MTFCA Forum

My 1926 engine has just been rebuilt for my Touring Car restoration project. It is a stock rebuild. The rebuilder ran it a bit before I picked it up, but I'm guessing there is a break-in procedure to follow? I am also wondering what engine oil is recommended for a fresh rebuild -vs- a well worn engine. I am reading conflicting information on the different forums, so I thought I would solicit updated information.

You're about to receive brand-new conflicting advice

I have always worked in a fresh rebuild very cautiously. First start up I run it for 5 minutes at an idle or until it starts to get hot. I then let it cool down completely and do the same thing next day but this time I run it for 10-15 minutes or until it gets hot. I then let it cool down completely again and on the third day I run it until it gets hot. If it doesn't get hot after 1/2 hour I assume it's ready for the road. I then keep it under 25 and avoid winding it out in first gear for the next 250 miles or running too long at any one speed. I run straight 30wt detergent oil for the break in and change it before I start driving it on the road. My rebuilds are very tight and I always have to pull start the first time. The variable is the condition of the radiator and that's why I also time the runs rather than wait for a tight engine to cause an overheat. I am sure others will have a different take on this but it has always worked for me. Of course if your rebuilder has run in the engine for you I guess you could skip the initial three day break in I do.

"... but I'm guessing there is a break-in procedure to follow?"

Why guess? Ask the place that rebuilt it. Do anything other than what they say and any type of warrantee that they might have offered is gone.

Well, your new Ford came with this sticker on the windshield. Likely factory advise is good.


Had one quality re-builder of many T engines who gave me similar advise on speed and break-in. To vary the speeds during this time, and check for leaks, oil or coolant. Adjust bands like low or reverse or brake during the first 50-100 miles, unless more needed from new setting that may be a bit loose for the new band linings.

Recommended non-detergent oil for the first 100 miles, then drain, and install quality detergent oil.

Reason for non-detergent break-in oil choice is that is froths less for good oiling of the trans and crankshaft and its parts. The detergent from then on to keep the new motor clean, but change oil every 500-700 miles anyway, same as Ford original instructions for long life.

This is going to be which oil to use and we know how this goes. Just for grins what did the rebuilder say since he’s probably gave advice before since he’s rebuilt T engines. Just curious.

I'd put 20 W or 10W30 in a new, tight engine. Run it at 600-700 RPM for a few minutes to check for leaks and make adjustments to carburetor, etc. Then drive the car, gentley, at various speeds up to 20-25 MPH, avoiding any hard pulls. As miles accumulate, increase speeds gradually, avoid constant speeds or hard pulls or prolonged idling. Take opportunities to coast downhill in gear. I'd change the oil at a couple of hundred miles, strain it, and save it for lubricating chassis parts. Model Ts do not like thick oil, and you sure don't want thick oil in a new, tight engine, especially in coler weather. I'd want a transmission cover strainer and magnet in a new engine, or any T engine.

Did your engine rebuilder give you any hints on how to break in a new engine?

Hi Robin,
I'm with most what did the engine builder say? Scott is right as usual. I don't build a lot of engines for others, I personaly use Time-Saver on all
my bearings so they are not a real issue on breakin. It sounds like your engine guy has a runstand if he ran it before you picked it up. I run my
engines 2-3 hours on the stand.. Checking everything I can this seats the valves, rings, bands, I check head bolt torque & clutch. Make sure
everything is good & on the last run I drain the oil & clean the screen to make sure nothing showed up, then it iether goe's in the car or under
the bench. If it goes into the car it's pretty much good to go, I do take it easy for awhile at first. That's just what I do.
Craig.

Several miles at low speed and then medium speed and repeat. over revving is not the problem, seating the rings is what running in is about. The likes of running in early engines, Dodge, Ford v8 Chevs etc. are doing 1600 rpm at 35/40 mph to run in on engines the rev out to 3400, that's about full bore on a T engine. The climate at my end of the world, I recommend 15w-30 or 40 on fresh engine.

Don't forget to re-torque the head!

The rebuilder recommended Rotella 15w50 oil. I was out of town when he finished my rebuild and he has since passed away.

Thank you to everyone who posted advice, I appreciate it.

I drop the fresh engine in. Drive the car around the barn and then onto a trailer bound for a national tour. I've done it many times with no regrets. Change the oil while on tour. Retorque the head as needed.

I actually did that exact thing once. So. Dakota National Tour...some of the toughest touring I've ever experienced. Loooooonnnnngggg grades in low worried me mightily, but everything worked out fine. Adjusted low and brake every day at lunch and changed the oil every evening...all of the above for all 5 days. That thing was broken in just fine when it made it's way back to my dad in TN.