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Bleyseng
Samba Member
Joined: July 03, 2005
Posts: 4752
Location: Seattle
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 Posted: Tue Jan 13, 2015 7:57 am Post subject: |
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| SGKent wrote: |
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| 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. |
I like the "K" springs in my 914 as I can rev it to 6500rpms without valve bounce..but in a bus with solids its too heavy of a spring.
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70 Ghia Black convert-9/69 build date-stock w/133k 1600 SP-barn find now with a rebuilt tranny and engine
77 Westy 2.0L w/Ljet, Camper Special engine-95hp and with LSD!(sold)
76 Porsche 914 2.1L L20c, 120hp Djet (sold)
87 Syncro Westy Titan Red 2.1L 2 knob 100k miles |
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Jake Raby
Samba Member
Joined: August 23, 2003
Posts: 7433
Location: Aircooled Heaven USA
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| Posted: Mon Jan 12, 2015 10:40 pm Post subject: |
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Valve springs that have weakened, due to overheated oil, cause lots of the problems.
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Jake Raby
Raby Engine Development
www.rabyenginedevelopment.com
"I've never given anyone Hell, I just told them the truth and they thought it was Hell" |
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Artvonne
Samba Member
Joined: January 03, 2015
Posts: 74
Location: Rogers, Ar
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| Posted: Sun Jan 11, 2015 5:33 pm Post subject: |
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| Wasted youth wrote: |
| If you have been out of the air cooled rabbit hole for awhile like I was, please brace yourself for unrealistic expenses and shiploads of crap parts. I spoke with Adrian at Headflowmasters about repairing my aged, cracked Type 4 two liter heads with sunken and loose valve seats. He quoted roughly $350 each for a basic reconditioning, which included welding, new valves and hardware, new seats, etc. He seems to have a good reputation. Also, there is one vendor listing rebuilt AMC Type 4 heads with a 12 month 12,000 mile warranty for about $260 each. |
Hmmmm |
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Wasted youth
Samba Member
Joined: July 06, 2012
Posts: 5134
Location: California's Hot and Smoggy Central Valley
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| Posted: Sat Jan 10, 2015 9:22 am Post subject: |
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If you have been out of the air cooled rabbit hole for awhile like I was, please brace yourself for unrealistic expenses and shiploads of crap parts. You might be better off smashing your fingers with that hammer. 
But... regarding heads... I have not looked for Type 1 heads yet, as I am bogged down with either failing Type 4 heads or Type 1 case and line boring expenses. However, about two or three weeks ago, I spoke with Adrian at Headflowmasters about repairing my aged, cracked Type 4 two liter heads with sunken and loose valve seats. He quoted roughly $350 each for a basic reconditioning, which included welding, new valves and hardware, new seats, etc. He seems to have a good reputation. Also, there is one vendor listing rebuilt AMC Type 4 heads with a 12 month 12,000 mile warranty for about $260 each. |
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Artvonne
Samba Member
Joined: January 03, 2015
Posts: 74
Location: Rogers, Ar
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| Posted: Sat Jan 10, 2015 9:09 am Post subject: |
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Is this the exception, or the rule? It looks pretty familiar to what I was seeing 40 years ago, most just seem to melt down, starting out at the heads and working inward.
The last few weeks I actually started thinking I could live with one of these lil beasties again, but the more I look and read, the more I want to go beat my fingers to a pulp with a hammer. Can you even get good parts for these anymore, that you can afford? $500 each for heads is pretty crazy. |
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MacLeod Willy
Samba Member
Joined: February 18, 2014
Posts: 933
Location: Ontario Canada
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| Posted: Sat Jan 10, 2015 7:21 am Post subject: |
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Yep, use to play around with it in the 70,s |
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FNGRUVN
Samba Member
Joined: October 27, 2007
Posts: 2237
Location: Fort Collins, CO
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| Posted: Fri Jan 09, 2015 9:57 pm Post subject: |
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| Amskeptic wrote: |
| raygreenwood wrote: |
So....anyone.....what causes that last bit of damage (the worn away keeper grooves)? Is that from a loose fit in the first place allowing up and down movement?
Ray |
Lack of lubrication - coked rocker arm drillings
*Cheap keepers (often too hard for the valve)*
Heavy springs - prevent oil film between rotating valve and stationary spring retainer during unload moments
All guesses, 
Colin |
I'm finding this problem in more than one set of heads that I'm going through. I'm trying to find two decent heads from the three pairs that I have. I will do some more investigating and report back.
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21520
Location: Oklahoma City
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| Posted: Fri Jan 09, 2015 8:26 pm Post subject: |
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With valves with a lot of miles.....this can happen. A lot of valves...in fact probably most...are two piece. This is how you get specially hardened stems of one and special high temp heads of another alloy. Some are fusion/induction welded in vacuum or special atmosphere. ...some are spin/friction welded.
A very well established, high tech art. Ray |
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SGKent 
Samba Member
Joined: October 30, 2007
Posts: 41031
Location: Citrus Heights CA (Near Sacramento)
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| Posted: Fri Jan 09, 2015 8:01 pm Post subject: |
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| MacLeod Willy wrote: |
Rolled off the table.
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you are aware that some VW bus valves are hollow and sodium filled near the head. That may be a sodium filled valve.
I warn you because this youtube is sodium and water. It can also do similar from humidity and air.
https://www.youtube.com/watch?feature=player_detailpage&v=NTFBXJ3Zd_4
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MacLeod Willy
Samba Member
Joined: February 18, 2014
Posts: 933
Location: Ontario Canada
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| Posted: Fri Jan 09, 2015 7:36 pm Post subject: |
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Rolled off the table.
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21520
Location: Oklahoma City
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| Posted: Fri Jan 09, 2015 5:12 pm Post subject: |
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| Amskeptic wrote: |
| raygreenwood wrote: |
Cool....I just had never seen that in anything I have worked on.
Learn something every day. Ray |
Just warming up here in Speculation World.
What if you put smaller valve stem keepers on bigger valve stems? They would be crushed against the valve grooves instead of contacting each other.
This would be horrifyingly noticeable to a conscious machinist. Occasionally, a machnist might be unconscious, however, like when I discovered 30mm fuel injection exhaust valves in my supposed-to-be-32mm-exhaust-valved singleport heads.
Colin |
You mean....smaller internal radius made for a smaller diameter valve...as compared to lapping the faces of the keepers slightly undersized so they dont touch together right?
Ray |
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Amskeptic
Samba Member
Joined: October 18, 2002
Posts: 8568
Location: All Across The Country
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| Posted: Fri Jan 09, 2015 4:21 pm Post subject: |
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| raygreenwood wrote: |
Cool....I just had never seen that in anything I have worked on.
Learn something every day. Ray |
Just warming up here in Speculation World.
What if you put smaller valve stem keepers on bigger valve stems? They would be crushed against the valve grooves instead of contacting each other.
This would be horrifyingly noticeable to a conscious machinist. Occasionally, a machnist might be unconscious, however, like when I discovered 30mm fuel injection exhaust valves in my supposed-to-be-32mm-exhaust-valved singleport heads.
Colin
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21520
Location: Oklahoma City
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| Posted: Fri Jan 09, 2015 2:50 pm Post subject: |
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Cool....I just had never seen that in anything I have worked on.
Learn something every day. Ray |
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airschooled
Air-Schooled
Joined: April 04, 2012
Posts: 12728
Location: on a bike ride somewhere
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| Posted: Fri Jan 09, 2015 2:40 pm Post subject: |
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| raygreenwood wrote: |
So....anyone.....what causes that last bit of damage (the worn away keeper grooves)? Is that from a loose fit in the first place allowing up and down movement?
Ray |
Poor rocker geometry, leading to increased radial force (and wear) on the keeper/valve union?
Terribly worn guides allowing the arc of the valve adjuster to cock the valve to the side on every actuation?
More guesses,
Robbie
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Amskeptic
Samba Member
Joined: October 18, 2002
Posts: 8568
Location: All Across The Country
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| Posted: Fri Jan 09, 2015 2:06 pm Post subject: |
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| raygreenwood wrote: |
So....anyone.....what causes that last bit of damage (the worn away keeper grooves)? Is that from a loose fit in the first place allowing up and down movement?
Ray |
Lack of lubrication - coked rocker arm drillings
*Cheap keepers (often too hard for the valve)*
Heavy springs - prevent oil film between rotating valve and stationary spring retainer during unload moments
All guesses,
Colin
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raygreenwood
Samba Member
Joined: November 24, 2008
Posts: 21520
Location: Oklahoma City
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| Posted: Fri Jan 09, 2015 1:55 pm Post subject: |
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So....anyone.....what causes that last bit of damage (the worn away keeper grooves)? Is that from a loose fit in the first place allowing up and down movement?
Ray |
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FNGRUVN
Samba Member
Joined: October 27, 2007
Posts: 2237
Location: Fort Collins, CO
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| Posted: Fri Jan 09, 2015 12:21 pm Post subject: |
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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.
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"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 |
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FNGRUVN
Samba Member
Joined: October 27, 2007
Posts: 2237
Location: Fort Collins, CO
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| Posted: Sat Dec 20, 2014 9:19 am Post subject: |
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| Wildthings wrote: |
| Tcash wrote: |
Sunken Valve Seat
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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?
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"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 |
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madmike
Samba Member
Joined: July 11, 2005
Posts: 5292
Location: Atlanta,Michigan
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| Posted: Sat Dec 20, 2014 6:47 am Post subject: |
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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
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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
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HerrMahnenschmidt
Samba Member
Joined: July 22, 2011
Posts: 94
Location: WY, NoCO, NoCA, here, there, elsewhere...
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| Posted: Fri Dec 19, 2014 1:18 pm Post subject: |
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Geezus, at first I thought this carnage was all from the same engine, and I couldn't help but wonder WTF???
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1977 Westfalia --
- rebuilt stock-spec 2.0l FI engine; 002 tranny w/stock gearing with 215mm flywheel/clutch/pp |
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