My BB only has about 600 miles on it since it was built, my question is what is the best way to break in the motor and get the rings to seat. I still have a little oil around the spark plugs when I pull them to check out. Living in Michigan its so flat around here the engine is never under any load. I started out with a straight 30 weight oil for the first 300 miles and since have changed to a 20-50 Valvoline.

 

I didn't catch what kind of rings you used, but in general: drive the car at varying speeds under light load for 500 miles. Change oil (in your case - you can do that now) and go another 500 with more load on the motor. Change oil again and rings should have seated... In your case, you may have a harder time getting the rings to seal if you drove differently. Many good rebuild books describe what the authors think is the optimum procedure. 20-50 seems a bit thick... I use 10w-40.

 

mine is getting bored .60 over right now. The mechanic recomendedthat i use SAE 40 raceing oil after the break in

 

At first I have to admit the temptation was there to hit the gas and wind it out to 6500rpms! But I did try and take it easy for awhile and keep the rpms varied. I was wondering too about the weight of oil that I am using, but my engine guy said to use it. I have a high volume oil pump that he went through to make sure it worked great. Maybe I should give the 10w-40 a try? Also what about the many synthetics that are out there?

 

I have been told to use mineral oil, like Pennzoil or Quaker state 20W-50, because of the adhesive effect of them.

GM recommends 500 miles of varied engine speeds below 5000 rpm, without hard use or extended periods of high loading. Change oil and use it like you wan't.
http://www.sallee-chevrolet.com/Info..._break-in.html

:cheers:


[Modified by Lasse, 8:57 PM 5/24/2003]

 

Tom:
It depends on what kind of rings you have. If you have moly rings, you are good to go. Moly rings seat in during cam break-in. If you have cast rings then I would continue to take it easy until around 1000-1500 miles.

I have moly rings. After my cam break-in I took it out and babied it around for about 35 miles to check for leaks and what not. After that I took it out and revved her to 6500RPMs and repeatedly took it to the track. I have made 30 1/4 mile passes with my motor and it is still running strong and uses no oil.

My opinion would be take it out and wind the motor out like you are going to run it at the track.

 

With good quality rings, the most important thing becomes the finish hone on the cyl. Cast iron rings will seat very quickly. That is one reason they are used on lots of circle track motors. They seat quick for during the week engine refresh/rebuild, and they resist wear enough to last for a season or two. Moly are better, but they do take a little longer to break in. In a street motor, though, I would never open up my engine until about a thousand miles or so, regardless of what I have for rings/hone. It is just too easy to do (alright it's not THAT easy :)), and you risk quite a bit of extra work for yourself. :cheers:

 

Actually the Moly rings seat in the fastest (during cam break-in). It's the cast rings that take longer to seat in.

There are always usually two stances on engine break-in edicate. The first being the person who says that you need to baby it around for the first 1000-1500 miles. The other person being the one who says "break it in like you are going to run it."

I fall into the second category, "break it in like you are going to run it." Almost every person that I have talked to that has built a high performance motor felt this way. There is a method behind this thinking. The idea is that if you baby your motor around for too long you will seat the rings in too low, thus building the ridge too low. Then whenever you do go to get on it and rev it out you run the risk of smacking a ring off of the ridge and busting a ring.

I have well over 7000 miles on my motor and that includes 30 1/4 mile passes. My motor uses no oil and runs 12.14 @ 117.72MPH down the 1/4. Gordon is also a good example of this type of thinking :) .

Whether one way is correct or not I don't know. It's all in the eye of the beholder.

P.S. If your motor is going to come apart on you, it's going to do it regardless of whether you wait 25 miles to romp on it or 25,000 miles. The idea is to take the time and build it correctly so it doesn't come apart. :cheers:

 

:iagree: How many race motors get broken in for 1000 miles. They break in the cam (if no roller cam) and then they let it rip. I ran mine for about 20 to 30 miles after break in and then ran it hard. I have about 6K on the motor and it burns no oil and runs great. It did loosen up a little more for the first 1000 miles but I sure did not take it easy.
The moly rings will seat almost right away and the cast iron will take a while to seat. My moly rings set right away. I have well over 150 passes on this motor and no signs of oil anywhere.

 

Thanks to all for the info on break in, I know one thing for sure my engine pulls very hard, all the way to 6500. I am not sure what type of rings I have, the pistons are Keith Black hypereutectic (spelling)? I built the thing to run and thats what I am going to do! Bence, congrats on the 12 second club.

 

I would not worry about ring seating, It usually happens very quickly like Shane stated during cam breakin. You certainly should have them seated by now. I don't like thick oil. I like 10-30.
The way to make a big block live is to not use large clearances. About .002 on the rods and mains. No more. Certainly not .003-.0035. I know this is fine on a race motor but if you want it to live on the street build it tight, break it in easy and it will not be an oil burner.
One more thing is oil MUST be at 180 degrees or better before you start pushing the motor. Cold oil spins bearings. Make sure the motor is up to temperature before doing any hard driving.
I know lots will argue that they back out the driveway and let it go right away. They are asking for trouble like spun bearings.

 

:iagree: I always let the motor get up to temperature before giving it some rpm. I have seen to many cold motors spin bearings. I even saw an oil filter get blown apart due to cold oil.

 

I agree with Norval. I always get my motor up to operating temperature before I ever run it hard. Like he said, you are asking for trouble if you back it out of the driveway and romp on it.

 

I was out for a run tonight, man what a difference with the new tires, the old 225's don't have the grip the new 255's have! Big time fun....