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I began this project in 2019.Here's a short video of this idler pulley bracket in action during my early prototype testing phase.
I ran the prototype for 5,000 miles to fully test for any problems.
Then later I swapped to a production bracket, which has over 15,000 miles
with great
results. https://www.youtube.com/watch?v=-O9fC3fR4ac
BELT SLIP RESISTANCE NOTE:
After installing this on my 242, I tested the belt slip resistance by putting
socket wrenches on the CRANK BOLT and on the ALTERNATOR PULLEY NUT and
I applied torque to see which one would slip first. Doing this test before with the stock setup
demonstrated almost NO grip on the alternator pulley. Testing with
this new configuration showed that the ALTERNATOR pulley now actually had MORE GRIP than the crank pulley. Think about THAT!
This is a big change!
Why is there BELT SLIP
Incurable Belt Slip during High Load.
The 240 original alternator design doesn't offer enough BELT WRAP (belt to pulley contact)
for an alternator that can pull a heavy load. Volvo
engineers added a SECOND BELT to the 240, which makes it better than one belt, but when you exceed
the grip capability for those belts, it's just going to slip. Adding a higher amp alternator make this problem worse. I spent more time than I should have over the years, trying different belts and cranking them tighter and tighter. In the end, I STILL HAD BELT SLIP.
This
was not really a problem back when the weaker 55 amp original Bosch
alternator was there, but it became intolerable with a high
output alternator.
I found that I needed to tighten the
alternator belts much more and then they usually needed more tightening
later as they began to wear. I was putting a LOT of stress on my belts. That can cause problems.
COMMON BROKEN BOLT That bolt on the front of the block for the adjusting bracket has been known to break off(it happened to ME).
I've also heard of a few people with broken water pump pulleys. See thread here: turbobricks.com/b21-b230.323223/. Over-tightening a V-belt is just plain BAD. It can also prematurely wear water pump bearings and generally your belts
don't last as long as they should. They just wear faster and then they begin
slipping again sooner.
This was NOT an alternator belt. This was a 240crank pulley to AC compressor belt.
It failed after about 300 miles of use because it was adjusted too tight. The belt didn't actually break, but it did jump off the pulleys after breaking those reinforcing cords.
That
long corded string stuff above was the embedded cord in the top-side of the
belt. The cord separated from the belt (or maybe snapped from too
much tension) and then eventually unraveled.
The belt eventually came off the pulleys and I found it sitting in my
belly pan. Most of that corded material ended up wrapped around my AC
pulley. Once that
corded part separated, the belt lost the ability to stay tight. After losing that corded material, the
belt became more like a big, soft, stretchy rubber band.
It was time to seriously deal with the BELT SLIP PROBLEM After
installing my new Mechman alternator in 2019 (The Mechman is in the photo below right) I found
I needed more belt grip. This was an immediate problem when running
the AC and cooling fans.
This is the reason for developing this ALTERNATOR IDLER PULLEY PROJECT.
Photo below showing how a 240 ALTERNATOR looks with stock POOR BELT WRAP:
So my idea to FIX BELT SLIP was to design an IDLER PULLEY (technically a back-side idler pulley). My goal was to significantly increase belt wrap on the alternator pulley. A back-side idler is NOT normally done with V-belts.
Some people will say you shouldn't try it. Some of those people will
also tell you the Volvo engineers knew what they were doing when they made the 240, so you
shouldn't
try to improve anything. I say the Volvo engineers made a COMPROMISE,
which only works (marginally) if you keep your car original and you can be
happy with 12.8 volts or less. The main
concern against a back-side idler seems to be the potential for faster
belt wear. Well, crap! I
already had faster belt wear because I was over-tightening my slipping
alternator belts and replacing them way too often to keep fresh
grip. I probably had faster water pump wear too. And so far all of
these negative "concerns" appeared to be based on opinion, not actual
experience. Other than for industrial machines, I have not found ANYONE
who has attempted this.
So if this concerns you, wait and see how this turns out. Here's my original concept introducing an idler pulley.
Observations and Rationalization:
I found there wasn't enough room for a pulley between the crank pulley and
alternator unless the alternator was moved over about 1 to 2 inches. A bracket (shown above) could also include the
BONUS of a mounting point for the upper adjuster bracket. This would eliminate the need for a new longer custom upper adjuster bracket. This also eliminates the bolt going into the front of the block, which so often BREAKS OFF! And after a careful look under my hood, I could see there was actually decent room in my 240 to move the alternator over, away from the engine.
Nothing interferes (if you have metal oil cooler pipes, CLICK HERE).
And this provides a lot more room for the oil pressure sender.
Let's proceed.
WAIT! WHAT ABOUT A SERPENTINE BELT? This kind of thing below has been considered. First,
let's look at how the Volvo 850 and 960 serpentine belt was arranged.
All of the accessories were designed to be on ONE side of the engine.
The water pump on this motor is turned by the timing belt, so it's not involved with the serpentine belt.
And here's an observation: the BELT WRAP on this alternator above is TERRIBLE.
So let's pause for a minute and I'll explain why I DID NOT pursue this. I've seen a few people do
variations of serpentine systems in Volvo 240s, but so far I have not seen
anyone do it for a 240 with proper pulleys foran alternator,
water pump, power steering and AC using actual RED BLOCK accessories OR
with a PROPER TENSIONER PULLEY, which is certainly recommended.
Yes, you can cobble together some pulley parts from a salvage yard and adapt them, but you will still need a custom crank pulley (for B21). Or for a B230 you'll need a custom B230 crank
dampener (see HERE). And you will STILL have to make all of the needed
brackets to hold those idler pulleys and a tensioner. So yes, it could be done, but it would be VERY expensive. In the end, after all this work, can you get better belt-wrap on the
alternator this way?
Building a custom serpentine system can be mind-boggling. This isn't a Volvo below, but it's an interesting project. This guy made a 7 part video project on all the work he did to get all these accessories to work using one serpentine. This photo is from part 7: https://www.youtube.com/watch?v=Sh61f7U9RHc
This 740 style idea has also been suggested: Below image from 700 900 Specification D24, D24T, TP30518 pg 117.
"Why don't I just give up and change to a 740/940 style alternator mounting?" I don't think there's really anything
wrong with changing your 240 to the 740/940 style
alternator mount. You just need the
parts. It requires new mounting brackets, maybe a new 740/940
style power steering pump and new or modified power steering
hoses. Plus changes to the alternator cables/wires. The only
question I still have is about potential belt slip. Yes, this
arrangement offers more belt-wrap on the alternator pulley than a normal 240, but it allows for only ONE alternator belt.
Mechman has an FAQ page: www.mechman.com/faqs/ and they have something to say about BELT SLIP. "A single V-belt or 4 rib serpentine
belts will start to slip at about 150 amps worth of load. For
minimal belt slip, 240 – 370 amp alternators should not be driven by
anything narrower than a 6 rib serpentine or a DUAL V-belt drive setup." So, would that ONE ALTERNATOR BELT like the 740 really be good enough for a high output alternator? I think NOT. Some
cars may be different, but I can tell you that I have tried just
one belt with my idler pulley setup. Even with really good belt wrap I've found ONE BELT will NOT
BE ENOUGH with an alternator as strong as mine. I discovered this when I had a mismatched pair and only one of the belts had full grip.
Test Engine B230:
For those who don't have a 240 nearby to look at, here's a view of the STOCK alternator pulley belt wrap situation.
Of course the alternator pulley slips. Look at that belt wrap.
This belt wrap on the alternator pulley is bad-bad-bad.
Stock Early 240 Alternator Mount Detail More original 240 bracket and tensioner arm info can be found in the installation guide below.
FIRST Plastic Prototype on Test Engine B230: So I started by making a bracket out of CARDBOARD (not pictured). Then I made a prototype bracket from PLASTIC (that's the PHOTO BELOW). This is 1/4 inch PVC I bought
from McMaster Carr. It's easy to cut
or grind and can easily be bent with some heat. This material made it
easy to make adjustments when test fitting over and over on an engine,
which in this case was on an engine stand. This plastic bracket was
pretty rigid and easily
strong enough to mount an alternator and try out some belts.
Here's the plastic prototype bracket
mounted on a B230 test engine with an
idler pulley and belts.
Moving the
alternator up to about 1.5 inches
away from the engine did not seem to be a problem. In my 240
there seemed to be plenty of
room. That amount of spacing allowed for the alternator to swing for a
good range of movement for belt installation or adjustments. And a very nice side-effect is there's now a LOT MORE ROOM for the oil pressure sender.
OIL COOLER PIPES CLEARANCE
On the subject of moving the alternator away from the engine, there is a possibility of interference with original steel oil cooler pipes
if your car has them, but I think interference can be fixed if it does
happen. I removed those pipes on my 242 years ago when I changed to a remote oil filter and larger oil cooler. Details about this change can be seen in my
OIL COOLER PAGE.
In the photos above, the oil pipes
appear close to the bottom of the alternator bracket, but probably not
so close that they would interfere when the bracket is moved outward. But
every car may not be the same, so study your pipes if you have them. On this 240 ABOVE, owned by
Vincent M., a high-performance 240 amp Mechman alternator has been fitted (Mechman PN B8206240B). My idler pulley bracket was
installed and the alternator was spaced away from the engine 1.5 inches. The oil pipes in this car
were not original to his car. He installed them from used parts. Vincent found them to be quite close to the bottom of
the alternator. Some bending of the oil pipes has been done and more could
be done to create clearance. The oil pipes are pretty strong and
carefully bending them can be done with good results. Otherwise, there are certainly still options to use other oil hoses if needed. SIDE NOTE: Vincent is using a smooth surface idler pulley found HERE.
WATER PUMP HOSE CLEARANCE
Here's a photo below showing the top clearance between my alternator and
my water pump hose. It's roughly about 3/4 inch from the
alternator at it's closest.
CLEARANCE Between Alternator and Frame
Here a photo below showing the side clearance between the alternator and frame after 1.5 inch spacers were added.
Again, the Plastic Prototype on Test Engine B230: I wanted this new bracket to be able to use the factory top adjuster bracket (tensioner arm) that I was using.
This is why I added a mounting ear to the bracket. The top adjuster bracket on my 1984 car is
an early one. A later 240 is different. I'll discuss the different
tensioner brackets later in the installation section.
If you have ever experienced the bolt for the adjuster bracket BREAKING OFF in the BLOCK
(like I have and many others have), then you'll appreciate that the design of this new bracket eliminates the use of that bolt forever. I have a section in this page on this subject HERE.
By the way, here's a video below showing how to repair this broken bolt if this happens to you.
Then I had a prototype steel bracket made.
STEEL PROTOTYPE BRACKET #1: I had this made by a local metal fab shop using 1/4 inch steel plate.
And I bought some steel spacers. These particular spacers shown are 1.5 inches long and 7/8 inch in diameter.
PN 4GVD9 from Grainger.com.
Here's a photo showing how much bolt thread usually goes into the Volvo block when
using a stock alternator bracket. There's about 14-15 mm of bolt thread sticking past the bracket.
The threaded holes in the block are usually about 15-16 mm deep, so your original bolts use up most of that thread depth.
The factory aluminum bracket is 15 mm thick at these holes, so your stock bolts are most likely M8 x 1.25 x 30 mm long.
BOLT LENGTH NOTE: A 30 mm bolt length is measured NOT COUNTING THE BOLT HEAD in case you're curious.
In my case the spacers used were 1.5 inches long. The new steel idler pulley bracket is
0.25 inch thick. The combined total was 1.75 inch (44 mm). So if
you used the same size spacers as I did, you would be using bolts with a length
of about 75 mm (not counting the head). Bolt length will be different if you use spacers with a different length.
CAUTION:
Always test your bolts in the block to check for the fit. If you
think they might BOTTOM OUT before the bracket is tightened, you should
add a washer or two.
Another photo of the Steel Prototype #1 with pulley on Test Engine B230:
Here's the first test-fitting of the STEEL prototype bracket and pulley.
You may have noticed that I changed to a different idler pulley in this photo ABOVE. There's more info
below on this different pulley.
Again, Steel Prototype on Test Engine B230:
Here's a view of the back-side. The mounting ear can be seen here for the top adjuster bracket.
CHOOSING AN IDLER PULLEY
This is the first idler pulley shown in the first prototype pics. I chose it mainly because I wanted to use a smooth pulley
with side flanges. It was not expensive, HOWEVER, I had some concerns
about the durability of this pulley, since it was originally intended for a lawn
tractor. I
couldn't find any useful specs other than what I have listed here, so I have
no real reason for having doubts, except that it just might not be durable enough for a car engine. So after thinking it over,
I decided instead to choose an idler pulley that wasactually
designed for automotive use at higher engine RPMs, high temperatures, etc.
DUAL BEARING PULLEY I
found this polymer (plastic) pulley listed in the Dayco Pulley Guide (PDF link below). So I ordered one. Yes, it's a GROOVED pulley. Keep reading for info about that.
Dayco offers a good variety of pulleys and the below guide lists a lot of them, but relatively few are"FLAT" or SMOOTH pulleys. Some have side flanges, which I liked. And even fewer are WIDE ENOUGH for
TWO V-BELTS (I think it should be well over 1 inch (26 mm) wide). This one is 30 mm wide.
The majority of the pulleys that Dayco offers are grooved
pulleys, which are designed for a grooved or ribbed serpentine belt.
All of these pulleys have sealed ball bearing
centers, but there is a variety of center bore diameters. Some in the
catalog have a 10 mm center hole (like THIS one) and some have 17 mm center holes. I preferred a 10 mm center hole. It's a good size for a standard sized 8 mm bolt.
The majority of the pulleys they offered had a SINGLE center bearing.Very few had DUAL BEARINGS.
An automotive grade pulley with a single bearing would probably be just fine for this
project, but I decided since something with two bearings was available, I would choose that.
I had concerns about using a pulley with RAISED GROOVES. The concern was about the
back-side of a v-belt running on a grooved surface potentially damaging the belt. So I tested this
using Gates belts for over 5,000 miles, my conclusion is it worked OK,
but it WILL eventually cause some wear damage to the belt. More
details and photos below CLICK HERE.
MY CONCLUSION: Grooves should be avoided. More below. Dayco Pulley Guide PDF:daycoaftermarket.com/PULLEY-DIMGUIDE.pdf Dayco Main Page:https://na.daycoaftermarket.com/en/
A WIDER DUAL BEARING PULLEY is available. I have not tried this one. If I did try this, I would remove the grooves and make it a smooth pulley.
This polymer (plastic) pulley is
similar to the above Dayco 89516, except it's wider and has larger
17 mm center bearing holes. If you choose this pulley and still want to use an 8 mm
bolt in the center, you would need to buy some center bushings which can be tapped into the holes to reduce it to 10 mm. More about these bushings can be found HERE.
There are concerns about using a pulley with RAISED GROOVES. The concern is about the
back-side of a v-belt running on a grooved surface potentially damaging the belt. I tested this
using Gates belts for over 5,000 miles, my conclusion is it worked OK,
but it does eventually cause some damage to the belt. More
details and photos below CLICK HERE. CONCLUSION: Grooves should be avoided.
Steel Prototype MODIFIED and fitted to Test
Engine B230: After initial testing, I decided to make an adjustment to the position or height of the idler pulley. I raised the idler pulley up more in order to increase belt-wrap around the alternator pulley even more than I had.
As you can see in this pic, there is now more than 180 degrees of belt-wrap on the alternator pulley. After this, I then did long term testing (more than 5000 miles) with this configuration in my 240.
Here's the modified steel prototype bracket installed for long-term road testing in my 240 with B21FT.
I installed the bracket in my 240 Turbo for long-term road testing and I put thousands of miles on it with no problems.
If this bracket looks a little different, YES, this prototype was modified before settling on this configuration. Belts in this photo: GATES METRIC-POWER XPZ 1120 These are 1120 mm in length, 10 mm wide. They have a cog on the bottom.
VERDICT:
This idler SOLVED all belt slip problems on my 242.
WHAT ARE THE EFFECTS OF
USING A GROOVED IDLER PULLEY?
Installation and testing on the B21FT: Lets discuss how THE GROOVES affected the belts. BELTS: GATES METRIC-POWER XPZ 1120 These are 1120 mm in length, 10 mm wide. They have a cog on the bottom. The only effect that was been found with these belts was some marks caused by the grooves in
this photo above.
The grooves etched some lines onto the backs of the
belts. This began to appear after only a few miles and then after well over 5,000 miles it did not change much.
It may look bad, but it did not become a serious problem with THESE BELTS. HOWEVER, since I think the grooves will eventually cause more damage, I don't recommended using a grooved pulley. Changing to a SMOOTH pulley is a much better idea. I'll be showing that below. SMOOTHING THE GROOVED PULLEY
There is a smooth pulley available shown further below, but I still have a preference for the DUAL BEARING pulley that I used above (DAYCO 89516).But I concluded it needed to be SMOOTH. So I decided to modify it. I used my bench grinder to slowly
grind down the raised grooves. I allowed the pulley to slowly spin on a
bolt while slowly grinding. So basically I turned this into a much smoother pulley. It only took 10 minutes. Worked perfectly.
Trying some other belts.
DIFFERENT BELTS (B230 test engine pictured).
I bought a set of the belts shown here to test as an alternative.
USING the STEEL PROTOTYPE BRACKET
This is a Dayco Top-Cog belt.
It comes as a Top-Cog as shown with a normal bottom 'V' section in 0.44 inch (11 mm) width. This
11 mm width will fit the 10 mm wide pulleys in a 240 just fine.
Note that since this belt is 1 mm wider, it will make the belt ride
slightly higher in the pulley groove, which can make the belt seem a
little shorter than a 10 mm belt.
Construction and internal reinforcement images for Dayco Top Cog. After
trying these belts, I found that I liked them because they
seem to have more internal reinforcement than the Gates belts. CAUTION: Make sure to get MATCHED BELTS. Here's something to be aware of. The belts I tried above are 1120 mm long, DAYCO TOP COG PN 15440. I ordered them through Summit Racing ($12 each).
Keep in mind that you need to buy belts like this as a MATCHED PAIR. I
had a bad experience with the first order and I got un-matched belts.
The belts in the above photo are un-matched because one belt is
slight less wide than the other. It meant that only one belt will be
tight. This caused a belt slip problem.
Summit Racing corrected this problem right away when I called them and they sent me new matched belts. www.summitracing.com/15440 So if needed, you might
need to talk
to someone in-person and ask them to send a matched pair.
Also keep in mind that this TOP COG belt may have changed to a NORMAL COG.
More recently I have ordered the same Dayco 15440 part number and they turned out to be normal BOTTOM cog types like this below
SMOOTH SURFACE PULLEY
So
after about over 5,000 miles of testing with the grooved pulley, I decided I
would try out this smooth pulley to see how things went. As expected, the smooth pulley worked perfectly. No issues st all.
Ultimately, I went back to the DUAL-BEARING pulley (and I
ground the grooves smooth). I just liked the idea of dual bearings
better. Dayco Pulley Guide PDF: daycoaftermarket.com/PULLEY-DIMGUIDE.pdf Dayco Main Page: https://na.daycoaftermarket.com/en/
PULLEY CENTER BORE: This polymer (plastic) pulley above only comes with a
17 mm center bore. Also it's a little larger in diameter than the other pulleys I tried. The outer diameter is not a problem.
I designed the idler bracket to use a smaller 8 mm bolt, so the 17 mm
center hole is too big on this pulley unless you want to drill out a
hole and use a 17 mm bolt. So I bought one of
the below pictured center bushings and installed it into the center of this pulley.
These bushings have a 17 mm outside diameter and a 10 mm (0.375 inch) center bore and
they are a nice snug press-fit into the center bore of the 17 mm
bearing on this pulley. No press was needed. I just tapped it in with a hammer.
Cost was small for this bushing. About $3 to $10: mrmowerparts.com/idler-bushing, amazon.com/B00AZ0OPPQ/, ebay.com/itm/176372873805. If you're searching, look for a 17 mm x 3/8 inch bushing for belt pulley.
Customer Vincent M. used this smooth pulley in his 240 project.
See BELOW PICS.His alternator is a Mechman PN B8206240B, which is an all black GM version with 240 amps.
Installation Guide
As
you can see here, this bracket has been made for a wide range of
adjustments for different size alternators, different size idler
pulleys, different positions for the pulleys and different positions for the top tension adjuster bracket, etc. The below photos show the installation into my my 1984 240 Turbo B21FT.
For my installation I used the below early style TENSION ADJUSTER BRACKET. A particular style is not required. You can use any style that you have. This
FIRST IMAGE below is the typical bracket found on early B21 or B23 equipped 240s up to about 1984. The bracket is always mounted behind the alternator mounting ear. This is the same as bracket #3 in the bracket assortment photo below. Volvo PN 1276128.
This later tension adjuster bracket below has a tension adjusting bolt. This type of bracket was found in
B230F equipped 240s beginning in 1985. This is bracket #4
in the bracket assortment photo below. It's Volvo PN 1346365. It appears that the Volvo diagram below is INCORRECTLY showing this bracket installed BEHIND the alternator mounting ear. The correct factory way is shown in the photo below showing it in FRONT of the alternator.
At least one person using my idler pulley bracket has used a LATER style tensioner mounted BEHIND the alternator. You can see a photo HERE.
I have NOT yet personally tried fitting one of these later style brackets in my
car or in my tests. If you have used this with one of my idler brackets,
please let me know the details.
Here's
a photo BELOW from a TB thread showing an assortment of Volvo tension
adjuster brackets that were offered for 240 and 740. The usual 240 brackets shown above are #3 (early) and #4 (1985 and later 240).
Source: turbobricks.com/1981-245-alternator-adjuster.356867/ LATER BRACKET UPDATE:
I have acquired the below style tension bracket and when I have some
time I'll be experimenting with it to see how well it fits my alternator
with the idler pulley bracket. I think it should do ok.
This bracket is similar to the
#4 later style bracket above, but clearly a bit different on the
bushing end. When I complete these experiments, I'll post that
info here. This is Volvo PN 1346024 acquired from iPd.
The PULLEY I ultimately continued using is Dayco 89516.
I chose this one because it has dual bearings and fits perfectly.
I don't think dual bearings is a requirement, but I just like stronger options where there is one. I smoothed out the grooves on this pulley with my bench grinder to provide a smoother surface for the back side of
the belts to ride on. More details about this Dayco pulley can be found HERE. There is more than one choice of pulleys. You can also choose a pulley that already has a smooth surface, but this one will not haveDUAL bearings. See that one HERE. Dayco Pulley Guide PDF: daycoaftermarket.com/PULLEY-DIMGUIDE.pdf Dayco Main Page: https://na.daycoaftermarket.com/en/
BOLTS
The
bolts I used below were M8 thread(M8 x 1.25) that I pulled from my spare bolt bin. I think the
length of that pulley bolt BELOW is about 50 mm.
The length of this bolt won't be standard, because there are a few
different pulleys you could choose from. I spaced the pulley away from
the bracket using a couple washers and it has about 1/8 inch clearance or less from the bracket. IMPORTANT: I strongly recommend using
LOCKING NUTS here. Normal
fasteners can vibrate loose over time and that would not be good. And if
one of these vibrates loose, accessing it without disassembly will be
pretty hard. So use a lock nut and it'll treat to nicely. There
are many choices for a good lock-nut. If you're using M8 bolts like
this, the lock-nuts pictured below are these from iPd:
https://www.ipdusa.com/products/11455/.
ENGINE BLOCK THREAD DEPTH
I checked both my B230 and my B21 engine blocks to see how deep the threads are
for the three alternator bracket bolts. Both blocks had holes that were about 15 -16 mm
deep. I measured by smearing a little grease on the end of a new
bolt (BELOW PHOTO) and threading it all the way in until it reached
bottom. Keep this thread depth question in mind during your
installation.
In my opinion, you should try to get at least 10 mm of bolt thread inserted into the block during your installation. Just be sureyour bolts are not be so long that they bottom out before becoming tight.
If a bolt length you choose is close to being too long, you can always add a washer.
HARDWARE TO MOUNT THE BRACKET:
I used 1.5 inch long
steel spacers and 75 mm long bolts (M8 x 1.25 x 75) with M8 washers (as pictured below). NOTE: The bolt length is measured without the head.
These bolts pictured are strong Grade 10. I recommend Grade 10 because of the long length. Grade 10 bolts are used in the kit offered here.
But if you use your own bolts and you only have Grade 8 bolts, they
should be ok. I tested the prototype bracket for over 5000 miles using
Grade 8 bolts. This included several different dis-assemblies and
re-assemblies. Not a problem.
SHORTER SPACERS:
BELOW PHOTO: I received some feedback from a customer who used
shorter spacers: 1 1/8 inch spacers instead of 1 1/2 inch. He wanted to add a little more clearance to some oil pipes and the results were good. The alternator in this photo is the Mechman B8206240B
, which is similar to mine, except it has 240 amp capacity and is BLACK in color. If you decide on a different length spacer instead of 1.5 inches I used, then you should change your bolt length.
OPTIONS FOR PULLEY AND TENSION ARM HOLE POSITIONS I designed the final version of this bracket to have many options for the mounting locations for the pulley and tension arm.
The current positions that I use for my 240 are: Pulley Hole #2 and Tension Arm Hole A. These images BELOW shows the top adjuster bracket mounted
in the NORMAL location for an
alternator with dimensions similar to the
Bosch. So then this configuration worked for me with an alternator that
was modified like Mechman did. (NOTE: That's a Bosch 100A in
this photo below).
BELT OPTIONS
GATES METRIC-POWER XPZ 1120 The belts I used FIRST were Gates Metric-Power XPZ 1120. These are 1120 mm in length, 10 mm wide. They have a cog on the bottom.
MATCHED BELTS.
Gates supposedly matches their belt lengths,
so when ordering these in pairs you *SHOULD* get matching length belts.
www.amazon.com/Gates-XPZ1120 Matched belts seems like a no-brainer, but some belt vendors DO NOT offer
this and I have had frustrating problems before with mis-matched belt pairs.
If a mis-match occurs, it will usually be because one belt it slightly
WIDER, which makes it slightly shorter when sitting in a V-pulley groove.
DAYCO 15440 1120 mm
I also tried using the below Dayco Top Cog belts. I liked
these belts also because they seem to have more inner reinforcement than most other belts.
The belts I used are 1120 mm long, Dayco PN 15440. I ordered them through Summit Racing ($12 each). GETTING MATCHED BELTS.
Keep in mind that these should be matched in length and width.Some places might send you un-matched belts if you don't specifically
ask for a matched pair. You definitely don't want one belt longer (or slimmer)
than the other. It has happened to me. So if you think it's needed, try to talk to someone in-person or by email
and ask if they can send a matched pair. Summit Racing did this for me after I got a set that were not matched. www.summitracing.com/15440
Alternate Belts: DAYCO 15435 43.5 inch (1105 mm) Web
B. told me he used the Dayco 15435 1105 mnm belts when he installed
this idler
bracket. A shorter belt like this will swing the alternator a little
closer toward the engine. It's possible that you'll lose some room to
push the alternator close to the engine when you're installing these
belts. It could make installation a little harder.
.
INSTALLING, POSITIONING, AND ALIGNING THE NEW BRACKET
BELOW left photo:
Working from under the car . . . With the alternator and original bracket removed and out of the way, I
first position the new pulley bracket against the engine block over the
mounting holes. I loosely thread in one SHORT original bolt into ONE of the holes to hold the new bracket in place.
This is only to hold the bracket so it doesn't fall and knock me
on the head when I let it go. Plus it helps a lot when I'm inserting the
stock alternator bracket,
spacers and longer bolts one-by-one while I have only two hands.
You can then remove that short original bolt after getting one of the long bolts
started through the factory bracket and spacer and into the block.
PULLEY ALIGNMENT
Before tightening the bolts, pay close attention to the alignment of the idler pulley.
Check it from below and above. It needs to be lined up and pretty close to being CENTERED on the two
rear belt grooves on the crank pulley. Also the idler pulley should be
straight, or at about the same vertical angle as the crank pulley. If
you have a short bubble level you can compare
the vertical angle of the crank pulley to the angle of the
idler pulley. Try to make them the same.
INSTALLING BELTS When I install these belts, here's the technique I use, in case this helps you. This image below is me installing Dayco 15440 belts, 1120 mm. I do this one belt as a time. First I install a belt over the water pump, crank and alternator inner pulley groove, WITHOUT wrapping it around the IDLER PULLEY yet.
Then the final step is pushing the alternator against the engine and then push the belt over the idler pulley. Then I do the same for the second belt.
SETTING PROPER V-BELT TENSION Most DIY Volvo owners don't
have special belt-tensioning tools. So my best technique for
setting v-belt tension is the same 90 degree flex method that's demonstrated in this belt video below. https://www.youtube.com/watch?v=FMiB3CnZpRc
Or
use this image below as a guide for deflection on the longest length.
This image is from the 1984 240 7,500 mile maintenance service manual. Also keep in mind that you should re-check belt tension after a period of use, perhaps after
a few hundred miles. Brand new V-belts will often get a little looser
after a period of use and I have found that they often need to be re-tightened. TIGHTENING MY BELTS USING AN EARLY TENSION BRACKET Since I use an early style tension
adjustment arm, I use a simple pry bar behind the alternator to pull the belts tight before
tightening the final bolt. Here's what that typically looks like.
Can this bracket be used to eliminate the problem of a BROKEN BOLT in the block?
YES it can.
If you have ever experienced a
sheered off boltin the front of the engine block like this below, this
section will concentrate on THAT PROBLEM. A few customers have asked if
they could use this idler pulley bracket to replace the adjuster
mounting point where that bolt commonly breaks in the engine block.
The below photos were sent by Tyler W., who experienced MULTIPLE broken bolts there.
So he mounted the new idler pulley bracket with spacers for just
the purpose of eliminating the need for a bolt in the block. His use of
this bracket was a little different than usual, but if experimentation works, I'm all for it.
Tyler originally wanted to try to use the
bracket without an idler pulley, because he wasn't using a high-amp
alternator. Eliminating the idler pulley is possible, but Tyler found
that the 1130 mm long V-belts he bought created some interference between
the belts and part of the original bracket under the belt (at that lower alternator bolt). I believe Tyler might have
avoided the use of the idler pulley by using a shorter belt, which I think would probably allow the alternator to tilt upward
enough to gain belt clearance away from that bolt. And if you're really observant, you'll notice Tyler placed the spacers between the block and the idler bracket, instead of between the idler bracket and factory alternator bracket. If it works, it works. It offers more possibilities.