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Dexter Johnson Samba Member
Joined: November 10, 2011 Posts: 6 Location: California
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Posted: Mon Nov 04, 2019 9:59 am Post subject: Stop belt slipping |
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The alternator belt slips at the crank pulley and causes the water pump and alternator turn slow, also the tension on the water pump is high because of the large belt wrap angle. By spacing the water pump pulley to line up with the ac pump and spacing the split pulley to fit the belt, the alternator is alone and it's belt wraps more around the crank pulley. This works on the 1.9L but on the 2.1L the pipe to the pressure tank gets in the way unless it is flipped and re welded, the same hose still fits but you cannot go back to the original belt arrangement. I blocked the pipe and connected the hose out of the way. This will still work without ac if there is the right crank pulley, then a short belt can be adjusted with pulley spacers. |
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dabaron Samba Member
Joined: June 21, 2018 Posts: 2558 Location: Philly, mang
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Posted: Mon Nov 04, 2019 11:26 am Post subject: Re: Stop belt slipping |
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i have not noticed slipping of the alt belt on my 2.1L, is that a thing? _________________ 1991 Vanagon GL Camper
i had no idea i wanted to be a mechanic
"burnin oil and cookin coils" -- Destructo
BiWerks Design, LLC |
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50260
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Posted: Mon Nov 04, 2019 11:55 am Post subject: Re: Stop belt slipping |
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I have certainly considered figuring out how to move the alternator over to the nearer the centerline of the engine, to give more wrap on the crankshaft pulley and less on the water pump and alternator. What I have done instead though is make the mounting of the alternator much more rigid so that the alternator doesn't move noticeably under load.
I have the Go Westy bracket for the forward end of the alternator pivot bolt and then this little added bracket for the other end. The alternator is now very rigid with no noticeable movement.
I have been running my engines (originally was a 1.9l and now replaced with a 2.1L) this way for 7'ish years and seldom give the alternator mounting a thought any more. Very easy bracket to make if you have the PS pump bracket to build off of. |
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MarkWard Samba Member
Joined: February 09, 2005 Posts: 17014 Location: Retired South Florida
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Posted: Mon Nov 04, 2019 1:56 pm Post subject: Re: Stop belt slipping |
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Dexter Johnson wrote: |
The alternator belt slips at the crank pulley and causes the water pump and alternator turn slow, also the tension on the water pump is high because of the large belt wrap angle. By spacing the water pump pulley to line up with the ac pump and spacing the split pulley to fit the belt, the alternator is alone and it's belt wraps more around the crank pulley. This works on the 1.9L but on the 2.1L the pipe to the pressure tank gets in the way unless it is flipped and re welded, the same hose still fits but you cannot go back to the original belt arrangement. I blocked the pipe and connected the hose out of the way. This will still work without ac if there is the right crank pulley, then a short belt can be adjusted with pulley spacers. |
In the picture above, it looks like the AC belt is riding along the bottom of the waterpump pulley. I don't think that is correct. Might be an optical illusion though. _________________ ☮️ |
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DanHoug Samba Member
Joined: December 05, 2016 Posts: 4715 Location: Bemidji, MN
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Posted: Mon Nov 04, 2019 2:24 pm Post subject: Re: Stop belt slipping |
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i run a loose alt-crank-wp belt on my 2.1 to save wp and alt bearings. i use a belt dressing spray periodically when i start hearing a squawk on startup. but i like the alt to ps bracket brace! _________________ -dan
60% of what you find on the internet is wrong, including this post.
'87 Westy & '89 Westy both 2.1 4spd
Past projects can be found at--
www.thefixitworkshop.com |
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Ahwahnee Samba Member
Joined: June 05, 2010 Posts: 9776 Location: Mt Lemmon, AZ
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Posted: Mon Nov 04, 2019 3:42 pm Post subject: Re: Stop belt slipping |
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I'm not seeing what is driving the water pump in that photo.
for
I have a 1.9 with AC but no power steering and have never had an issue with belt slip.
Like Dan, I keep the Alt/WP belt far from dead tight to spare excessive forces on the bearings.
I also use the additional GW bracket the alternator. |
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crazyvwvanman Samba Member
Joined: January 28, 2008 Posts: 9895 Location: Orbiting San Diego
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Posted: Mon Nov 04, 2019 4:19 pm Post subject: Re: Stop belt slipping |
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NG. Part of the designer's INTENT was to have the alternator warning light come on as an early warning in case of a belt failure that keeps the water pump from turning.
Mark
Dexter Johnson wrote: |
... By spacing the water pump pulley to line up with the ac pump and spacing the split pulley to fit the belt, the alternator is alone and it's belt wraps more around the crank pulley. .... |
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Dexter Johnson Samba Member
Joined: November 10, 2011 Posts: 6 Location: California
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Posted: Tue Nov 05, 2019 9:57 am Post subject: Re: Stop belt slipping |
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There is no warning light if the water pump stops but there is an over-temp light. I have a brace on the front and back of the alternator, when I braced the pulley end, the brace broke, indicating it was not enough so I added a brace to the other end and use a stronger one at the pulley.
I used to smell rubber when my wife parked in the garage after using the AC. The indication that the belt was slipping is when the cap blew off the coolant tank after driving in a parking garage. When driving slow with the AC on full blast, the radiator fan draws a lot of amps and so does the rest of the system, the alternator requires at lot torque and slippage will slow down the water pump because the slippage is at the crank pulley. Now there is no indication of overheating.
The water pump is driven by a small deflection of the AC belt, I use the same stock length belt. |
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MarkWard Samba Member
Joined: February 09, 2005 Posts: 17014 Location: Retired South Florida
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Posted: Tue Nov 05, 2019 11:58 am Post subject: Re: Stop belt slipping |
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Luckily AC compressor and clutches never seize up. Hey if it works for you great. _________________ ☮️ |
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E1 Samba Member
Joined: January 21, 2013 Posts: 6378 Location: Westfalia, Earth
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Posted: Tue Nov 05, 2019 11:03 pm Post subject: Re: Stop belt slipping |
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Count me amongst the loose belters.
I think the thumb pressure spec is like 0.56" but mine probably approaches an inch. I very rarely get a squeak of any kind, but if so I do carry belt dressing. I've only used it on a former alternator whose bearing was getting tight and surmised the real issue causing the squeak was a tightening bearing. _________________ ‘84 Westy, 2.1L with Digijet, 5.43 R+P, GT Gears
"Adding power makes you faster on the straights.
Subtracting weight makes you faster everywhere."
— Colin Chapman |
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tencentlife Samba Member
Joined: May 02, 2006 Posts: 10067 Location: Abiquiu, NM, USA
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Posted: Wed Nov 06, 2019 7:38 am Post subject: Re: Stop belt slipping |
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MarkWard wrote: |
Luckily AC compressor and clutches never seize up. Hey if it works for you great. |
I guess you're being facetious, because they sure as hell do. There's a reason AC is an accessory belt. _________________ Shop for unique Vanagon accessories at the Vanistan shop:
https://intrepidoverland.com/vanistan/
Please don't PM here, I will not reply.
Experience is kryptonite to doctrine. |
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kamzcab86 Samba Moderator
Joined: July 26, 2008 Posts: 7893 Location: Arizona
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Posted: Wed Nov 06, 2019 9:40 am Post subject: Re: Stop belt slipping |
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tencentlife wrote: |
MarkWard wrote: |
Luckily AC compressor and clutches never seize up. Hey if it works for you great. |
I guess you're being facetious, because they sure as hell do. There's a reason AC is an accessory belt. |
Mine didn't lock up, but one of the screws behind the pulley somehow backed out, which caused the belt to flip. Discovered it on a pre-flight inspection... cut the belt off and was on my way. No way, no how would I use the A/C belt to drive the water pump.
As for belt slipping... only once has it happened and that was because I didn't adjust the alternator quite tight enough after installing a new belt. _________________ ~Kamz
1986 Cabriolet: www.Cabby-Info.com
1990 Vanagon Westfalia: Old Blue's Blog
2016 Golf GTI S
"Real knowledge is to know the extent of one's ignorance." - 孔子 |
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dabaron Samba Member
Joined: June 21, 2018 Posts: 2558 Location: Philly, mang
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Posted: Wed Nov 06, 2019 1:21 pm Post subject: Re: Stop belt slipping |
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kamzcab86 wrote: |
No way, no how would I use the A/C belt to drive the water pump.
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quoted for truth. just send me the money you have to burn on the costly repairs of a failed water pump. _________________ 1991 Vanagon GL Camper
i had no idea i wanted to be a mechanic
"burnin oil and cookin coils" -- Destructo
BiWerks Design, LLC |
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Dexter Johnson Samba Member
Joined: November 10, 2011 Posts: 6 Location: California
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Posted: Tue Nov 19, 2019 8:46 pm Post subject: Re: Stop belt slipping |
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Some way some how millions of cars have the same belt drive the AC and water pump. This is a quote of Mike Ales. "If the water pump is driven by the serpentine belt (it is often driven by the *timing belt), the engine might overheat as well." |
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kamzcab86 Samba Moderator
Joined: July 26, 2008 Posts: 7893 Location: Arizona
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Posted: Tue Nov 19, 2019 9:33 pm Post subject: Re: Stop belt slipping |
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Dexter Johnson wrote: |
Some way some how millions of cars have the same belt drive the AC and water pump. This is a quote of Mike Ales. "If the water pump is driven by the serpentine belt (it is often driven by the *timing belt), the engine might overheat as well." |
In most modern engines, including my 2.0 TSI and (departed) VR6, there is a serpentine belt driving the water pump, alternator, A/C compressor, power steering pump, etc. with a separate timing chain (or belt). The serp belts utilize a tensioner and one or more idler pullies and are driven by the crankshaft. The WBX uses old-fashioned V-belts in a completely different configuration. Your modification is merely using a traditional V-belt as a quasi-serp belt, something a lot of us wouldn't want to tempt fate with (some of our vans have enough problems as it is😂).
One of the exceptions to the above is the Subaru flat-four, which does use a serpentine belt as a timing belt as well. However, even it has a tensioner and idler pullies, as shown below.
FWIW, even the old inline-4 Volkswagen engines utilize multiple V-belts to drive the water pump, alternator, and accessories, in addition to a timing belt. Some out there have been converted to a modern serpentine set-up though. _________________ ~Kamz
1986 Cabriolet: www.Cabby-Info.com
1990 Vanagon Westfalia: Old Blue's Blog
2016 Golf GTI S
"Real knowledge is to know the extent of one's ignorance." - 孔子 |
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Steve M. Samba Member
Joined: July 30, 2013 Posts: 6798 Location: Fort Lauderdale, Fl.
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Posted: Wed Nov 20, 2019 2:18 am Post subject: Re: Stop belt slipping |
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I continue to get belt squeal if my alt. belt is not tight. It is undoubtably causing bearing wear.
I've tried sanding the V grooves on the pulleys to belt dressing spray. Checked alignment of the pulleys, etc., etc.
It is the proper belt as it fits the V groove on the pulley nicely. 1100mm length
These is on new water pump and alternators.
Stopped squealing, but I know it is tighter then it should be. _________________ This free advice is worth exactly what you paid for it.
There are seven days in a week. Someday is not one of them. |
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Ahwahnee Samba Member
Joined: June 05, 2010 Posts: 9776 Location: Mt Lemmon, AZ
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Posted: Wed Nov 20, 2019 5:49 am Post subject: Re: Stop belt slipping |
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Steve M. wrote: |
I continue to get belt squeal if my alt. belt is not tight. It is undoubtably causing bearing wear... |
I doubt that a squeal causes bearing wear (though it can indicate a failed bearing).
I consider a bit of squeal right after startup to be acceptable (most commonly on a cold morning, headlights on, van has sat awhile). Unpleasant but preferable to the effects of a overtightened belt. |
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E1 Samba Member
Joined: January 21, 2013 Posts: 6378 Location: Westfalia, Earth
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Posted: Wed Nov 20, 2019 7:03 am Post subject: Re: Stop belt slipping |
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That's the only time I get any squeal, too -- a tiny chirp at startup and maybe once in ten starts. To clarify, it sounds nothing like Ned Beatty.
Ahwahnee, why would headlights play a part in bearing squeal?
I also don't think loose belts are hard on the bearing, Steve. Could be wrong of course, but I can't visualize a connection there.
I do know that too tight a chain really drags down a bike engine (or kart engine, in my experience), and actually robs power. The process of a tight belt stressing an alternator bearing is pretty much identical. _________________ ‘84 Westy, 2.1L with Digijet, 5.43 R+P, GT Gears
"Adding power makes you faster on the straights.
Subtracting weight makes you faster everywhere."
— Colin Chapman |
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Steve M. Samba Member
Joined: July 30, 2013 Posts: 6798 Location: Fort Lauderdale, Fl.
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Posted: Wed Nov 20, 2019 8:15 am Post subject: Re: Stop belt slipping |
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Ahwahnee wrote: |
I consider a bit of squeal right after startup to be acceptable (most commonly on a cold morning, headlights on, van has sat awhile). Unpleasant but preferable to the effects of a overtightened belt. |
Yeah, but it's "Social Embarrassment #342" The way mine was anyway!
It does put a side load on the bearing. Granted it might take 50,000 miles or more to have an effect, but it's a load none the less...probably less. _________________ This free advice is worth exactly what you paid for it.
There are seven days in a week. Someday is not one of them. |
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50260
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Posted: Wed Nov 20, 2019 9:43 am Post subject: Re: Stop belt slipping |
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The squeal isn't going to cause any bearing wear, it just wears the belt an extra bit. Bearing load is caused by the static load on the belt more than anything else. The dynamic load doesn't much increase the load on the bearing, because as the load on the belt increases slack occurs on the return side offsetting the load.
As a guess I would say that within the "normal" range of belt tightness a tighter belt isn't going to use much more power than a looser belt. This should be easy enough to test, by just tightening the belt to the loose end of the range, running the engine at 4000 rpm for several minutes and then checking the belt temperature and then repeating the test at the higher tension end of the normal range.
I would expect notched belts to take less power than regular belts, but this too would require testing. |
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