Guess who's back ( Aaron A.K.A. qnz )

[Sleepervr-4]

You guys know the best place to break in an engine is on the dyno, right? http://www.mototuneusa.com/break_in_secrets.htm

Both of you having rebuilt engines, I wouldn't be surprised if you have ring sealing problems in the near future because you were too easy during break-in.

Aarons car just got boosted not rebuild. He only has 36k on that motor so should be fine.

[WarmAndSCSI]

well different people have different theories. Brians engine is rebuilt but not mine. I just slapped a turbo onto my stock engine. from what i understand, there is a breakin time for brand new turbo.

Ah, didn't realize that. But trust me on the engine break-in thing. People with new cars can get away with being easy because of extremely tight manufacturing tolerances, but engine break-in after machine shop work with aftermarket rings is a whole different story. There's a "safe" way to break in an engine, and there's a right way to break it in. Do you think pro NHRA guys putt their dragster engines around town before putting it on the line?

[Stewi]

well different people have different theories. Brians engine is rebuilt but not mine. I just slapped a turbo onto my stock engine. from what i understand, there is a breakin time for brand new turbo.

Ah, didn't realize that. But trust me on the engine break-in thing. People with new cars can get away with being easy because of extremely tight manufacturing tolerances, but engine break-in after machine shop work with aftermarket rings is a whole different story. There's a "safe" way to break in an engine, and there's a right way to break it in. Do you think pro NHRA guys putt their dragster engines around town before putting it on the line?

Not trying to take this too far off topicm but if you have a competent machine shop, your rebuilt motor should have tight tolerances. See if have a good machine shop, not only does he build motors, but he races cars on engines he builds. He told me flat out, no more than 15psi during break in and no WOT runs. He said after 500 miles to do a compression test and if it checks out, OK to dyno tune. If not, put another few hundred miles on it. I know about 15 people with EVO motor built by this guy and not a single one of them has had problems after a soft break in. Engine break in on a dyno is for a race car, a car thats always ran at WOT, beat on for maybe 6 total minutes of driving time at a drag track, then back to the trailer.

[WarmAndSCSI]

well different people have different theories. Brians engine is rebuilt but not mine. I just slapped a turbo onto my stock engine. from what i understand, there is a breakin time for brand new turbo.

Ah, didn't realize that. But trust me on the engine break-in thing. People with new cars can get away with being easy because of extremely tight manufacturing tolerances, but engine break-in after machine shop work with aftermarket rings is a whole different story. There's a "safe" way to break in an engine, and there's a right way to break it in. Do you think pro NHRA guys putt their dragster engines around town before putting it on the line?

Not trying to take this too far off topicm but if you have a competent machine shop, your rebuilt motor should have tight tolerances. See if have a good machine shop, not only does he build motors, but he races cars on engines he builds. He told me flat out, no more than 15psi during break in and no WOT runs. He said after 500 miles to do a compression test and if it checks out, OK to dyno tune. If not, put another few hundred miles on it. I know about 15 people with EVO motor built by this guy and not a single one of them has had problems after a soft break in. Engine break in on a dyno is for a race car, a car thats always ran at WOT, beat on for maybe 6 total minutes of driving time at a drag track, then back to the trailer.

I'm talking assembly-line-tight-among-all-cars-that-roll-off-the-line tolerances. IE: tolerances precise enough so that a manufacturer can guarantee the engine for 100,000 miles with their set break-in procedure for 1000's of identical vehicles/engines.

All I'm saying is that I've done this twice with no complications. Both times all cylinders reached peak compression within 80 miles of hard driving.

[xd_01]

Do you really think a Nitromethane powered 7000 hp NHRA motor uses the same ring material as you did in your pistons? You comparing apples and oranges here, people have engine rebuilds in their 10-15 year old cars with well 100k all the time and they still go for another 100k. A good machinist can make that happen for you. I would ask your machinist the best way to break in the motor they built for you, im sure he would know better then anybody