Serpentine Belt / Pulley Conversion?

Some progress today. Moved engine from (freezing) garage to basement. Projected belt/ancillary/tensioner layout.



The compressor on the floor is a Volvo SD-709, from a old 760 V6. I can bolt that up to the block for gauging tensioner placement and belt length.
Ordered the SD4514 serpentine clutch assembly.
(Thought) I inverted the WP pulley here...


Went through my Volvo parts, after spending hours looking at any number of crank pulley/damper permutations for something close.

The '99-04 V70 power steering pump has a metal (approx) 5" OD pulley. The slight increase in OD should help overdrive the water pump and alternator for low rpm increase in circulation & voltage output..



So, I'm going to have the inset machined off, and the stock pulley machined down so that the serpentine pulley will be an interference fit. Pulley has to be offset about 1/8" back over the inner lip to allow belt to sit correctly. I'll make final adjustments to the offset before welding/pinning the pulley to the hub. Much less machine work than reducing the stock pulley to a hub & drilling/tapping to fit an Audi/VW style damper.

Alternator with serp pulley



Idler stuff. I have at least three different OD tensioner pulleys.



possible tensioner setup



belt alignment (WP Pulley is inverted in these two pics)



gauging water pump pulley offset needed



EDIT: Not sure there is enough clearance for a 1/2" deeper WP pulley. Edit2: Not a problem, see later posts



Stock compressor pulley - may need to offset compressor 1/4-1/2" outward

Impressive.

With our 1600 engine build under way, I'm watching this thread closely!

It would make perfect sense to adopt a similar system while we are assembling our engine.

But I have a question:

lookforjoe said:

The '99-04 V70 power steering pump has a metal (approx) 5" OD pulley. The slight increase in OD should help overdrive the water pump and alternator for low rpm increase in circulation & voltage output..

Click to expand...

Wouldn't you need to decrease the OD to achieve a higher speed??? :confuse2:

Keep up the great work Hussein! Appreciate the effort you're putting in to this.

Cheers,

Rob

lookforjoe said:

The plan will be to use an auto-tensioner, if possible. Space may not permit. Nissan uses a 4-rib idler pulley, so that could be made to work.

I want the tensioner in between the WP & alt, pushing downward to maximize belt coverage on the WP & Alt pulleys.

This pic is of my Volvo setup - you get the idea as far as % of pulley coverage

Alternate version, closer to older (-98) setup that used an idler in addition. You can see that the crank & AC coverage is not as good, this is the type of thing I want to avoid.

Click to expand...

Looks like the alternator spins in different directions in these two setups...

It does, but that really doesn't matter on the Volvo. The side of the alternator faces the front of the bay, having the alt spin backwards makes no difference to charging, just the internal fan blades are flow reversed.

I drove it like that for about 10k, then had a 180 amp reverse rotation alt built for it.

rjplenter said:

It would make perfect sense to adopt a similar system while we are assembling our engine.

But I have a question:
Wouldn't you need to decrease the OD to achieve a higher speed??? :confuse2:
Keep up the great work Hussein! Appreciate the effort you're putting in to this.

Cheers, Rob

Click to expand...

Maybe you're correct - I get confused about which pulley OD needs to change to increase RPM. Smaller pulleys are called underdrive - I thought that meant they turned slower, but overdrive in a transmission drops rpm , so I'm confused..... Either way, it's pretty close to stock so I'm not really concerned about that.

If you make the drive pulley smaller

lookforjoe said:

Maybe you're correct - I get confused about which pulley OD needs to change to increase RPM. Smaller pulleys are called underdrive - I thought that meant they turned slower, but overdrive in a transmission drops rpm , so I'm confused..... Either way, it's pretty close to stock so I'm not really concerned about that.

Click to expand...

Then it will make the driven pulleys spin slower. If you make the driven pulley smaller then it will make that accessory spin faster, because you're moving the same amount of belt across less pulley, therefore the pulley has to turn more times.

Pete

Ok so I was correct the first time

Progress. Spent a few hours trying to figure out the tensioner. Ended up with a short stepped offset bracket that is bolted to the end of the Alt base mount. To tension the serpentine, I'll start with the alt all the way extended, and push it back towards the motor to tighten. The reverse of stock alt adjustment.



Original layout for comparison



Idler/compressor clearance. As long as the serpentine AC clutch is not over 5", this will work. EDIT: Serpentine Clutch is listed at 4.68"/119mm



Ideally, a tensioner inbetween these two would be better



Temporary idler bracket. Going to tie it to the alternator support bracket



WP pulley (4.25" OD Toyota Corolla / Geo Prism) arrived - just need to cut it down to match depth of other pulleys.

Looks good so far except for

the cutting down of the WP pulley part. You're getting into "machining" territory that some of us may not be able to follow. It seems like the WP is a tad large in diameter. Wasn't there anything slightly smaller than the stock one? Also, I take it that you will be using the alternator as the tensioner adjustment. That makes sense. Keeps the whole thing simpler...except for that cutting down the WP pulley part!

LarryC said:

the cutting down of the WP pulley part. You're getting into "machining" territory that some of us may not be able to follow. It seems like the WP is a tad large in diameter. Wasn't there anything slightly smaller than the stock one? Also, I take it that you will be using the alternator as the tensioner adjustment. That makes sense. Keeps the whole thing simpler...except for that cutting down the WP pulley part!

Click to expand...

The pulley is the same OD as the Fiat - just deeper offset. I haven't found anything else close in hours of searching.

If the only issue you have will be machining this, I can always have one done for you by my machine shop. The crank pulley needs machining as well, for the ZF/Volvo serpentine pulley to fit. Significantly lighter than the Punto pulley with the tooth wheel. I'll know how much the machining will cost during the week.

I have my old Fiat/Bosch alternator, and I have a Volvo/Bosch alternator with serpentine pulley. I'll see if the pulley fits the fiat alternator, otherwise you'll have to look for an alternate unit.

More revisions.

Found a Saab Idler (43 56 127) that looked to be smaller than the Volvo - and it is - 2.5" OD



Pulley is ribbed, though, so dual rib serpentine will be needed for this. I cut a rib off an old Volvo dual 6 rib, to test it over the water pump pulley





decided to make a tensioner for the idler, to make fine adjustments, VS. the coarse adjustment of the alternator body







Have to shift the lever point - it's too far over to the right



When adjusting, the tensioner arm is hitting the water pump bolts







EDIT: May have to shave the idler smooth - I can't find any 5DPK belt listings from Goodyear or Continental (with cross references for Bando & Gates).

Later Bosch serpentine pulley fits the Fiat/Bosch alternator.

VolvoV70 Bosch alternator shaft



Fiat Bosch alternator shaft



with fan & spacer, depth matches serpentine pulley offset



same shaft OD - 17mm



so, remove v-belt pulley w/integral fan, remove woodruff key, install serpentine pulley - use spring washer from serpentine.

Thinking it may be better to have a idler between the AC & crank to improve pulley coverage, just not happy with the level of coverage without. I can make a support bracket that mounts on the steel AC mounting bracket.



EDIT: Going to use two Gates 36322 (65mm OD, 24.5 W) idler pulleys instead of the Saab ribbed idler. The selection of dual 5 rib belts is too sparse, and expensive. Standard 5 rib (pg.886) are plentiful, inexpensive, in a wide range of lengths.

EDIT: Gates reference link now goes to full pdf catalog - over 900 pages(!) I have saved the catalog to dropbox HERE, for anyone to access. Page in PDF viewer is now 962. Be prepared to wait awhile for it to load!

Had the serpentine pulley machined to accept the hub



And the stock crank pulley machined to be an interference fit in the pulley



Made a idler bracket built off the front AC compressor mount bracket. Standoff has a 17mm shoulder cut to the depth of the idler bearing.





braised together - it'll look pretty once it's cleaned up & painted



idler will sit so..



finished up the tensioner adjuster



setup will be like this - with slightly smaller (65mm) OD idler & tensioner pulleys. Water pump pulley was also cut down to appropriate depth, and redrilled for Fiat bolt pattern. Had to insert a collar to center the pulley properly on the hub prior to drilling.



Just waiting for the AC clutch/serpentine so I can finalize the belt alignment & get the crank hub/pulley welded.

Loving Hussein's Ingenuity....

...and thinking, "Hey, my car doesn't have A/C, so maybe just maybe could I use the brackets and space taken up by the A/C compressor for, ahem, another kind of "compressor"..........

Dan Sarandrea (Phila) said:

...and thinking, "Hey, my car doesn't have A/C, so maybe just maybe could I use the brackets and space taken up by the A/C compressor for, ahem, another kind of "compressor"..........

Click to expand...

As in a supercharger? Certainly could be done...

Finished up the idler (Gates 36322) setup and tensioner bracket alignment. You may notice that the casting of the water pump housing needs shaving for the tensioner arm to not bind when making an adjustment. This tensioner is certainly not a necessity, and could be substituted for a fixed mount idler.



Belt measures out at 53" (Gates 5 rib - K050523 is 52 7/8"), close enough - I set the single strand into the compressor pulley V. There is room to move the AC compressor for initial setup, then I'll lock it down and use the alternator coarse / fine adjusters from there. Belt alignment looks good, just not 100% convinced on the crank/WP - I may have to remove the snail mount to confirm before going ahead with welding the crank pulley to the hub. Clutch won't be here until after New Years.

Crank pulley offset needs adjustment - rubs the timing belt



brackets needed







Measurements

Non-A/C version?

Hussein, sensational work so far.

I'd love to have something similar on our 1600 build. But we won't be running with A/C so need a setup to mirror this:


Photo borrowed from Ricardo

Do you have part numbers for the alternator and water pump pulleys you're using? I looked right through the thread and may have missed them, but couldn't see any.

Thanks,

Rob

rjplenter said:

Hussein, sensational work so far.

Do you have part numbers for the alternator and water pump pulleys you're using? I looked right through the thread and may have missed them, but couldn't see any.

Thanks, Rob

Click to expand...

Hello Rob

WP pulley is from 89-97 (maybe other years, but that's what I found it under) Toyota Corolla/Geo Prism, off eBay.

I'm using a Denso alternator - whose pulley won't work for you. The Bosch Serpentine pulley should be standard 6 rib pulley, non-clutch style. Using the stock alternator will require a spacer on the WP pulley, as the pulley offset is off by the thickness of the required alt. fan blade.

If you have JY access, 93-98 Volvo 850/ S/V70 alternator pulley is what you want. EDIT: This one looks the same

The crank pulley is Volvo S/V70 '99-'04 ZF PS pump pulley (5" OD) - which is not sold separately, so you'd need to buy a junk pump to get it. Later pumps and new replacements usually have plastic pulleys.

EDIT: this Mazda PS pump pulley looks the same - may be worth PM'ing them for pulley OD