Author |
Message |
Tcash Samba Member
Joined: July 20, 2011 Posts: 12844 Location: San Jose, California, USA
|
Posted: Sun Oct 19, 2014 8:53 am Post subject: Valve Train Failures |
|
|
To link to this thread
Code: |
[url=http://www.thesamba.com/vw/forum/viewtopic.php?t=609967&start=0&postdays=0&postorder=asc&highlight=]Valve Train Failures[/url] |
-----------------------Valve Train Failures------------------------
Watch this: Sunken Valve Seat
Sunken Valve Seat Video
Dropped seat
Dropped seat. This is indicative of a dropped valve seat. In this case it may be carbon build up, holding the valve open.
Dropped seat
Dropped seat intake type 4
Sunken seat. Valve seat being pounded into head, shelf collapsing.
Sunken seat
aeromech wrote: |
Here's a pic of #3 intake on a 1979 bus I was involved with once.
|
Sunken seat
Burnt valve.
Burnt valve.
Valve broken. Broken valve head
Valve broken. Broken valve tip
Valve broken. Broken valve tip
Valve broken. Type IV intake broken valve head broke off.
Valve broken. Broken valve tip.
Broken valve adjuster tip.
Broken valve guide.
Broken valve adjuster.
Broken valve springs 1000 miles.
Broken valve springs. Note the rust eats through the hardened surface and weakens the springs.
Broken valve spring.
Broken rocker shaft.
Broken rocker stands.
Broken rocker shaft.
Broken push rod.
Bent push rods.
Bent push rod.
Bent push rod and tube.
Push rods cut by push rod tube retaining wire on a Type IV. This can be found on the cam side of the push rod as well. Why, because the PO flipped the push rods. Link: Pushrods
Worn Cam lobe.
Worn Cam lobe.
Flattened cam lobe. Note pitting.
Pulled rocker stud.
Burnt head gasket
May be why VW sent out a Technical Service Bulletin (TSB) to remove and discard the Type IV (4) cylinder head gaskets.
thnx to mayor ratwell
http://www.ratwell.com/technical/Heads.html#gaskets
Burnt Spark plug insert
Type I rocker shaft spring clip failure.
Type I another rocker shaft spring clip failure.
Type IV Broken intake rockers.
Broken boss on VW head. Diameter of Boss cut for dual springs.
Broken guide boss.
Last edited by Tcash on Fri Jun 29, 2018 9:16 pm; edited 28 times in total |
|
Back to top |
|
|
Brian Samba Moderator
Joined: May 28, 2012 Posts: 8340 Location: Oceanside
|
|
Back to top |
|
|
skills@eurocarsplus Samba Peckerhead
Joined: January 01, 2007 Posts: 16878 Location: sticksville, ct.
|
Posted: Sun Oct 19, 2014 9:41 am Post subject: |
|
|
Brian wrote: |
This thread is pretty gruesome |
I was thinking it was a morbid way to start the day myself
but, it is a good way to reference the failures that occur with these old rigs
tcash is my hero _________________
gprudenciop wrote: |
my reason for switching to subaru is my german car was turning chinese so i said fuck it and went japanese....... |
Jake Raby wrote: |
Thanks for the correction. I used to be a nice guy, then I ruined it by exposing myself to the public. |
Brian wrote: |
Also the fact that people are agreeing with Skills, it's a turn of events for samba history |
|
|
Back to top |
|
|
Wildthings Samba Member
Joined: March 13, 2005 Posts: 50347
|
Posted: Sun Oct 19, 2014 10:20 am Post subject: |
|
|
Cha ching, cha ching |
|
Back to top |
|
|
Waves2day Samba Member
Joined: October 15, 2008 Posts: 408 Location: Bay Area, CA
|
|
Back to top |
|
|
raygreenwood Samba Member
Joined: November 24, 2008 Posts: 21518 Location: Oklahoma City
|
Posted: Sun Oct 19, 2014 10:46 am Post subject: |
|
|
All of that can be traced to dual valve springs with otherwise stock valve train parts.
1. The thin guide bosses. ..done for dual springs
2. Spaghetti shaped PRs.....excessive valve spring preszure....along with the enertia of the deztructive moment. With dual springs I would move to thicker PRs or chromoly.
3. Valve tips and screw breakage....and hammering on the cam...probably too, much apring pressure.....high lift or high ratio of rocker or both....combined with too much slack in the valve adjustment.
4. All of this with rpm and load.
My question is whether dual springs were needed with the application. Ray |
|
Back to top |
|
|
Wasted youth Samba Member
Joined: July 06, 2012 Posts: 5134 Location: California's Hot and Smoggy Central Valley
|
Posted: Sun Oct 19, 2014 3:22 pm Post subject: |
|
|
Wow... in one thread, so many curiosities explained.
So... What's the idea behind dual/heavy valve springs? |
|
Back to top |
|
|
timvw7476 Samba Member
Joined: June 03, 2013 Posts: 2205 Location: seattle
|
Posted: Sun Oct 19, 2014 3:46 pm Post subject: Valve Train Failures |
|
|
the duals are for dragstrip high revs
those engines live for several hours
not several thousand hours : ( |
|
Back to top |
|
|
Wasted youth Samba Member
Joined: July 06, 2012 Posts: 5134 Location: California's Hot and Smoggy Central Valley
|
Posted: Sun Oct 19, 2014 3:54 pm Post subject: Re: Valve Train Failures |
|
|
timvw7476 wrote: |
the duals are for dragstrip high revs
those engines live for several hours
not several thousand hours : ( |
Ah! Well, that's good to know, thanks. |
|
Back to top |
|
|
raygreenwood Samba Member
Joined: November 24, 2008 Posts: 21518 Location: Oklahoma City
|
Posted: Sun Oct 19, 2014 4:28 pm Post subject: |
|
|
Well.......high pressure/high tension duals live at the drag strip. Plenty on the streets as well.....but usually with large heavy valves and the need to control high lifts to keep valves from bouncing.
Looking back through its obvious a few of the more bent pushrods got that way from the tubes being pried on.....and some of this looks like an over the redline problem....and wome lik3 the cam wear looks like no oil and no oil changes.....and the pie shaped wedges missing from valve heads.....look like classic burned valves.
Amazing amount of abuse, neglect and damage documented there. Ray |
|
Back to top |
|
|
SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
|
Posted: Mon Oct 20, 2014 9:37 am Post subject: |
|
|
Quote: |
So... What's the idea behind dual/heavy valve springs? |
springs have harmonic rates. They oscillate like a kid on a swing. To eliminate that two different springs are used so it dampens any chance of harmonic oscillation.
The spring closes the valve mass. The higher RPM the engine goes, the stronger the spring is needed to close it. A race engine that turns 10,000 RPM needs much stronger springs than a bus engine that turns at best 5.,000 to 5,500 RPM.
Springs also control the bleed down rate on later hydraulic lifters. Too light and the lifters pump up and don't bleed down.
In Type 4 engines the /E spring was used to control valves on the bus, 411, 412, 914-4 and 912E. Then on the 2L motor VW went to a /J spring that existed for a very short time. Then hydraulic lifters came out and they went to a /K which is very heavy duty. It is overkill on a solid lifter engine. _________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
|
Back to top |
|
|
Wasted youth Samba Member
Joined: July 06, 2012 Posts: 5134 Location: California's Hot and Smoggy Central Valley
|
Posted: Mon Oct 20, 2014 2:52 pm Post subject: |
|
|
Thanks! PM sent with question... |
|
Back to top |
|
|
Vanapplebomb Samba Member
Joined: November 03, 2010 Posts: 5411 Location: Holland, MI
|
|
Back to top |
|
|
my59 Samba Member
Joined: August 13, 2003 Posts: 3793 Location: connecting the dots
|
Posted: Tue Oct 21, 2014 2:54 am Post subject: |
|
|
Vanapplebomb wrote: |
Brian wrote: |
This thread is pretty gruesome :-& |
Gruesome, but very cool to see how parts fail. |
Cool to see when it is not your engine. _________________ my59: Well son, my grandfather died before I got to drive it, so does that answer your question?
our79: sunroof bus w/camper interior and 2.0 FI
Other:'12 Jetta, '77 Benz 300D, and a 74 MG Midget. |
|
Back to top |
|
|
Tcash Samba Member
Joined: July 20, 2011 Posts: 12844 Location: San Jose, California, USA
|
Posted: Fri Dec 19, 2014 9:34 am Post subject: |
|
|
Sunken Valve Seat
Alex6373 wrote: |
Been there , brake fluid |
Last edited by Tcash on Sat Dec 27, 2014 9:24 am; edited 1 time in total |
|
Back to top |
|
|
Wildthings Samba Member
Joined: March 13, 2005 Posts: 50347
|
Posted: Fri Dec 19, 2014 9:41 am Post subject: |
|
|
Tcash wrote: |
Sunken Valve Seat
|
Good example of a 2.0L head gasket failure as well. |
|
Back to top |
|
|
HerrMahnenschmidt Samba Member
Joined: July 22, 2011 Posts: 94 Location: WY, NoCO, NoCA, here, there, elsewhere...
|
Posted: Fri Dec 19, 2014 1:18 pm Post subject: |
|
|
Geezus, at first I thought this carnage was all from the same engine, and I couldn't help but wonder WTF??? _________________ 1977 Westfalia --
- rebuilt stock-spec 2.0l FI engine; 002 tranny w/stock gearing with 215mm flywheel/clutch/pp |
|
Back to top |
|
|
madmike Samba Member
Joined: July 11, 2005 Posts: 5292 Location: Atlanta,Michigan
|
Posted: Sat Dec 20, 2014 6:47 am Post subject: |
|
|
What's that noise? ?? maybe WE can make it to the next exit,,,,,,,,,,,,,,
I've had single HD springs break,, pulled over when I felt the motor start to miss,, My fault,I over revved it ,, easy fix since I run CM pushrods,,
Who would use aluminum PR's with duals
as for stock rockers and duals, They work fine if set up RIGHT!!!!!,must used 'Bolted shafts!!! valve caps will help to.
This carnage must be from No maintenance?,, "Drivel it like u stole it" OR
Drive till it quits,,,, and go 20feet more _________________ 'Black Ice'Drag Buggy 'Turbo'
Rail Buggy 1915 turbo
76 Drag/Street bug 2180cc 'Turbo' 11:85 @113 mph"If I go any faster I'll burn up the Hamster" ,gets 28 mpg. also 10/09/22 11.90 @115 mph
"If I'm ever on Life Support,UNPLUG Me, Then Plug me back In see if that Works" |
|
Back to top |
|
|
FNGRUVN Samba Member
Joined: October 27, 2007 Posts: 2237 Location: Fort Collins, CO
|
Posted: Sat Dec 20, 2014 9:19 am Post subject: |
|
|
Wildthings wrote: |
Tcash wrote: |
Sunken Valve Seat
|
Good example of a 2.0L head gasket failure as well. |
Hey, that's my head! I'm knee-deep in that engine right now. It came out of a very neglected '77 westy. The cooling flaps and thermostat had been removed. That's #3. If I remember correctly, that's not the hottest running cylinder like it would be on a type 1 engine. The other combustion chambers were OK. The corresponding cam lobe was worn more than the others, but the other lobes were severely worn, as well. The rest of the engine looks really good. Very little wear in the bottom end and aside from a slight scuff mark on one of the piston skirts, the P/C look good.
Any ideas as to why the cam and lifters took such a beating? It did have hydraulic lifters. Didn't they come with solid lifters in '77? _________________ "Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote." - Benjamin Franklin |
|
Back to top |
|
|
FNGRUVN Samba Member
Joined: October 27, 2007 Posts: 2237 Location: Fort Collins, CO
|
Posted: Fri Jan 09, 2015 12:21 pm Post subject: |
|
|
Here's another example of valve failures(from the same engine).
I noticed one of the valve stem tips riding a lot lower in the valve spring keeper.
I discovered the grooves for the keepers were worn completely away. Here's a comparison.
_________________ "Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote." - Benjamin Franklin |
|
Back to top |
|
|
|