Overheating engine to seat rings on rebuild

Captain D · 02-24-2008, 05:49 PM

I talked to an old General Motors mechanic today and he told me he puts a piece of cardboard or plexiglass in front of the radiator to overheat the engine in order to seat the rings after an engine rebuild. He waits until he gets an idiot light or the temp gauge shows the engine is overheating and then waits an additional 2 minutes before turning the engine off. He then lets the engine cool completely before starting the engine again. He said he has rebuilt 300 to 400 engines this way. It sounds crazy to me. I would appreciate any thoughts or experience in this procedure.......Thanks

tbonitz301 · 02-24-2008, 06:00 PM

That is crazy talk. Im looking foward to peoples posts on this topic

Jeff_Ciesielski · 02-24-2008, 06:13 PM

Old chevy smallblocks are all iron, which means that they arent as prone to head warpage or blown headgaskets as a result of overheating. Overheating the motor would indeed cause the pistons/rings to expand more than usual, which could lead to better ring seating. However, on a motor like ours which uses an aluminum head, this is indeed crazy talk. Intentionally overheating a new engine for several minutes would most likely cause a blown HG at best, and a warped head at worst.

Note: It is also likely that I'm talking crazy... but it sounds reasonable

tbonitz301 · 02-24-2008, 06:18 PM

I do see where your comin from about the old iron blocks and such. Like you said bad idea with aluminum.

jusmx141 · 02-24-2008, 06:31 PM

You think that's nuts, check THIS procedure out:

Break In Secrets--How To Break In New Motorcycle and Car Engines For More Power

Jeff_Ciesielski · 02-24-2008, 06:36 PM

Quote:

Originally Posted by jusmx141

You think that's nuts, check THIS procedure out:

Break In Secrets--How To Break In New Motorcycle and Car Engines For More Power

What, the motoman method? Thats not nuts, thats the proper way to break in an engine like ours. I finished assembling my engine the day before I drove my car from Indiana to Seattle, I took it out on some back roads, beat the piss out of it, and ended up with 150psi across the board.

tbonitz301 · 02-24-2008, 06:37 PM

I know right. Who wants to chance blowin there new setup

.

Jeff_Ciesielski · 02-24-2008, 06:42 PM

Quote:

Originally Posted by tbonitz301

I know right. Who wants to chance blowin there new setup

.

If its put together properly, its not going to blow up. Taking it easy isn't going to make problems go away, it will just take more time to notice them.

My1GLaser · 02-24-2008, 06:43 PM

I just broke in my motor yesterday using the motoman method. It doesn't smoke at all and hasn't since about 10 minutes into the breakin. Theres not a f_cking chance I would have blocked the radiator on my brand new forged motor. If you want more ring expansion turn up the boost.

I have about 60 miles on the motor and I am running 15 psi, and have taken it to 6000 rpms plenty of times. The motor sounds excellent, but I was very meticulous on the rebuild. Oh and I'm on my 3rd oil change.

Another 100 miles or so and I'll check the compression.

jusmx141 · 02-24-2008, 06:53 PM

I do the same as Motoman when breaking in customer's turbos that I install.

TONS of sites recommend dropping the synthetic oil and installing petroleum, then letting it idle forever and taking it easy for 1500 miles or so to break in a turbo....not me. I bolt the turbo on the car and start it, then check for leaks while the car's warming up. Once the car has reached full operating temp, I take the car for a short ride (approx 3 miles) to be sure the turbo has been warmed up accordingly and has enough oil. If everything seems kosher, I turn around a drive back to the shop at FULL BOOST. I've yet to have one let me down.

Mr Peepers · 02-24-2008, 06:58 PM

Priming is the only thing needed to "break in" a turbo.

jusmx141 · 02-24-2008, 07:21 PM

I agree, but other's don't feel that way:

TURBO BREAK-IN

jusmx141 · 02-24-2008, 07:25 PM

To be honest, I don't even prime the turbos I install as long as they're one of my rebuilds. Anytime I rebuild a turbo, it's fully lubricated upon assembly with engine assembly lube so there are no chances of a dry startup.

Mr Peepers · 02-24-2008, 07:43 PM

I'm not seeing *why* you'd need anything other than priming the turbo. I guess you could possibly find a problem before you start boosting it, idk... There isn't a hard reason like seating the piston rings etc.

tbonitz301 · 02-24-2008, 07:47 PM

Quote:

Originally Posted by Jeff_Ciesielski

If its put together properly, its not going to blow up. Taking it easy isn't going to make problems go away, it will just take more time to notice them.

Im not new to building engines. I have an exstensive backround in building 2strokes and some experience in building dsm's. I know all about motoman and his theory about the extra cylinder pressures needed to seat the rings and the decelleration process and all that, but i wouldnt wouldnt want to spin a bearing in the process. I know a guy that builds ford motors and he puts a brick on the gas pedal for 2 minutes for breakin. Thats his way of doing it. Everyone's different.