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cylinder leak down to figure out where the air is going is a good next step
Took yesterday off the project and rest my ankle. Left ankle needs fused someday. Should have gone for a bike ride before the heat hits.
Plan for the day, pull the valve cover so I can see when both valves should be closed and do just that. Pump air into that cylinder and hope it doesn't go to the crankcase.
First. I tested my test setup on the old engine on the stand. Air through a compression test hose, rotate the crank a bit, i ject air. See if it comes out intake or exhaust. Yes, easy on the stand. When both valves are closed, air pressure moves the piston. Cranks moves forward or back depending on the point the piston is in the cycle. So, this is my "control".
On the engine in the truck...
First. Pics to verify that the cam followers were in correct position. This was a suggestion as a possible failure. But they seem in place. And there doesn't appear to be any debris between the follower and valves, which was another suggestion. A third, hard to duplicate, but doubtful was a lash adjuster not pumping up. That would have kept a valve closed. So. This rules this out. Fairly sure the valve train itself is not at issue.
I removed the valve cover to see when the valves should be closed. Injecting air in the cylinder as in the above test, is a bit tougher to rotate the crank. I was able to get air to move the piston but nowhere near as "energetic". And not through as much of the stroke as the stand engine.
What have I proved? I'm not sure at this point. Other than I have a weak cylinder that seems to have spark and fuel.
I'm not sure how to see if I have air getting in the crankcase with the valve cover off. So I should put the valve cover back on, and close off either the pcv opening or the opening on the driver's side cover, and see if air comes out that way.
More later. Trying really hard not to over think this, but too late...
With no pressure on the exhaust valve, it still leaks. So. I guess I'll swap the head. I have to wait for new headbolts and head gasket. So later in the week. Besides, just getting to this step, I sliced a couple fingers open, not stitches bad, but made me mad bad. Give them a couple days off.
On the other hand, I got everything I need for a 4" lift for my 95 Jeep Grand Cherokee yesterday for only $20. Never installed. So maybe I'll start soaking down nuts and bolts with penetrant tomorrow.
I didn't bother with 4 and 8, 4, the rubber of the NEW COP is still on tbe cylinder, and don't "believe" it is an issue. And 8, the bolt for the COP might be stripped, it's not budging. And frankly, my fingers are bloody enough to not bother right now, it can come out with tbe intake. I'm waiting for a new head gasket and bolt set anyway. I will swap the head, engine in the truck. I might have a friend help, if not, well. It can't weigh as much as a Jeep 4.0 head. Did that myself two different engines....
So. I think I'm done for today. I'm going to pull the doors off my Jeep for the next few days now, and have some fun...
when you get ready to pull the head, lift the back bolts most of the way up, and then zip tie them towards each other. You don't have enough room to pull them all the way out, but if you do it like that you'll be able to get the head out with them still in the holes
when you get ready to pull the head, lift the back bolts most of the way up, and then zip tie them towards each other. You don't have enough room to pull them all the way out, but if you do it like that you'll be able to get the head out with them still in the holes
SWEET tip. Not unlike the 4.0 heads in ZJs and XJs...
Spent the day cleaning the garage, putting stuff away. Yes, I'll need SOME of it back out. Head bolts showed up today. Headgasket should be here tomorrow.
I'm down to setting timing before pulling the head. The head from the original is still resting on it's original block. But loose. Had numerous distractions from my wife, or at the least, the other head would be in place. Well. Breaking a 1/4" drive ujoint meant a trip to the store, and yes. Misplaced 10mm and 8mm sockets. After 3 trips to the parts store,, of course,, the sockets reappeared.
And of course, doorless Jeep made my errands more fun. Yes, I have mirrors... And no. As long as I have mirrors, this is legal here. Getting that lift kit the other day, already has my mind trying to turn Over to that as a project. Not yet... That lift will actually only get me 1 1/2" more than it has now. 240,000 miles. Still kicking...
Now I wonder, how an engine I heard run, granted 6 years ago, had enough buildup on the exhaust valve seat, to not seal. Perhaps as long as it sat, this exhaust valve was a touch open and condensate of many sorts formed? I have little doubt running any sort of top cylinder cleaners or any fuel system cleaners would have resolved this.
Interestingly. I had the chambers sitting visible. Pulled the cam. Put in a spark plug and filled the combustion chamber with water. After 15 minutes, the exhaust port was still dry. After an hour though, the chamber was wet.
Looking at all the valve seats on my old head while prepping it to go back in service...
05-30-2020, 10:16 AM
