| Author |
Message |
Tram
Samba Socialist
Joined: May 02, 2003
Posts: 22711
Location: Still Feelin' the Bern- Once you've felt it you can't un- feel it.
|
 Posted: Thu Jul 02, 2015 2:51 pm Post subject: Attention: Quality Control Alert- Engine Builders |
 |
|
I'm sure a lot of you read the saga that D/A/N and neena have had with the main bearing behind the flywheel letting loose.
This isn't the first engine we've seen do this since the steel- backed bearings have been discontinued. We've actually had three other engines do this after running less than an hour.
The thing that was unique about the "misadventures" engine is that it lasted so long.
Between the Disciple and I chatting with other shops we know and people who have had similar problems with these bearing sets, one thing is really beginning to stand out as being consistent to every one of these stories:
ALL of the major failures involving the non- steel backed main bearings so far appear to have involved .040 second- oversize bearing sets
We're aware of probably at least 25-30 catastrophic main bearing engine failures due to .040 non- steel backed main bearings. Standard, .020, and .060 do not seem to have produced any failures.
Take this advice for what it's worth, but if you are using .040 bearings you'd best get the steel backed ones that Berg still has.
_________________
Немає виправдання для війни! Я з Україною.
| Bryan67 wrote: |
| Just my hands. And a little lube. No tools. |
To best contact me, please use the EMAIL function in my profile |
|
| Back to top |
|
 |
blues90
Samba Member
Joined: March 14, 2009
Posts: 1912
Location: Hollywood ,CA
|
| Posted: Thu Jul 02, 2015 4:20 pm Post subject: |
|
|
| I assume you are talking about bearings that are used with re- ground crank shaft's. |
|
| Back to top |
|
|
Tram
Samba Socialist
Joined: May 02, 2003
Posts: 22711
Location: Still Feelin' the Bern- Once you've felt it you can't un- feel it.
|
| Posted: Thu Jul 02, 2015 5:15 pm Post subject: |
|
|
| blues90 wrote: |
| I assume you are talking about bearings that are used with re- ground crank shaft's. |
Line bored cases, or align bored cases... whichever you prefer. I'm not a huge believer in reground cranks on ACVWs.
_________________
Немає виправдання для війни! Я з Україною.
| Bryan67 wrote: |
| Just my hands. And a little lube. No tools. |
To best contact me, please use the EMAIL function in my profile |
|
| Back to top |
|
|
Dlglobal1
Samba Member
Joined: March 25, 2013
Posts: 350
Location: Denmark
|
| Posted: Thu Jul 02, 2015 10:07 pm Post subject: |
|
|
Tram, I'm preparing to order bearings etc for my rebuild. Mains will be std. Do you have recommendation for brand?
_________________
Cheers, David
1969 Bug
1972 Bug
1968 Mercedes 230 "Heckflosse"
1970 Type 3 Fastback 1600 TA L60D |
|
| Back to top |
|
|
Nate M.
Samba Member
Joined: August 11, 2003
Posts: 1306
Location: Anacortes, WA U.S.A.
|
| Posted: Fri Jul 03, 2015 10:30 am Post subject: |
|
|
I'm not trying to argue the issue here, so please don't take as such; just trying to understand what happened to the engines with these bearings. . .
Did anyone mic out the cranks prior to install?? Where were they within the tolerance limits?? High side or low??
Did the bearings get checked with calipers or Plastigage prior to final assembly?? What did they find??
What brand were they?? KS, Mahle, Silverline, etc.
How did they fail?? In the thrust area?? In the bore I.D./O.D.?? Both?? All three??
There are many things that can be just slightly off that can cause bearing failure. There could be problems with the align bore cutters (the .040 cutter could have been dropped or is otherwise out of spec; this will cause too much crush on one bearing), the skill of the individuals doing the thrust cutting, the crank grind/polish, the torque of the case at assembly and finally the bearings.
Simply saying beware of .040" main bearings that are not steel backed because we've seen a few failures doesn't really say much without context. Again, I am NOT trying to argue the failures or their cause, just trying to understand what actually happened and why you feel it's the bearings.
Thanks.
_________________
Regards,
Nate M.
Squarsche build
Heavy Metal Affliction feature
For heaven's sake, put a type4 and a Porsche 5-speed in there. . . It's the right thing to do!! |
|
| Back to top |
|
|
Tram
Samba Socialist
Joined: May 02, 2003
Posts: 22711
Location: Still Feelin' the Bern- Once you've felt it you can't un- feel it.
|
| Posted: Fri Jul 03, 2015 10:33 am Post subject: |
|
|
| Dlglobal1 wrote: |
| Tram, I'm preparing to order bearings etc for my rebuild. Mains will be std. Do you have recommendation for brand? |
If you can get NOS Glyco, go that route.
_________________
Немає виправдання для війни! Я з Україною.
| Bryan67 wrote: |
| Just my hands. And a little lube. No tools. |
To best contact me, please use the EMAIL function in my profile |
|
| Back to top |
|
|
Tram
Samba Socialist
Joined: May 02, 2003
Posts: 22711
Location: Still Feelin' the Bern- Once you've felt it you can't un- feel it.
|
| Posted: Fri Jul 03, 2015 10:54 am Post subject: |
|
|
| Nate M. wrote: |
I'm not trying to argue the issue here, so please don't take as such; just trying to understand what happened to the engines with these bearings. . .
Did anyone mic out the cranks prior to install?? Where were they within the tolerance limits?? High side or low??
Did the bearings get checked with calipers or Plastigage prior to final assembly?? What did they find??
What brand were they?? KS, Mahle, Silverline, etc.
How did they fail?? In the thrust area?? In the bore I.D./O.D.?? Both?? All three??
There are many things that can be just slightly off that can cause bearing failure. There could be problems with the align bore cutters (the .040 cutter could have been dropped or is otherwise out of spec; this will cause too much crush on one bearing), the skill of the individuals doing the thrust cutting, the crank grind/polish, the torque of the case at assembly and finally the bearings.
Simply saying beware of .040" main bearings that are not steel backed because we've seen a few failures doesn't really say much without context. Again, I am NOT trying to argue the failures or their cause, just trying to understand what actually happened and why you feel it's the bearings.
Thanks. |
I can only speak in specifics to the engines we've actually done here, and everything was miked. cranks that show any wear at all are replaced. The replacement cranks are miked.
The engine failures we experienced were align bored by three different machinists, all with many years of specific ACVW experience, and all have a good history with me.
When I say that I've been able to track this through multiple contacts in multiple states this sort of precludes the line boring bar being the issue.
The bearing failures have been of all three types. What has happened in my direct experience (and I do Type 3 only) is that the engine goes together, is test run or test driven, and develops a "fan noise" within a few miles that's not a fan noise- it's the crank knocking in the mains. Upon teardown, it's the front or rear main that has developed excess slop- once along the thrust angle as well- bad enough that the flywheel started chewing into the bell housing of the test stand after about a 15 minute run under no load.
At first I thought perhaps the non steel backed bearings were just not equal to use in a Type 3 with the fan mounted on the crank as our suppliers kept telling us there was 'no known issue" with these parts. But then, we started hearing of failures on Type 1s as well.
One of the people we've conferred with is the owner of one of the best- known ACVW shops in Eugene. He was the one that first mentioned the .040 connection, and on reviewing my notes, I found that all of our failures were with .040 bearings as well. Since then, in asking around or chatting about fresh engine rebuild failures, they always seem to be .040 bearings... always.
All the engines that failed on us were re- bored to .060 and have been fine right out of the gate here. Since we've stopped using .040 as an option we haven't had any more failure issues.
Again- this is just observation plus anecdotal evidence, but- damn.
Oh, and we've had failures with both Mahle and KS non- steel backed bearings.
_________________
Немає виправдання для війни! Я з Україною.
| Bryan67 wrote: |
| Just my hands. And a little lube. No tools. |
To best contact me, please use the EMAIL function in my profile
Last edited by Tram on Sat Jul 04, 2015 2:25 pm; edited 1 time in total |
|
| Back to top |
|
|
rosevillain
Samba Member
Joined: December 28, 2005
Posts: 1289
Location: roseville, ca
|
| Posted: Sat Jul 04, 2015 2:17 pm Post subject: |
|
|
| I thought that the silver line bearings were steel backed.? |
|
| Back to top |
|
|
Tram
Samba Socialist
Joined: May 02, 2003
Posts: 22711
Location: Still Feelin' the Bern- Once you've felt it you can't un- feel it.
|
| Posted: Sat Jul 04, 2015 2:24 pm Post subject: |
|
|
| rosevillain wrote: |
| I thought that the silver line bearings were steel backed.? |
Whoops- right- I meant KS, sorry.
_________________
Немає виправдання для війни! Я з Україною.
| Bryan67 wrote: |
| Just my hands. And a little lube. No tools. |
To best contact me, please use the EMAIL function in my profile |
|
| Back to top |
|
|
rosevillain
Samba Member
Joined: December 28, 2005
Posts: 1289
Location: roseville, ca
|
| Posted: Sat Jul 04, 2015 7:29 pm Post subject: |
|
|
| I'm sure that some of my problems were self-inflicted, but my last engine was not built by me with unknown bearings. The case was new and so were the heads. Thrust was toast, like better than 1mm, and the line bore on that saddle was trashed, probably like .038". Bearings looked better than the case. Two different heads, one with the shoulders around the valve guides, one without. Both of the exhaust seats on the head without the shoulder recessed into the head. 60,000 miles. |
|
| Back to top |
|
|
CBDZ_CBDZ
Samba Member
Joined: December 27, 2007
Posts: 363
Location: Eastvale, CA
|
| Posted: Sun Jul 19, 2015 10:26 pm Post subject: |
|
|
I may be a victim of this. I bought a kit from the local "well-known" VW shop here in SoCal. Everything was new aftermarket stuff, except for the case, which I had align-bored .04" over. After about 30-40 min. run time, the engine seized. Pulled it, and the main bearing (flywhee) is locked up to the crank. Everything else looks great.
_________________
Tube Bender Rental in So. Cal.
http://www.rentabender.com |
|
| Back to top |
|
|
W1K1
Samba Member
Joined: March 04, 2004
Posts: 4917
Location: Southern AB
|
|
| Back to top |
|
|
Nate M.
Samba Member
Joined: August 11, 2003
Posts: 1306
Location: Anacortes, WA U.S.A.
|
| Posted: Mon Jul 20, 2015 11:47 am Post subject: |
|
|
If bearings get checked with Plastigage, this does NOT happen. I've rejected a few sets of Silverline bearing sets because they were way too tight and this would have resulted had I not Plastigaged them at mock-up. I've also had the same issues with their rod bearings on occasion too. I don't use Silverline anymore because of this.
Again, if checked with Plastigage, there are no surprises. . . Plastigage is the ONLY way to check bearing fit when torqued and the bearing is "crushed" by the torque.
_________________
Regards,
Nate M.
Squarsche build
Heavy Metal Affliction feature
For heaven's sake, put a type4 and a Porsche 5-speed in there. . . It's the right thing to do!! |
|
| Back to top |
|
|
rosevillain
Samba Member
Joined: December 28, 2005
Posts: 1289
Location: roseville, ca
|
| Posted: Thu Jul 23, 2015 5:46 pm Post subject: |
|
|
Certainly taking my time. Found this playing around with the last engine of mine that melted down. This was built by someone else. You're looking in the oil pump suction. See the discharge side of the oil pump? The case hole is offset by maybe a little less than half. 30mm Shadduck pump. The 26mm pump that I have also does this. Case was new like 8 years ago. Checked pumps on a different case and they are fine. Good thing that it's the most expensive part that is wrong...
|
|
| Back to top |
|
|
Tram
Samba Socialist
Joined: May 02, 2003
Posts: 22711
Location: Still Feelin' the Bern- Once you've felt it you can't un- feel it.
|
| Posted: Thu Jul 23, 2015 8:27 pm Post subject: |
|
|
| Nate M. wrote: |
If bearings get checked with Plastigage, this does NOT happen. I've rejected a few sets of Silverline bearing sets because they were way too tight and this would have resulted had I not Plastigaged them at mock-up. I've also had the same issues with their rod bearings on occasion too. I don't use Silverline anymore because of this.
Again, if checked with Plastigage, there are no surprises. . . Plastigage is the ONLY way to check bearing fit when torqued and the bearing is "crushed" by the torque. |
Sorry, but I've had bearings that Plastiguaged fine start knocking 15 minutes later, and continued running causes them to develop noticeable play at the crank... up and down play.
I've had this happen twice, and both time it was 40 over non- steel backed mains.
I agree that they won't seize if they PG correctly, but on the other end of the spectrum...
_________________
Немає виправдання для війни! Я з Україною.
| Bryan67 wrote: |
| Just my hands. And a little lube. No tools. |
To best contact me, please use the EMAIL function in my profile |
|
| Back to top |
|
|
Tram
Samba Socialist
Joined: May 02, 2003
Posts: 22711
Location: Still Feelin' the Bern- Once you've felt it you can't un- feel it.
|
| Posted: Thu Jul 23, 2015 8:29 pm Post subject: |
|
|
| rosevillain wrote: |
Certainly taking my time. Found this playing around with the last engine of mine that melted down. This was built by someone else. You're looking in the oil pump suction. See the discharge side of the oil pump? The case hole is offset by maybe a little less than half. 30mm Shadduck pump. The 26mm pump that I have also does this. Case was new like 8 years ago. Checked pumps on a different case and they are fine. Good thing that it's the most expensive part that is wrong...
|
Some aftermarket cases are also notorious for the pickup tube being loose and even falling out. We've gotten into the practice of subbing an old German pickup tube.
rose, that really sucks, man. Who would have even thought...
_________________
Немає виправдання для війни! Я з Україною.
| Bryan67 wrote: |
| Just my hands. And a little lube. No tools. |
To best contact me, please use the EMAIL function in my profile |
|
| Back to top |
|
|
Clatter
Samba Member
Joined: September 24, 2003
Posts: 7537
Location: Santa Cruz
|
| Posted: Fri Jul 24, 2015 10:44 am Post subject: |
|
|
| rosevillain wrote: |
Certainly taking my time. Found this playing around with the last engine of mine that melted down. This was built by someone else. You're looking in the oil pump suction. See the discharge side of the oil pump? The case hole is offset by maybe a little less than half. 30mm Shadduck pump. The 26mm pump that I have also does this. Case was new like 8 years ago. Checked pumps on a different case and they are fine. Good thing that it's the most expensive part that is wrong...
|
That's a Brazilian case?
Man, those need _everything_ checked...
_________________
Bus Motor Build
What’s That Noise?!? |
|
| Back to top |
|
|
Clatter
Samba Member
Joined: September 24, 2003
Posts: 7537
Location: Santa Cruz
|
| Posted: Fri Jul 24, 2015 10:47 am Post subject: |
|
|
So, wanting to make sure I have this straight..
Tram _doesn't_ believe in crankshaft grinding,
But _does_ believe in line-boring??
This just to disagree with Gene Berg or what?
You lose in arm-wrestling to him back in '62 or something??
_________________
Bus Motor Build
What’s That Noise?!? |
|
| Back to top |
|
|
Tram
Samba Socialist
Joined: May 02, 2003
Posts: 22711
Location: Still Feelin' the Bern- Once you've felt it you can't un- feel it.
|
| Posted: Fri Jul 24, 2015 10:57 am Post subject: |
|
|
| Clatter wrote: |
So, wanting to make sure I have this straight..
Tram _doesn't_ believe in crankshaft grinding,
But _does_ believe in line-boring??
This just to disagree with Gene Berg or what?
You lose in arm-wrestling to him back in '62 or something?? |
Naw, I kicked his ass.
Who said I don't believe in crankshaft grinding? Of course I believe in it- it exists.
_________________
Немає виправдання для війни! Я з Україною.
| Bryan67 wrote: |
| Just my hands. And a little lube. No tools. |
To best contact me, please use the EMAIL function in my profile |
|
| Back to top |
|
|
Clatter
Samba Member
Joined: September 24, 2003
Posts: 7537
Location: Santa Cruz
|
| Posted: Fri Jul 24, 2015 3:04 pm Post subject: |
|
|
Just because you got a crank or two ground wrong, doesn't mean they are all bad.
Now that beaings SUCK dimensionally more often than not,
Having your crank grind and line-bore cutter adjustment tweaked a little is part of the routine, if you want the numbers all correct.
Try it - crush a bearing into place in a case and measure the ID with good tools.
When you mic everything, all standardized and right and all,
most of the bearings today are not going to give you clearances in the right range of the spec.
If even within spec at all...
_________________
Bus Motor Build
What’s That Noise?!? |
|
| Back to top |
|
|
|
