so the finish will be similar to a broken-in cylinder. If the honing process is not done correctly, the rings may never seat.
This is especially important on engines with aluminum alloy cylinders or hard coated (Nikasil) cylinders.
Also, many late model engines are factory-filled with low viscosity synthetic oil (5W-20, 0W-20, 0W-40, etc.) to reduce friction and improve fuel economy.
Low viscosity oil is thinner so it can leak past rings and valve guide seals easier than heavier viscosity oils.
Synthetic oil is a great lubricant for all types of driving but it is NOT a good break-in oil - especially if the cylinders were not honed properly.
Most aftermarket engine builders break-in new engines with a conventional non-detergent SAE 30W or 10W-30 motor oil or a special break-in oil.
Once the piston rings have seated (a process that can take 45 minutes to an hour or more on a dyno, or several hundred miles of normal driving if the engine is broken-in in the vehicle),
the break-in oil is drained and the engine is refilled with what ever oil will be used for normal driving (conventional or synthetic).
There's no easy fix for improperly honed cylinders or incorrectly installed rings other than to rebuild or replace the engine - an expensive fix that most car manufacturers want to avoid.
So if your new car dealer tells you high oil consumption is "normal," they are full of BS!
A late model engine that has been honed and assembled correctly should use less than a half a quart of oil between normal oil changes
(and that includes engines that specify oil changes every 5,000 to 7,500 miles!).
目前日系車大部分的汽缸製造方法是這種:
http://www.stealth316.com/2-breakin.htm
Fill the engine with the appropriate amount of 10W30-weight, petroleum-based oil. Start the engine and let it run for about 20 minutes at low (about 2000) RPM. Drain the oil while it's hot and inspect the oil for metal particles. There should be no chunks of aluminum, brass, iron, or steel. Refill with oil (see below for type) and drive the car (after any other considerations have been addressed) for 500 miles and drain the oil again. During those first 500 miles, the loading on the rings should be moderate and varying. This is accomplished by varying speeds (no long-distance constant speeds, especially full-throttle) and occasionally increasing the cylinder pressures by quick acceleration or full-throttle uphill climbs. Stay away from redline though. If very-hard rings are used with hard cylinder liners (which are not used in the Mitsubishi 6G72 cast-iron block), the full break-in period may take longer than 500 miles.
目前 EA888 引擎看起來在引擎膛線(十字紋)磨出來後,多了一到細磨使得汽缸表面很接近已磨合過的狀態,
所以製造完的引擎第一次發動就已經很接近磨合完成,所以對於汽缸環與汽缸直徑的精度要求比以往高很多,
因此如果稍有不準確就容易吃機油,所以從目前查到的資料來看最主導的原因是製造公差.
所以,http://www.aa1car.com/library/plateau_finish.htm 這篇文章提到: 1.2萬公里吃 473 cc 以內仍為合理範圍.
不過,這還是比原廠的保固表準嚴苛很多了.
該文提到,這種製程的磨合約在正常道路上駕駛數百英哩就已經完成,而原廠手冊是限制 1000 km 內轉速不要超過 4000 rpm,
我還是比較認同原廠的作法,而該文建議磨合後使用原廠規範的油, VW 就是 VW 504.00 的 longlife 機油.
只是我觀察 1250 km 的油裡完全看不到金屬屑,而且多位 Golf R 的車友都有相同的現象.所以沒有馬上換似乎也還好.
但因為原廠加的油或許是礦物磨合油,或許是等級比較低的合成油來幫助磨合,代表它潤滑沒這麼好,所以磨合後拉轉速前,
我還是比較建議換好的合成油對渦輪的軸心比較好.
而磨合後要不要換就看你的選擇了,但我是覺得至少用1000km,最常我覺得不要超過 5000km(我是 1250 km換掉),不要 400~500 就換掉,
我們 R 的車友有人 400~500 就換掉了...換掉再來拉高轉速我還是覺得令人安心一點,此時期我放寬轉速到 4000 rpm,因為 1250 km 內我控制在 3000 rpm 以下...
而我自己是 5000km 以後才放寬到紅線區
這些動作基本上主要是日系舊的汽缸製造技術需要嚴格遵守,引擎的壽命會比較長,但 EA888 我還是堅持這樣做,因為跟原廠車主手冊的要求比較接近,
只是目前看來非必要.
