I know the feeling, I am cutting and splitting wood now and it is a lot of work, plus winding down the garden.
I finished the leakdown test this evening but it has been sitting for almost a week. I did all the cylinders again and all have pretty consistent blowby. 15-19% on the gauge. Even the cylinders that had 5% last week now are leaking the same as the others. Not enough oil cling after a week to seal the rings? Air is coming out the valve cover grommet and dipstick tube. Is it possible ALL the rings have not seated across the board?
Face it please. This issue you have called for yanking the motor out and taking it apart even last week with what's been going on. I know it's not fun to think about, but that's firmly what your looking at now.
No. The rings should have seated in the first 10 minutes of getting on it when the engines was fresh. Pull 'er out and tear it down and critique
Do the umbrella valve seals look ok to you folks as far as the pictures show? My machinist thinks they might be the problem. He insists the rings should not be letting a quart by every 200mi. I'm going to cooperate with him of course to get things rectified and stay on good terms.
Air up the cylinders and remove the springs, I/we can’t see anything past the inner dampener. Your GOING to have to take parts off this engine if not remove the whole thing to find your source of oil consumption.
I'm just doing what the machinist requested.....Umbrella seals go up and down with the valves correct? It looks like they are all up.
Well then ask the machinist why you are leaking 15+% on a rebuilt engine? I don't think you can suck that much oil down the valve guides with the engine running. The plugs look like crap and look like they are gas fouling. do the compression test again and put a spoon full of oil in the cylinder after you do a dry test. some engines do not use the seals at all. Were the valve guides replaced or redone so there is a good fit with the valves? Take spring out like Demko said and look at the seal you can put rope in the cylinder to help the valve from dropping.
I can't see things well enough passed the flat wire damper part of the spring assy to make a comment as to what might be going on, but umbrella seals do ride up and down with the valve. It looks to me like your going to need to take them back to the shop to be disassembled and reviewed. When you remove the Intake to pull the heads you will be the first to know what's going on. If you see oil film coating the Intake port wall and a lot of wetness on the back side of the valves then excess oil is coming down the guides. In that cases while the heads are off I would have the shop cut the guide tops for positive valve seals and nip any further oil issues from the guides in the Bud! The rule of thumb when rebuilding heads is that if you are re-using the valves and they have more then 30k miles on them then you do not go with the stock umbrella seal set up if you want good valvetrain oil control. Also any used valve that checks in at more then .001" of stem ware should get replaced, not just so they don't rock and cause loss of cylinder pressure, but for reasons of oil control also.
Also note that if you need to add oil in a cylinder to get the highest cranking compression test reading then your fooling yourself big time on the condition of the cylinder, you have a issue that is only going to worse with added mileage!
It IS a lot of oil! Another thing that came to mind was the intake port seal from manifold to head, if its leaking, its very possible to suck in a ton of oil mist from the crankcase, but the vacuum leak could be so minor you wouldnt notice it in the way the engine runs, ESPECIALLY if it has a cam. Speaking of which, how does it run? Smooth idle, or mild cam installed? Factory metal bathtub gasket? Who assembled the engine? Buick 350/455's do not use umbrella seals as Mart said, the seals have a tight fit on the guide boss, as a matter of fact Buick does NOT use seals on the exhaust valve.
Compression did go up with oil addition but I would like to do it again with all spark plugs out this time. They're new stage 1 valves with new guide liners.
I'm not sure what you mean about intake port seal. I used the felpro valley pan/bathtub gasket with a little right stuff around coolant ports. It seems to me the car doesn't run on the carb idle circuit. Mixture screws do nothing at hot idle. 284-88h mildish cam. The car smoked a LOT at start up when I had the timing too far advanced because of the wrong timing indicator. But now not so much. My son-in-law said he saw blue smoke on deceleration. The machine shop installed bearings and pistons. I assembly the rest of long block.
