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NB valvetrain/lifter noise? Help
Heard after running 7 psi and hitting 2 step a little too hard.. anyone ever heard anything like this on a nb? I know the lifters usually aren't a big issue on nbs like the na's, could the VVT be causing issues? Really want to figure this out.
Car is a 2001 Canadian se Video: https://photos.app.goo.gl/hjYQWg7jodiYddev6 |
So it didnt make noise.
you bounced it off the limiter Now it does make noise. Valvetrain noise is usually a result of there being too much lash between cam lobes and lifters. HLA often make noise because they pump up with oil pressure to reduce the lash, when they clog they dont pump up as fast, and get noisy. NB uses solid lifters, so they dont have that issue. Either lifter type can still get noisy for other reasons: wear busted valve spring chipped cam lobe etc. Short answer, take off the rocker cover and have a look at everything in there. |
Originally Posted by hks_kansei
(Post 1545542)
So it didnt make noise.
you bounced it off the limiter Now it does make noise. Valvetrain noise is usually a result of there being too much lash between cam lobes and lifters. HLA often make noise because they pump up with oil pressure to reduce the lash, when they clog they dont pump up as fast, and get noisy. NB uses solid lifters, so they dont have that issue. Either lifter type can still get noisy for other reasons: wear busted valve spring chipped cam lobe etc. Short answer, take off the rocker cover and have a look at everything in there. Yep, hate to be that guy but that's what happened. Tommorow I'm gonna go down to the shop and look under the valve cover. Appreciate the helpful reply. Definitely sounds valvetrain related to you though right? No weird vibrations or anything just that awful noise. Thanks, James Gasek |
I did that once, turned out it was the piston skirts contacting the crank counter weights.
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Originally Posted by curly
(Post 1545545)
I did that once, turned out it was the piston skirts contacting the crank counter weights.
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I'm at work, so cant listen to the noise.
But i'm assuming it's like the typical lifter tick sound. A rough way to help narrow down the source of sounds is to take a screwdriver and put the end of it on the rocker cover, and then put your ear against the handle. The sound will travel up like a ghetto stethoscope. try a few places around the engine and see where it's loudest. it's not ideal, since there's a lot of background noise, but can help at least trace the bigger noises to some degree. I'd still track the issue before continuing to drive it much. if it is excess lash from a busted spring, or worse, it spat a shim, then you may chew up a cam lobe, which would mean having to source a new cam (or have the current ones reground if there's enough meat left) |
Originally Posted by hks_kansei
(Post 1545547)
I'm at work, so cant listen to the noise.
But i'm assuming it's like the typical lifter tick sound. A rough way to help narrow down the source of sounds is to take a screwdriver and put the end of it on the rocker cover, and then put your ear against the handle. The sound will travel up like a ghetto stethoscope. try a few places around the engine and see where it's loudest. it's not ideal, since there's a lot of background noise, but can help at least trace the bigger noises to some degree. I'd still track the issue before continuing to drive it much. if it is excess lash from a busted spring, or worse, it spat a shim, then you may chew up a cam lobe, which would mean having to source a new cam (or have the current ones reground if there's enough meat left) |
Bent rod contacting the bottom of the bore ...
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Race cars that use a "2 step" have a forged bottom end and are rebuilt every 50 hours of runtime or less.
:party: Sounds like you might get to do both also. We've got really weak rods known to stretch or bend and very poorly balanced engines that are prone to harmonics related failures. Treated with some empathy they can survive being boosted for quite a while. A stretched rod due to over-revving can cause contact with a valve. A slightly bent valve will not seat properly and there will be excess valve train noise due to the additional lash created. It is also possible to burn a valve using a two-step. |
Just had a listen.
that sounds a bit more severe than lifters with too much lash. But not like knock. I'm leaning more towards big head issue (like a spit shim) or as others said, maybe bent rod clipping something. |
Just listened. Does not sound like lifter tick.
It also sounds like the frequency is a bit too often. Remember, the pistons cycle twice for every movement of the valve. |
Originally Posted by Gee Emm
(Post 1545560)
Bent rod contacting the bottom of the bore ...
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Originally Posted by sixshooter
(Post 1545582)
Just listened. Does not sound like lifter tick.
It also sounds like the frequency is a bit too often. Remember, the pistons cycle twice for every movement of the valve. |
If the rod stretches the Piston can hit the head or the valves
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Originally Posted by James Gasek
(Post 1545608)
Wouldn't it have to be bent pretty severely to be contacting the bottom of the bore? Or is the clearance really that tight.. the engine is still very smooth and I don't hear any weird vibrations.
--Ian |
Quick update:
Pulled the valve cover, didn't see any damaged loves or anything, all the springs are intact. Video of everything just in case I missed something obvious: https://photos.app.goo.gl/DStXDFivNxvwHstF8 Compression test next... Thanks to everyone for your time and help. Looking more and more like a bottom end issue now that I checked everything out and talked with a few more people. If I did bend a rod or something the plan is to put some forged rods in and have it ready to rip for the spring or late fall. |
Cylinders 1-3 were around 130-140 psi, cylinder 4 (where I think the noise is coming from) is around 120. Could be slightly lower as a result of not reading TDC due to a bent rod. At least I have good compression!
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I don't have nearly as much experience as some of the other people on this forum, but isn't good compression more like 180+ PSI?
Your numbers sound pretty concerning to me. |
Originally Posted by dglb99
(Post 1545699)
I don't have nearly as much experience as some of the other people on this forum, but isn't good compression more like 180+ PSI?
Your numbers sound pretty concerning to me. |
Originally Posted by dglb99
(Post 1545699)
I don't have nearly as much experience as some of the other people on this forum, but isn't good compression more like 180+ PSI?
Your numbers sound pretty concerning to me. |
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