Belt issue with Vintage Air system

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Nov 15, 2008
Tampa, FL
Hey guys, thank in advance for reading.

I'm a pretty good home mechanic and done a bunch of upgrades on my 81 fj40... my most recent issue is a simple one and hoping someone out there with a VA A/C can shed some light on!

I have original 2F 81 engine without power steering. Installed my Vintage Air system last year. Read lots of posts and had a few fitment issue, but now working well. Installed per VA recs with compressor and alternator on passenger side of engine with their installation bracket (I've contacted VA and got no reesponse). However, my fan belt continues to slip despite alternator being at max tightening. I've gone to Napa and previously tried the next size belt down (mine is a 25-9590, I think 58.7 inch), but couldn't get the next size belt to fit. Belt is very tight but the issue seems to be the compressor is at the 10 o'clock position compared to the fan/waterpump pulley and crackshaft pulley is directly under the waterpump/fan pulley.(picture shows config) So the fan/waterpump pulley only has about 2 inches of contact with the belt. I can turn the fan with my hand and make it slip while the engine is off!

Anyone added a tensioner pulley or added a second belt from crankshaft to waterpump/fan? My last resort would be to just remove the fan and replace with an electrical fan but hoping someone else has some ideas.
Landcruiser belt config.jpg
I run a similar C/WP/ALT/AC set up, but use the Gates Green Strip II - TR24597 belt.


But I also run a power steering pump, thus I have a Gates Green Strip II - TR24438 belt for my C/WP/PS.

Thanks GA, only problem is that your setup has another belt so it may not be slipping due to the added tension. I guess I could always add power steering!! Hell of a solution to a slipping belt but a great upgrade!

Thanks for the reply buddy.
Adding an electric fan wont help, you still have to turn the water pump. I'd look at running 2 belts. You have extra V grooves on the w/p and crank pulleys. Can you off set the compressor or alt to line up w/ the inner pulley grooves? We can't see how the alt and compressor are attached.
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You could consider adding an idler pulley to your air pump bracket, lined up with the inner sheave, driving the water pump with plenty of "wrap".
Agree with water pump, just figured the resistance in the waterpump was minimal compared to the fan.

My alternator has a single belt groove so adding another belt to the alternator is not an option.

All the replacement alternators are double belt types, but this also changes the setup to a larger alternator (50 amp) with an internal voltage regulator. So additional wiring would be required and I'm not sure the offset distance between the mounts would be exactly the same. There is no play at all on the Vintage Air alternator mount to shift the alternator to the front or back of the engine to line up belts/pulleys.

During my (re)investigation of your alternator idea, I did find this on SOR, (Page 048 Land Cruiser Emission Pump, Bracket, O2 Sensor & ABV 9/72-8/92). "A smog pump eliminator pulley". It seems my belt slippage is due to lack of tension from a power steering pulley and/or smog pump pulley. Since I don't have PS, looks like the lack of smog pump is the issue. However, my smog pump was already gone on my engine when I purchased it. Nobody seems to have an adjustment bracket for 1981 without A/C... I gambled and bought the pulley with a bracket for 76-80 FJ40 2F.

if this combination works, I'll post it up so the next guy with the same question will have the answer! Lots of Vintage Air systems out there, probably a few on desmogged engines.
You could consider adding an idler pulley to your air pump bracket, lined up with the inner sheave, driving the water pump with plenty of "wrap".

Looks like I eventually came to the same conclusion... thanks 73fj40.
Maybe try another belt?
If you look at GA Architect's photo, his belt is wider and has full contact with the pulley groove. Your belt rides about halfway down the groove. I would think you're loosing a lot of contact surface with your belt/pulley combo.
Maybe it is just me but looking at your photo it appears as though the belt is inside out; pointy side out instead of down into pulleys. That would severely decrease contact with the pulleys and allow it to slip.
Well... I'm a little stumped now. First of all, the belt it not inside out :)....

I bought the smog pump eliminator pulley from SOR and got two different adjustment brackets for Air/smog pumps for 1981 2Fs. One of the adjustment brackets looks consistent with pics I've seen on Mud. However, the pulley on the eliminator bracket is off-line with the waterpump/fan pulley by 1/2"? I took a pic of the smog pump bracket (which looks stock to me) that has been on my 40 since I bought it, there was never a pump attached or power steering. Also pics of how the pulley doesn't line up?

I guess I could just take off the pulley from the bracket, find a thicker spacer and lengthen the bolt to push it closer to the radiator 1/2" but wondering am I missing something?.

smog bracket 1.jpg

smog bracket 2.jpg

smog bracket 3.jpg
FWIW: It may be worth your while to get a wider belt (17mm) for the C/WP/AC/ALT to see if that would eliminate the slippage. Note, If you do, it will not be the same length as the thinner belt you are running.
Several years ago I dealt with the same squealing belt problem. I kept trying to tighten the belt, with no success. What I found was that the narrow belt, like yours, was being driven primarily by the bottom of the V on the pulleys, with very little contact with the sides of the belt. I changed to a larger belt, that had much better pulley contact with the sides of the belt, and the squealing problem was gone. The correct size belt had to be ordered because it was not a common width and they didn't keep them in stock.

What Don said above.

Start by installing the correct belt: Gates TR24597.

If the belt still slips w/ AC on, then install trinary AC switch that will cut out compressor when pressure (load) is too high.
I still haven't seen a good picture of your A/C compressor, but here is my set up. I had some issues with squealing at first. Alignment and new belt fixed me up. As others have said, I think you need a heavy duty thicker belt, and make certain the alignment is good. If the belt has slipped a bunch, I would suggest throwing it away and starting over with a good fresh belt. Once they get glazed they lose their friction. If you have a set up like mine, I can check and get you the part number of my belt

sounds good, thanks for the help. If it works it will be a very cheap fix.
FYI, for anyone reading this thread in the future, Vintage Air did contact me and stated that they have a new bracket setup for their FJ40 kits so the alternator and the compressor run on different belts, allowing more contact with the waterpump/fan pulley. This should resolve this issue for future new installations.

However, in my case I would have to take out battery/bracket, the alternator, compressor, unbolt bracket and reinstall. May need to take off the compressor lines and recharge as well. I'm going to try to avoid that if possible but wanted everyone to know their kit has been improved.
Power steering will be your best solution ;)
I've been accumulating the parts for years but haven't started the install... yet! I've heard it's the best possible mod to a 40.

The only comparison I have was the '71 Nova I learned to drive with... I hated the arm strong steering. After installing a 3 turn box, it was a pleasure to drive... I'd have kept it if I'd not already been bit by the 40 bug.
To add to what others are saying/showing, if you notice on their pics, the belt sits in the pulley so that is almost even with the outer diameter of the pulley. Your belt sits far into the groove which shows it is the wrong belt, too narrow. HTH

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