Regardless of what year Corvette you are driving today, if you are reading this there is a good chance you remember V-belts. Sure, the serpentine systems have been around a while, but many vintage Corvettes are still being put back together using old-fashioned V-belts.
Obviously, if you are doing a 100-point restoration you will have V-belts on the engine. To make it even more interesting, many vintage Corvettes have had engine swaps and various modifications over the years resulting in mismatched pulleys. So now you get to the play the pulley game. Three-groove crank pulley, two-groove water pump pulley, belt alignment, accessory adjusting arms and the list goes on. Yes, the pulley game and the find that part number game can be challenging.
These very thoughts prompted us to search for a better way to drive the accessories on our 1968 Corvette. For a quick review, our project car is a “resto-rod” light, meaning we are doing gentle upgrades to the car while retaining a factory stock appearance. Some of the improvements include a five-speed transmission from American Powertrain and improved stock suspension with QA1 shocks for better handling. Since this is not a restoration we were open to accessory drive solutions and after some research we decided to install a front serpentine system developed by the same folks who built the car and the engine 50 years ago. Yes, the Bowtie boys, Chevrolet Performance, have a serpentine belt system to retrofit the small-block Chevrolet accessory drive.
Driving your accessories with a serpentine belt system provides performance, reliability and low maintenance. What’s not to like about that? Paul Taylor at Hot Rods by Dean had this Chevrolet Performance serpentine system installed in a day.
The system is based on the front drive system off the Tuned Port Injection (TPI) engines of the ’90s. The kit employs factory-engineered brackets, pulleys and tensioners. This provides you with a durable front drive that is easily serviced and, should replacement parts ever be needed they are as close as your local Chevrolet dealer. We have installed a Vintage Air unit inside our car, but if you live in cool country, or are so performance minded you don’t want air conditioning, Chevrolet Performance offers the serpentine belt system with or without air conditioning. The serpentine system kits include all the necessary brackets, hardware, pulleys, tensioner, alternator, power steering pump, water pump and, of course, the serpentine belt. It should be noted that due to the routing of the serpentine belt, the supplied water pump is a reverse flow unit, so do not attempt to use a standard pump with this system.
The advantages of a serpentine system over the old V-belt are many. With the spring tensioner the belt is always set to the proper tension. No more adjusting belts by moving the accessories. Likewise, this constant perfect tension, along with the wider grooved belt eliminates belt squealing. The system even comes with a tensioner indicator to show when the belt requires replacement, and the serpentine system keeps all of the accessories mounted compactly in front of the heads. Finally, we liked the factory look of the ACDelco compressor, alternator and power steering pump. At first glance, one might think this is a factory original system for our 1968 Corvette. It should also be noted that this same system would work for C2 Corvettes.
The kit is complete with water pump, 105-amp alternator, power steering pump and A/C compressor. All nuts, bolts and the all-important serpentine belt are supplied.
Of course, every installation has its own special fitment issues and ours was no different. While everything aligned and bolted in place perfectly, we discovered the passenger-side lower idler pulley was contacting the control arm. As we looked and wondered aloud if there was a way to modify the bracket, Paul Taylor of Hot Rods by Dean was holding the idler and bracket when he simply flipped it top to bottom, rotating the bracket 180-degrees. The holes lined up and it moved the idler pulley inboard. Yes, we did have to grind about 1/4-inch off what was now the top end of the bracket, but beyond that it was a direct bolt-in cure. Honestly, we can’t remember when a potential problem “self-solved” like this one, but the good news is, problem solved. Mounting the lower passenger-side pulley inboard did require a slightly longer belt. The kit uses a 97 1/4-inch belt. By moving the pulley inboard we required a slightly longer belt, and a 99 5/8-inch Gates belt (PN K060990) was purchased at the local parts store.
One other note, the crankshaft pulley is very close to the crossmember since Corvette engines are mounted low for hood clearance. We recommend you check your engine mounts to ensure they are in excellent condition and when in doubt, change them out. A sagging or soft motor mount could be enough to cause problems.
After draining all the coolant from the engine we removed the old water pump and scraped off any gasket residue. We then bolted the new water pump in place with the new gaskets supplied with the kit. The bolts were torqued to 30 ft-lb.
And finally, we did have to “clock” the alternator (rotating the back half) so the wiring connections would work for our application. This is a fairly straightforward procedure, simply lock the brushes in place with a straightened paper clip (or a very thin piece of plastic), then remove the three bolts holding the casings together and gently rotate the rear half. Those were the only changes required to fit this system in our 1968 Corvette.
The Chevrolet Performance Accessory Drive kit instructions are complete with wiring diagrams to ensure you get the new A/C compressor and alternator wired properly. We won’t get into the wiring here, but be advised the supplied alternator is 105-amp so it can drive all modern electrical accessories. (On the subject of the alternator: A stock 1968 Corvette would have an externally regulated alternator. We’ve kept the stock appearance with the external regulator, but the fact is we converted the charging system over to a modern internally regulated three-wire system as supplied by Chevrolet Performance.) That also means it required a minimum 8-gauge wire connecting from the stud on the alternator to the battery. The wiring is simple enough, but read the directions to ensure you have it right before connecting the battery cables.
The new pulley was bolted to the water pump with the four supplied bolts torqued to 37 ft-lb. Due to the configuration of the serpentine belt, this is a reverse flow water pump.
Most home mechanics should have no problem installing this front mount kit. Chevrolet Performance includes a detailed instruction sheet and parts list explaining the process. Of course, now you also have this step-by-step story so things should go even smoother. Having said that, let’s go out to the Hot Rods by Dean shop and follow along as Paul Taylor installs the Chevrolet Performance Early Small Block Accessory Drive Package (PN 19369258) in our 1968 Corvette. Vette
This is the A/C compressor, lower idler pulley and belt tensioner (not shown) mounting bracket. The bracket attaches to the passenger side of the small-block Chevy engine.
The bracket mounts to tappings in the head and the block. First install the supplied stud in the uppermost tapping of the passenger-side head.
Next, install the two supplied bolts through the lower holes in the bracket. These bolts should be torqued to 22 ft-lb.
Here is the passenger-side bracket mounted to the engine, ready to receive the A/C compressor. Everything fit perfectly so far.
This belt idler mounts between the A/C compressor and the crankshaft pulley. The kit calls for the pulley to be on the left, or outboard, side but when we tried to install the pulley it contacted the control arm.
As fate would have it, the solution proved to be quite simple. We simply rotated the bracket 180-degrees (flipped it top to bottom) and the bracket fit. Here is the inverted bracket bolted in place. As you can see, it moved the idler pulley mount inboard and slightly higher.
The only modification to the bracket was grinding a small flat area on what is now the top of the bracket. This allowed the bracket to seat flat against the main bracket.
Here you can see the flat that was made on the bracket with a belt sander. A hand grinder or file could also handle the task. We also installed the idler pulley at this time.
The idler pulley assembly was then installed using the supplied bolts torqued to 37 ft-lb. As you can see, there is ample clearance between the pulley and the control arm.
The compressor is held in place by one bolt on the inboard hole. Thread the bolt in place first, then thread the supplied stud through the bracket, the compressor and into the tapping in the front of the bracket.
Paul Taylor of Hot Rods by Dean then threads a nut onto the backside of the stud and tightens it and the bolt 37 ft-lb.
The compressor is now properly located and all the pulleys are perfectly aligned. We like the “factory A/C look” the compressor gives to the system.
The A/C compressor creates quite a bit of torque when called into service. To stabilize the compressor, a tubular brace must be installed.
After a quick test-fit, Paul noticed the bracket was just barely touching a casting edge on the exhaust manifold. A quick hit with the sander removed just enough material to ensure the bracket would seat flat on the exhaust manifold.
The supplied bolt mounts the brace to the exhaust manifold, while a second nut is used on the compressor stud to hold the opposite end of the brace. If you are running headers, Chevrolet Performance has a spacer (PN 12490679) to compensate for the difference in the exhaust manifold thickness and the header flange.
With the A/C compressor mounted, team Hot Rods by Dean turned their attention to mounting the serpentine belt tensioner. It mounts directly next to the A/C compressor. The hole in the top of the bracket is for the alignment pin on the tensioner.
The tensioner was positioned on the bracket with the alignment pin located in the bracket hole. Then the supplied center bolt was installed and torqued to 37 ft-lb.
Here is the tensioner installed. This unit maintains the proper belt tension at all times and even compensates for belt stretch. No more squealing V-belts.
We removed the stock crankshaft pulley and the center bolt holding the harmonic balancer in place. The pulley was bolted to the harmonic balancer with three bolts and then the center harmonic balancer bolt was reinstalled.
As you can see, the crankshaft pulley is very close to front crossmember on the C3 Corvette. There is ample clearance and just enough room to install the belt. The three pulley bolts are torqued to 43 ft-lb while the crankshaft center bolt is torqued to 70 ft-lb.
Next, Paul Taylor turned his attention to mounting the driver-side bracket. This bracket has the power steering pump pre-installed and also mounts the alternator.
Five supplied bolts hold the bracket in place, three threaded into the head and two into the block. On some engines the inboard bolt on the cylinder head may not line up. The system has been tested with four bolts and found no failures, so it is not a concern. In some applications this inboard hole can be drilled slightly oversized and the bolt will then thread in place.
The power steering pump was pre-installed onto the driver-side bracket with the fill cap easily accessible. At this point we had torqued all five bolts (or four if the above alignment problem exists) to 37 ft-lb.
The last component to be installed was the 105-amp alternator. When we test-fit the alternator we were not satisfied with the wiring location so we decided to “clock,” or rotate, the rear of the alternator.
Paul used a small piece of thin plastic tie-wrap pushed through the hole in the rear of the alternator. This will hold the alternator brushes in place during the clocking process.
The three bolts that hold the alternator together were removed and the rear section of the alternator was gently rotated one hole.
After adding a dab of antiseize on the threads, the three bolts were reinstalled in the alternator and tightened.
With the alternator clocked, the battery stud has plenty of clearance from the valve cover. Since this is a serpentine system, the alternator will never be moved for belt adjustment like it would in old-fashioned V-belt systems.
Satisfied with our new wiring location (the plug in on the lower outboard side of the alternator) the two bolts were tightened to 37 ft-lb.
The final step was installing the serpentine belt. Follow the diagram in the instruction book to route the belt, then release the tensioner arm and the belt is installed.
Because we rotated the passenger-side idler pulley, our installation required a slightly longer belt. The normal kit uses the supplied 97 1/4-inch belt, we used a 99 5/8-inch Gates belt (PN K060990) because of the relocated pulley.
And there it is, the Chevrolet Performance Early Small Block Accessory Drive Package (PN 19369258) installed by the pros at Hot Rods by Dean. All that remains is a bit of wiring, A/C hoses and power steering hoses.
Photography by Brian Brennan