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snowman snowman is offline
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Join Date: Feb 2003
Location: So California
Posts: 3,787
I don't think so. NEVER run your engine at higher than normal temps.

All the preceeding info on breakin is basically correct. By heat cycling I beleive they mean a cold engine, running to normal temp, and shutting down to get back to cold. I have not read anywhere where temp cycling is beneficial, its usually what wears things out. An engine is designed to run at a single temp. The closer you can keep the engine to that temp the better. All new cars hold temp very well and consequently are able to make a lot of power and still meet pollution reqs.

Ring break in is dependant on proper machine operations during rebuild. If done correctly the rings will be broken in within a few minutes and only one or two full throttle accelerations and decellerations will be required to finish the job. Common rebuilds do NOT utilize the proper steps to machine the cylinders so that the rings will break in this quickly, so you still do the same thing but several times and you must keep an eye on the temps so that they do not go higher than normal. If the temp does creep up, back off, let it cool. Some of the worst done rebuilds may require up to 12,000 miles for the oil consumption to stabilize (the rings are broken in at that point), but a proper job will have them broken in before you get the car home for the first time.

What are the proper machine steps? Final honing is the critical last steps. The surface finish must be within mfg specs, which for newer cars in on the order of 5 micro inches. In addition a step called plateau honing is required. A special hone is required for this step, which removes sharp peaks from the cylinder wall finish and proivides proper oil retention on the cylinder walls. These steps must also be done while using a torque plate to compensate for cylinder distortion due to the head bolts, and for the really anal types it must be done at operating temp of the engine.

Another assumption is that truly modern ring designs are used. Modern rings are ready to go, ie they have been machined to perfact circles and in theory do not need breaking in. Many euro rings are made using 200 year old technology so sometimes you just cannot get what you want. Euro talk is big but their tech lags somewhat. Mahle is a good company with current products. Most of the others may be somewhat out of date.

Last edited by snowman; 07-29-2005 at 07:00 PM..
Old 07-29-2005, 06:46 PM
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