Leakdown test a newly rebuilt engine + other ways to verify

[GSLENK]

I am trying to test a built engine (long block, assembled, with timing components, on a pallet in plastic wrap) to verify condition before I go through the process of buying/installing it.

It was built and never ran. Sat in climate controlled storage for a while. I was thinking of ways to prevent a headache...

Hand crank engine:
To make sure nothing is seized/interference etc...

Leak down test:
I realize things (rings, other?) haven't fully seated/sealed/etc... so #s may be low, but they should be at least consistent. What would a ballpark leak down % on a fresh rebuild be?

Also its going to be a "cold engine" as it cant be ran...

Compression:
I don't think it is possible or even a good idea (starter doesn't mount to engine alone)

Any other ideas?

 

[GST with PSI]

Personally, I like to pop the cams out and do a leakdown test. I've seen around 20-25% on my new motors. I've also seen up to 40% on others. In both cases though, the motors were healthy after break in. On a fresh motor, I'd be more concerned about similar readings between cylinders, and less with the actual leakdown percentage. I'd shoot for less than 5% variation between cylinders. Keep in mind also, if the the supplied air to the leakdown tester varies, so will your results. Make sure you dial in the gauges correctly, and keep consistent air pressure at your regulator. Lastly, make sure your pistons are at true TDC, or it will also cause your readings to vary between cylinders as well.

IIRC, I leak down tested my last motor build around 25% leakage before break in. Here's my ~500 mile compression test: http://www.dsmtuners.com/threads/gstwithpsis-galant-vr4-1837-2000.482807/page-6#post-153588586

Try and do the leakdown test with the intake and exhaust manifolds removed. I'd be more concerned about finding leaking valves than I would be with the piston rings leaking. Let's be honest, if the rings were installed in a way that causes them to leak, you're building a short block at that point anyways. Do what you can on the stand, and don't worry about the rest, unless you're going to comb through the entire motor before install.

Good luck. We should meet up sometime when you get this thing back together!

 

[GSLENK]

There are no manifolds on the motor. Good point on removing the cams. Would it be easier to pop off the rockers instead?

I am doing this test in a storage unit. I don't think it would be fun to pull cams there. I could do it easily once I bring the motor home.

Seller just verified that the engine turns over by hand. At this point, what would be the worst case scenario of things that could be wrong? Assume all internals are new and properly machined/installed by a reputable shop.

Maybe need a re-ring and valves lapped? If oxidation had occurred from storage... This is the block that sat for a long time in climate controlled storage.

 

[GSLENK]

Turned over easy and smoothly. Leakdown test was as follows: 1=16%, 2=18%, 3=10%, 4=14%. No leaking from valves. I went for it. It has a ton of goodies not in the original receipt. Ported head, hks272, non-stock springs (cant't ID yet), adjustable cam gears, all blue valve stem seals. Should really wake up this FP red. Now I just need a million gaskets and bolts etc...

 

[diambo4life]

Those are not acceptable numbers in my opinion. You should see no more than 10psi leakage from every cylinder at the most. The 8% variance from hi cylinder to lo cylinder is not great. If the water pump, thermo housing and water pipe are installed, I would add water in there and repeat leakdown. I would not pay top dollar for this engine.

 

[GSLENK]

Those are not acceptable numbers in my opinion. You should see no more than 10psi leakage from every cylinder at the most. The 8% variance from hi cylinder to lo cylinder is not great. If the water pump, thermo housing and water pipe are installed, I would add water in there and repeat leakdown. I would not pay top dollar for this engine.

I hope that's just a side effect of sitting so long and never being ran (rings never seated). I got the engine installed, spent a LOT of time priming the oil system. It started right up on the first try. Just in time for me to go back on vacation for a few more weeks. when I get back again, I'll do a real compression and leakdown (warmed up). I'll see how this plays out then.