T4 alternator and belt alignment

[SGKent]

Trying to adjust the alternator as the engine is put back together I MAY have an issue. Or it may be design. If you have seen it before feel free to comment.

The 55 amp alternator goes into a bracket. That is a new VW one. That bracket more or less holds the alternator in the plane it will go. That plane is slightly different than the plane of the fan. The shroud is good and undamaged. The alternator is undamaged.

The alternator pitches in just a little like if the fan were about 3/8" closer to the engine. The hub and fan are good so that isn't the issue. I might be able to tweak the bracket a little to change the angle but before I do that, if they all are like that then I may be wasting my time. Putting shims under the bracket is out of the question and would only cause the shroud to fail there I think.

That said, I might be able to tweak the bracket to get it a little better. I don't know.

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"Most people don't know what they're doing, and a lot of them are really good at it." - George Carlin

[telford dorr]

Try rotating the mounting bracket 180 degrees? If one hole is for some reason closer to the base, it might change the angle...

_________________
'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)

[SGKent]

[ivwshane]

I had a similar issue and I didn’t see any areas I could adjust. I thought maybe I forgot the hub spacer but nope, it was there. I put a laser leveler on the belt and it was straight but the pulley and hub didn’t look aligned so we’ll see.
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77 westy 2.0 FI
69 ghia coup 1600dp
70 single cab

[Wildthings]

Never had a problem with this, the belts on all of my Type 4 engines have run nice and true. I would pull the bracket and measure the height from its mounting surface to the center of each hole and see what you get. I have kind of wondered how the factory made this bracket and got good alignment, did they drill/punch the holes before the bracket was bent or after?

[RalphWiggam]

My 1.7L is like this. I didnt see anything I could adjust either.

[raygreenwood]

Yes.....virtually all of the 1.7L and 1.8L have some amount of this.....and yes.....eventually the level of misalignment can get to be too much and you can get a mounting and fan combo that is prone to throw a belt at high rpm. I have only found maybe two engines that bad.


However......I found "SOME" of this same prohlem on very high mileage Saab 900s. They used different brackets and used the Motorola style Bosch Alternator. But.....the pivot point and locking mechanism used the same geometry as our alternators. It was roughly the same problem.
Over time and high miles ....especially in hot weather which is harder on the belt (especially on my application with a sealed engine compartment as compared to a bay without one).....I found that these engines went through at a faster rate. They would start fraying the rearward side of the belt faster. It also almost always required one or two tension adjustments more than just belt initial break in..... within the first 10k miles. Hard on the belts.

When I first started seeing this on my first couple of engines.....I thought maybe the shroud alignment was off....but no. It was correct.
This problem is NOT a pulley to pulley misalignment....meaning one simply being out of plane to the other. Its the alternator pulley being "cocked" in relation to the fan pulley.

The problem is a small "stack" of tolerances. On a few of these there was a small amount of stretch or bend to the pivot bracket (this is just another symptom and not the complete root cause). The biggest problem I found....iirc.....is the pivot point bolt hole in the alternator housing is sometimes not perfectly aligned. In itself not the complete problem.....but add to that the hole through the housing for the pivot bolt is slightly larger than the bolt.
Yes.....this variation is small.....but when you put side load on it.....these little variations stack up and let the alternator cock. Also you get some bend to the pivot point bracket.....and the steel locking bolt arc arm is a bit too flexible and allows this bend to happen.

The fix that worked for me at first was a shim using thin sheet aluminum around both ends of the pivot point bolt and a shim washer ....spacer....between the alternator housing ear and the locking bolt to space it back away (forward) from the steel alternator locking arm.

After many years of looking at the fan and pulley set up on the type 4 engines.....and the small amount of flex I see to the fan....and the higher level of flex and misalignment I see to the alternator....I came to the conclusion that the vast majority of owners over tighten the belt. In the beginning at 15 years old.....I did the same thing.
I found after working on other cars/engines.....I dislike the system. After changing the belts and pulleys on my Golf a few weeks back.....I thought it would be wonderful to have the same set up on my type 4 engine....where the alternator is locked solid in a specific position and the exact correct tension is applied to the belt by a spring tension roller in a spot on the belt between alternator and fan.
The nice thing is that the spring tensioner system allows much LESS tension to be used...but is more effective in keeping the belt on as it ages slightly and stretches out/gets larger.... because its not causing the only tension being applied..... to be the belt being stressed under elastic tension. Its an external tension source....that constantly takes up the slack.

It would be pretty easy I "think" to install an external tensioner on a type 4. Ray

[ImAddicted]

[SGKent]

[telford dorr]

Assuming the fan housing pads are parallel to the crankshaft: Check that the bracket base is flat. If not, correct. Then put the bracket with the bolt going through it on a flat table. Measure the distance from the bottom of the bolt to the table. Grind the higher hole with a burr on a die grinder until the bolt is level. Weld in the top of the hole and grind smooth so the bolt fits snugly. Paint. Done.

Just a thought...
_________________
'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)

[Wildthings]

I know you said you don't want to shim things, but if you got a caster wedge of the correct angle you need, like used on the front of a 4WD with a solid front axle and leaf springs you could cut out a piece the size you need to fit under the bracket. This would give nice even support for the bracket. The other thing you could do would be to cut off the forward ear, shorten it a bit and weld it back on. Done well the repair would be invisible.

You might check too that the holes in the alternator itself are not wallowed out. This happens readily on some rigs and can be corrected by bushing the bore. Vanagon WBXer engines have this problem.

I have a zero mile factory bracket and alternator somewhere if you want any measurements.

This system has always seemed very chintzy to me but seems to work well enough. The bracket on my '77 is probably pushing 500K miles at this point in time, between its miles on the 412 it started life on, and the 32 years that I have been running it on a Bay, often as a daily driver and typically as my primary tour the continent vehicle.

[SGKent]

[raygreenwood]

[SGKent]

[ivwshane]

They still sell new shrouds?!! Do you have a link? I searched and found nothing.
_________________
77 westy 2.0 FI
69 ghia coup 1600dp
70 single cab

[SGKent]

[SGKent]

Reading thru the Orange factory manual I found a photo. The bracket in this photo is completely different and more robust than what is in the bus. Do I even have the correct bracket.

Style that came on my bus and what I am using

Photo of bracket in Orange manual. Ignore the arrow pointing at oil boot. Kinda looks like a draft tube next to it so maybe this is a European model photo.

Another photo a couple pages later. Same as mine. What's up?

_________________
"Most people don't know what they're doing, and a lot of them are really good at it." - George Carlin

[Wildthings]

This one appears to have an integrated nut.

[SGKent]

I saw that. It is weird that the manual shows two versions of the same bracket. Probably would have ignored it but that one with the captured nut looks so much more robust. Almost makes me want to go have a custom bracket fabricated. thicker steel and wider base.
_________________
"Most people don't know what they're doing, and a lot of them are really good at it." - George Carlin

[raygreenwood]

Since you asked....and....…this off angle alternator pulley problem used to drive me nuts a long time ago....still does....here is what I have done for it over the years

First I do not fully agree that the brackets are all that “fragile”. Yes...I get your point that you don't want to fiddle with them much....but in my opinion...you will have to SOME.

The long arc shaped piece of steel where you lock the alternator locking bolt (called bracket-heat exchanger right-part # 021 256 304 or 304 A)…the few that I have seen that WERE cracked were either cocked or twisted because the lower end was not mounted to the heat exchanger correctly (or not at all) and the combination of movement, rust and heat will crack it.

Bluntly put if that bracket is not parallel to the boss on the alternator housing so it just kisses it…all the way through the alternator arc…. it’s either crooked or twisted. This you alreasy know.

Further…if the boss on the alternator housing contacts the bracket on one edge…the alternator is cocked as well…and that’s what we are talking about in this thread.

First….as an example of not so fragile….this bracket set and shroud below has the better part of 500k miles on them. They have been through the factory build with over 225k miles, another build with a little less than 200k and a third build that had a cam-cident at about 89k miles. Three alternators….the original, a used one and the used one rebuilt. About 6-7 mufflers….and more times in and out with the engine than I can remember (have to check the log)…and I think three car chassis. Snow, ice, salt, rain and hideous heat. Lots of parts attached to them came and went…in and out.

These alternator mounts are still straight as an arrow. They are not the problem we are having here with the cocked pulley….not totally.

They only get broken (in my experience) usually when they get abused…..taken loose and installed wrong (been there on my first car)…..or driven loose….or the alternator gets cocked due to the OTHER reasons….and it gets run this way which can crack and bend the brackets….or…and this is VERY common…they get re-installed…and not adjusted properly.
Yes….they can be adjusted.

And from what I have seen…the cocked alternator is NOT primarily to do with the brackets being bent or broken. Worn....yes.

The FIRST problem is usually this…with the inner pivot point bracket:

See the range of motion on the inner hole in those three pictures?

The square hole is on the outer end so it allows the alternator pivot bolt to shift sideways. Over time they always work loose…. it’s one of those things you need to keep an eye on….and probably get a better washer than the stock one.

And…its not ALL the washer and nuts fault that this gets loose. There is more than one wear point. Get to that in a minute.

So how much of a “cocked” pulley does this slop cause? Let’s find out.

So, I set this up level using a long 8mm bolt in the hole. Yes…there is a little roughness to the housing surface but this is a good baseline. The alternator is clamped in place.

The little arrow in the red circle means that to read perfectly level…you need to move in that direction. So, the left end of the housing is 0.3° too high.

So, I installed the bracket and pushed the left end (the inner end) down as far as it would go as I tightened up the nut. And….

….I got a further 0.3°…which means when the bracket is cocked in that direction its 0.3° off. Not bad.

Then I unlocked the nut and shifted the bracket all the way the other direction and locked the nut….

….and got a reading of 2.1°. So the total range of possible “cocking” motion...+ and -.... is 2.4°.

So, ….its somewhere around 2.1° of slant to the pulley when under tension.

What can you do besides find an un-worn bracket or welding (which WOULD wreck it) or drilling to a larger bolt size (don’t do that!)…or making a new one from scratch (not too hard if you have a straight pattern)?

Well…a long time ago I installed a bronze flange bushing and drilled out the center. It worked perfectly but was too soft and always worked loose. Right idea…wrong material.

I did this too,….worked great! Little chintzy….but it fits well. I picked one up on the way home today to do one live.

Its an 8mm Tee nut. I bought it at Ace Hardware for $1.16. You MAY get lucky as I did on this one and the last time…and have it fit dead on.
I cut off the tabs and cut it down to size. Took less than a minute.

Did it do any good? Let’s see….

So….it cleaned up the “0” angle by +0.3°. This is with the left end pushed down in the direction of the red arrow to take up any slack in that direction.

So, I loosened the nut and pushed it upward in the direction of the red arrow and then tightened down and got 1.4°.

It made an improvement of 0.3° + 0.7° = 1.0°. Where is the rest of it?

Well…first….we saw it move from 0.3° to 0.00°…because I did NOT re-center the hole with regard to the square hole opposite. I just bushed this hole. Its still out of alignment by 0.3°.

Part of the rest of it…if not all of it….is HERE:

The inner hole is worn a little oval from vibration. It allows it to cock just a little no matter how tight the bracket is.

Can this be fixed? Yes…..

The inner end “hole” of the pivot point on the alternator housing is a steel bushing. It can be replaced with a metric drill bushing. Its about 13mm long under the flange, about 2.5mm thick and has a 20mm head flange diameter.

The outer end is straight aluminum…part of the housing,

Its done this way precisely because the inner end is the highest point of side load/leverage.
I also see no reason you cannot install a steel bushing in the outer hole as well if needed.

This part should be fine from Mcmaster car. You can get them in 7.9mm ID, 8.0mm ID and 8.1mm ID with a 15mm outer flange diameter and 2.5mm thick….13mm in length.

Second to last thing…..these are adjusting holes. Any time you have had the whole engine apart, have bought a different alternator or heater boxes, different shroud….etc. etc…..adjust this bracket until the boss on the alternator housing just kisses and glides along the arc shaped locking bracket.
If not…it can put a load and angle on the whole set up.

Last thing….I learned this from working on my Mk2 cabrio and my Saab 900…which were VERY sensitive to ground quality…even more so than L-jet and D-jet. It also works very well on type 4 engines.

The pivot point and locking point of the alternator…are one of its man ground transfer points. The locking bracket with age gets to be a VERY poor ground with rust on the heater box.

The pivot point…commonly grows electrolytic corrosion inside against the bolt and between the bolt and bracket and that’s where some of the aluminum disappears too…especially in wet and salty climates. Suffice to say it makes a poor ground and can actually get hot enough to burn metal at that point on some engines.

This is why many Mk-2 and some other Euro cars like the Saab…all of which used virtually identical alternators as the type 4 at some point in time…..uses a ground braid wire connected at the pivot point bolt or on the alternator case.

There are lots of ways to fix the cocked pulley.

Really…while the Tee nut trick is cheap and works just fine..…the better more proper way to fix the pivot bracket is to by one of those drill bushings from McMaster Carr that is for like a 4mm ID drill ….and drill out the center to 8mm and press it in and cut it off. Ray