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Re: Interesting article about engine break in.

Posted: December 18th, 2008, 9:54 am
by wytbishop
RX8SE3P wrote:I can understand that you'd let it warm up a bit, then start varying the revs, under no load in neutral obviously. Do this for a little bit. Then drive a bit taking it easy. Changing oil fairly often. I think you shouldn't keep it at certain revs for too long. Always vary the revs, it actually says that in our manuals I think.

I would not thrash it first shot and put it under tremendous load! Screw that. My daily driving usually includes only revving to about 3,000 and generally taking it easy. I only push hard when someone in a crap car is trying to drag me.

Remember, you can rev it up, but without putting 100% load on it. Make sense?

Dunno I'm not an expert but I'd be against loading it up for at least a couple thousand kms.
This issue that this whole thing is really based on is tolerance. Each mating part is designed to have a very specific clearance to the part with which it mates. Engines have very precise tolerances...often less than 0.001" between too small and too big. When the engine is new, the "fits" of the various mating components are at the tightest they will ever be. This is why it is so important to warm the engine thoroughly before breaking in, but really it has no impact on the strength of the machine or it's ability to withstand a load. He is just telling us to take advantage of the tight new clearances to wear the rings in as perfectly as possible.

Every part that goes into making the engine work is specifically designed for a maximum design load and is perfectly capable of withstanding that load from the minute it is produced. If something is going to fail during breakin, it is because it is either flawed in design or manufacture, or improperly assembled. If a critical part is flawed or put together wrong, I would want to push it to it's limit sooner than later than later. I want it to fail under my control...not driving down the road a couple thousand Km later when I think it's finally ready.

Re: Interesting article about engine break in.

Posted: December 19th, 2008, 1:44 am
by RX8SE3P
Yeah it's an interesting debate isn't it. I actually have three brand new K8 short blocks with pistons and all...

I need to buy another MX-3 and rebuild the heads etc. Would be interesting to test out. Good thing is I have two more blocks if one stuff up :lol:

Re: Interesting article about engine break in.

Posted: January 2nd, 2009, 8:03 am
by RX8SE3P
@ Fowljesse, you ask your dad yet about this theory? If he has built heaps of engines without issues in the past, I would trust his opinion.