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Maximillion Samba Member
Joined: August 07, 2016 Posts: 46 Location: Seattle, WA
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Posted: Wed Dec 23, 2020 12:19 am Post subject: Replacing Piston Rings |
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Hey there,
Just to be blunt: I am a total noob who plans to learn about engines by taking one apart (and hopefully fixing it?). I have a 1600 dual port from a Ghia that is/was in my '65 bus. The bus sat for a few years and the engine lost compression. When I got back to it I didn't know that yet so I changed the oil and fired it up but really had to rev it high to move anywhere. I got the engine out and took all the bits off and took off both heads. Going to buy a soda blaster and clean everything real well. I have not taken the pieces of metal that go around the pistons off yet but saw a video where the guy took a rubber mallet to them to allow them to slide off the studs. Right now I can just look at the carbon coated piston ... flat parts? faces? Sorry, my terminology is not quite there yet!
From my understanding of compression this has to do with either the rings or the metal pieces that fit around the pistons.
The real question: What should I be looking at/measuring/doing while I have this hunk of metal taking up half my shop? Can I just take it apart, clean it real well, replace the rings, put it back together, and assume it will run? Also, this was about three years ago that I tested the compression (I had posted a pic asking about the center of gravity and had a hoard of people tell me I was going to kill people on the highway because the trailer was really just good for lawn mowers lol... despite wanting to cart this thing across the country for cheap I listened to them and hired someone to ship it... thank you if you posted there) so it could have other problems. From what I recall of my foggy memory of driving this thing across the country a bunch of times in my youth the clutch slipped a lot especially in high gear if that makes sense, like up hills on the highway... kinda weird! I noticed there were little steel loops between the engine and the transmission that were almost worn clean through when I took the engine off - maybe that has something to do with it?
Happy to post pictures of stuff too if that helps.
-Max |
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modok Samba Member
Joined: October 30, 2009 Posts: 26790 Location: Colorado Springs
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Posted: Wed Dec 23, 2020 2:30 am Post subject: Re: Replacing Piston Rings |
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That's quite the ramble. Ok I'll bite
Me answering a novice question on piston rings is a bit like using a sledgehammer as a flyswatter. Not the right "tool" for the job?
ON the other hand, you could just read a book or google it if you wanted normal advice for normal people, so lets do this.
General advice about piston rings SHOULD go like this:
#1-IF you remove the piston from the cylinder the rings should be replaced.
#2 IF the rings are to be replaced...... first
the piston ring grooves should be measured to see the ring side clearance is ok.
the piston skirts should be measured to make sure the skirt size...( and/or skirt clearance) is in spec,
and the cylinder should be honed, and measured to make sure it's in spec for size and roundness/taper
"Can I JUST replace the rings and leave everything else alone?"
Is like asking can I JUST replace the brake pads and not even look at the brake rotor....... same situation.
The answer is "maybe sometimes depending" If the brake rotor is too smooth, or too rough, or too warped, your brakes are not going to work right.
If it IS good enough it will work fine, but not knowing 100% is flying blind.
With brake pads it's a chance worth taking in many cases, but with piston rings it is usually not worth the risk.
I suppose the other difference is a brake rotor might live to need 3 brake pads while the average piston usually only lasts about 1.5 sets of rings.
So, why do they even sell rings separately?
You could be tearing down the engine for other reasons and elect to hone cylinders and replace the rings while you have it apart, or sometimes rings are just bad from the start, or get damaged by fuel wash and need to be replaced.
Overall I'd GUESS there is a
75% chance you will end up buying a new piston and cylinder set,
15% chance it's other problems are found, cylinders and pistons ok, and honing and re-ringing will make them better than new.
5% chance that you could just replace the rings and that would be a good idea if the piston and cylinder are in good shape and you get the correct kind of rings that will seat without honing.
5% other |
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Maximillion Samba Member
Joined: August 07, 2016 Posts: 46 Location: Seattle, WA
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Posted: Wed Dec 23, 2020 7:55 am Post subject: Re: Replacing Piston Rings |
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modok wrote: |
That's quite the ramble. Ok I'll bite |
Haha thank you!! I really appreciate it and the analogy to brakes as I have definitely replaced brakes the wrong way before. That said, I plan to replace the piston cylinder too (I guess this is the word I was looking for!). If the piston itself only lasts for 1.5 sets of rings I should probably replace those too... Time to buy some stuff!
Thanks for your help modok. |
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Cusser Samba Member
Joined: October 02, 2006 Posts: 31380 Location: Hot Arizona
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Posted: Wed Dec 23, 2020 8:04 am Post subject: Re: Replacing Piston Rings |
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Instead of just re-ringing, I suggest a complete 85.5mm/1600cc piston/cylinder/ring kit.
I used such in my own 1600cc engine in 2016, I used Moresa (used by VW of Mexico) from CB Performance. _________________ 1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297 |
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volksworld Samba Member
Joined: November 26, 2011 Posts: 2529 Location: formerly NY currently NC
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Posted: Wed Dec 23, 2020 8:07 am Post subject: Re: Replacing Piston Rings |
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by the time you buy all the stuff necessary to do all the measurements( mike, bore gauge ,feeler gauges) then get a ring groove cleaner(trying to clean a ring groove with a piece of a broken ring without screwing it up is so much fun) then a cylinder hone( there are various types with varying degrees of accuracy) you would have spent half as much buying a piston and cylinder set and everything will be new and properly sized...usually the end result of a re-ring is an engine that behaves like a decent running engine with 50,000 miles on it rather than a new one...be thankful you have the ability to throw it all out and start over, unlike the water cooled v8 and inline 4 community that has to wrestle with these decisions constantly |
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Bruce Amacker Samba Member
Joined: December 26, 2007 Posts: 1786 Location: Cleveland, Ohio
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Rome Samba Member
Joined: June 02, 2004 Posts: 9654 Location: Pearl River, NY
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Posted: Wed Dec 23, 2020 6:24 pm Post subject: Re: Replacing Piston Rings |
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Quote: |
I noticed there were little steel loops between the engine and the transmission that were almost worn clean through when I took the engine off - maybe that has something to do with it? |
Those sound like the 2 hooks/clips that hold each side of the clutch throw-out bearing to the swinging fork that comes down from the transmission. There's also another style that does not have the small full-circle loop on the one end. http://vwparts.aircooled.net/HD-Spring-Loaded-T-O-Bearing-Clips-Early-Pair-p/111-141-177ahd-pr.htm
Since you have your cylinder heads off, take a look at the faces of each of the 8 valves. It's possible that there is a small "chip' broken off/worn at the edge of a valve head, which would cause the cylinder compression pressure to quickly pass by the chip. Such chips tend to form more on the smaller exhaust valve due to the extreme combustion heat that passes by it.
There are 2 good engine manuals to help you as a beginner: The "compleat idiot" manual by John Muir (also covers other mechanical systems such as brakes; the manual covers Beetle/Ghia/Bus/Type 3), and "How to rebuild your aircooled VW engine" by Tom Wilson. Have the manual next to you at the engine so that the photos make sense on your engine. |
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Maximillion Samba Member
Joined: August 07, 2016 Posts: 46 Location: Seattle, WA
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Posted: Thu Dec 24, 2020 12:18 am Post subject: Re: Replacing Piston Rings |
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Folks I can't thank you enough for all of this! I think this is exactly what I needed to hear. I will proceed with buying a new set of pistons and cylinders as I'm more tight on time these days. I will also get my hands on a copy of the Tom Wilson book. The John Muir book is already pretty brown from all the oil and dirty brake fluid haha.
You mention a few types to buy (Moresa and OEG) and also mentioned cleaning and checking a set. I'm fine just buying one of these two, but do you just go off reviews to decide where to buy or is there something in particular that you look for? Also is cleaning and checking a set just a measuring process or is this a more involved procedure that I would find in that book?
Also Rome those are the exact little metal things that are getting all eroded by... something? Not sure, but I'm definitely going to buy some more! Maybe this is an issue with putting a 70's Ghia motor in a 60's Bus? Those clips go between the transmission (Bus) and engine (Ghia), so just my 'basic troubleshooting' lol.
Thanks again for such thoughtful replies to such a rant of a post. I trust this community so much - I doubt my bus would still be alive without y'all! |
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nsracing Samba Member
Joined: November 16, 2003 Posts: 9481 Location: NOVA
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Posted: Thu Dec 24, 2020 12:31 am Post subject: Re: Replacing Piston Rings |
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Kind of like everyone's 'first time' - you had an idea where to put it. But how to proceed is the kicker. Do you point it ...or aim it?
Next time around, you don't even think about it. |
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modok Samba Member
Joined: October 30, 2009 Posts: 26790 Location: Colorado Springs
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Posted: Thu Dec 24, 2020 2:07 am Post subject: Re: Replacing Piston Rings |
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If your transmission is like this:
Then you use this kind of pressure plate
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modok Samba Member
Joined: October 30, 2009 Posts: 26790 Location: Colorado Springs
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Posted: Thu Dec 24, 2020 2:07 am Post subject: Re: Replacing Piston Rings |
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if your transmission is like this
Then you use a pressure plate like this
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Maximillion Samba Member
Joined: August 07, 2016 Posts: 46 Location: Seattle, WA
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Posted: Thu Dec 24, 2020 7:51 am Post subject: Re: Replacing Piston Rings |
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Oh my, I am definitely mixing those up. My transmission has that F shaped lever thing and my pressure plate has all the teeth in the center. I put a lot of miles on that combo back in the day. Maybe that's why my clutch always seemed to slip. I assumed it was the engine's used-ness the whole time (pulled from Ghia that was getting sliced in half, popped into Bus). Which do you think is easier to replace, the pressure plate or the transmission ... joining end? Or is that just replacing the transmission? |
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Dale M. Samba Member
Joined: April 12, 2006 Posts: 20380 Location: Just a tiny bit west of Yosemite Valley
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Posted: Thu Dec 24, 2020 8:22 am Post subject: Re: Replacing Piston Rings |
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Maximillion wrote: |
Oh my, I am definitely mixing those up. My transmission has that F shaped lever thing and my pressure plate has all the teeth in the center. I put a lot of miles on that combo back in the day. Maybe that's why my clutch always seemed to slip. I assumed it was the engine's used-ness the whole time (pulled from Ghia that was getting sliced in half, popped into Bus). Which do you think is easier to replace, the pressure plate or the transmission ... joining end? Or is that just replacing the transmission? |
ITs all about whether the transmission/pressure plate/throw out bearing combination requires a ring or not.... Generally you get a pressure plate that matches trans type.... IT not rocket science ..... On most pressure plates the ring can be added or removed as necessary....
Dale _________________ “Fear The Government That Wants To Take Your Guns" - Thomas Jefferson.
"Kellison Sand Piper Roadster" For Street & Show.
"Joe Pody Sandrover" Buggy with 2180 for Autocross (Sold)
============================================================
All suggestions and advice are purely my own opinion. You are free to ignore them if you wish ... |
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Maximillion Samba Member
Joined: August 07, 2016 Posts: 46 Location: Seattle, WA
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Posted: Fri Dec 25, 2020 1:02 pm Post subject: Re: Replacing Piston Rings |
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Okay! Thank you Dale, that makes a lot of sense. Well folks, once my parts and soda blaster arrives I’ll post some photos of the progress! |
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Maximillion Samba Member
Joined: August 07, 2016 Posts: 46 Location: Seattle, WA
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Posted: Fri May 07, 2021 2:48 pm Post subject: Re: Replacing Piston Rings |
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So this took a while, and while only in the teardown steps I'm already running into a 'noob' issue here. The Tom Wilson book says there are 13 case seam 'fasteners' (bolts, studs) for the Type 1-3 engines. My case number is U0426744 which I understand from (https://www.thesamba.com/vw/archives/info/engine_letters.php) that this is a Type 3 engine (AFAIK it was pulled from a Ghia that suffered an odd fate, the car was sliced in half lengthwise). I am actually seeing 15 fasteners not counting the 6 big ones by the cylinders. I'm not too worried as I plan to take all the stuff apart to at least clean it out.
I am unsure of a few things: I had to use a vice grip to take out two of the studs, but some of the studs have a really small tip sticking out. Is there an 'expected' way to remove these properly? I usually use the two-nut trick but some of these studs don't have enough sticking out to do that. Should I just vice grip 'em all out and buy new ones?
Lastly one of the nuts looks 'extra special' - is this something that I need to get more of if I wreck 'em or will normal ones (like off the shelf at HD) work well? |
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modok Samba Member
Joined: October 30, 2009 Posts: 26790 Location: Colorado Springs
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Posted: Fri May 07, 2021 4:26 pm Post subject: Re: Replacing Piston Rings |
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That is a sealing nut, missing the seal.
Vw used these sealing nuts in a few locatons, such as the oil pump cover.
They arent very useful, A good flange nut and thread sealant is totally superior.
You do not need to remove any studs.
Except maybe two of the oil pump studs.... IF the oil pump is totally stuck in there. |
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calvinater Samba Member
Joined: September 06, 2014 Posts: 3333 Location: 802 The Pointless Forrest
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Posted: Sat May 08, 2021 2:57 am Post subject: Re: Replacing Piston Rings |
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i have that same kitchenaid mixer, but it lives in the kitchen.
what do you use it for in the shop? _________________ "Albatross"! |
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vwinnovator Samba Member
Joined: July 11, 2005 Posts: 1555 Location: Still doing it in the back of your VW
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Posted: Sat May 08, 2021 6:15 am Post subject: Re: Replacing Piston Rings |
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calvinater wrote: |
i have that same kitchenaid mixer, but it lives in the kitchen.
what do you use it for in the shop? |
variable speed drill press |
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