Hi, is there anyone who can supply good info (or web-site) about break-in period for an 4.9 ???

I’m scarred of messing my freshly rebuilt engine !

Thanks

 

From the 1981 Ford Truck Owners manual:

New Vehicle Break in:

Your New Vehicle doesn't require a extencive break in. Do not exceed the lawful speed limit. Also try not to drive continuously at the same speed, as parts tend to better adjust themselves to other parts if various speeds are used during the first 4000 miles. aproximetly 100 miles of city or 1000 miles of highway driving is requiered to fully break in a new set of brake linings. Repeated heavy stops should be avoided during this period. It can take as much as 4000 miles to properly and fully seat piston rings.

Don't expect top fuel economy untill at least 4000 miles. All new engines use more fuel until they are well broken in. conserve fuel by avoiding fast starts and sudden brake stops.

A break in oil is not used or recomended. The engine oil is the same specified type as you will use in regular changes. Change the oil and filter every 3000 miles or as stated in the matenace schedual in this guide. Don't add anti friction compounds such as STP oil treatment (or slick 50) or special break in oils during the first 4000 miles of operation as these oils and additves may prevent piston ring seating. The engine may burn some oil until the engine is fully broken in. Do not be alarmed, as this is normal. Please check your oil often, or at every fuel stop.

Hope this helps...

 

Thank you very very much,

You seem to know quite a bit on the subject, and what you just wrote helped me calm down !
I’m very nervous because it’s the first time that I have something near new in my hand and I don’t want to spoil everything by ignorance …
I’ve finally found a web-site that talk about rebuilted engines … they’re telling a good trick to prime the oil pump with a hand drill … so, I did it, and it went well !
Thank you for the detail like fuel economy, break-in oil, etc. the way you wrote the reply also help me understand what I’ve read in the web-site, and will keep me calm until I reach 4000miles !
I will keep a good eye on my oil too !

Thank, and take care !

 

If you put a new cam and lifters in, then you will need to break the cam in on first startup. Keep the rpms at 2000+/- for 20-30 minutes. Then you can go drive it. I changed oil and filter at 50 miles on my rebuild to get rid of the lubes and metal particles.

 

My Haynes manual pretty much agreed with the above and added that you should find a deserted stretch of road and accelerate from 30 up to 50, then engine brake (coast down with throttle off in gear) back down to 30, then repeat several times to help seat the rings.

I always heard years ago to break it in the way you intended to drive it, i.e., hard or easy. Don't break it in easy if you intended to hot rod it, in other words.

A little of each in moderation is probably best. With new rigs, it's almost a non-issue I think, if you believe how they drive new models in the commercials!

-Smoky

 

If you put a new cam and lifters in, then you will need to break the cam in on first startup. Keep the rpms at 2000+/- for 20-30 minutes. Then you can go drive it. I changed oil and filter at 50 miles on my rebuild to get rid of the lubes and metal particles.

This is pretty important, and I also recommend changing the oil after about 50-100
miles. You will be surprised at all the fine metal shavings, particles, lint, etc, that
comes out. Also...It's a good idea to save the filter with a filters worth of oil in it.
That way, if you have any problems, you have a sample that can be used for
analysis. As far as driving, most have mentioned most of the usual. Don't drive the
same speed for long, and do a lot of engine braking, if a standard. Engine braking
sort of acts to clean the cyl walls, etc, with fresh oil. Myself, I change the oil/filter pretty often on a rebuild until about 5k miles. Then I go to my normal 3k sked.
After the break-in, recheck all the bolt torques. IE: head, manifold, etc...
You should be ok, if the rebuild was good, and install ok... I put a rebuilt in my 68
about feb 02 or so, and haven't had any problems so far. It still runs the same now,
as when I installed it. Runs good too... If the engine builder has any extra things
to check, do them, and keep a record. Actually, keep a record of everything...
Could come in handy if there is a problem. BTW..Don't use synthetic oil for break-in.
Use dino oil, and then after the break in , you can switch if you want. Synth oil
is *too* slippery for a good break in on a rebuild. You can end up with glazed cyl walls, etc...
MK

 

Wow, I can only remember one time I was involved in breaking in a brand new motor. It was like a special moment or something. Good luck with yours and many happy miles!
-Smoky

 

Wow, I can only remember one time I was involved in breaking in a brand new motor. It was like a special moment or something. Good luck with yours and many happy miles!

The one in my 68 was the first I'd ever changed. Did 95%
of it myself, and took about 8 days or so. The original engine
spun a bearing. I bought a longblock from a local rebuilder.
Quite cheap too. So far, it's been ok. The valve setup was a wee
tad sloppy for my tastes, and I rigged up an adjustable rocker
setup using back to back rocker bolts. I only keep mine about
1/4 to 1/2 down from zero lash. A couple were too tight using
the non adjustable setup.
But I know the feeling about nervous... It's quite a bit of
money, quite a bit of work, and you know if it bombs you
gotta yank it and do it all over again. Also, you hope if it
does bomb, it ain't from something you did while installing..
Thats why I took a long time to do it. Took my time, and any problems I checked the correct method before going any farther.
I know a few mechanics, so advice was easy to come by in my
case. I also cleaned and repainted the firewall and fender wells
while I was at it. New clutch too... MK

 

Hi, everyone,

First of all, I want to thanks each and everyone of you who have answered (and by the same time, calm me down) my post ! … There was a times when I thought that I was trying to change too many things at the same time and it was beginning to weight on my shoulders !
Now that all is done, I’m please to announce that I just came back from a long trip vacation (at least from my point of view) I just drove 1500 miles in two weeks …The engine had only 250 miles on it when I attached a 18foots caravan on it, plus a dirt bike in the bed and all the stuff that is needed for two adult and a 1½ year old kid … And all went extremely well !!!

The only little shadow on the voyage was a little pinking on rough climbing that happened in the last 100 miles of the course … So, the minute a gas thank has emptied, I fill it up with premium, and the problem was solved ! Then I kept a thank filled with premium the rest of the trip for the hard working manoeuvres !

I have to explain that the pinking surely come from the fact that I change my single barrel carb for a holley 570cfm 4brl, I also passed from my 86 stock manifold to a 95 double and from 2¼ to a full 3inch exhaust syst (dynomax full 3" muffler) that exit in front of the rear well … And I had to disconnect the automatic advance on the distributor because of heavy pinking in whatever degree the timing was … But in the end, the result was amassing, way better than I expected (from what I heard in the forum, I always thought that they were exaggerating) it’s like I have a 8 cylinder engine with tons of torque ! Now I have to control myself when I drive … A thing that I never have to do before the mod !

I’m very glad that this site exist, and I’m pleased that even if my English is not 100%, cause over here the first language is French, many people are answering anyway !

So, thank you guys, I’ll kept reading !

Cris

 

Glad it went well! Time for an oil and filter change to rid it of the metal shavings left over from break-in. Make a schedule for maintenance and stick to it, you'll get many miles.
-Smoky