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SpenceSuper11
Samba Member
Joined: October 31, 2008
Posts: 146
Location: Arlington, WA
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 Posted: Sun Feb 15, 2009 5:50 pm Post subject: Engine problem. loose flywheel? |
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Sorry for the long winded post, but here goes nothing...
My situation:
Recently I had finished rebuilding my 1600dp and finally got the rest of the car ready for the road. I took the car around the neighborhood blocks for the first few days never really going any faster than 25mph or so. The first time I tried going on the main road it stuttered a bit getting up to 40. After driving down that road for a bit I downshifted to slow the car down a bit then turned into a parking lot. When I was on the brakes turning the engine slowed, sputtered, then died. After i restarted it there was a very loud knocking noise and a pulsation in the clutch pedal. I towed it home not wanting to make anything worse.
A friend of mine had listened to it and said it sounded like it might be a loose rod or spun bearing and I was thinking more a long the lines of a loose flywheel since there was a good chance the gland nut hadn't been torqued down properly during the rebuild. When I pulled the engine and got the clutch off this is what I saw:
There was oil on the flywheel and metal shavings around the general area around the gland nut. I saw no metal shavings when I drained the oil. This area was the only place they existed.
I cleaned everything, tightened the flywheel back down with an impact wrench, put the clutch back on, and put the engine back in (I also readjusted the valves for good measure). When I started it back up it purred like a kitten. No knocking.
I drove it around the block a bit and it sounded great and drove normal now that there wasn't oil all over the flywheel and clutch. End of story; fixed the problem right? Not really...
This morning I get it to the main road and suddenly it seems incredibly gutless on acceleration. I stop at the next light and it doesn't seem to want to idle and it starts to sound like the knocking is coming back. The light turns green, I start to go, car dies as soon as I let off the clutch. Restart it and the same thing happens. It just doesn't want to go anywhere anymore. I push it from the middle of the intersection to the next parking lot. Out of curiosity I restart it and let it run for a couple seconds: same as before. There's a loud knocking and a pulsation in the clutch pedal.
My question:
1.)Because the knocking wasn't there after I put the engine back in does this automatically rule out an internal problem as being the cause of the knocking?
2.)Assuming the problem is a loose flywheel could the problem have come back because the impact wrench wasn’t strong enough?
3.) Is there a possibility all this could be an endplay problem?
I have the engine back out and it looks exactly the same as the first time with the metal shavings and oil on the flywheel. I thought I'd ask about this before tearing the engine apart.
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1600cc '73 Super baja
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DarthWeber
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Joined: November 24, 2007
Posts: 7543
Location: Whittier,CA
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| Posted: Sun Feb 15, 2009 5:56 pm Post subject: |
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Never use an impact wrench to tighten the flywheel. Get yourself a torquemeister tool or take it to someone with a big enough torque wrench to do the job.
Did you measure your endplay before you installed the motor? |
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rosevillain
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Joined: December 28, 2005
Posts: 1337
Location: roseville, ca
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| Posted: Sun Feb 15, 2009 6:02 pm Post subject: |
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You should check your crank and flywheel for any damage due to the loose gland nut. Then, set your endplay to spec. Make sure that you have all of the parts assembled correctly, apply some high temp locktite to the gland nut, and TORQUE the flywheel to spec.
If it fails after this, call back. |
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SpenceSuper11
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Joined: October 31, 2008
Posts: 146
Location: Arlington, WA
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| Posted: Sun Feb 15, 2009 6:02 pm Post subject: |
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| DarthWeber wrote: |
| Did you measure your endplay before you installed the motor? |
No I did not. I'm new to engines and that's something I haven't even so much as thought about until I was writing this. 
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1600cc '73 Super baja
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SpenceSuper11
Samba Member
Joined: October 31, 2008
Posts: 146
Location: Arlington, WA
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| Posted: Sun Feb 15, 2009 9:49 pm Post subject: |
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Well, it is indeed the flywheel. This is what I found after looking closer at the back:
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Mongo63
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Joined: February 15, 2007
Posts: 1358
Location: prison city, IL
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| Posted: Sun Feb 15, 2009 10:16 pm Post subject: |
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| DarthWeber wrote: |
| Never use an impact wrench to tighten the flywheel. |
Blah, blah, blah... DOCUMENTED AND CALIBRATED impact gun and KNOWN PSI air supply...worked for me for many a year. Small stockers, big strokers. Verify your end play, agreed. If you know, the proper gun with the right pressure is good for 530 lbs. Get a good gland nut and give it what you got... Your mileage may vary of course.
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Scott Novak
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Joined: October 12, 2004
Posts: 1586
Location: Minneapolis, Minnesota
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| Posted: Mon Feb 16, 2009 2:02 am Post subject: |
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| DarthWeber wrote: |
| Never use an impact wrench to tighten the flywheel. |
| Mongo63 wrote: |
| Blah, blah, blah... DOCUMENTED AND CALIBRATED impact gun and KNOWN PSI air supply...worked for me for many a year. Small stockers, big strokers. Verify your end play, agreed. If you know, the proper gun with the right pressure is good for 530 lbs. Get a good gland nut and give it what you got... Your mileage may vary of course. |
The calibration of the air impact wrench doesn't have much to do with it. Air impact wrenches are great for breaking bolts loose because of the shock applied.
But an air impact wrench is indeed a lousy way to tighten a gland nut. In order to tighten the gland nut sufficiently you will also overstress the gland nut, and, or threads of the crankshaft at the same time.
One of the most important laws of physics is that Force equals Mass times Acceleration.
An air impact wrench accelerates the gland nut too quickly and that acceleration develops an enormous force. You twist the head of gland nut but the threads don't have the time to adequately turn and catch up. The gland nut untwists a bit in time and some of the bolt stretch is reduced and the force holding the gland nut to the flywheel is reduced, and the gland nut can come loose and allow the flywheel to wobble.
You need to torque the gland nut dead slow and hold the force on the gland nut for a time. This will allow a greater holding force with less force applied to the head of the gland nut. Lubrications is also important. Loctite does provide adequate lubrication.
I wouldn't let anyone, that uses an impact wrench to tighten a gland nut, anywhere near my engine!
Scott Novak
Last edited by Scott Novak on Mon Feb 16, 2009 3:58 am; edited 1 time in total |
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Marv [UK]
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Joined: January 07, 2009
Posts: 2225
Location: UK
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| Posted: Mon Feb 16, 2009 3:54 am Post subject: |
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| SpenceSuper11 wrote: |
Well, it is indeed the flywheel. This is what I found after looking closer at the back:
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You've got oval holes there dude.
Either time to redrill them or get a new flywheel.
Check the same thing hasn't happened to the end of your crank. See if the dowel pins have got any play in them... If they have.... 
Then torque it up with a 200Lb mechanic on a foot and a half bar. It need to be at least 257 LB ft of torque whether thats by impact wrench or big ass breaker bar. If it's a 12v impact wrench for wheel nuts, use it for wheel nuts only.
Torque is force multipled by lever arm so 100lb on a 3 ft bar is 300ft lb's of torque..... |
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The Noof
Samba Member
Joined: January 25, 2005
Posts: 4346
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| Posted: Mon Feb 16, 2009 6:35 am Post subject: |
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| Mongo63 wrote: |
| DarthWeber wrote: |
| Never use an impact wrench to tighten the flywheel. |
Blah, blah, blah... DOCUMENTED AND CALIBRATED impact gun and KNOWN PSI air supply...worked for me for many a year. Small stockers, big strokers. Verify your end play, agreed. If you know, the proper gun with the right pressure is good for 530 lbs. Get a good gland nut and give it what you got... Your mileage may vary of course. |
Remind me to never send work your way.lol
What are torque wrenches for? |
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flashburn2020
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Joined: July 25, 2005
Posts: 35
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| Posted: Mon Feb 16, 2009 6:50 am Post subject: |
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Almost looks like the dowel pins may be a bit too long? Pin located at approx. 1 o'clock position in the top photo has shiny edges like it has been rubbing against the gland nut washer? Check that crank for loose pins before going any further....
Last edited by flashburn2020 on Mon Feb 16, 2009 6:56 am; edited 1 time in total |
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Marv [UK]
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Joined: January 07, 2009
Posts: 2225
Location: UK
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| Posted: Mon Feb 16, 2009 6:50 am Post subject: |
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| The Noof wrote: |
What are torque wrenches for? |
Looking pretty in the tool box?  |
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Scott Novak
Samba Member
Joined: October 12, 2004
Posts: 1586
Location: Minneapolis, Minnesota
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| Posted: Mon Feb 16, 2009 6:54 am Post subject: |
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| Marv [UK] wrote: |
You've got oval holes there dude.
Either time to redrill them or get a new flywheel.
Check the same thing hasn't happened to the end of your crank. See if the dowel pins have got any play in them... If they have.... |
Even after the holes are drilled for larger dowel pins, he may need to have the end of the crank resurfaced flat and also have the mating surface of the flywheel resurfaced flat.
Either way it isn't giving me the warm fuzzies.
I've had flywheels come loose on at least 2 used stock engines. The absolute minimum that I do with a used engine is to remove the flywheel, replace the oil seal, often reshim, replace the graphited o-ring, then with a heavy duty aftermarket gland nut (Preferably a forged Gene Berg gland nut) with liberal amounts of Loctite #620 on the threads, I torque the flywheel to 450 foot pounds. I use cotton tipped swabs through the center of the gland nut to remove any excess Loctite that has oozed out inside the gland nut. I've never had a flywheel comes loose when I do this.
I usually add 4 more dowel pins that I match ream while the fhywheel and crankshaft are bolted together.
Scott Novak |
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turboblue
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Joined: October 09, 2003
Posts: 4216
Location: Central Indiana
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| Posted: Mon Feb 16, 2009 8:57 am Post subject: |
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Not that it matters but that looks like a cast flywheel.
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Turbo VW Sand Drag Buggy
"If you don't run into the Devil every once in awhile, you must be going in the same direction!" |
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SpenceSuper11
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Joined: October 31, 2008
Posts: 146
Location: Arlington, WA
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| Posted: Mon Feb 16, 2009 4:01 pm Post subject: |
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| Marv [UK] wrote: |
Either time to redrill them or get a new flywheel.
Check the same thing hasn't happened to the end of your crank. See if the dowel pins have got any play in them... If they have.... |
I will be getting a new flywheel. Notice that the center has begun to look like a square.
So elaborate on the . I just checked and two have no play, one has just a little, but one has a bit of wiggle. Will this mean I need a new crank or could I just drill it for eight dowels.
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The Noof
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Joined: January 25, 2005
Posts: 4346
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| Posted: Mon Feb 16, 2009 4:17 pm Post subject: |
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| SpenceSuper11 wrote: |
| Marv [UK] wrote: |
Either time to redrill them or get a new flywheel.
Check the same thing hasn't happened to the end of your crank. See if the dowel pins have got any play in them... If they have.... |
I will be getting a new flywheel. Notice that the center has begun to look like a square.
So elaborate on the . I just checked and two have no play, one has just a little, but one has a bit of wiggle. Will this mean I need a new crank or could I just drill it for eight dowels. |
If the end of the crank is fine, and I doubt it,just redrill 4 new stock holes for a GOOD stock German flywheel.Before you do, clean the crank as best you can.TORQUE the flywheel to the correct value (250 to 300 fl/lbs. is fine on a stocker) with a GOOD gland nut.Then, check run-out on the maximum o.d. of the flywheel.No more than .015" for me.If it's good, then relocate and drill your new dowels.Then set your end play,replace your seal, and put it back together. |
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SpenceSuper11
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Joined: October 31, 2008
Posts: 146
Location: Arlington, WA
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| Posted: Mon Feb 16, 2009 4:38 pm Post subject: |
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OK, thanks for the help.
Oh, and one last question. I've found a lightweight 8 dowl flywheel that I can get ahold of for the same price i could get a stock 4 dowl. Would there be any problems having the 4 extra dowl holes on the flywheel and leaving the crank alone or would everything act exactly the same?
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The Noof
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Joined: January 25, 2005
Posts: 4346
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| Posted: Mon Feb 16, 2009 6:18 pm Post subject: |
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| on a stocker, I would keep the stock weight.No advantage to a lightened flywheel at all.I would use O.E. stock 4 dowel, redrill 4 stock size new dowel holes. |
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Scott Novak
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Joined: October 12, 2004
Posts: 1586
Location: Minneapolis, Minnesota
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| Posted: Mon Feb 16, 2009 9:08 pm Post subject: |
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| SpenceSuper11 wrote: |
OK, thanks for the help.
Oh, and one last question. I've found a lightweight 8 dowl flywheel that I can get ahold of for the same price i could get a stock 4 dowl. Would there be any problems having the 4 extra dowl holes on the flywheel and leaving the crank alone or would everything act exactly the same? |
I wouldn't consider using a lightened flywheel unless you were also going to use a Berg 6-1/4 lb steel pulley along with it.
An 8 dowel flywheel does very little good unless the holes are match reamed with the fhywheel bolted to the crankshaft so that the dowels have a slight interfernce fit. And yes, this means that the holes in the stock flywheel and crankshaft are also too big. It's one of the reasons that many flywheels have come loose on stock engines when they are driven hard.
I'm assuming that you want to try to salvage your engine. At the least you will need to drill the holes in the crank and flywheel and match ream them for 11/32" dowels, or drill the crank and flywheel for 4 additional 8 mm dowel pins. You could drill the existing 8 mm holes deeper as the holes in the stock crankshaft are shallow. You will need to buy a good crank and flywheel drill jig for this. i would recommend using a 4 holes flywheel and drilling the holes yourself.
I have done this with the engine assembled using a heavy duty Milwaulkee low RPM hand drill. But it is difficult and NOT recommended. You also only want to use very high quality drill bits, as the crankshaft is hard to drill. A dull drill bit is useless. Cleveland drill bits are some of the best drill bits out there.
You really need a drill press and the stand the engine up on the pulley. A very tricky operation at best. And before you turn the engine on it's side, you want to get any crud in the crankcase out. I would use kerosene in the crankcase and let is sit overnight and then drain it. Repeat a few times until you are sure there is not any built up crud in the crankcase that could come loose and fall into the other engine parts and cause damage.
Drill the 4 existing holes deeper. Drill 4 new holes in the crankshaft using the drill jig. Drill 4 new holes in the flywheel using the drill jig. Slightly deburr the holes with a countersink bit. Use a small diamond hand whetstone over the end of the crankshaft to make sure that it is flat. Then bolt the flywheel to the crankshaft. Some of crank flywheel drill jigs come with parts to hold the crank and flywheel together. I made my own. I cut off the threaded portion of an old gland nut. I rounded the hex on a bolt and fit it through the gland, and then brazed it together. I cross drilled the threaded portion of the bolt. I screw the gland nut threaded portion into the end of the crankshaft. I install 4 stock dowels in the four original holes. I install the flywheel. Then I have a heavy washer that I clearanced into a star shape that I put over the end of the protruding bolt, so that four of the holes are exposed. I put a nut on the bolt and tighten it. I put a rod through the crossdrilled hole in the bolt to hold it while I tighten the nut. Then I match ream the new holes in the flywheel and crankshaft together. I unbolt the flywheels and remove two of the dowels and then bolt it back together and ream the two open original holes that I drilled deeper. I unbolt the flywheels and reinstall the two dowels in the original holes and then remove the two other dowels and then bolt it back together and ream the two open original holes that I drilled deeper. Again I deburr all of the holes with a countersink bit.
Be clear that this is a bastard fix and it will not be as good as removing the crank from the engine case. However, it can buy you a lot of extra miles from a used engine that you don't plan on rebuilding.
Scott Novak |
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OvalWindowBucket
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Joined: April 23, 2003
Posts: 694
Location: Reviving my Microbus
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| Posted: Wed Jan 13, 2010 5:32 pm Post subject: |
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A friend of mine has a 1600cc in a 68 beetle. He pulled the motor to replace the a broken return spring on the clutch/throwout arm on the trans. At the same time he decided to change the front main seal while he was at it. So I brought by the torque meister tool and flywheel lock. The previous builder used a bunch red loctite and it seemed like it must have torqued that thing to 400lbs because of how hard it was to remove even with the torque meister. So the VW book he had said 218ft lbs of torque on the gland nut / flywheel. We torqued it to ~300lbs (33 ft lbs on click-type torque wrench w/ torque meister (9x torque) = 297 ft lbs??) and the flywheel came loose after the first drive around the block!?? Im wondering if maybe there was some old crusty loctite in the threads of the crank that prevented the gland nut from properly torquing. Im trying to figure out the reason for it coming loose w/ 300 ft lbs of torque.
Is there such thing as over torquing the gland nut, can I torque it to say 350-400 ft lbs? That is if the dowel holes on the fly wheel and crank are still ok? |
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Max Welton
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