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with all new bearings and new HKS nickel/moly pistons and rings, a new bore, how would you run in the engine to get the most out of the rings and bearings? exactly what type of mineral oil (weight, brand) might you use? opinions seem to vary on this one, from mileage to max rpm to style of driving to boost levels while running in a new engine...would like your thoughts please :)
 

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run for 20 mins in neutral at 3k rpm let everything bed in ie cams and rings, and drain the oil. then run for 100 miles with varying load up to 3k limit, drain oil. then upto 500 miles and add anoter 500 -800 rpm and drain oil, again varying the load ie try some hills and lower gears. drive again uping the revs to say 4.5-5k with some brisk acceleration and load. at 1000 miles you can introduce some boost and you should use up to 6k rpm. at 1500 miles you engine should be bedded in and do a compresion test to check the seals of te compression rings. they should all be with in a fraction f each other.

Remember only use cheap 15w40 Dino oil during run in as using synthetic is a big NO! At 1500 miles you can use a good quality synthetic like motul etc.
 

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Discussion Starter #3
with all those oil drains thank god running in requires cheap oil! why is synthetic a big nono during run in though? I've pretty consistently heard that, but never a good explanation as to why?
 

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I used the same method on an Opel 16V engine and it worked very well for me. Dino oil is not as slick at synthetic oil and will allow the rings to bed in where as synthetic oil is more efficient at offering protection. Im no technical expert on oil and its properties so thats the best I can do im afraid.
 

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We have discussed this quite a bit on a Subaru forum I frequent and someone posted the following link wich is quite persuasive. I would like to see it done on a small cheap engine first but the theory does seem to hold up.

Break In Secrets--How To Break In New Motorcycle and Car Engines For More Power

I also heard about doing it this way when I purchased my new EVO a bit back. Also found it very interesting, however I didint have the faith to try it!


-Sayajin
 

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There has been loads of debate about this for years :runaway: .

Every engine is different so would depend on what the manufacturer reckons to be honest.

What that article says about honing on modern engines and radial pressure (on the top ring and to a far lesser degree on the next ring etc) is fairly correct but he seems to think the honing roughness can wear down piston rings while it is really for making the oil stick to the cylinder wall. The gas pressure is not as great as he thinks as normally it would reduce the oil film by about 20% compared to the ring tension alone - the fiction force is about 3 times or more under full load than with no load.

The piston rings are ALWAYS divided from the cylinder wall by a very thin oil film or else they would stick like glue to it and you would have a very hot wall and no engine - although sometimes it is only boundary lubrication.

The higher the torque load and the higher rpm will make this film thinner and put the rings closer to the wall but there is no real reason why this would make a different if done early on or not. Top piston rings are also normally coated with a hard chromium plated overlay or molybdenum so the honing has no chance of affecting them.

It is mainly thought that modern engines need far less running in than the old school ones although the article seems to be mainly aimed at bike engines which may be a different kettle of fish.

The reasons that less running in is needed are mainly due to modern machining of cylinders is so much better than the old ways. The easy running-in process was meant to cut of high points without damaging pistons ring etc but these high points don't really exist anymore unless the cylinders have been bored out to make them bigger etc by a tuner who normally don't have the high tech stuff like the manufacturers.

But (always a but) the first few 100 miles or so should be gentle and the oil changed to stop metal contamination from scraping ESPECIALLY in a turbocharged engine which can cause other huge problems in the turbo bearings.

I would do whatever the manufacturer says as each engine design is different and that guy on that site looks very dodgy anyhow lol.
 

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Not saying this is gospel but the way I ran mine in post rebuild was the first 500 miles at no boost and nothing over 3K. Drain oil and refill. (Cheap 15w40)

The next 300 miles with a little boost and a 5K limit. Drain and refill.

With respect to the rev limits placed, the entire range was used with varying loads using the gears etc.

800ish miles reached....Done, engine run in and once drained and refilled with Silkolene 10w50 it was ready for dyno time.
 

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Drive it and drive it hard from the word go, then it will be a sweet high power engine, and also show up any problems early on.

When you get a new car does it have 1000 miles of 'running in' on it??? No you just jump in it and thrash the nuts off it as its a new toy.

If the engine is built right then it will be fine.

Just my thoughts on the subject......
 

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Discussion Starter #13
what did Nissan recommend for new GT-R owners taking delivery of their RB26DETT cars with 5km on the odo?
 

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We have discussed this quite a bit on a Subaru forum I frequent and someone posted the following link wich is quite persuasive. I would like to see it done on a small cheap engine first but the theory does seem to hold up.

Break In Secrets--How To Break In New Motorcycle and Car Engines For More Power
I have built 3skyline engines and run them in this way. No prob at all.
I have built loads of loads of audi, vw, mazda, s14 etc engines, and run them all in this way. As far as i know the only one i had problems with is my current engine, and that was due to oilpump failure.

I have also been at the racetrack and put in new piston at the track, just started it, ran it hard for 1hour or so, changed oil, and then full boost at the track... works like a charm.

Asim...
 

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I have built 3skyline engines and run them in this way. No prob at all.
I have built loads of loads of audi, vw, mazda, s14 etc engines, and run them all in this way. As far as i know the only one i had problems with is my current engine, and that was due to oilpump failure.

I have also been at the racetrack and put in new piston at the track, just started it, ran it hard for 1hour or so, changed oil, and then full boost at the track... works like a charm.

Asim...
so would you run in an engine hard, even with a brand new bore? I can see this working if the engine were normal, but I'd have to wonder about microscopic imperfections in the new overbore I'm getting, from 86mm to 87mm....
 

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so would you run in an engine hard, even with a brand new bore? I can see this working if the engine were normal, but I'd have to wonder about microscopic imperfections in the new overbore I'm getting, from 86mm to 87mm....
All engines i mention here were new bore and new pistons....
 

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what do you do about mapping with this method though?

for example my rebuild will be using a different plenum and FMIC so in thoery my current map will be incorrect and need adjusting before I can properly run the car.

Simon
 

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how many miles have you gotten on your engine since then?
over 5000 now :)

also my friend done it to a 2 stroke bike last weekend....he is an old school mechanic and considers it "thrashing" and does not understand the reasons why i run my engines in like this but to try to prove a point he done it to a bike he rebuilt.....he came back and said that its the fastest 2 stroke he had ever been on and that it makes a different sound to the other 2 stroke engines he has rebuilt in the past....in fact he is selling it now because it flipped over and threw him off at WOT lol

the process seems like a "hard" break in but i used to work on race cars for the kumho championship that only had the pit lane to run in and those engines were taken apart "just for a look" after each race and even after races that were stopped within two laps the hone in the bore was gone......after that hone has gone the rings will not bed in and it will be leaky forever, get them cut in before 20 miles is up!
 
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