gomarlins3

Opps, sorry. I ment 60,000. Editted for my protection.

N2oExpresS2k

Actually when i went to aviation school you were always taught then after you overhual an engine that you run it WOT after you warm it up to seat the rings. The idea of honing your cylinders is to cause the rings to wear into the cylinder walls. If you dull that hone before the rings are sat they will never seat. You would have to rehone and install new rings and start all over to get those perfect cylinder walls.

I read a read up on motorcyle engines that stated that the hone usually dulls within 20 miles of driving around. So it is extremely important to go WOT in a higher gear to load up the rings while the hone is still fresh. Later on the read showed an engine that was babied during break in torn down compared to one that was opened up in the first 20 miles and the engine that was babied had markings all over the pistons. While the engine that was opened up in the first 20 miles had brand new looking pistons and cyliner walls.

I know this isn't a motorcycle engine or a plane engine but the same rules should apply to all reciprocating engines. The hone on your cyclinders is there for a reason and if it's dulled before those rings seat properly I think some iol consumption and inadequit hp would follow. No matter how much you don't abuse it.

ShocK

Well these un mentioned people have built a couple engines, ran them hard and they both blew up within 40 miles. I'm not talking bout the S2000 I'm talking motors in general. I strictly beleive you should let a car idle upon its first start ever for 30 minutes drain the oil refill then drive it easy for 500 miles. One of you mentioned idling is a bad idea, you're right. Idling is the hardest thing on a motor, an engine is meant to have a load on it and when it does not its more likely to see more wear. So the best way to break and engine in is the highway at a varying speeds and rpms that is below 3-4 with the 4 cylinders. What the engineer told me was that the tolerances are so tight that if you dont allow it to wear before putting an extreme load on it you could cause it to spin a main bearing, which is exactly what happened to the unmentioned people. not just once but twice in the past 3 months.

Tyraid2K

this is always the way this topic turns out, conflicting opinions, it's frustrating to read without a definite answer

SpitfireS

N2oExpresS2k Posted on Feb 17 2007, 03:55 AM
Do they all use FRM cylinder liners?


Tyraid2K Posted on Feb 17 2007, 09:23 AM
Especially if people completely disregard the fact that different materials were used to make their engine and completely disregard the break-in procedures that come with them.

brimstone

Just some additional info I found, those interested in the rest of the thread may find it here: http://theoildrop.server101.com/forums/sho...art=1&vc=1&nt=2

[QUOTE=DaveW from BITOG forums]
I drive a BMW and the manual tells us to vary the speed. What they attempt to get us to do, but don't say why, is to limit the amount of heat applied to the various reciprocating/rotating components for any long period of time.

You have two opposite functions to perform at break-in:

1)Apply enough pressure to the piston rings (via high-load) to have them expand and match the cylinder bore (in fact, they both wear a bit and fit each other). This also applies to valve to valve-seat interfaces and all plain bearings.
2)Avoid excessive heat that would cause distortion that will prevent these parts from mating.

So how do we do this?

N2oExpresS2k

I've never heard of a main bearing failing because of improper break in.. There's also the possibility that the engine was put together with incorrect bearings. They are supposed to break in but if you plastiguage them and select the correct bearing there will always be a layer of oil between the rotating parts and none should ever come in contact.

N2oExpresS2k

In avaition school they stressed that if an engine is going to fail. It should fail during break in, cuz there's no place to pull over in the sky! If built correctly it will break in and run its throughout its life with no problems untill it has to many hours and must be overhualed again.

TurboDSMJ

I was alway's told to run it around for a few miles, then put it to work to help seat the rings properly. We broke my Brother's DSM in like that after the motor was built. It runs just fine.

ShocK

I think it depends on how tight your tolerances are. If you're building a race motor the tolerences will be a little looser, if you're re-building your moms civic you make the crank to bearing tolerance as tight as recommended for longevity.