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markiemark9
Samba Member
Joined: October 05, 2011
Posts: 237
Location: Omaha, NE
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 Posted: Fri Apr 17, 2015 3:06 pm Post subject: Knock...Knock... Knock... Engine Knock |
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I was driving down the road the other day and all of a sudden I heard an engine knock on my 1600cc dual-port (single stock carb, SVDA Distributor, all tins and rubber in place, etc.). Luckily after I heard it knock a few times I immediately killed the engine and coasted into a parking lot. After I got it home I pulled the valve covers and the springs/valves all looked normal so I moved to pulling spark plugs. The 3rd cylinder piston is contacting spark plug but the piston is moving in rotation as appears to be normal and valves are opening and closing as what appears to be normal. Knocking occurs when running tho (occurred out of nowhere). Have good oil pressure, and plugs 1, 2 & 4 are all a beautiful smokey brown so engine was running well.
I imagine this is a wrist pin on the 3rd. Is my only option a rebuild/new motor? I don't want to just throw a band-aid on it and have other issues in a few months.
If a rebuild is necessary, am I nuts to think I can do this as a first timer in my garage (following the Tom Wilson "How to Rebuild Your Volkswagen air-Cooled Engine" book)?
Will I gain much by remaining with stock internals (Crank, rods, cam) and these P&Cs (http://vwparts.aircooled.net/Piston-Cylinder-Set-88mm-x-69mm-Forged-Slip-In-p/mahlet188f.htm)?
Thanks in advance Samba Nation!
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Bret2094
Samba Member
Joined: March 22, 2012
Posts: 665
Location: Linden, Texas or College Station Texas
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| Posted: Fri Apr 17, 2015 3:34 pm Post subject: |
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You should not have a piston hitting the spark plug. How can you tell this has happened? Did you pull the heads to see if this was the case?
Did someone recently change the spark plugs? there are short and long reach plugs. If you have the wrong ones installed it can cause you to hit
IMHO I think Mahle is a bit of a waste of money on a budget or stock build. AA pistons/cylinders have good results until you start pushing high compression ratios or boost. Save your money for other parts.
Personally I would break down the engine to shortblock and check to see if everythign was within spec, including endplay. If everything checks out, I would clean everything up, reassemble, and have your heads gone through, providing the spark plugs are correct
Bret
_________________
1959 baja beetle ragtop( going back to Full body)
1959 beetle
1960 Beetle frame Custom buggy
1962 Karmann Ghia
1967 beetle( august 66, first car)
1967 beetle (parts car)
1977 Westfalia Camper
1972 Plymouth Duster
Just another 22 year old jackass who caught the bug, and lives by the motto " NO fatchicks allowed" , I've got too many cars as is (buses N/A) |
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markiemark9
Samba Member
Joined: October 05, 2011
Posts: 237
Location: Omaha, NE
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| Posted: Fri Apr 17, 2015 3:45 pm Post subject: |
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I pulled the plug and saw it had definitely been contacted on the firing end. Same plugs I've driven with for 6 months so no changes there.
You're suggesting I could get away with pulling heads and possibly going from there only? Any harm in upping the jugs and Pistons to the size I put in the original post if that's the case?
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markiemark9
Samba Member
Joined: October 05, 2011
Posts: 237
Location: Omaha, NE
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Bret2094
Samba Member
Joined: March 22, 2012
Posts: 665
Location: Linden, Texas or College Station Texas
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| Posted: Fri Apr 17, 2015 3:56 pm Post subject: |
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| markiemark9 wrote: |
I pulled the plug and saw it had definitely been contacted on the firing end. Same plugs I've driven with for 6 months so no changes there.
You're suggesting I could get away with pulling heads and possibly going from there only? Any harm in upping the jugs and Pistons to the size I put in the original post if that's the case? |
You could also have some foreign material like part of the carb fall down the intake. It's really hard to say what you will need to do without inspection, cleaning, and more measurements than I want to type right now. You could get lucky and just have to disassemble, and remove the crap in the cylinder, or It could get drawn out and lead to machine work. Either way don't cut corners. Use tom Wilson's book and have at it
There are mixed opinions on the slip in's. My first build was a 1600 DP and later built a 1641 when I was shy of machine work. I personally did not see much improvement, but I ran a stock cam and carb. If you do wind up doing a full rebuild I highly suggest a little more of a performance cam , even with a 1600. Makes a difference that is notable, but you have to make some carburetor adjustments to reap it's benefits as well
Some will say yea use larger slip ins, and others will say they are thin crap and run hot. Really up to whatever you feel comfortable with. For a first build, I would say stock is the way to go. Make another build later that is all out wack and burns rubber
Bret
_________________
1959 baja beetle ragtop( going back to Full body)
1959 beetle
1960 Beetle frame Custom buggy
1962 Karmann Ghia
1967 beetle( august 66, first car)
1967 beetle (parts car)
1977 Westfalia Camper
1972 Plymouth Duster
Just another 22 year old jackass who caught the bug, and lives by the motto " NO fatchicks allowed" , I've got too many cars as is (buses N/A) |
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Max Welton
Samba Member
Joined: May 19, 2003
Posts: 10697
Location: Black Forest, CO
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iowegian 
Samba Curmudgeon
Joined: February 16, 2005
Posts: 9829
Location: Somewhere between Dubuque and Keokuk
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| Posted: Fri Apr 17, 2015 5:12 pm Post subject: |
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| Bret2094 wrote: |
| markiemark9 wrote: |
I pulled the plug and saw it had definitely been contacted on the firing end. Same plugs I've driven with for 6 months so no changes there.
You're suggesting I could get away with pulling heads and possibly going from there only? Any harm in upping the jugs and Pistons to the size I put in the original post if that's the case? |
You could also have some foreign material like part of the carb fall down the intake.
Bret |
Good point. Are you absolutely sure that there has been metal to metal contact between the piston and the spark plug?
A few years back I had a big old Olds 98 that suddenly came down with a rod knock. I had the beast towed to my favorite old-time mechanic expecting a rebuilt long block was in my future. Bob called me the next day and said the car was ready. No charge !!!! How could it be? When I wasn't around he had given it the old ATF-down-the-carburetor treatment. Turns out there must have been a chunk of carbon that had broken loose and bounced around on a piston.
Years later a similar thing happened to my '66 Beetle that had only been driven around Colorado Springs for 30+ years by a little old lady. On my first road trip on I-80 we stopped for lunch after an hour and on start-up there was a knock (same sound). Shut it off. Restarted it. Shut it off. Started again and the noise was gone. Cautiously drove back home and pulled the engine. Nothing wrong. Everything in spec. Must have been carbon------or maybe just a miracle.  |
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markiemark9
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Joined: October 05, 2011
Posts: 237
Location: Omaha, NE
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| Posted: Fri Apr 17, 2015 5:17 pm Post subject: |
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So easiest to most involved (please confirm):
*Drain oil and look for metal
*If no metal, pull head and look for contact between piston and head/spark plug or any foreign matter
Anything else?
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Bret2094
Samba Member
Joined: March 22, 2012
Posts: 665
Location: Linden, Texas or College Station Texas
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| Posted: Fri Apr 17, 2015 6:11 pm Post subject: |
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| markiemark9 wrote: |
So easiest to most involved (please confirm):
*Drain oil and look for metal
*If no metal, pull head and look for contact between piston and head/spark plug or any foreign matter
Anything else? |
Draining the oil is gonna be the first step regardless. Pull the oil strainer out and everything. Look for chunks of metal. If you find bearing metal you are going to go straight to complete diss-assembly involving separating the case.
If the oil is clean of metal, pull apart the tin, exhaust, intake, and such to get you to a long block. Hell while you are at it, clean up the case as best you can to avoid contamination of the insides when you take the heads off.
remove the valve cover, rocker assembly and then the washers and nuts holding the head on. pull the head off and have a gander. Post some pics when you get this far. If it looks ok, It's up to you on what to do.
route a is cheap
you just clean and reassemble everything, put some new plugs in, and put it back in the car and see if it knocks. If I was in a pinch for time and money, this is what I would try. If i had more than a few hours rote b is the best, aside from c which is the endgame for the unfortunate
route B is just as cheap, but leaves less room for head scratching
after pulling the heads, pull the cylinders and remove the wrist pins on the cylinders. check tolerances for the rod and wrist pins. if everything checks out, reassemble and change plugs. run it and see if it knocks. this takes a whole extra hour or so out of your life
route c is the most costly, but it assures everything is mint
You will either land here if metal is in the oil, or if a or b do not pan out. If you have the time and dough I wouldcompletely tear down the engine and send the case, rods, crank and heads off to be reworked. buy all new p/c kit, gaskets, carb rebuild, distributor rebuild. Make it a new engine. If you found metal you will do this anyway. You shouldn't have problems if you assemble everything right This option is the best, especially on a high mile engine
Figure out what you want, provided you have a choice based upon the metal in the oil
Bret
*Edit note*
_________________
1959 baja beetle ragtop( going back to Full body)
1959 beetle
1960 Beetle frame Custom buggy
1962 Karmann Ghia
1967 beetle( august 66, first car)
1967 beetle (parts car)
1977 Westfalia Camper
1972 Plymouth Duster
Just another 22 year old jackass who caught the bug, and lives by the motto " NO fatchicks allowed" , I've got too many cars as is (buses N/A) |
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johnnypan
Samba Member
Joined: October 24, 2007
Posts: 7431
Location: sackamenna
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| Posted: Fri Apr 17, 2015 7:12 pm Post subject: |
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| iowegian wrote: |
| Bret2094 wrote: |
| markiemark9 wrote: |
I pulled the plug and saw it had definitely been contacted on the firing end. Same plugs I've driven with for 6 months so no changes there.
You're suggesting I could get away with pulling heads and possibly going from there only? Any harm in upping the jugs and Pistons to the size I put in the original post if that's the case? |
You could also have some foreign material like part of the carb fall down the intake.
Bret |
Good point. Are you absolutely sure that there has been metal to metal contact between the piston and the spark plug?
A few years back I had a big old Olds 98 that suddenly came down with a rod knock. I had the beast towed to my favorite old-time mechanic expecting a rebuilt long block was in my future. Bob called me the next day and said the car was ready. No charge !!!! How could it be? When I wasn't around he had given it the old ATF-down-the-carburetor treatment. Turns out there must have been a chunk of carbon that had broken loose and bounced around on a piston.
Years later a similar thing happened to my '66 Beetle that had only been driven around Colorado Springs for 30+ years by a little old lady. On my first road trip on I-80 we stopped for lunch after an hour and on start-up there was a knock (same sound). Shut it off. Restarted it. Shut it off. Started again and the noise was gone. Cautiously drove back home and pulled the engine. Nothing wrong. Everything in spec. Must have been carbon------or maybe just a miracle. |
Nice reply snapperhead,tell the poor bastard to pray for a miracle.. I like the wrist pin response too..thats about as far fetched as praying for your miracle..Let me put this in a way that's easy to understand...VW type 1 engines lose big end rod bearings ,its a fact...its one of the major causes of catastrophic engine failure,and nobody wants that..So when you drop the engine and pull 3/4 head,pull 1/2 as well..take off jugs and pistons then remove the rod cap for #3... |
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Bret2094
Samba Member
Joined: March 22, 2012
Posts: 665
Location: Linden, Texas or College Station Texas
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iowegian
Samba Curmudgeon
Joined: February 16, 2005
Posts: 9829
Location: Somewhere between Dubuque and Keokuk
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| Posted: Fri Apr 17, 2015 7:29 pm Post subject: |
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| johnnypan wrote: |
| iowegian wrote: |
| Bret2094 wrote: |
| markiemark9 wrote: |
I pulled the plug and saw it had definitely been contacted on the firing end. Same plugs I've driven with for 6 months so no changes there.
You're suggesting I could get away with pulling heads and possibly going from there only? Any harm in upping the jugs and Pistons to the size I put in the original post if that's the case? |
You could also have some foreign material like part of the carb fall down the intake.
Bret |
Good point. Are you absolutely sure that there has been metal to metal contact between the piston and the spark plug?
A few years back I had a big old Olds 98 that suddenly came down with a rod knock. I had the beast towed to my favorite old-time mechanic expecting a rebuilt long block was in my future. Bob called me the next day and said the car was ready. No charge !!!! How could it be? When I wasn't around he had given it the old ATF-down-the-carburetor treatment. Turns out there must have been a chunk of carbon that had broken loose and bounced around on a piston.
Years later a similar thing happened to my '66 Beetle that had only been driven around Colorado Springs for 30+ years by a little old lady. On my first road trip on I-80 we stopped for lunch after an hour and on start-up there was a knock (same sound). Shut it off. Restarted it. Shut it off. Started again and the noise was gone. Cautiously drove back home and pulled the engine. Nothing wrong. Everything in spec. Must have been carbon------or maybe just a miracle. |
Nice reply snapperhead,tell the poor bastard to pray for a miracle.. I like the wrist pin response too..thats about as far fetched as praying for your miracle..Let me put this in a way that's easy to understand...VW type 1 engines lose big end rod bearings ,its a fact...its one of the major causes of catastrophic engine failure,and nobody wants that..So when you drop the engine and pull 3/4 head,pull 1/2 as well..take off jugs and pistons then remove the rod cap for #3... |
Hey-----I din't tell him to put oatmeal in the crankcase, did I ? |
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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 Apr 17, 2015 7:31 pm Post subject: |
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Before I even took the engine out if the car, I would stick a good camera "boroscope" down the plug well and look for damage on the piston and debris. If the spark plug really truly hit the piston, there would be matching damage in only one tiny spot of the piston. But I see more damage on the ring of the plug than the tip...? Then you can use the camera to check for debris, like carbon chunks and buildups, or a busted carb needle or something else small and dangerous.
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Learn how your vintage VW works. And why it doesn't!
One-on-one tech help for your Volkswagen:
www.airschooled.com |
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Bret2094
Samba Member
Joined: March 22, 2012
Posts: 665
Location: Linden, Texas or College Station Texas
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| Posted: Fri Apr 17, 2015 7:46 pm Post subject: |
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| asiab3 wrote: |
| Before I even took the engine out if the car, I would stick a good camera "boroscope" down the plug well and look for damage on the piston and debris. If the spark plug really truly hit the piston, there would be matching damage in only one tiny spot of the piston. But I see more damage on the ring of the plug than the tip...? Then you can use the camera to check for debris, like carbon chunks and buildups, or a busted carb needle or something else small and dangerous. |
If he even has one...hell I dont have one, but I have borrowed one in the past. Pretty decent advice, and would save a bunch of time as well.
I always tell my friends this:
The Volkswagen engine is a greasy lego's kit that everybody tries to avoid building at first. Once you imagine all of the ways that wishing won't build it, people get their heads out of their asses and follow the instructions.
Bret
_________________
1959 baja beetle ragtop( going back to Full body)
1959 beetle
1960 Beetle frame Custom buggy
1962 Karmann Ghia
1967 beetle( august 66, first car)
1967 beetle (parts car)
1977 Westfalia Camper
1972 Plymouth Duster
Just another 22 year old jackass who caught the bug, and lives by the motto " NO fatchicks allowed" , I've got too many cars as is (buses N/A) |
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johnnypan
Samba Member
Joined: October 24, 2007
Posts: 7431
Location: sackamenna
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| Posted: Fri Apr 17, 2015 7:46 pm Post subject: |
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| iowegian wrote: |
| johnnypan wrote: |
| iowegian wrote: |
| Bret2094 wrote: |
| markiemark9 wrote: |
I pulled the plug and saw it had definitely been contacted on the firing end. Same plugs I've driven with for 6 months so no changes there.
You're suggesting I could get away with pulling heads and possibly going from there only? Any harm in upping the jugs and Pistons to the size I put in the original post if that's the case? |
You could also have some foreign material like part of the carb fall down the intake.
Bret |
Good point. Are you absolutely sure that there has been metal to metal contact between the piston and the spark plug?
A few years back I had a big old Olds 98 that suddenly came down with a rod knock. I had the beast towed to my favorite old-time mechanic expecting a rebuilt long block was in my future. Bob called me the next day and said the car was ready. No charge !!!! How could it be? When I wasn't around he had given it the old ATF-down-the-carburetor treatment. Turns out there must have been a chunk of carbon that had broken loose and bounced around on a piston.
Years later a similar thing happened to my '66 Beetle that had only been driven around Colorado Springs for 30+ years by a little old lady. On my first road trip on I-80 we stopped for lunch after an hour and on start-up there was a knock (same sound). Shut it off. Restarted it. Shut it off. Started again and the noise was gone. Cautiously drove back home and pulled the engine. Nothing wrong. Everything in spec. Must have been carbon------or maybe just a miracle. |
Nice reply snapperhead,tell the poor bastard to pray for a miracle.. I like the wrist pin response too..thats about as far fetched as praying for your miracle..Let me put this in a way that's easy to understand...VW type 1 engines lose big end rod bearings ,its a fact...its one of the major causes of catastrophic engine failure,and nobody wants that..So when you drop the engine and pull 3/4 head,pull 1/2 as well..take off jugs and pistons then remove the rod cap for #3... |
Hey-----I din't tell him to put oatmeal in the crankcase, did I ? |
bondo and metal chips instead of oatmeal,the bondo is the glue,the chips for machinability..fuck I have to tell you everything..
save the borescope for playing post office with your troop leader,anything that slams the electrode gap shut on the plug is beating the living shit out of the top of the piston ..your top end is toast bunkie,and thats for starters....and anyone who doesn't do rod bearings when doing a top end has a tough lesson to learn.. |
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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 Apr 17, 2015 7:51 pm Post subject: |
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Hey I resent that LEGO advice!  building a good engine is much more than that too. 
Boroscopes are often rentals (free) at FLAPS in most cities. I never like to pass up an opportunity to diagnose or forensically investigate at issue.
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Learn how your vintage VW works. And why it doesn't!
One-on-one tech help for your Volkswagen:
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johnnypan
Samba Member
Joined: October 24, 2007
Posts: 7431
Location: sackamenna
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| Posted: Fri Apr 17, 2015 8:19 pm Post subject: |
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| iowegian wrote: |
| Bret2094 wrote: |
| asiab3 wrote: |
| Before I even took the engine out if the car, I would stick a good camera "boroscope" down the plug well and look for damage on the piston and debris. If the spark plug really truly hit the piston, there would be matching damage in only one tiny spot of the piston. But I see more damage on the ring of the plug than the tip...? Then you can use the camera to check for debris, like carbon chunks and buildups, or a busted carb needle or something else small and dangerous. |
If he even has one...hell I dont have one, but I have borrowed one in the past. Pretty decent advice, and would save a bunch of time as well.
I always tell my friends this:
The Volkswagen engine is a greasy lego's kit that everybody tries to avoid building at first. Once you imagine all of the ways that wishing won't build it, people get their heads out of their asses and follow the instructions.
Bret |
And then when they get in trouble they go crying to people like JohnnyPan
to bail them out. |
damn,now I almost feel bad for calling you a snapperhead..but nah,ill get over it.
This is one of the finest engines ever put into manufacture,then refined by german engineers for forty years.. it isnt a greasy lego unless your a hack..simple in design,tolerant of abuse except for a few areas..rod bearings are one of them,consider yourself fortunate it knocked enough for you to realize it.. some only rattle for a bit before launching directly through the case destroying just about everything in the process..and even if it turns out to be an old accelerator pump tube that fell out and jiggled its way into the combustion chamber you'll be glad you tore it down and replaced damaged parts...along with the rod bearings,because your already there.. |
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markiemark9
Samba Member
Joined: October 05, 2011
Posts: 237
Location: Omaha, NE
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| Posted: Fri Apr 17, 2015 8:22 pm Post subject: |
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That all escalated quickly! 
So consensus is that regardless I need to do a rebuild. I've done nearly everything else in my body off restoration (see thread in signature). Any reason I shouldn't attempt a rebuild by the Tom Wilson book myself?
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My '72 Super Beetle Build Thread: http://www.thesamba.com/vw/forum/viewtopic.php?p=7684856#7684856 |
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johnnypan
Samba Member
Joined: October 24, 2007
Posts: 7431
Location: sackamenna
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| Posted: Fri Apr 17, 2015 8:31 pm Post subject: |
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| markiemark9 wrote: |
That all escalated quickly!
So consensus is that regardless I need to do a rebuild. I've done nearly everything else in my body off restoration (see thread in signature). Any reason I shouldn't attempt a rebuild by the Tom Wilson book myself? |
None whatsoever..three tips..
1. Measure out all parts against spec..even new ones.
2. Work food grade clean.
3. measure out all parts against spec..even new ones.
there that should cover it...any questions? |
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iowegian
Samba Curmudgeon
Joined: February 16, 2005
Posts: 9829
Location: Somewhere between Dubuque and Keokuk
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| Posted: Fri Apr 17, 2015 8:34 pm Post subject: |
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| markiemark9 wrote: |
That all escalated quickly!
So consensus is that regardless I need to do a rebuild. I've done nearly everything else in my body off restoration (see thread in signature). Any reason I shouldn't attempt a rebuild by the Tom Wilson book myself? |
Nope, not necessarily.
But JohnnyPants seems to want to have his way (as usual) so some of us just gave up.  |
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