6.2L Winter Refresh

[SpareParts]

Plugging the numbers in at Wallace racing the dynamic CR should be 213.53
Wonder if my compression gauge is junk.

 

[West 1]

Test it on another engine, off by 90 psi is way off. A leak down tester will put 100 psi in your cylinder and show if it is holding or bleeding past the rings or valves. You could test one cylinder in 10 minutes and at least rule things out.

 

[SpareParts]

Went out this morning and checked the compression on the engine in my Yukon. Cold it is 150 psi on cylinder 1. Compression gauge checks good.

Talked to the cam maker this morning for about 1/2 hour. He said if the center line and lift are checking out the cam is correct. He also said he would expect cranking at 150 rpm
compression should be close to 150 psi.
I'm not sure the starter im using can spin it that fast and i know my cables are not giving all the amps it should probably get.

After sitting all night i did a leak down test. Two cylinders are leaking 8 psi from the exhaust valves and probably 2 psi from rings and are reading 125 psi. The remaining cylinders are 135/140 psi and loosing 2 ish psi. @ 80 psi.

Push rods are almost to long. 1-1/4 turn. Everyplace says between 1 and 1-1/2 turn is perfect. Push rods should not be a problem.

Sooooo.
I could take the heads off and lap the valves until they are 100% sealed and reinstall with 0.048 head gaskets. Or,
As @West 1 mentioned i could just put it in knowing i might need to take the heads off at a later date but maybe not.

 

[West 1]

Did you use 100PSI on your leak down test? I only ask because some guys use less air for the test. 8 PSI leaking at 100 is only 8% leak. On the last 6.2L I did with new Piston and Rings running on the factory hone I had 3% leak down after the build, I did test it after I ran the engine for an hour or so. That block had 175,000 miles on it. Both heads were rebuilt due to a dropped valve seat on that one. Motor Machine in Sacramento did the heads for me. On your engine once it runs the valves will pound in and seat fine if the push rod geometry is correct. You might back off the two leaking cylinders rocker arm nuts/bolts and see if anything changes just as a test. Do you have a high amp battery charger to keep on it while testing, maybe 25 amp. That might help spin faster. New engines are tight and will spin a little slow. I assume all plugs are removed.

I would not pull the heads unless something showed up making me do that.

 

[SpareParts]

Tried backing em off. No change. No plugs.
Yeah, battery is on a charger. The problem with that is im using 2, 15 foot long cable's that are i think 6 gauge wire and i don't wanna cut em down.
I used 90 psi for the leak down.

I'm putting it in and running it.