BREAKING IN NEW RINGS

GENE DERRINGER · Jun 13, 2019

This might be a dumb question, but here it is anyway. How many hours under load does it take for new rings to "set" or "seat" in a 4020 gas engine. I want to do some light work, but not until it is "broke in. Thanks

David G · Jun 13, 2019

IMHO, a good solid day of load will break it in.

David G · Jun 13, 2019

Also, use a good break in oil for first oil change.

I would not worry about retorque on a 4020.

tlock0331 · Jun 13, 2019

i know times change, but on a gasser, we would spend about 10-15 minutes at 1/4 throttle, 10-15 on half, 10-15 on 3/4, then 10-15 on full throttle, fine tuning it, timing, carbs, etc etc, during that period, then start putting it under loads varying the throttle again for an hour or so then kinda turn it loose.

Always checking oil pressure and water temp, use a digital thermometer on temps, not rely on gauge.

rustred · Jun 13, 2019

about a day working in the field under varying load conditions. idling is bad till broke in. light pulling is ok, don't need to run engine to max rpm on a light load.

Logan in SE Texas · Jun 13, 2019

In the early 80's I had a '79 Chevy truck with 77K miles. An old school mechanic rebuilt it. I was about 20 and he knew my driving habits, fast. We finished it at 6:00pm and at midnight I took out for Intercostal City, La. He begged me to not hammer on it going and I didn't. Seven days later I checked the oil and water and filled up the tank and ran the dog poo out of it on the way home. Went straight to his shop and he checked everything out. I told him what I had done and he said if it stood up to that it would last. I drove the crap out of it for over 100K miles.

JDEM · Jun 13, 2019

Much depends on the cylinder-wall finish. Did you just hone it out and install new rings? Or does it have new sleeves and pistons too?

Generally speaking, just vary the loads for the first 10-20 engine hours and no steady max-loads. Main thing is not sitting with the engine at no-load, low-idle speed. Actual break-in time depends on the types of rings, type of engine oil, and cylinder-wall finish.

Steve@Advance · Jun 13, 2019

David, why would you not retorque the head?

My thoughts are anything with a thick composition head gasket would need to be retorqued.
I'm assuming it would have a thick gasket, as most everything back then did.

Retorquing would theoretically tighten the valve lash slightly, so the reason to readjust.

I always like to readjust the valves anyway, just in case something settles in, something was under a pushrod or a rocker bushing "finds it's groove".

Not disputing, just learning and sharing...

Deutz Lover · Jun 13, 2019

The break in period will be much shorter if you plateau finish honed it. This removes the top sharp edges left from the 220-260 grit stones and is one of the reasons engines last a lot longer than they used to. Done properly it leaves the deeper cross hatch responsible for lubrication. Generally a 600 grit stone is used, but others use a finer one.

David G · Jun 13, 2019

Factory does not do it, and do not think Tim S has done it, he has done hundreds of JD's.

I think this was much more important with the super long head bolts on the 2 cylinders.

I have never done it.

MSM · Jun 13, 2019

If the headbolts have been replaced, they are more than likely "torque to yield" and are a single use bolt. Once torqued properly, they have taken a set and stretched to manufactures spec. They should never be retorqued.

mmfan55 · Jun 13, 2019

There is a difference between hard use and abuse. Abuse is bad on any engine. I tried to break one in how I planned to run it

BushogPapa · Jun 13, 2019

Have it "under Load" before it has run 20 minutes, sooner if possible.
Must be Before the cylinders glaze..

Dieseltech · Jun 13, 2019

I won't let a tractor engine leave if the head's been off WITHOUT checking head hardware torque when hot. Some will lose 20-30 ft lb on each bolt/stud.

buickanddeere · Jun 14, 2019

A non issue if the proper design and proper materials are used on a properly machined and finished cylinder wall.
Work it instead of old lady operation.
I would be more concerned about cam and cam follower lubrication. You did send them out for a regrind to compensate for wear, loss of lift and loss of duration ?

BREAKING IN NEW RINGS

GENE DERRINGER

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David G

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David G

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tlock0331

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rustred

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Logan in SE Texas

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JDEM

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Steve@Advance

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Deutz Lover

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David G

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MSM

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mmfan55

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BushogPapa

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Dieseltech

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buickanddeere

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