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crazyvwvanman
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Joined: January 28, 2008
Posts: 9923
Location: Orbiting San Diego
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 Posted: Thu Jun 13, 2013 12:10 pm Post subject: 'lifter noise' gets louder as engine warms up?Found Problem! |
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I am very familiar with the usual wbx habit of sometimes making a loud tappet sound when started up cold. That sound always goes away, sometimes taking longer to do so than we would like. I have a van that has only a very minor sound when started cold but it gets much worse after a few minutes of idling in the driveway. Reving the engine at 3000 for a minute doesn't help, as soon as it drops to idle the loud noise is there. Once the engine is hot enough for the rad fan to run the noise is very distinct and attention getting. I'd hate to think it was something besides a lifter...........
Any suggestions of how to fix or further diagnose this?
Any other explanations for the noise, besides the strange letters stamped in the block that say something like GEX?
thanks,
Mark
Last edited by crazyvwvanman on Thu Jun 13, 2013 4:02 pm; edited 1 time in total |
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insyncro
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Joined: March 07, 2002
Posts: 15086
Location: New York
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| Posted: Thu Jun 13, 2013 12:19 pm Post subject: |
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| Rod knock? |
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rubbachicken
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Joined: October 05, 2004
Posts: 3058
Location: socal
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| Posted: Thu Jun 13, 2013 12:22 pm Post subject: |
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you have the tool for removing the lifters, have a look at the cam lobe, maybe it has a flat spot
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djkeev
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Joined: September 30, 2007
Posts: 32591
Location: Reading Pennsylvania
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ragnarhairybreeks
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Joined: October 26, 2009
Posts: 1890
Location: Sidney B.C. Canada
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| Posted: Thu Jun 13, 2013 12:44 pm Post subject: |
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Mark,
is the noise similar to the lifter noise we know about? If so, it might still be a lifter, but one that does not get pumped up completely due to low oil pressure. If the noise goes away when engine revved to 3000, but returns on idle, then I would check oil pressure at idle.
Just a thought.
alistair
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'86 7 passenger syncro, converted to westy pop top, project still in progress
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crazyvwvanman
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Joined: January 28, 2008
Posts: 9923
Location: Orbiting San Diego
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| Posted: Thu Jun 13, 2013 1:02 pm Post subject: |
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Alistair, it does sound like the lifter noise I have heard many times on many wbx engines. I guess I could try to check the hot oil pressure, but how does that really help? It sounds like it is just 1 lifter doing this, assuming it is a lifter. I would be happy to change that lifter if that is what it is but only if I can identify with some certainty which lifter.
Mark
| ragnarhairybreeks wrote: |
Mark,
is the noise similar to the lifter noise we know about? If so, it might still be a lifter, but one that does not get pumped up completely due to low oil pressure. If the noise goes away when engine revved to 3000, but returns on idle, then I would check oil pressure at idle.
Just a thought.
alistair |
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djkeev
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ragnarhairybreeks
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Joined: October 26, 2009
Posts: 1890
Location: Sidney B.C. Canada
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| Posted: Thu Jun 13, 2013 1:17 pm Post subject: |
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Mark,
I'm thinking that low oil pressure at idle affects a leaky lifter more than a good lifter. ie a lifter that would act normally under good oil pressure.
The fact that the noise diminishes (right?) when engine revved (oil pressure higher), but comes back at idle (lower oil pressure) supports the hypothesis.
If he noise is worse, or only present when engine hot is also supportive.
Checking the oil pressure really would help in this situation. If the OP is low then the lifter noise is the lesser problem.
good luck
alistair
| crazyvwvanman wrote: |
Alistair, it does sound like the lifter noise I have heard many times on many wbx engines. I guess I could try to check the hot oil pressure, but how does that really help? It sounds like it is just 1 lifter doing this, assuming it is a lifter. I would be happy to change that lifter if that is what it is but only if I can identify with some certainty which lifter.
Mark
| ragnarhairybreeks wrote: |
Mark,
is the noise similar to the lifter noise we know about? If so, it might still be a lifter, but one that does not get pumped up completely due to low oil pressure. If the noise goes away when engine revved to 3000, but returns on idle, then I would check oil pressure at idle.
Just a thought.
alistair |
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_________________
'86 7 passenger syncro, converted to westy pop top, project still in progress
'82 westy, diesel converted to gas in '94, now gone...
https://shufti.blog/
Old address still works...
http://shufti.wordpress.com |
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jordauto
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Joined: August 12, 2011
Posts: 218
Location: Sorrento,BC
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| Posted: Thu Jun 13, 2013 1:35 pm Post subject: |
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| A cold and hot oil pressure test, and a compression test would be a good place to start, so you have some idea of the basic mechanical condition. Next I would try a mechanics stethiscope to try and isolate the source of the noise. You should be able to narrow it down to one side or the other. It could be a collasped lifter that won't pump up. It could also be a rod bearing or other internal failure. A piston pin will give a distinctive double knock. To try and isolate an internal noise such as rod noise,try diasabling cylinders one at a time. You can either remove a spark plug wire or unplug an injector. Do this for each cylinder, one at a time paying close attention to your sound and see if it changes. If it does then this points to a rod,pin, or other internal fault. Draining the oil and inspecting for metal will also confirm bearing failure. If disabling cylinders makes no difference to the sound then its most likely in the valve train somewhere. Lifter,valve,valve seat, etc. Good luck. |
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hansh
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Joined: January 13, 2004
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Location: Bend, OR
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| Posted: Thu Jun 13, 2013 4:06 pm Post subject: |
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I've had this happen. My theory is that the cold oil is thick and coats the lifter thereby decreasing the clacking noise. If its not pumped up before the oil heats and thins, the noise is sharper/louder. The stuck lifter eventually pumps up and the noise disappears. Mine did this a few times before running a significant amount of MMO for a while.
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crazyvwvanman
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Joined: January 28, 2008
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Location: Orbiting San Diego
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| Posted: Thu Jun 13, 2013 5:29 pm Post subject: |
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Well, it looks like I found the problem. I decided to look closer at the valve adjustment and noticed that when I turned the adjuster screw the pushrod moved in and out as the screw went only in. I pulled the screw and the end is a disaster. It is not the only one. All of them on that side are mushroomed, a couple so badly that the mushroomed head made it hard to back the screw out all the way through the hole in the rocker arm.
Here are 2 bad ones next to 2 new ones.
Mark |
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Wildthings
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| Posted: Thu Jun 13, 2013 5:58 pm Post subject: |
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| What do your valve stem ends look like? You may need to take a Dremel and flatten them and/or get lash caps. |
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crazyvwvanman
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Joined: January 28, 2008
Posts: 9923
Location: Orbiting San Diego
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| Posted: Thu Jun 13, 2013 6:09 pm Post subject: |
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Surprisingly the valve stems look pretty good. Not mushroomed at all, a couple had slight cupping. I wonder if the lash screws had been ground by the rebuilder, removing their surface hardening?
I don't have 4 decent replacement screws for the other side so I am leaving it alone for now. More new screws on order. About $8 each.
Where do you get lash caps for wbx valves?
Mark
| Wildthings wrote: |
| What do your valve stem ends look like? You may need to take a Dremel and flatten them and/or get lash caps. |
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Howesight
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Joined: July 02, 2008
Posts: 3274
Location: Vancouver, B.C.
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| Posted: Thu Jun 13, 2013 6:35 pm Post subject: |
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Hey Mark:
The VW dealer used to stock lash caps. You might be lucky on enquiring. CB performance sells them also. You might find (don't know) that Rocky Jennings has some. They are not on his website, but he would have the quality items. Like the screws themselves, there are good and not-so-good parts out there. Here's one supplier selling Empi lash caps:
http://www.sandparts.com/servlet/the-4403/Empi-00-dsh-4006-dsh-0-Hardened-Lash/Detail
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Wildthings
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| Posted: Thu Jun 13, 2013 7:23 pm Post subject: |
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| crazyvwvanman wrote: |
Surprisingly the valve stems look pretty good. Not mushroomed at all, a couple had slight cupping. I wonder if the lash screws had been ground by the rebuilder, removing their surface hardening?
I don't have 4 decent replacement screws for the other side so I am leaving it alone for now. More new screws on order. About $8 each.
Where do you get lash caps for wbx valves?
Mark
| Wildthings wrote: |
| What do your valve stem ends look like? You may need to take a Dremel and flatten them and/or get lash caps. |
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Some screws are just made from junk metal or not hardened properly. I had a hell of a time 20ish years back when I put the 2.1 together for my Syncro. I tried buying screws from a variety of different sources and they all wore quickly. For a couple of years I just replaced them about every 10K miles and then once better ones showed up at the parts houses again the problem disappeared, with the last set still looking good after a 100K miles. |
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