I've got a new 383 w/ a D1SC. Looking for opinions on a recommended break-in. With or without boost? Limit the RPMs., etc?

 

The guy who built my motor told me to run it for about 30 minutes with different amounts of load. Don't just let it idle. Then change the oil after 30 minutes and reset the valve lash with the motor still hot. After the first 3000 miles it would either break or run really well.

 

People have a different ways of breaking in motors. One of things that is usually agreed on by most is to NOT baby it not matter how much you'd have a tendency to do so. You need to vary the load and rpm on accel AND decel. Change the oil frequently and you'll be fine. Oh and keep the boost on but don't hit 10psi coming out of your garage or anything like that... just use some common sense.

 

The way I did my last 2 motors seemed to work well. I was told it helps the rings seat.

I warmed up the car in the drive way idling, then took it for a ride, took it up to 3000 RPMs and let off the gas, let the load slow down the car, then up to 3500, then up to 4000, then up to 4500, then up to 5000... Obviously letting the car slow back down to idle by itself.

 

Good information. Thanks for the replies.

 

I ran mine for about 20 minutes in the garage ranging from 1500 to 2500 rpm's on inital start up. Then immediatly drained the oil and changed the filter. That gets a lot of the garb out from the build. Hopefully there isn't a lot, but the'll be some. Then drove it around town and highway like I would normally would, getting on and off of it every once and a while. Then after about 300 to 400 miles, started hammering on it and really getting in the boost. Changed the oil and filter again at 500 miles, then i'll change it at 1000 miles again. Then go on regular 3k intervals.

Ken R.

 

I ran mine for 20 minutes , Changed the oil & filter and cut the filter open to check for any metal, Drove it for 100 miles, Changed oil & filter and again cut open filter and inspected. Changed oil & filter again at 500 miles. I change my oil about every 2000 miles since. I stayed out of boost for 1000 miles. after about 3000 miles I could tell the rings were completely seated cause it runs way stronger than the first 2000 miles.

 

You should try to stay away from the freeway when breaking the motor in for at least 100 miles i'd say. You want the revs varying, not constant like they are on the freeway.

 

.....unless your on the highway specifically to hammer on it a bit.

Ken R.

 

My motor took 10,000 miles before it finally stopped using oil. I think I babied it too much.

 

I plan on having a friend tune my car N/A before I put the blower belt on and have it dyno tuned with a wide band. Last thing I want to do is install the belt along with the 83lbs injectors only to have it go way too lean and blow stuff up or end up washing the cylinder walls clean. =(

-B

 

You guys should go to an race engine shop and watch them build then dyno a motor. Within the first 5 minutes of run time, they're at full throttle. The first few pulls are "short" pulls from 4500 - 6000, then they hammer it from 4000 - 7500. I find myself feeling sorry for these fresh motors.

The turbo carb'd 377 we just built was at 4 psi boost on within 5 minutes of startup and 12 psi boost / 720 hp on the 5th dyno pull.

I've always had good luck and low oil consumption by running the pee out of it on the maiden voyage. If something is going to let go, babying it won't stop it.

 

I'm pretty sure that's an urban legend. When you run Methanol, it runs at 6/1 A/F rather than 14/1. Wouldn't that wash the rings out? Also, Methanol doesn't lubricate nearly as well as gasoline.

Mike

 

Its not an urban legend. The higher AFR of methanol and its tendancy to still run very well when on a rich tuneup lead to a need to freshen the cylinders more often. All you have to do is chat with some sprint car engine builders to get an idea of the difference. Sprint cars, such as 410 Outlaws also use a constant flow injection that can be plumbed right into the cylinder head. There's not much time for vapoization with that type of system and the air bleed in the injector body can get clogged with dirt leading to a pretty wet cylinder. The engines will come out after 10-15 nights of racing for a freshening.

The advent of EFI has directly led to longer running engines due to tight fuel control and better cold running characteristics.

There are tons of propane powered vehicles out there that routinely go 200k+ miles on an engine with only timing chain replacement. The oil life is dramatically extended on these engines due to lack of fuel contamination. Take apart or look at one of these engines at a machine shop sometime. You'll be amazed at the lack of wear to the cylinder walls.

Oil well engines often run on natural gas and can run for years with only oil changes. These things run night and day non-stop just chugging away. Neglected as there really isn't anything to do to them except stay on top of the ignition and change the oil. Many are oldsmobiles by the way.

Running overly rich on a fresh motor will harm its power producing potential. With modern moly filled rings you should get good seal pretty much as soon as a load is placed on the engine. Don't let it just sit there and idle away.

 

I do agree that Methanol will wear out an engine quicker. In fact, the my friend's engine shop/dyno will make a few dyno pulls on Methanol in a fresh engine to aid in ring seating. If it makes the rings seat quicker, then it probably accelerates wear. However, at 6/1 A/F ratio with a non-lubricating liquid, it doesn't wear out instantly like most of the "wash out the rings" crowd might have you believe. Part of the problem with straight Methanol is that it produces alot of water in the crankcase, which probably doesn't help the oil's lubricating characteristics.

I believe the lack of oil contamination is key reason for the longevity. By the way, I'm not saying that running 8/1 A/F ratio on gasoline won't reduce long-term reliability of an engine, just that it won't wear out within the first 2, 10, or even 100 miles. Some of the local 4-wheeler guys claim you can "wash out the rings" simply by flooding the engine 1 time.

Funny you should mention that. At work, I support many types of Machinery, including 7 natural gas engine-driven reciprocating compressors. 6 of them are 300 hp Clark engines and the last one is a 600 hp Cooper. They run at 300 rpm and the Cooper makes 10,500 ft-lb torque. They were built in 1942 and are still running today. I wouldn't say that they are the epitome of reliability and low maintenance, but they work surprisingly well considering the age. We spend roughly $200,000/year maintaining all 7. Oil change intervals are much longer than the equivalent number of hours in vehicle, but that's partly due to 2 sets of rings with oil injected inbetween them. The bottom set of rings (on the skirt) include 2 rings and the top set is 4. That's alot of rings for the combustion byproducts to try to get by.