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VWLover77 Samba Member
Joined: June 20, 2003 Posts: 999 Location: North Canton, Ohio
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Posted: Sat Dec 04, 2021 5:05 pm Post subject: Main and Camshaft Bearings - Can they be reused? |
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If an engine case is split open, does it automatically mean that the main and cam bearings must be replaced? Or is there some "mileage limit" under which the bearings can be reused?
I'm considering the possible disassembly of my 2.0L Type IV that was rebuilt with an align-bored case and all new bearings 3,000 miles ago.
Thanks! _________________ Don
1978 Westy
1971 Super Beetle Convertible
"If more of us valued food and cheer and song above hoarded gold, it would be a merrier world." - J.R.R. Tolkien |
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Glenn Mr. 010
Joined: December 25, 2001 Posts: 76939 Location: Sneaking up behind you
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Posted: Sat Dec 04, 2021 5:12 pm Post subject: Re: Main and Camshaft Bearings - Can they be reused? |
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Can they be reused... sure. Should you... only if they are VERY low mileage.
Ask yourself this: Is it worth the $100 saving to reuse them and risk having to replace them in the near future. _________________ Glenn
74 Beetle Specs | 74 Beetle Restoration | 2180cc Engine
"You may not get what you pay for, but you always pay for what you get"
Member #1009
#BlueSquare |
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aeromech Samba Member
Joined: January 24, 2006 Posts: 16971 Location: San Diego, California
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Posted: Sat Dec 04, 2021 5:13 pm Post subject: Re: Main and Camshaft Bearings - Can they be reused? |
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Why are you splitting the case? _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound |
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VWLover77 Samba Member
Joined: June 20, 2003 Posts: 999 Location: North Canton, Ohio
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Posted: Sat Dec 04, 2021 5:20 pm Post subject: Re: Main and Camshaft Bearings - Can they be reused? |
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I'm not sure I am splitting the case, but it may come to that. The engine has a noise that I can't figure out.
Glenn, would you consider 3,000 miles "very low"? _________________ Don
1978 Westy
1971 Super Beetle Convertible
"If more of us valued food and cheer and song above hoarded gold, it would be a merrier world." - J.R.R. Tolkien |
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VWLover77 Samba Member
Joined: June 20, 2003 Posts: 999 Location: North Canton, Ohio
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Posted: Sat Dec 04, 2021 5:47 pm Post subject: Re: Main and Camshaft Bearings - Can they be reused? |
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I know it's very difficult to diagnose engine noises from iPhone videos, but here you go....
Hear all that "clacking"? This engine has hydraulic lifters. Inside the Bus with all the windows up, it's quite noticeable at idle. It gets lost in the other noise as engine revs increase. Pulling plug wires makes no difference. Engine temperature makes no difference.
Link
_________________ Don
1978 Westy
1971 Super Beetle Convertible
"If more of us valued food and cheer and song above hoarded gold, it would be a merrier world." - J.R.R. Tolkien |
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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Sat Dec 04, 2021 6:16 pm Post subject: Re: Main and Camshaft Bearings - Can they be reused? |
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unless they are scored or damaged I'd reuse main, cam and rod bearings if they only have 3,000 miles on them, unless you have deep pockets and lots of new old stock items lying around. If they had 40,000 miles on them in a T4 I'd say probably toss a coin if they looked good, 50,000 miles yes. I raced, worked in a shop that did high end racing machine work, and rebuilt engines for a living at one time. That is what I base my suggestion on. They MUST go back in the same spots you take them from.
Try to use a stethoscope or long screwdriver to pinpoint where the sound is loudest. Use a small (1/4" etcT) diameter hose to your ear to listen for exhaust leaks. You can also put a rag over the exhaust to listen for hissing and if the sound gets louder. Last, it it is an automatic, did you inspect the flex plate for cracks? They will make all sorts of weird noises. _________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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aeromech Samba Member
Joined: January 24, 2006 Posts: 16971 Location: San Diego, California
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Posted: Sat Dec 04, 2021 6:26 pm Post subject: Re: Main and Camshaft Bearings - Can they be reused? |
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Does the sound go away when you increase rpm’s up over 2000? Loose cam gears can act that way.
Edit: have you inspected your sump screen for metal? _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound |
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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Sat Dec 04, 2021 6:48 pm Post subject: Re: Main and Camshaft Bearings - Can they be reused? |
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aeromech wrote: |
Does the sound go away when you increase rpm’s up over 2000? Loose cam gears can act that way.
Edit: have you inspected your sump screen for metal? |
9ft lbs max on nut when done! _________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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VWLover77 Samba Member
Joined: June 20, 2003 Posts: 999 Location: North Canton, Ohio
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Posted: Sat Dec 04, 2021 8:10 pm Post subject: Re: Main and Camshaft Bearings - Can they be reused? |
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I will check the noise level at 2000 rpm and above.... (I do find it hard to believe the cam gear is loose - I used both star washers and loctite on the bolts.)
An oil change will be done soon, and will include checking the sump screen as well as checking the oil itself for swirls.
Yes! I'm well aware of the need to carefully torque the sump cover nut. _________________ Don
1978 Westy
1971 Super Beetle Convertible
"If more of us valued food and cheer and song above hoarded gold, it would be a merrier world." - J.R.R. Tolkien |
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aeromech Samba Member
Joined: January 24, 2006 Posts: 16971 Location: San Diego, California
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Posted: Sat Dec 04, 2021 8:39 pm Post subject: Re: Main and Camshaft Bearings - Can they be reused? |
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Did the sound exist a the beginning or did it develop after some mileage? _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound |
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raygreenwood Samba Member
Joined: November 24, 2008 Posts: 21520 Location: Oklahoma City
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Posted: Sat Dec 04, 2021 10:27 pm Post subject: Re: Main and Camshaft Bearings - Can they be reused? |
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aeromech wrote: |
Did the sound exist a the beginning or did it develop after some mileage? |
Good question...and check the gap between the cam gear bolts and the oil pump nuts. About 0.080" minimum. Ray
and....it sounds to me like an exhaust leak. |
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Abscate Samba Member
Joined: October 05, 2014 Posts: 22670 Location: NYC/Upstate/ROW
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Posted: Sun Dec 05, 2021 5:17 am Post subject: Re: Main and Camshaft Bearings - Can they be reused? |
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If you are a typical Bay window driver of 5-6k A year, a used set can last 5-10 years. No need to replace on a “ while you are in there” basis
Cost of a DIY engine pull amd tear down is about 20 hours at $25, so $500 _________________ .ssS! |
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TrollFromDownBelow Samba Member
Joined: January 04, 2005 Posts: 414 Location: Metro Detroit
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Posted: Sun Dec 05, 2021 9:39 am Post subject: Re: Main and Camshaft Bearings - Can they be reused? |
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raygreenwood wrote: |
and....it sounds to me like an exhaust leak. |
That was my thought...have you ruled this out yet? _________________ 1976 Westy (aka Tripod)
2.0 liter FI solid lifters
212k miles |
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airschooled Air-Schooled
Joined: April 04, 2012 Posts: 12728 Location: on a bike ride somewhere
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Posted: Sun Dec 05, 2021 11:15 am Post subject: Re: Main and Camshaft Bearings - Can they be reused? |
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I hear uneven induction/exhaust pulses and a deeper grumbling from heavy parts, not the “snap” of an exhaust leak. Can we have a 20-second video from one vantage point with the deck lid open?
Robbie _________________ 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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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Sun Dec 05, 2021 12:45 pm Post subject: Re: Main and Camshaft Bearings - Can they be reused? |
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I hear a light pffffst sound in the back ground like an small exhaust leak. I do not hear the uneven pulses Robbie is hearing. My ears are 71 years old so I don't have as good of hearing as someone younger generally does. I also heard a light clickity which sounds a bit like an uneven valve adjustment.
use the methods I suggested earlier to pinpoint the noise that concerns you. Those are the only methods I know to isolate noises. _________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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raygreenwood Samba Member
Joined: November 24, 2008 Posts: 21520 Location: Oklahoma City
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Posted: Sun Dec 05, 2021 1:03 pm Post subject: Re: Main and Camshaft Bearings - Can they be reused? |
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SGKent wrote: |
I hear a light pffffst sound in the back ground like an small exhaust leak. I do not hear the uneven pulses Robbie is hearing. My ears are 71 years old so I don't have as good of hearing as someone younger generally does. I also heard a light clickity which sounds a bit like an uneven valve adjustment.
use the methods I suggested earlier to pinpoint the noise that concerns you. Those are the only methods I know to isolate noises. |
I hear the same thing....and while I do not hear uneven "pulses"....I do hear uneven running...like a bit of a "lope". It sounds a little like a diesel idling (and that is not quite explaining it). That may be what Robbie is describing.
It is mechanically noisey though. Had to re-listen. Still hear an exhaust leak. The kind that is downstream...not sharp like at the exhaust manifold to head joint. More like a crack in the muffler or more likely cracks inside the muffler from chamber to chamber.
To add to that....it has hydraulic lifters. What is the adjustment like? A lot of that potential mechanical rattle could be poorly adjusted lifters and/or....does it have the solid spacers on all rocker shafts? Those can cause a crap load of noise especially if the lifters are misadjusted. Ray |
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telford dorr Samba Member
Joined: March 11, 2009 Posts: 3555 Location: San Diego (Encinitas)
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Posted: Sun Dec 05, 2021 2:06 pm Post subject: Re: Main and Camshaft Bearings - Can they be reused? |
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Considering that the lifters can be removed for inspection without splitting the case, I'd avoid splitting... _________________ '71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST) |
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Starbucket Samba Member
Joined: April 30, 2007 Posts: 4026 Location: WA
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Posted: Sun Dec 05, 2021 2:58 pm Post subject: Re: Main and Camshaft Bearings - Can they be reused? |
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For the original question, the only time the Main and cam bearings are ever touched by their shafts is the last rev.s of the motor and the first rev.s of start-up So the bearings are fine Unless you see wiping from poor assembly. They still sell plasti gage so if in doubt measure. |
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VWLover77 Samba Member
Joined: June 20, 2003 Posts: 999 Location: North Canton, Ohio
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Posted: Sun Dec 05, 2021 3:51 pm Post subject: Re: Main and Camshaft Bearings - Can they be reused? |
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In an attempt to respond to most of the comments and questions....
- It's a manual trans, so no flex plate to crack
- The noise has been there from the start of this engine build
- The noise is there at 2K rpm and higher, but gets lost in all the other noise as the revs increase
- I double-checked the cam bolt clearance when assembling the engine and there was no concern. The cam gear is an original VW that was machined to provide bolt clearance (See photo at the bottom of this post)
- The lifters are all set to 2 turns after contacting the valve stem
- Solid spacers are on all rocker arm shafts
To try to get away from any exhaust leak noise, I shot this video from the driver's seat with the windows up. You'll probably need to use headphones. (The changes in volume are not real and due to the iPhone reacting to something other than the engine)
Link
Cam bolt clearance
_________________ Don
1978 Westy
1971 Super Beetle Convertible
"If more of us valued food and cheer and song above hoarded gold, it would be a merrier world." - J.R.R. Tolkien |
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airschooled Air-Schooled
Joined: April 04, 2012 Posts: 12728 Location: on a bike ride somewhere
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Posted: Sun Dec 05, 2021 6:40 pm Post subject: Re: Main and Camshaft Bearings - Can they be reused? |
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There's deep resonant "thudding" around 400 cycles per second. It has an overtone in the higher "clacky" register, which may be more prevalent in person. That speed means once every other rotation, which corresponds with the four-stroke cycle for one cylinder.
If you bunt the cat with your wrist do you hear rattling sounds?
As always, take the belt off and listen. Try it for 10-20 seconds with the fan off too, if you want a different perspective. Oil cap off at idle may also give you a different earshot, though a blown PCV diaphragm will allow that to serve as a giant vacuum leak and stall the engine.
Robbie _________________ 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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