Breaking in a Motor, and Compression tests

[lifewater]

I'm going to be building my motor and I'm wondering what you guys do for break-in period? There are a lot of different ways to do this and I'm looking for advice on whats worked for you guys?

Do you let the car idle for a period of time? If so what RPMS?Do you boost during breakin period?How many pulls? Does it matter what gear I do this in?

Also second question. Im going with 9.0:1 Compression ratio... I have no decided what size headgasket to go with. When I do a compression test on my car would my numbers overall be higher or lower then stock 180-190 compression?

I apologize for the newbie questions here. This is my first venture into motor building :P

Thanks.

[virus77]

Start the car and check for leaks and whatnot. Its going to have to idle for a little bit until its deemed safe to be driven. Once everything looks kosher go out and drive the damn thing and don't baby it or bounce the thing off redline at full boost. Don't keep it at one rpm for a long time (like the fwy) try to fluctuate the rpms as you drive and always decelerate in gear, the vacuum is good for sealing rings. Change the oil/filter in about 40 miles and just start enjoying it. Compression will be around 140-160 on a new rebuild, could be more but dont freak out if its 140. Also if your car needs to be dyno tuned before you can drive it don't freak out about that either, the dyno session will break her in just fine

[s13-t]

that helped me out alot, thanks now I dont have to ask that question

[pauliedrft]

Do not break in with synthetic , Use regular oil ,or royal purples break in formula.You can have it dyno broke in too.Gl want kind of numbers you going for ???

[V8slayr]

All good advice. Just make sure to load the car. Drive up hills in a high gear, varying the load. I drove mine for about 300 mi. just going 1/2 - 3/4 throttle up hills and such and then began to boost it after that. I was boosting about 15 psi for a few hundred miles, shutting the car down no later than 6K. I waited until the car had around 700-1000 mi. on it before I started doing full RPM pulls. Also, change the oil a few times in that first 1000 miles, and use regular oil as paulie said.

[Blown240sx]

What a good engine builder told me rings are seated within the first 30 min of operation. His break in which Ive done on several motors is....

Use standard oilStart car let idle (check leaks)Warm all the way to operating temp then drain and change filter.Refill and change filterGo out and hammer on the car a bit. Dont bounce it off the rev limiter but pretty much drive it like you stole it for about 30 min. come back drain oil and change filter then drive for 200 miles normal to let the bearings wear in and your good to go.

Dont be afraid if the oil has some metal residue in it when you first break it in. The bearings will wear a little and whatever else was left in the motor when machine work and assembly was done will show up in the pan.

I freaked out on my V8 build when the first oil change has some flakes in it.Next change was cleaner. The last change was perfectly clean.