Hi all! Looking for a bit of a sanity check here. Think I have my answer already but this is my first rodeo leakdown testing a used motor that has been pulled from another car.

Got my donor 2.5L for my NC yesterday and leakdown tested it this afternoon. Ran my tester at 90psi and got 20-50% leakdown per cylinder, all from the exhaust ports. I turned the motor over by hand before this but nothing else. Exhaust ports were pretty filthy with carbon (I should have taken pictures) so I filled them all up with sea foam for a bit then blew them out with brake clean and some compressed air. Rotated the motor a couple times and tried again. Cylinders 3 and 4 sealed up below 20% and cylinders 1 and 2 improved. The exhaust valves on 1 and 2 nearly perfectly sealed, but they were now leaking a tad from the intake valves. I think I blew some of the exhaust valve deposits into the intake valves.

Based on this, I believe my current/previous leakage to be from the aforementioned carbon deposits. My current plan is to sea foam all of the valves and blast everything off a couple more times. I’m assuming that even if I didn’t notice or do this, the valves would knock any carbon off of the valve faces once it was fired up. Anyone who has had a similar experience to this: is there anything additional I should consider doing? Or am I just being a hypochondriac?

 

 

My shop does a large number of used motor swaps. We buy from non-roll over donors, known sellers, and usually with some sort of warranty. But it's near pointless to do a leak down on a cold engine that's been sitting for a while. You'll get a decent idea of it's health, and maybe fix it a bit with some initial cleaning (like you did), but it's real health comes from a proper warm up, fresh fluids, and either a fatty burnout or a couple dozen dyno pulls. Most sellers also include a compression check. Pour some atf in the cylinders now, it'll smoke like a train when you start it up, but should help clean the rings up a bit.

Consider yourself lucky if it works out, for the past few years we've had zero luck with used BPs, they've all gotten a quick ball hone, fresh rings, and refreshed head. The time of decent used BPs is gone, for all but the luckiest.

 

What are you using for rings? I'm in the same space as the OP. Bought a used BP, scattered leakdown numbers. Tore the head off and didn't see much, save for some carbon. Lower end is looking decent, haven't pulled the pistons yet; but thinking if I pull those, might as well ball and ring as I already plan to replace bearings.

 

Six & Curly. These are the collectively the answer I was looking for. Thanks, gents.

That's about what I hoped would be the case. Figured after startup, I'd get the thing hot, run some cleaner through it, then give 'er the ol' Italian tune up. The motor in question is a 2.5L out of a 2015 Ford Fusion w/ 84k miles on it. Photos on the eBay site showed the car got shunted from the rear. Hoping all is well. I've yet to talk to someone who got a dud Duratec motor for their NC, but maybe I'll be the first! Honestly these motors are so inexpensive I'm thinking of grabbing a second one to rebuild on the side once I get another couple projects done.

 

OEM from Mazda, $100.40 last time I purchased, which was last month. Ball hone with heavy use of ATF, cheap rods/mains (no race bearings), great time to throw some china rods at it (manly, eagle, k1, maxspeeding). While you're buying the rings at Mazda, get front/rear oil pan seals, pickup tube gasket and oil pump o-ring, and front/rear main seal and a tube of RTV later, you've got a $500ish 300hp bottom end. /threadjack

 

Good details, thanks!!