The Ford Barn - View Single Post - What is Engine 'Break-in'??

Gene F · 03-04-2021, 06:45 PM

Hmmmmm. I recently had my engine rebuilt. I know 2 things:

1) My rebuilder was very specific about me running it at varyed sppeds, and not on jack-stands either. 20 - 30 MPH for 20 to 30 miles to start with. He also wanted me to use very specific oil, but then he gave me a bottle of ZDP to add to that oil. I have already ran the engine around the neighborhoods for about 30 miles.

2) The reason my engine needed to be rebuilt to start with was because my crankshaft snapped. When you speak of machining techniques, I recall sending my crankshaft over to what I thought was the most notable shop for Model-A engines I knew of. That expensive place in PA. It was machined wrong. I had it turned, counterwighted, and balanced. It was also balanced and matchmarked with the flywheel and pressure plate.
Turns out there were 2 surprises to that machine work.

Brent, I'm interested to see the further comments to this thread since I am not a machinist expert.

03-04-2021, 06:45 PM	#3
Gene F Senior Member Join Date: Mar 2012 Location: Ohio Posts: 1,958	Re: What is Engine 'Break-in'?? Hmmmmm. I recently had my engine rebuilt. I know 2 things: 1) My rebuilder was very specific about me running it at varyed sppeds, and not on jack-stands either. 20 - 30 MPH for 20 to 30 miles to start with. He also wanted me to use very specific oil, but then he gave me a bottle of ZDP to add to that oil. I have already ran the engine around the neighborhoods for about 30 miles. 2) The reason my engine needed to be rebuilt to start with was because my crankshaft snapped. When you speak of machining techniques, I recall sending my crankshaft over to what I thought was the most notable shop for Model-A engines I knew of. That expensive place in PA. It was machined wrong. I had it turned, counterwighted, and balanced. It was also balanced and matchmarked with the flywheel and pressure plate. Turns out there were 2 surprises to that machine work. Brent, I'm interested to see the further comments to this thread since I am not a machinist expert.