nipper Posted January 23, 2008 Share Posted January 23, 2008 Hi Nipper; Replaced head gasket upon reassembly. Haven't reused gasket assumed that you can only torque it once, is that true? Wayneb Yes thats true. It may be time to take the heads to a machine shop. The seats may have sunk. You may have properly adjusted valves, but with a sunk seat, you would have a valve leak. The valve wont burn because there is no compression. nipper Quote Link to comment Share on other sites More sharing options...
wayneb Posted January 23, 2008 Author Share Posted January 23, 2008 Hi Nipper; Could I have had a bad head gasket seal? wayneb Quote Link to comment Share on other sites More sharing options...
nipper Posted January 23, 2008 Share Posted January 23, 2008 At 215,000,i am afraid to suggest alot of work. It sucks that i cant see things myself. Keep in mind i am way over here, and your way over there. It sounds like you need a valve job. The problem with doing a valve job on a old engine, is that the increased compression can cause blow by. Now that said, you do have strong compression numbers. One cylinder with poor compression is a valve problem. One cylinder with lower numbers, or all cylinders with lower numbers is ring wear (over 100 psi). If it was me, I would chance the valve job (or at the very least have a machine shop look at the heads), and not be too pissed off if it upsets the rings. Here is another thought, can you open and close the valves manually? If so get some Dykem blue (i think thats the name) and put it on the valve seat. Cycle the valce a few times and see if there is even contact while the dykem is wet. Next do it the other cylinder, and see if the pattern is the same. This may or may not work. Why was the original valve replaced? nipper Choice B is a used engine. Quote Link to comment Share on other sites More sharing options...
wayneb Posted January 23, 2008 Author Share Posted January 23, 2008 Hi Nipper; I replaced the valve and three others on cylinder #1 due to cam belt failure and subsequent cranking causing bent valves. I'll have to try the dykem, I also plan on putting head back on engine and performing compresssion test again after checking/re lapping all four valve seats. The plan is to leave the camshafts off the heads so all valves remain shut and performing compression test by rotating engine with a ratchet on balancer bolt. I think I'll dykem the seats before reassembly. I can also listen for hissing past seats and or pour fluid around seats through ports to test seal Then I think I'll try again with cams and belt in place. I think if head gasket is issue, then I won't be able to get any compression with valves completely closed. If seat is problem then compression test with cams and belt in place should show a big difference. If that doesn't prove successfull then the head is going to a machine shop! Wayneb Quote Link to comment Share on other sites More sharing options...
nipper Posted January 23, 2008 Share Posted January 23, 2008 Hi Nipper; I replaced the valve and three others on cylinder #1 due to cam belt failure and subsequent cranking causing bent valves. I'll have to try the dykem, I also plan on putting head back on engine and performing compresssion test again after checking/re lapping all four valve seats. The plan is to leave the camshafts off the heads so all valves remain shut and performing compression test by rotating engine with a ratchet on balancer bolt. I think I'll dykem the seats before reassembly. I can also listen for hissing past seats and or pour fluid around seats through ports to test seal Then I think I'll try again with cams and belt in place. I think if head gasket is issue, then I won't be able to get any compression with valves completely closed. If seat is problem then compression test with cams and belt in place should show a big difference. If that doesn't prove successfull then the head is going to a machine shop! Wayneb Both heads have to go the machine shop, otherwise you will have an unbalanced engine, especially if the machine shop resurfaces the head. nipper Quote Link to comment Share on other sites More sharing options...
WAWalker Posted January 23, 2008 Share Posted January 23, 2008 Lay the head upside down, fill combustion chamber with gas. Gas should leak out quickly around a valve that is not sealing. Quote Link to comment Share on other sites More sharing options...
Wicked_36 Posted January 23, 2008 Share Posted January 23, 2008 i'm not sure what the ECU reads to determine a "misfire" code but if it's one of the engine sensors that isn't in use until it's up to operating temperature then that would make sense to me...of course the bad cam/crank would as well, i know a few people have had failed cam/crank sensors i'd be interested to know if those codes appear before/after the car warms up. maybe someone will unplug one for you and see! or you could try the same...clear your codes and unplug the cam sensor (easiest one to get to). that still doesn't verify anything if nothing happens, but if the CEL comes on right away that might prove something. My cam sensor only codes after my car has warmed up. Quote Link to comment Share on other sites More sharing options...
nipper Posted January 23, 2008 Share Posted January 23, 2008 My cam sensor only codes after my car has warmed up. Thats a typical begining to electrical failure. As the component heats up, the solder joints or connections or wires that are weak expand, and presto malfunction. nipper Quote Link to comment Share on other sites More sharing options...
wayneb Posted January 24, 2008 Author Share Posted January 24, 2008 Hi All; Talked to guy at maching shop and he suggested looking at valve guides for damage. Did that and didn't notice anything obvious. Next tried pouring alcohol in intake ports with head on side with intakes facing up. Left for 1/2 hour no leaks. Did same with exhaust ports and three of four exhaust valves leaked! Relapped valves and they sealed tight! Next put head on engine and tested compression with cams out. compression wqay up in #2 cylinder, in fact 5psi higher than others. Will try with cams & belt installed tomorrow but I think I found the problem, leaking exhaust valves! Wayneb Quote Link to comment Share on other sites More sharing options...
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