Breakin Engine Myths !! Whos right ?
 

Every meckanic telz me that I need 500 miles of good driving to break in my engine before I race it. Then I get thiese sites that say 1000 miles for break in. I did a rebuild with a streetport using used apex seals ( within mazda spec ) and rotors and housings. Who is right.

#2 is that I cant use synthetic for 6000 miles. I used GTX 20w-50 right now so is this going to hurt my engine for 6000 miles ?

What weight should I use for summer? Thicker seems better since its hotter and if the oil gets to thin it will break down...

Someone pelase give me the right ansewers with the resasoning behind them. Thnx

i've always heard 200 miles for break-in, take your time, it's worth it
thicker the better for those hot summer days
don't know anyhting about synthetic

oops i mean 2000 miles

Break in is completely up to the owner...if you want your engine to last? be easy for 1000 miles not going over 5000RPM. You want a race purpose engine that doesnt see the street? Build it, Race it. I've heard different sides of each one...one of the only factors that I think makes a differnce, is NEW parts..and USED parts. NEW seals, housings, and such don't seal so great right off the bat, they have to BUILD compression in some cases...hense the reason that BRAND NEW motors flood, don't run as hard as a NEW engine that has been babied for a few hundred-thousand miles...nor an engine that has used housings and or compression seals. That is my theory. I babied my new engine for 800 miles before I hate fucked her the first time....4th pass I exploded the clutch disk...but not the engine. Now she has 7500 or so on her...still good, and I run the piss out of everything I own.

yeah, I'd go 2000+ if I were you. When I eventually rebuild mine that's how long I'll go.
How did you explode the clutch disc?

When KD did mine last August, 500 miles with 10/30 oil. Don't baby it, but no full throttle blasts. Dropped oil/filter, put in 20/50 oil and let it ripe. It's been fine.

With used seals, you wont see full compression for about 3K miles. But my recommendation is 500 miles below 4K, change the oil, and then 500 miles of normal driving. Dont beat on it, but dont be afraid to rev it.

As far as oil, I dont see a problem with using synthetics. Oils have come a long way, and synthetics dont seem to have the problems with leaving deposits liek they used to. Everything Ive read says use mineral oil for break-in, but after that, synthetic is fine.

1st pass was great...
2nd pass was great...
3rd pass 2nd felt kinda hard to get into...
4th pass when to shift from 1st to 2nd, clutch in-shift-clutch out...stuck between gears and wahhhh POP, smacked Revv. And that was it. Wouldn't go into gear with the car running, and with the car off, trying to start it..the car just jerked forward and wouldnt start...Clutch wouldn't disengage. Took it apart, and the disk was in over 30 pieces...that was a NEW semi heavy duty clutch...I replaced it that day with a ACT 4 puck, solid copper unsprung..no more fucking around.
And back to the breaking in..I say it can't HURT anything to NOT get on it for a few hundred miles..I mean..just stay out of it!!

I have used everything mazdaspeed7. How does it take longer for a used parts to break in or did you mispell it ?

For mine I went 300 miles below 4000 RPMS and then I let her rip. Those numbers were given to me by RacingBeat.

Used parts take longer to break in b/c theyre already worn in to the rotor housings, but when you took them out and put them back in, theyre not going to be exactly like they were. So the old worn part has to be worn out, and then the seals can wear into the rotor housings again.

Just to be safe, I would say go about 1000miles before you go above 5krpm, just to be safe, you can't take too long to break in an engine but you can do it to fast. Better safe then sorry. I don't think there could be anything worse (car wise) then having to rebuild or buy a new core again after only 50k miles or something like that.