No compression after valve seal replacement
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No compression after valve seal replacement Just like it says I yesterday put new valve stem seal on my 5.3. Aired up each cylinder pulled the valve spring off swapped the seals then put everything back together starting with the aluminum bar the rockers ride on then each rocker. Rolled the motor over so each lifter was at its base circle then tightened and torqued each rocker. With all that done I have to compression. I double checked everything and I'm at a loss for words. Has any one seen this? Oh and its on every cylinder not just one.
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From: Washington
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See if any pushrods turn easily. How would the lifters pump up WHILE the engine is off AND disassembled??
You replace one seal or all of them? You mention them in the singular tense.
You replace one seal or all of them? You mention them in the singular tense.
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Lifter plungers tend to live their whole life in one spot. Removing rockers allows the plunger to rise to the top, a normally unused part of the bore, where they can stick if there's any varnish/etc. built up. Reinstalling the rockers with the plungers stuck in the 'up' position results in the valve being opened instead of the plunger dropping back down.
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Lifter plungers tend to live their whole life in one spot. Removing rockers allows the plunger to rise to the top, a normally unused part of the bore, where they can stick if there's any varnish/etc. built up. Reinstalling the rockers with the plungers stuck in the 'up' position results in the valve being opened instead of the plunger dropping back down.
Thats what is exactly happening. I let it sit all night and this morning 4 of the cylinders came back to life after there lifters went back to normal while sitting over night. Its also pretty cold here so I set up my heater infront of my truck to help heat up the motor and help with oil not being so thick. This issue is definitely lifter related. Because everything is put together correctly. Im no novice by any means.
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The 3100/3400 V6s, with the magic disintegrating lower intake gaskets, were TERRIBLE about this same thing. Most of the time it was only a few cylinders and it would still run after reassembly well enough for the others to clear up eventually, but I think I remember one that held the valves open enough to bend a few pushrods on first crank.
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Yikes
yeah this is only hanging them open a tiny bit just enough for the valves to not seal.. I know this because I had air in the cylinder and started Tightening down the rockers and once almost fully tight and cracked the valve open
yeah this is only hanging them open a tiny bit just enough for the valves to not seal.. I know this because I had air in the cylinder and started Tightening down the rockers and once almost fully tight and cracked the valve open
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Its fixed and running. The lifter plungers were the issue. I heated the motor up with my shop heater then put the other rockers back together that I had off and regained 1 cylinder so i said screw it im going to try and start it on 5 cylinders. Fired right up and ran rough for about 45 seconds then started to clear up. She runs nice and smooth now with no issues. Thank for your input on the plungers cause I was pulling my hair out haha