Torquing rocker arms to spec causes valves to leak = No compression!
11-05-2015, 07:37 AM
#31
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I promised myself that I wouldn't offer anymore advice because I have been wrong too many times. But there really could be another cause for the issue this OP is having here and he needs to get it going.
Cam timing...When I put a new timing chain set on mine I was a bit baffled that they allowed the old "loose chain" style setup to continue through all the years of this engines history. About everyone else went to a tight chain setup on all their inline sixes that had chains instead of gears.
What I mean by loose chain is that even new there is a drooping amount of slack in the timing chain. it keeps it's self tight when turning the correct direction and there is a plastic rubbing block that is supposed to take up the slack on the top side where the chain hangs loose.
So here is what may have happened and should be checked. If the chain and rubbing block are worn all it would take is to be counter rotated while working on it and it very well could jump a tooth on the chain and crank gear. This would cause the exhaust valves to start opening before TDC instead of just after TDC.
The action of backing off the rockers would delay and compensate for this exhaust valve timing issue to let it run. To check for this just turn it over by hand in the correct rotation through the cycle on number one and watch your rockers as they push the valves. If it starts to push down on the exhaust valve before the timing mark comes up on TDC instead of just after then the cam timing is off and the chain needs attention.
Just wanted to share another possible cause to check out.
Cam timing...When I put a new timing chain set on mine I was a bit baffled that they allowed the old "loose chain" style setup to continue through all the years of this engines history. About everyone else went to a tight chain setup on all their inline sixes that had chains instead of gears.
What I mean by loose chain is that even new there is a drooping amount of slack in the timing chain. it keeps it's self tight when turning the correct direction and there is a plastic rubbing block that is supposed to take up the slack on the top side where the chain hangs loose.
So here is what may have happened and should be checked. If the chain and rubbing block are worn all it would take is to be counter rotated while working on it and it very well could jump a tooth on the chain and crank gear. This would cause the exhaust valves to start opening before TDC instead of just after TDC.
The action of backing off the rockers would delay and compensate for this exhaust valve timing issue to let it run. To check for this just turn it over by hand in the correct rotation through the cycle on number one and watch your rockers as they push the valves. If it starts to push down on the exhaust valve before the timing mark comes up on TDC instead of just after then the cam timing is off and the chain needs attention.
Just wanted to share another possible cause to check out.
11-05-2015, 07:41 AM
#32
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[QUOTE=CCKen;3166327]
I tested 3 of the lifters and they wouldn't budge. Could they be stuck open? or maybe there is just gunk down in there. The engine didn't have a lot of gunk, BUT there was a lot of water in the oil and it was sitting for three years.. If the engine didnt start before i ripped the head out i would say a million things could be wrong. BUT the engine DID run before i replaced the head gasket. I do still plan to change all of the lifters out because i dont think it can hurt. I know my cam may suffer, but im not replacing the lifters because they are worn.
I attempted to compress the lifters by hand and it was no good. I'm no a small dude, and they wouldn't budge. But when the rocker hits the top of the valve when im tightening, the gap between the bottom of the bridge screw and the head is like 1/8th of an inch, like A LOT. we aren't talking .02-.06 of an inch.
If it can't be the push rod and it cant be the rocker, it must be the lifter?[/QUOTE]
Correct.
Is this with all lifters or just one?
The lifters should be allowed to drain down at least over night.
It sounds like they may be gummed up. How doe it look under the valve cover when you pulled the head...all sludgy?
If it can't be the push rod and it cant be the rocker, it must be the lifter?[/QUOTE]
Correct.
Is this with all lifters or just one?
The lifters should be allowed to drain down at least over night.
It sounds like they may be gummed up. How doe it look under the valve cover when you pulled the head...all sludgy?
11-05-2015, 08:13 AM
#33
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[QUOTE=Kale;3166503]
I tested 3 of the lifters and they wouldn't budge. Could they be stuck open? or maybe there is just gunk down in there. The engine didn't have a lot of gunk, BUT there was a lot of water in the oil and it was sitting for three years.. If the engine didnt start before i ripped the head out i would say a million things could be wrong. BUT the engine DID run before i replaced the head gasket. I do still plan to change all of the lifters out because i dont think it can hurt. I know my cam may suffer, but im not replacing the lifters because they are worn.
Maybe you have a bent valve stem (?). If you do a compression check on each cylinder you may be able to pin point the offending valve(s).
Replacing all the lifters won't help a bent valve stem.
You can try this: Remove all rockers. Using a steel straight edge that will span all the valves, place it on top of the valve stems. Look to see if one or more valve stems are further down than the rest. a variance of .005" may be acceptable.
I tested 3 of the lifters and they wouldn't budge. Could they be stuck open? or maybe there is just gunk down in there. The engine didn't have a lot of gunk, BUT there was a lot of water in the oil and it was sitting for three years.. If the engine didnt start before i ripped the head out i would say a million things could be wrong. BUT the engine DID run before i replaced the head gasket. I do still plan to change all of the lifters out because i dont think it can hurt. I know my cam may suffer, but im not replacing the lifters because they are worn.
Maybe you have a bent valve stem (?). If you do a compression check on each cylinder you may be able to pin point the offending valve(s).
Replacing all the lifters won't help a bent valve stem.
You can try this: Remove all rockers. Using a steel straight edge that will span all the valves, place it on top of the valve stems. Look to see if one or more valve stems are further down than the rest. a variance of .005" may be acceptable.
11-05-2015, 08:20 AM
#34
You avoided my question.
Which head gasket?
Did you have the head decked?
If so, did the machine shop mill the top of the valve stem?
If you used the early gasket (thin) and you decked the head and not relieved the stems.........There is your difference.
You can get shims and go .040 under the rocker.....see if that helps.
Which head gasket?
Did you have the head decked?
If so, did the machine shop mill the top of the valve stem?
If you used the early gasket (thin) and you decked the head and not relieved the stems.........There is your difference.
You can get shims and go .040 under the rocker.....see if that helps.
11-05-2015, 08:22 AM
#35
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That is definitely something to check out, thank you for typing all of that out. I did turn the engine in the opposite direction (CCW?) during all of this. It just still is iffy to me because ALL of the valves are open, like 5 turns of the ratchet open, once the rockers hit the top of the valve stem. They are all pushed open a descent amount.. If it was the timing, they would all tighten correctly, but the engine would just have little compression.
I see what you are saying and understand. Apparently I misunderstood that it was all of them and once again I am off. I just fired myself again. lol
It will be interesting to find out what this issue ends up being, especially if you didn't have any head work done to it. I have seen this when a head had been milled too much and the valves and valve seats were all ground at the same time.
11-05-2015, 11:13 AM
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You avoided my question.
Which head gasket?
Did you have the head decked?
If so, did the machine shop mill the top of the valve stem?
If you used the early gasket (thin) and you decked the head and not relieved the stems.........There is your difference.
You can get shims and go .040 under the rocker.....see if that helps.
Which head gasket?
Did you have the head decked?
If so, did the machine shop mill the top of the valve stem?
If you used the early gasket (thin) and you decked the head and not relieved the stems.........There is your difference.
You can get shims and go .040 under the rocker.....see if that helps.
I didn't have anything decked or machined, i just scrapped the old one off and put the new one on. It seemed like a normal thickness head gasket, but unless it was really thin, i dont see how this would give me my condition. Thicker would give me more of a gap between the rocker and stem.
11-05-2015, 11:53 AM
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Kale,
Look at the photos in this link. They are the lifter preload data. Pass your curser over the pic to see their titles, then click a photo to enlarge it. Click it again to make it larger yet.
Hope this data will give you some insight.
https://www.cherokeeforum.com/g/album/4533483
Look at the photos in this link. They are the lifter preload data. Pass your curser over the pic to see their titles, then click a photo to enlarge it. Click it again to make it larger yet.
Hope this data will give you some insight.
https://www.cherokeeforum.com/g/album/4533483
11-05-2015, 04:22 PM
#38
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Kale,
Look at the photos in this link. They are the lifter preload data. Pass your curser over the pic to see their titles, then click a photo to enlarge it. Click it again to make it larger yet.
Hope this data will give you some insight.
https://www.cherokeeforum.com/g/album/4533483
Look at the photos in this link. They are the lifter preload data. Pass your curser over the pic to see their titles, then click a photo to enlarge it. Click it again to make it larger yet.
Hope this data will give you some insight.
https://www.cherokeeforum.com/g/album/4533483
11-05-2015, 06:58 PM
#39
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When you install the lifters do not submerge them in oil to prelube them. Leave them dry internally. Lube the outside with engine assembly oil and coat the surface that will rub on the cam lobe with engine assembly lube (grease).
Go by the preload instructions and review that tappet data.
11-05-2015, 07:17 PM
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Just thought of another possibility. You said you had water in the oil....what if the lifter bores had gotten rusty from sitting so long? It is possible a lifter or lifters could have become stuck after the cam pushed it up into the rusted bore!
11-07-2015, 03:16 PM
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Okay so the issue is resolved!
It was the lifters..
The ones i pulled out didn't look terrible, but they were never able to drain, so they were at the lowest clearance. Since the jeep's oil was contaminated with water and sat for a long time, im guessing that had a lot to do with it.
Thank you for all of your input guys!
It was the lifters..
The ones i pulled out didn't look terrible, but they were never able to drain, so they were at the lowest clearance. Since the jeep's oil was contaminated with water and sat for a long time, im guessing that had a lot to do with it.
Thank you for all of your input guys!
11-07-2015, 03:30 PM
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Did you compare the OAL of the new and old lifters? Lets say previously the old lifters were pumped up and seized with rust, tho the engine still ran. Simply removing the cylinder head wouldn't allow the lifter to get "any taller". Almost had to be the head gasket height or incorrect part application. Sounds like the new proper gasket resolved the issue? Did you measure the thickness of the old & new gaskets?
11-07-2015, 03:58 PM
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Okay so the issue is resolved!
It was the lifters..
The ones i pulled out didn't look terrible, but they were never able to drain, so they were at the lowest clearance. Since the jeep's oil was contaminated with water and sat for a long time, im guessing that had a lot to do with it.
Thank you for all of your input guys!
It was the lifters..
The ones i pulled out didn't look terrible, but they were never able to drain, so they were at the lowest clearance. Since the jeep's oil was contaminated with water and sat for a long time, im guessing that had a lot to do with it.
Thank you for all of your input guys!
11-07-2015, 04:00 PM
#44
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Okay so the issue is resolved!
It was the lifters..
The ones i pulled out didn't look terrible, but they were never able to drain, so they were at the lowest clearance. Since the jeep's oil was contaminated with water and sat for a long time, im guessing that had a lot to do with it.
Thank you for all of your input guys!
It was the lifters..
The ones i pulled out didn't look terrible, but they were never able to drain, so they were at the lowest clearance. Since the jeep's oil was contaminated with water and sat for a long time, im guessing that had a lot to do with it.
Thank you for all of your input guys!
11-07-2015, 04:20 PM
#45
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Longer? LOL
Gasket thickness does not come in to play here I believe.
If the lifter plunger is frozen in place at the top of its travel you essentially have a solid lifter and there is no preload.
Read the data in this link to get a bit of understanding.
https://www.cherokeeforum.com/g/album/4533483