Quote:
Any reason for one valve to be like this?
Worn-down cam lobe. 
Quote:
What does this sound like?
It probably sounds like "Tick! Tick! Tick! Tick! Tick! Tick!"(sorry, couldn't resist)
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| Uneven Valve Lash https://slantsix.org/forum/viewtopic.php?t=47184 |
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| Author: | 73dart_swinger [ Fri Dec 02, 2011 8:13 pm ] |
| Post subject: | Uneven Valve Lash |
A couple of weeks ago, I had an issue with my pressure relief valve. I have since fixed that problem but was uneasy about the metal I found in my filter. I pulled the rocker assembly and checked all the push rods and rockers and put everything back together. When I did, I had one rocker that was very loose. I did not notice this when I took it all apart. Is there anything out of the ordinary that I am missing that would cause only 1 valve to be so loose? There's only 4 places the issue could be; the cam, lifter, push rod or rocker. With the metal I found, I'm concerned I have wiped out a lifter or cam lobe. |
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| Author: | ceej [ Fri Dec 02, 2011 8:57 pm ] |
| Post subject: | |
Whenever things are disturbed there will be variation. How loose? Did the push rods go back into the same locations? Did you remove the lifters to inspect them? Did each one go back where it came out? Are there any loose adjusters? Could the adjuster have been disturbed when removed? Inspect the pushrods again. Did they get correctly installed in the lifters? Are they all straight. I use the bed of my lathe to check to make sure they are true. find a known flat surface to check them. Double check that the rocker shaft is correctly installed. Did it get torqued down differently? Any binding? How did you tighten it in? Are there any valves that are hanging up? Is it possible that a piece of valve seal is hung up in a spring? CJ |
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| Author: | 73dart_swinger [ Fri Dec 02, 2011 9:28 pm ] |
| Post subject: | |
I did not remove the lifters. All the push rods went back in the same locations. I torqued the rocker shaft back down with the torque wrench to 25 ft/lbs. I did not remove any of the rockers from the shaft so they are in the original locations. Everything seems to be working as it should except the one rocker that was excessivlely loose. |
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| Author: | 73dart_swinger [ Thu Dec 08, 2011 4:42 pm ] |
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I have reset the lash on my valves. The one that was overly loose was number 3 cylinder exhaust valve. They are all set but that valve is out of threads for adjustment. Push rod appears straight. Any reason for one valve to be like this? What does this sound like? |
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| Author: | SlantSixDan [ Thu Dec 08, 2011 5:40 pm ] |
| Post subject: | |
Quote: Any reason for one valve to be like this?
Worn-down cam lobe. Quote: What does this sound like?
It probably sounds like "Tick! Tick! Tick! Tick! Tick! Tick!"(sorry, couldn't resist) |
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| Author: | 73dart_swinger [ Thu Dec 08, 2011 7:32 pm ] |
| Post subject: | |
I'm afraid it very well may be the cam. Problem I have with this is, when I disassembled the rocker assembly, I didn't notice the rocker being loose. I'm 99% sure that I put my hand on every rocker before disassembly. I surely would have noticed the rocker being loose. Also, if the rocker would have been that loose before disassembly, I can't imagine any way I wouldn't have noticed it. It would have been terribly loud. I am going to try and get my hands on a dial indicator to try to measure the lift. Is this a good way to see if it is indeed a bad cam lobe? |
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| Author: | sandy in BC [ Thu Dec 08, 2011 7:38 pm ] |
| Post subject: | |
Yes......compare to other valves. |
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| Author: | 73dart_swinger [ Thu Dec 08, 2011 7:46 pm ] |
| Post subject: | |
I'm sure that is the best way. Any other symptoms to look for? It is not backfiring thru intake or carb. It doesn't have a miss. Valve seems to be working as it should. But it has been adjusted now. So will the dial indicator yield me the answers I'm looking for? This has all come about since my issue with Lucas and my stuck pressure relief valve. That's when I changed oil and cut open the old filter to find very fine metal shavings that WERE magnetic. |
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| Author: | 73dart_swinger [ Wed Nov 25, 2015 12:51 pm ] |
| Post subject: | It's been too long.... |
It's been about 4 years since I had my incident with the Lucas gumming up the pressure relief on my oil pump. My car has been sitting since this all occurred. I am motivated to get the car back on the road. I have been doing a bit of reading and it sounds like quite a bit has changed with cam development for the Slant 6 since I was hanging around last. I am planning on throwing a battery on the car and trying to get it to my house so I can spend some time working on it. I think I will start by pulling the valve train again to try and track down the reason for the uneven valve lash. I need to pull all the lifters out before I decide it was definitely a cam lobe that went. If it turns out to be the cam, I'm hoping to pull the head to verify compression ratio and be able to pull the cam without pulling the entire motor. I will continue researching cam choices but I'm sure I will have a few questions. I may just post my progress as a journal here. Being able to go back and read some posts I made has been invaluable to remembering exactly what I have done to the car. Mods that were made to the motor when it was rebuilt in 2004-2005: Block 30 over Home ported head Head milled to yield approx. 9.0 to 1 compression(it was never measured to be certain though) Comp Cams 264 Carter BBD on a Super Six Manifold Clifford Shorty Headers A904 and stock 2.76 rear gear Hopefully putting this in writing will keep me motivated to get the car back on the road. My goals would be to maintain good fuel mileage and have a motor with good torque that is fun to drive. The car never felt as peppy after the rebuild as it did stock so I suspect the cam and it not being degreed in had a lot to do with that. I would be open to any suggestions to helping me reach my goals since I have been out of the loop for some time now. Hope to have some updates coming soon... |
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| Author: | SlantSixDan [ Wed Nov 25, 2015 4:31 pm ] |
| Post subject: | |
I have a new-in-box Erson Dutra RV10-RDP cam on my shelf, which is a highly excellent street cam. Send me a PM if interested. |
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| Author: | Sam Powell [ Wed Nov 25, 2015 7:50 pm ] |
| Post subject: | |
I would expect a serious miss if the lobe is wiped. Sam |
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| Author: | Dart270 [ Thu Nov 26, 2015 3:43 am ] |
| Post subject: | |
I very much doubt a lobe is wiped. I would suspect a recessed valve seat first. Just readjust the valve and go with it. Maybe retard your final mechanical advance some (get to 28-30 max) and/or run higher octane fuel to try to avoid further recession. Lou |
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| Author: | SlantSixDan [ Thu Nov 26, 2015 10:06 am ] |
| Post subject: | |
Quote: I very much doubt a lobe is wiped. I would suspect a recessed valve seat first.
Recessed valve seat = lash grows tighter and tighter, not looser and looser.
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| Author: | 73dart_swinger [ Thu Nov 26, 2015 5:16 pm ] |
| Post subject: | |
Would a recessed valve seat cause metal like I found in the oil and filter? |
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| Author: | Dart270 [ Fri Nov 27, 2015 5:15 am ] |
| Post subject: | |
Oops, you are both right. I must have been drunk from (pre)Thanksgiving feasting... Best of luck, Lou |
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