fellow members,
some of you may remember me as the fellow who began his 240D engine rebuild some month and a half ago. i am pleased to report that the project has come to a close. that is, the engine is finished and will be installed this saturday with a little help from my brother. i have only the break-in procedure in the haynes manual to go by, and would like any additional input on how to effectively break this engine in. are there any seasoned engine guru's out there with prior experience? i'd appreciate any input, thanks
william gum
some info on whats been done to the engine:
new main and rod bearings
crank balanced and polished
new pistons
new cyl sleeves
head reworked w/ new valves
new cam shaft and rocker arms
new timing chain
new gaskets all arround
various other small parts replaced
(say a little prayer, and keep those fingers crossed on saturday when i turn the key............)

The break in period is one of the most crucial periods in an engines life, and it can play a large part in determining the life of your engine. I got the following information from a book called, "Drive it forever." Great book, lots of good advice. It is writen by Bob Sikorsky. (ISBN 0-9657577-0-6).

The break in should be done in the most favourable conditions possible. This means that in the first 500 miles cold starts and excessive idling should be minimized. The car should be run under load almost immediately after starting. Drive in a medium gear around 1,500-2,000rpm until the engine has reached it normal operating temperature. The engine, once hot, should be run moderately, not exceeding 2,500 rpm or 40mph (in top gear). Do not let the engine labour, and don't let the engine speed fall too low. Driving situations that call for more than half throttle should be met by shifting into a lower gear.

Other considerations:

-Change your oil after the first 1000 miles
-The first 500-1000 miles of break in driving are best covered in 3-4 longer trips than in many short trips
-Don't run the air conditioner for the first 2-300 miles
-Occasional full throttle acceleration is beneficial when the car is already in motion. (you're driving at 40, push the pedal to the floor and keep it there until you are at the limit, then let off)
-Try not to drive at constant speed for more than 5 miutes at a time, and occassionally let your foot off the gas alltogether and let the car slow down. (this creates more engine vacuum and gets more oil into the top half of the engine.
-Never accelerate fully from a dead stop.

Your new bearings will have much closer tolerances than the old one, restricting oil flow more. Also, as your new parts break in you will get more metal in your oil than at any other time. Personally I would take it out for a 500 mile trip, varrying the speed, accelerating occasionally, and then change the oil. 3 or 4 more trips to get it up to 1500 miles and then another oil change. After that change the oil at regualar intervals, but keep the driving moderate until you reach 5000 miles.

Just my 2 cents. I really believe that if you give your engine this royal treatment for the first 5000 miles and the first 1500 especially that it will pay dividends far into the future.

I personally believe that such extreme measures would have produced benefits many years ago. By following them with a new Chevy six in the fifties, you could have stretched the engine life from it's normal 50,000 mile life to maybe 60,000 miles.<g>

With modern engines, however, I believe that as long as you don't lug it, during the break in period, and don't let it run for extended intervals at a constant speed, your engine will live a long useful life.

The text from the book referred to above about keeping a constant light load, is probably the best part of the advice.

Having said that, it never hurts to be extreme. Most people think my oil change methods/intervals are extreme. But they would have a tough time proving that they hurt anything.

By taking extreme measures during break in, it may be healthy for your peace of mind.

Enjoy your new 240D,

thanks for the advice guys. i'll take it to heart and do the best i can. my only concern is that its january.... which means temps have lately been anywhere from 15-45 degF, which translate into cold starts. lets hope for the 45 degrees the first few times i crank her up. oh, and as far as working on the engine goes, the winter weather doesnt make the project much fun when you are working in a carport :eek: again, thanks for all your help, and pray that i;m not chiming in again at about 4pm saturday afternoon.
william gum

I was going to ask what the temerature was like where you lived. DO you have a block heater? If not you can also use a trouble light. A 100 watt light bulb will usually warm an engine almost as well as a block heater ina few hours. Just turn on the light and stick it near the oil pan, making sure it isn't touching anything easily meltable. Like Larry said, these might be extreme measures, but it sounds like you've already put a lot of work into this rebuild, a little more during the break in sure couldn't hurt.

Let us know how it goes.

block heater
 

420SEL,
i've thought very seriously about installing a block heater, especially since weather often dips into the teens (not extreme....)
the reason, however that i did not install such a heater is becuase i do not have, nor could i find an allen socket large enough to unscrew the freeze plug. does anyone out there have one of these allen head sockets??? if so, where did you purchase such a device? or, could i borrow this tool to install a heater? also, how difficult is it to install a heater when the engine is in the car? i am going to reinstall the engine this weekend and will not be able to attain a heater or freeze plug tool before then. thanks
william gum
p.s. i cant use the heater before initial start-up because there wont be any coolant in the block yet, therefore the heater will not transfer hfeat through the liquid.

If you start it on Sunday, there may not be too many people out on the roadways between 6 and 10 pm EST.

Bamboo77,

These cars will usually fill the block with coolant by simply filling the radiator. If the system doesn't seem to take somewhere around 8 quarts of coolant, vent at the thermostat or something to see that the coolant is surrounding the cylinders. You don't want to start a fresh engine without coolant around the cylinders.

Good luck with the start up,