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Valve Lash Adjustment on a 3.5


kefferjoe
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Hello,

I'm getting a terrible ticking under the passenger side valve cover. I'm going to a shop on Wednesday to have the cover taken off and possibly have the valve lash adjusted. I've tried reading up on the forums about this ticking issue in the 3.5s and haven't yet found what exactly causes this ticking issue. Would a valve adjustment be effective or is it pointless on the shim bucket type lifters?

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No and no. In order to remove the " buckets" on the valves you will need to remove the cams. Removing the cams will require removing the timing chain cover. Realistically you need to pull the cams and buckets and inspect all to check for wear, however maybe make sure the oil level is ok prior to anything.

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Your are correct depending on the year, after 08/2001 the went to a shimless type. Before tearing into the engine I would make sure oil is full, oil pressure is ok (15 psi at idle, 43 at 2000 rpm), if ok then check valve clearance and make sure you're getting oil to the top end/valvetrain.

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Just pulled off the valve cover...lots of sludge in lower plenum and some gunk under valve cover. Going to clean and check clearances of shims... How much oil should I have found in this area just after pulling the valve cover off? There wasn't much free standing oil

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That's a real bummer, sludge is not a good sign. And unfortunately trying to clean it out can cause other problems. As far as oil flow to the valve train make sure you unplugged all the coils(in case you only pulled one valve cover) so it will not start. Have a buddy crank the engine while you look at the cams etc.. You will want to see a reasonable amount of oil flowing around all the cam lobes and caps. If you see one area that's not getting sufficient oil to it that is likely causing noise. If the cam "buckets" can't get sufficient oil they can wear into the head and bind when the cam pushes the valve down.

That being said, I'm sure that there are a lot if different opinions on my next thought based off what you are describing. If the valves are out if adjustment, why? That design does not typically need to be serviced.

If you remove all the sludge you can get to, I personally would immediately change the oil and filter, run the engine until it's at operating temp and drain the oil only, refill it with fresh oil and run again until at operating temp then change the oil and filter again. Reason being is to try to flush out any debris left from removing the sludge. I would not use a flush to try to clean it. Lastly oil pressure, there's oil passage plates on the rear timing cover that van blow out the gaskets causing low oil pressure at idle and starving the top end of oil, thats why checking oil pressure is so important. However that will typically cause codes p0011 @ p0021 intake valve timing. Hope that helps. Real bummer about the sludge though.

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I plan on cleaning it out as best I can and then it looks like one of the shims is really close to being out of spec (I'm measuring .34 max spec is .35). I'm going to let the engine cool off completely and then remeasure the clearances again. There was a ton of sludge build up a lot of places obviously the PO did a terrible job on oil maintainences.

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My understanding is that the hydraulic lifters are supposed to make valve shimming unnecessary. I would suspect an issue with a lifter, especially given the sludge buildup you found. The sludge you found under the valve cover could easily have found its way into the lifter and gummed it up, or it could be preventing oil from reaching the lifter in the first place.

 

I've seen Youtube vids of people trying to clean out sludged motors with scrapers and solvents. :P Didn't look like fun. Hopefully yours goes back together without too much hassle.

Edited by Slartibartfast
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Update: I have a 3.5L and it for sure does have the shims. I looked at the clearances and all of them are in tolerance, and pretty well within it with the exception of one of them being at .33mm (max spec being .37). I am noticing not much oil is reaching the lifters on cylinder 1. So I'm back to trouble shooting. Maybe the plate behind the rear timing plate is leaking? Or maybe excessive sludge build up? I want to try and clean the sludge out first then worst case scenario pull the timining cover. Any solid suggestion for sludge removal to try and help get more oil up top?

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Update: I have a 3.5L and it for sure does have the shims. I looked at the clearances and all of them are in tolerance, and pretty well within it with the exception of one of them being at .33mm (max spec being .37). I am noticing not much oil is reaching the lifters on cylinder 1. So I'm back to trouble shooting. Maybe the plate behind the rear timing plate is leaking? Or maybe excessive sludge build up? I want to try and clean the sludge out first then worst case scenario pull the timining cover. Any solid suggestion for sludge removal to try and help get more oil up top?

Not really, just try to get as much out as possible, not sure if any one else has any suggestions. But very important to change the oil when your done.
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Sounds like the oil passage to the #1 lifters is clogged. You can look up the Youtube vids (IIRC they were titled things like "what happens when you don't change your oil") to see how they cleaned it out, IIRC they just went at it with scrapers and solvent. The risk is what happens if a great wad of the dislodged sludge finds its way into an oil passage (or pump) and clogs that up instead.

 

You might try just removing the lifters that don't seem to be getting oil, cleaning them, and cleaning as much gunk out of the heads as you can. There are a few videos on Youtube showing guys doing this in shops, so you might watch those for tips. I imagine doing it properly would mean dropping the oil pan and cleaning out the crank case as well, but I'm pretty sure you have to drop the front diff to get at the pan. You might get away with flushing it somewhat from the top end and seafoaming the bejeezus out of it.

 

I talked to a machinist a while back who was rebuilding a Ford motor (out of a late-model Ranger IIRC) that had died a sludgy death. He was actually drilling the hardened gunk out of the oil passages to make sure he'd gotten it all. I got the impression that he was going to be at it for a while.

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I worked for Lexus for 8 yrs. some of the 3.3 motors had a bad sludge problem due to poor pvc system. Once opened up, they looked like the classic penzoil sludge back in the day. We would clean with wire brush, break clean and a shop vac best possible. Then a new updated valve cover. Then we would drop the oil pan and replace the pick up screen. Which was normaly clogged. Then a oil change at 1k. After that. The oil should clean the rest.

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  • 1 year later...

Update: I have a 3.5L and it for sure does have the shims. I looked at the clearances and all of them are in tolerance, and pretty well within it with the exception of one of them being at .33mm (max spec being .37). I am noticing not much oil is reaching the lifters on cylinder 1. So I'm back to trouble shooting. Maybe the plate behind the rear timing plate is leaking? Or maybe excessive sludge build up? I want to try and clean the sludge out first then worst case scenario pull the timining cover. Any solid suggestion for sludge removal to try and help get more oil up top?

I'm sorry for bumping such an old thread. But I've got a terrible clicking coming from my engine as well. It seems like its coming from everywhere... valve covers, front, and bottom of the engine...

 

My strongest guess is that its coming from the chain guides. But because its easier to check the valve clearances first, I plan on doing so.

 

I have the feeler gauges needed to check the clearances, but if I do have to end up shimming to get back into spec, do I need any Nissan specific tools?

 

I own this generic valve adjustment tool https://www.amazon.com/dp/B0002Q8TU0/ but will I need anything else?

 

OP after cleaning out your sludge, is your noise gone? Any chance you're still around and can share an update?

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