Engine break in time.

john charlton

john charlton

Well-known member
Thank you all for the drain tube info.I did think not having one would maybe increase any rear main leak.I will MIG tag one in. This engine is very stiff to turn on the crank handle with the pistons at mid bore.Looking up the bores I can see the new looking pistons are tight in the bores.Never ever had a recently rebored engine so this "stiffness" is unknown territory for me !!! I guess make sure you have a good rad and take it easy initially. Typically how many miles/hours before the engine frees up completely ???

John in cool cloudy morning England.
 
john charlton said:
I guess make sure you have a good rad and take it easy initially.
Click to expand...

The best advice I can give is that you run the engine at varing RPM's (around town driving) during the break in period.

What is that break in period? You are going to get many opinions, even from engine rebuilders. My suggestion is to take an average.
 
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From my very reputable engine rebuilder, his "rule-of-thumb" is - varying speeds below 40 MPH for 500 miles. Avoid low speed lugging. Change oil at about 100 miles after beginning the "break-in" to remove the initial (largest) collection of friction wear particles. Re-torque head at about 100 miles also.

Of course, a rebuilt engine isn't suddenly nice and "loose" at the magic 500 mile mark. That's a process that can last another 1000 miles or more, but you're "over the hump" in the peak wear-debris generating period.

During the break-in period a lot more heat is being generated by the higher friction conditions and the engine will be more prone to overheating if the cooling capacity of your radiator is compromised or marginal for any reason (low flow rate, clogged tubes, sludge, etc.) together with a very hot day - I found this out the hard way...

All the best with your car!

Earle
 
Thank you both for the info,most appreciated.This engine will most likely find a home in my sons newly aquired 29 pickup. Last on the road in 1961 but alas the previous owner got it running without cleaning out the pan and valve chest so I will bet my sweet bippy that the engine will be suffering a surfiet of looseness !!!

John in son is cooking sunday lunch ,bless him,cloudy afternnon England.
 
Tight engine, as stated above I agree with varying rpm's, no high speed runs, and keep her from lugging [working too hard] and several oil changes real quick within a few 100 miles. Follow the regiment for 500 or more miles. Additionally soft iron piston rings will seat in much faster than hard chrome rings, which I hope you don't have. If your really brave a palm full of regular baking soda gently blown into the horn of the carburetor while the churn ticks over at a quick idle will seat in the pistons to the bore a bit quicker. Don't over do it.

Now as you may know the factory simply hooked up a zero time engine to a 20 hp electric motor and spun her over with oil and water in the appropriate areas till the electric motor amps dropped, indicating that the engine was broke-in enough to handle the fire, friction and heat of combustion. Each engine varied in 'time in the saddle'.

skip.
 
John
Your engine is a long stroke, at mid bore it will be tight. On a long stroke the pistons have to travel faster at that point to get to the top at the same time a short stroke would. There for it takes more force.
 
John, If this is the swap meet engine that you don`t know the history on how long its been setting I would advise you to soak the bores with atf or some thing like as to make sure any rust is softened that mite have grow around the rings and a little lube at start-up. Just my thinkin. I`m always for a well oiled machine. Monte
 
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