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early
Samba Member
Joined: January 19, 2012
Posts: 184
Location: Glen Carbon, IL
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 Posted: Sun Oct 14, 2012 4:08 pm Post subject: piston / head dings from foreign object - questions |
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I pulled my engine a few months ago to find a missing Solex dump tube and to start the body work on the car.
I found the dump tube located in the intake manifold on # 4 it was slightly bent.
months later i have completed the body work and decided to pull the heads since I had engine out and have a look and maybe do a valve job.
what I find is Dents in #4 piston and small dents in the Head .
1600cc dual port, stock mahle 85.5 pistons , mexican 043 heads.
I dont know the complete history of the engine as it was supposedly rebuilt a few years back.
while on the floor, i hooked up starter jig and did a compression test on cold engine #1 -120 #2 - 130, #3- 118 , #4 -135
added a squirt of oil to each cylinder and went another round
#1 - 130, #2 140 , #3 - 135, #4 145
anyway after pulling the heads I have noticed dents in #4
Im wondering if I should replace the pistons & cylinders or if they would be safe to run after cleaning them up a bit.
thanks in advance for your opinions!..
here's some pics:
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early-
Barnfind westy project
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miniman82
Samba Swamp Donkey
Joined: March 22, 2005
Posts: 9515
Location: Southern Maryland
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| Posted: Sun Oct 14, 2012 5:49 pm Post subject: |
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Compression test was good, why not just buff out the dings and run it?
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| Glenn wrote: |
| satterley_sr wrote: |
I just wanted to bitch but I'm getting no sympathy. |
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slalombuggy
Samba Member
Joined: July 17, 2010
Posts: 9145
Location: Canada
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| Posted: Sun Oct 14, 2012 6:02 pm Post subject: |
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I've had this on a couple of engines. I simply check for cracks in the piston top, make sure the ring moves freely. then I draw file the piston top smooth and use a carbide scraper to remove the rough area from the cylinder head.
As long as there is no sharp edges cause detonation you'll be fine.
brad |
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early
Samba Member
Joined: January 19, 2012
Posts: 184
Location: Glen Carbon, IL
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| Posted: Sun Oct 14, 2012 6:13 pm Post subject: dings |
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miniman. I can clean up the head combustion chamber, but for the piston, i think i will have to remove the piston from the cylinder to avoid causing any damage to cylinder and then I guess I would have to re ring it at that point ? thoughts?
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early-
Barnfind westy project
https://www.thesamba.com/vw/forum/viewtopic.php?t=...highlight=
my 73 sports bug project build
http://www.thesamba.com/vw/forum/viewtopic.php?t=497088
Current Projects :
73 Sport Bug - L13M gone now
67 Westfalia
57 oval window ragtop - sold june 2021
61 sedan
68 Corvette Roadster - Small Block, 4 Speed
86 GMC Sierra Classic- 4x4, Shortbed
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miniman82
Samba Swamp Donkey
Joined: March 22, 2005
Posts: 9515
Location: Southern Maryland
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| Posted: Sun Oct 14, 2012 7:00 pm Post subject: |
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Why would you re-ring it, it's going back into the same cylinder isn't it?
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Build thread: http://www.thesamba.com/vw/forum/viewtopic.php?t=212747
| Glenn wrote: |
| satterley_sr wrote: |
I just wanted to bitch but I'm getting no sympathy. |
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JoeD
Samba Member
Joined: October 09, 2012
Posts: 146
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| Posted: Sun Oct 14, 2012 7:33 pm Post subject: |
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Some years ago My wife drove my bug and came back saying that it made a terrible noise but it went away after a while.
Next time I went to do a tuneup I noticed the bolt for the air cleaner was missing. I looked everywhere and just couldnt find it. I completly forgot about what she had said to me about the noise.
About 60,000 miles later I pulled the engine with my daughter during the summer to rebuild the engine.
When I took the head off I noticed the bolt embeded into the head and both the combustion chamber and the top of the piston were completly abraded. Looked like someone took a box of shotgun shells and blew away at them.
But still the bug ran fine for 60,000 miles. |
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damicotile
Samba Member
Joined: September 16, 2004
Posts: 1069
Location: WOODLAND CA.
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| Posted: Tue Oct 16, 2012 12:14 pm Post subject: |
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| slalombuggy wrote: |
I've had this on a couple of engines. I simply check for cracks in the piston top, make sure the ring moves freely. then I draw file the piston top smooth and use a carbide scraper to remove the rough area from the cylinder head.
As long as there is no sharp edges cause detonation you'll be fine.
brad |
I had this happen to me to. Turned out to be a washer from the intake manifold. I had to replace and balance the piston cause it pinched the top ring groove.
It looks like yours might be pinched too.
Check also that the valves aren't bent.
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'73 SB
82x94
W-120 w/ CB light weight lifters
Silicon bronze sleeves
Scat 1.25:1
CB H-Beams
Straight cuts
42x37 Steve Tims
44 IDF's
9.2:1
A-1 Sidewinder coated
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early
Samba Member
Joined: January 19, 2012
Posts: 184
Location: Glen Carbon, IL
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| Posted: Thu Oct 18, 2012 6:04 am Post subject: Update |
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I pulled #4 cylinder and Piston.
Top Compression Ring Land was pretty tight near the damaged area. it measured out at < .05 MM when the spec is > .07 MM. that might explain the Higher compression reading on #4.
anyway I sent the heads to the shop for a 3 angle valve Job and Ordered New Pistons and Cylinders.
Dont want to risk it so I'm gong with new parts.
cheers.. thanks all.
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early-
Barnfind westy project
https://www.thesamba.com/vw/forum/viewtopic.php?t=...highlight=
my 73 sports bug project build
http://www.thesamba.com/vw/forum/viewtopic.php?t=497088
Current Projects :
73 Sport Bug - L13M gone now
67 Westfalia
57 oval window ragtop - sold june 2021
61 sedan
68 Corvette Roadster - Small Block, 4 Speed
86 GMC Sierra Classic- 4x4, Shortbed
94 Harley Flstn |
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