Serpentine Belt System


After installing the electric fans, the alternator belt would squeal until the alternator would spool up. When ever a heavy load was on the alternator (electric fans running, headlights on, air conditioning running, etc.), the squeal would often not stop. I'd tighten the alternator belt and things would be good for a while, then it would start squealing again. In addition, under heavy load, quite often the alternator voltage would struggle to get up to 12V and would not reach 12V at idle. Replacing the battery helped, but the belt would still squeal. After a while I decided it was time to move up to a serpentine belt system. With power steering and air conditioning, a new full belt system runs over $1500. I don't need a fancy billet, full dress system, so it was time to start looking through the junk yards. The block in this truck is a '68 302 with 28 oz harmonic balancer and a three belt crank pulley. Serpentine belt systems on the Ford 302 appear in the mid 80's and run through the mid 90's. In particular, it seems I needed a system from an '85-'93 Mustang, or an F series truck up to '95.

Fortunately, LKQ Pick Your Part in Rockford, IL maintains an on-line inventory of its vehicles. Watching for a couple months I eventually saw a half dozen potential candidates in their inventory - and they were new additions which meant there was a good chance they hadn't been stripped. One fine December day (50oF in Illinois!!!!) my daughter and I headed up there to look around. Truck #1 on our candidate list had a complete system still in place. We tore into it.....
Here's the on-line listing for the donor truck I found at LKQ Pick Your Part in Rockford, IL
The belt routing tag on the truck - mostly for historical purposes, but it confirms the system on this truck has what I was looking for.
Here's what we were looking at when we first came up to the truck. Alternator, air pump (I don't need this), water pump (reverse flow), crank pulley, A/C compressor and power steering pump. The serpentine belt was there, too, but sitting loose in the engine bay.
The alternator was siezed up and is only a 60A unit, but thinking I might need the pulley we pulled it and kept it - cheap insurance
The idler pulleys and water pump pulley look well used, but spin smoothly. I'm sure the rust will wear off quickly.
The A/C compressor looks to be good and I need the pulley, so it comes out. Later on I recognized this is transverse mounted and the one I currently have on the truck is longitudinally mounted - so I need to use this compressor.
Frankly, when we were taking this stuff out, I had no idea what the unit under the alternator was. It's the air pump - part of the thermactor emission control system. We pulled this - again, as much for the pulley as anything. In the end this got thrown out and I replaced it with a new bypass pulley.
Here's the truck as we left it. All parts associated with the serpentine belt system have been removed. There's a couple hoses I wish we had pulled as well, but we didn't think of it at the time. In particular the outlet hose from the water pump to the heater has a mounting bracket that attaches to the alternator mount and keeps the hose out of the belt (see the picture of the alternator above). Without this mounting bracket, zip ties are needed - not as nice as the bracket.
Back home, here's what we have:
  • Front row: idler pulleys / alternator mount and crank pulley
  • Middle row: alternator, A/C compressor, air pump, water pump
  • Back: power steering pump with bracket for it and A/C compressor
The air pump was a total pain to take off the alternator / idler pulley bracket. The main mounting bolt was seized in place. No amount of break-free or heat would break it loose, and I eventually broke the bolt head off. Since I really didn't need this, the sawzall came out and I cut it out. Once it was out, I was able to remove it's mounting bolt. I probably won't be able to return this for the core refund!
The water pump was a critical acquisition. The V-belt system rotates the water pump clockwise when viewed from the front. However, the serpentine system wraps around the pulley the other direction and rotates the pulley counter-clockwise. Hence, I need to replace the existing water pump with the reverse-flow pump that came of the '93 F150. All the gaskets on the "new" water pump were shot, so a new set of water pump gaskets were ordered. Of anecdotal interest, when I pulled the backing plate off the '93 water pump, there was still casting sand in it (in the "unused voids")!
Here's a front view of the reverse flow water pump. The original fan clutch was a real pain to remove. Lot's of break free and a rubber mallet were needed to get it to break loose from the water pulley's center shaft.
Here's the V-belt system that was on the '56 F100. No air pump, with the alternator in the 7 o'clock position.
On the driver's side is the A/C compressor and power steering pump - fortunately in the same location as what was on the donor '93 F150.
The A/C compressor was un-mounted. It had been held in place primarily with turnbuckles!
The original power steering pump mount was removed.
Original (left) vs. "new" power steering (and A/C compressor) mount.
Original A/C compressor mount (blue) vs. "new" mount (again shared with power steering pump).
Original alternator and mounting bracket......
Original alternator removed.
Original water pump pulley removed.
Original water pump removed.
Original crank pulley removed. At this point, everything that's coming off is off. Or so I thought.
Trial fitting the new alternator mounting bracket revealed the oil check tube was in the way. I'm guessing the later 302s likely had these mounted towards the rear of the engine. After pulling this tube and trying to bend it to stay out of the way, I eventually broke the tube.
After a short mental debate I decided I can live without the tube and I sealed off the tube mounting hole. I may revisit this later.
With the oil check tube out of the way, the alternator mounting bracket slid in easily. I did have to bend the fuel line (which runs under the engine from the mechanical fuel pump on the driver's side to the carb inlet on the passenger side) a bit to clear the bracket.

This also shows the bypass pulley I bought to sit in place of the air pump. This is from Tuff Stuff Performance, product #1700, listed for a '90-'93 Mustang with 302. However, it appears to be a generic part for all/most Ford 302s of that era.

This is the new 200A, transverse mounted alternator I put in. This generates 140A at idle and should handle any electric demand I put on it. This is a Powermaster, stock #477681.
The alternator installed - it appears to line up fine. I did upgrade the ground going to the alternator with a 4 gauge strap.
Here's the old crank pulley I pulled out. Note the three mounting holes.
This shows the depth of the old crank pulley - significantly deeper than the serpentine crank pulley (below).
Here's the crank pulley for the serpentine belt system. Not only is it significantly "shorter" than the V-belt pulley, but this mounts with four bolts to the harmonic balancer.
I considered re-drilling the serpentine belt crank pulley to fit the three hole mounting and building some form of spacer. However, Google is a wonderful thing. I found this March Performance crankshaft pulley spacer / adapter (part number 1432). It mounts to the harmonic balancer with three bolts and allows a four bolt pulley to attach to it. Perfect, if not particularly cheap.
Here's the serpentine belt crank pulley and March Performance spacer installed.
Next in line is the mounting bracket for the power steering pump and A/C compressor. The first thing that jumped out is that the bracket mounted to the '93 302 using 7/16" bolts, whereas the '68 302 heads are drilled for 3/8" bolts. I'm not sure about drilling out and retapping the heads in the '68, so for now I'm just using grade 8 3/8" bolts.
The 3/8" bolts did rattle around quite a bit in the bracket holes (which are even large for 7/16" bolts). I picked up some thin brass tubing and slipped it over the 3/8" bolts to help fill the holes in the mounting bracket - creating sort of a shoulder bolt.
However, when I tried to mount this bracket on the '68 block the next point of interference reared its head - the mechanical fuel pump is in the way. Presumably, by '93 everything was using EFI with high pressure electric fuel pumps in the gas tanks - hence there is nothing in this area of the engine to get in the way of the bracket. However, back in '68 it was all carburetors and mechanical fuel pumps. Once again, I had a choice - try to hog out the mounting bracket to fit around the mechanical fuel pump, or convert the truck to an electric fuel pump and delete the mechanical pump. I decided to change the truck to an electric fuel pump. This was not too hard a decision since I had an old Holley Red fuel pump sitting around that I pulled out of my Cobra when I upgraded it to an in-tank fuel pump.
Mechanical fuel pump removed.
A fuel pump blocking plate installed in its place (Summit Racing SUM-402035).
The power steering / A/C compressor mounting bracket in place, with the power steering pump mounted. (pulley not yet installed).
The A/C compressor temporarily installed to check fitment - looks good!