Technical Water in #5 cylinder?

Doing a compression test this morning on a SBC 350. Pulled all the plugs and #5 was wet. Hooked up compression tester to #1 and windmilled the motor. A fair amount of water came out of #5 cyl. Continued with the compression test and #5 had 210 lbs. Where might the water be coming from? Would this indicate a crack in the head and water leaking into the intake or exhaust port above the valve?

 

Sounds kinda like a broken cylinder if it will build that kind of compression but water is also coming out of it?

 

Pull the head and be done with it.

 

I have recently put in a freshly rebuilt SBC 350. Cam break-in went well. The procedure was completed without any issues. I now have approx. 100 miles on the hotrod. Haven't abused it, I don't think I've exceeded 60 mph. I've been varying the speed between 1500 and 2500 rpm (in town and country driving).
Issue...
I performed a compression test this morning. Here's the result...
1= 202, 2=205, 3=220, 4=180, 5=210, 6=170, 7= 200, 8=190
A low of 170 to a high of 220 exceeds the 10% acceptable variation. Am I premature in expecting closed variations at this point and it's just taking a little time for the rings to get fully seated?

 

I now see that you have at least three threads started about this engine. The information about it being fresh would have helped. Anyway, you have a problem of some sort in #5 or it wouldn’t have water in it. So, looks like you need to at least pull that head. And, would be easier to help if all this information was in one thread.

 

Since the two that are a bit low are together, I might suspect a head gasket leak. I would probably re-torque the head and see if that made any difference. FYI, properly re-torqueing a head is done by first loosening the head bolt and then pulling it up to proper torque. If you want to see if the bolt was originally loose, make a paint mark on the bolt and head before you start.

So, re-torque, put some miles on it and retest the compression. As long as it runs okay I would put another 200 or 300 miles on it before retesting. Put some load on it, don't baby it.

I have seen many methods of properly breaking in an engine. On my race engines, we started the engine, brought it up to temperature and then raced it. That changed my idea about taking it easy at the start. I do, however, believe in breaking in a flat tappet cam via the normal method.

 

BluePrint engines start them, put them on the Dyno, and print off the results…that’s what they told me when I questioned them about the break-in period

 

I'd say you have three options ... talk to whoever rebuilt the engine, or pop the head off yourself and look for the cause of water in the cylinder (losing any possible warranty if there is one), or retorque the heads and run it a bit although, if there is a real issue with water in the cylinder, you risk hydraulic locking and major engine damage.

After only 100 miles on it, what made you want to check compression? With so few miles, I'd have assumed the rings hadn't fully seated yet making a compression tests somewhat meaningless (just my thought). White smoke out a tailpipe?

 

In my opinion you're going to have to pull the head and look closely at the head gasket. Pay attention to bolt torque when removing them...looking for looseness. If the gasket shows no distress, magnaflux the head to check for cracks. Hopefully you find the problem at that point or it's going to be ugly.

 

Were the parts taken in, machined and you assembled? Or did the shop assemble it?

As mentioned, don’t turn a bolt until you talk to the shop if they put it together.

Otherwise pull the heads.

 

In the time you took starting multiple threads about this you could have pulled the head and found the blown head gasket...