15% difference on 4th cylinder doesn't look to bad. What are your compression readings for wet test? A great difference between dry and wet on a cylinder may indicate piston ring issue.

 

Valve lash should be checked with the engine cold I believe. Low compression and blue smoke indicate worn piston rings or valve seals. That cylinder is eating oil.

Start by checking the spark plug. If its covered in soot you'll know you've got a problem.

The vacuum gauge test will most definitely verify the problem.

 

All of the compressions are near limit for most Accords (135 psi), so may be time for an overhaul.

good luck

 

Valve lash was checked, no tight valves, plugs were very black and sooty. During the process of testing the car began to start smoking all the time, not just on start up. The decision was made to change the engine out. A friend and I bench tested the compression on two other engines, one failed to develop any compression and the other generated 150# in all four cold. Stripped the both engines down to long blocks and put all of the sensors and components on the new engine. After a short run in (7 miles) and a minor adjustment of the idle mixture screw and idle speed screw the car pasted emissions with 23 of 220 on the high speed test and 63 of 220 on the idle test.

Of course things can't always go perfectly, this new motor has low oil pressure at idle, oil light blinks. Mechanical gauge shows at hot idle the oil pressure is only 11-12 pounds. Next step now is to open the bottom up and check journal size and replace the bearings.

Thanks for all of your helpful suggestions.

 

Suggest checking oil inlet screen for blockage. This could also account for low oil pressure.

good luck

 

2 psi should not be that far off? You have 12 and the book says 14.

I'm not a fan of throwing parts at an issue but oil pressure switches are pretty cheap.

 

Pulled the pan, a lot of bearing chunks in there. #3 rod on the crank was really dark, not all black and cooked but definitely shows signs of heat. Pulled the bearing and it definitely got warm, pulled #4 main as that is what feeds #3 rod and that bearing is coming apart. Pulled all of the rod caps, after marking them. #1, #2 and #4 look ok. #3 main also looks good. No signs of damage to the crank, no scoring or galling.
New bearings have now been ordered as well as a pan gasket.

 

Engine bearings replaced, did find some wear on #3 main at the point that both #2 and #3 are at the bottom of their stroke. Plastigauge says clearance is between .002 and .003, when rotated 90º clearance is between .0015 and .002.
On start up at idle oil pressure is 65 psi, cold at 2,000 rpms oil pressure is at 75 psi. Engine hot, oil pressure drops down to 35 psi.
And best of all, when dropping from high speed to idle, no knock!
Will have to figure out how to get some pictures on here to show you the bearings and the pan before I cleaned it.
With changing out the bearings, I am still less than the $200 that I would have had to spend to get the emissions deferment and I don't know that the original engine would have lasted that much longer.
Thanks for all of your help and input.