Alternator Alignment 1963 327/250HP

[Harry S.]

Re: Alternator Alignment 1963 327/250HP

I've been looking through all the pictures I have and don't have one with a clear shot of an original car (250hp) of the alternator and pulley.

What I can say is that the pulley on your alternator looks identical to the pulley on my alternator on my 250hp 63. I also have the belt on the forward groove.

I did find a picture in a book. If you have "Original Corvette Stingray 1963-1967" by Tom Falconer. Look at page 27. As far as I know that is the correct set-up.

Cheers

[Joe L.]

Re: Alternator Alignment 1963 327/250HP

I've been looking through all the pictures I have and don't have one with a clear shot of an original car (250hp) of the alternator and pulley.

What I can say is that the pulley on your alternator looks identical to the pulley on my alternator on my 250hp 63. I also have the belt on the forward groove.

I did find a picture in a book. If you have "Original Corvette Stingray 1963-1967" by Tom Falconer. Look at page 27. As far as I know that is the correct set-up.

Cheers

Harry-----


I agree. I first thought that the alternator pulley was incorrect, but very shortly thereafter came to the conclusion that it is correct.

[Jim L.]

Re: Alternator Alignment 1963 327/250HP

Here are a couple of pictures of the alternator belt and alternator of my '63, with a 327/300 engine. AFAIK, the 250 and 300 engines used the same belt and pulley configuration.

I like to use a straight edge to verify pulley alignment; my eyes can play tricks on me otherwise. I lay the straight edge against the machined surface of the alternator pulley and see how the path of the belt tracks the path of the straight edge:



Since there is some question about the position of your alternator, I also made a picture that shows the alternator relative to the valve cover:



Hope these help.

Jim

Edit: A sharp eye will notice the rear sheave of the water pump pulley has a belt in it. That's a redundant belt that circles only the water pump pulley and crank pulley. I drive this car everywhere (note the dirt/dust) and don't want a belt failure to leave me stranded.

[Timothy B.]

Re: Alternator Alignment 1963 327/250HP

Nice pics Jim, Here are some from my car showing the relationship between the lower bracket and exhaust manifold.

I don't know if you can determine if the lower bracket is correct from these pics but if you need me to later I can take a pic of a spare bracket next to the passenger car bracket.

Also, look at the routing of the 5/8" heater hose that runs forward of the top alternator adjustment bracket. I believe this is correct and the arrangment keeps the hose from rubbing the bracket.

[Stuart F.]

Re: Alternator Alignment 1963 327/250HP

Jim;

What you failed to mention is that your "redundant" belt is adjusted by a power steering pump, right? Then it isn't really a redundant belt, is it?

Nice photos though. Thanks for posting. Hope we all can help Joseph out with this for the same reason you mentioned for your "redundant" belt. No one likes to throw a fan belt, and his looks rather precarious (good thing it's not a 389 Pontiac engine with reverse cooling).

Stu Fox

[Harry S.]

Re: Alternator Alignment 1963 327/250HP

Stu, I think the P/S has the third belt that goes from the P/S unit to the front groove in the lower engine pulley. There are three grooves in that pulley.

That belt can not be seen in any of the pictures.

[Jim L.]

Re: Alternator Alignment 1963 327/250HP

Jim;

What you failed to mention is that your "redundant" belt is adjusted by a power steering pump, right? Then it isn't really a redundant belt, is it?

It really is a true, redundant belt. As manufactured, the rear sheaves of the water pump pulley and crank pulley are left vacant. I added the belt that circles those pulleys and only those pulleys.

My '63 does have factory power steering. The PS pump is driven by a third crank pulley sheave that is a bolt-on addition.

Jim

[John G.]

Re: Alternator Alignment 1963 327/250HP

My first time trying to post photos so, not sure I got it right but, am attempting to upload two photos of the alternator. Would like to know if the 1/4" offset between the alternator and the fan pulley is correct. BTW, I tried the belt on the other fan pulley slot and the offset is the same, just in the other direction. Thanks.

[ATTACH]28051[/ATTACH]

[ATTACH]28052[/ATTACH]

Joseph ..

I have the same thing going on with my 300 hp '64.

[Stuart F.]

Re: Alternator Alignment 1963 327/250HP

How do you tension the belt, Jim?, or install it for that matter?

Stu Fox

[Joe L.]

Re: Alternator Alignment 1963 327/250HP

How do you tension the belt, Jim?, or install it for that matter?

Stu Fox

Stuart------


I'm not Jim but I think I can answer the question. One does not tension this kind of a belt (unless one uses it with an idler pulley). A belt which encompasses only the water pump and crankshaft pullies is called a "captive" or "captured" belt. These were actually used in PRODUCTION on MANY Corvettes from about 1965. For this type of belt to function properly, it must be of an exact length---it can't be 1/8" too long or 1/8" too short.

How does one install such a belt? With difficulty!. There are several ways to do it and I have found the easiest is to unbolt the crank pulley, install the belt on the appropriate groove (usually, the innermost groove), and pull the pulley down so that the indexing center ring on the rear of the pulley snaps into the center orifice on the balancer. Then, rotate the pulley as required to align the pulley bolt holes and install the bolts.

[Jim L.]

Re: Alternator Alignment 1963 327/250HP

How do you tension the belt, Jim?, or install it for that matter?

Stu Fox

Joe's explanation is spot on. The belt has to be the exact length and you install it by unbolting one of the pulleys. I found it more convenient to remove the water pump pulley than the crank pulley, but either would work.

It's cheap peace of mind for a car like mine that gets driven a lot.

Jim

[Stuart F.]

Re: Alternator Alignment 1963 327/250HP

Joe and Jim;

Proves we are never too old to learn something. I never heard of such an application from a factory before.

I used to work as an engineer/designer of cooling systems back in the late 50's for a major mfg. My boss always told us that before we made a critical decision or major design change, go to the bathroom and sit on it for a while. Guess someone at GM could have used the same advice. I never designed any belt drive application without a means of adjustment. Granted, the one of which we speak has a short sheave center to center dimension, but belts will always be belts and stretch with time and use. When I first saw this I thought it was some backyard mechanic's wet dream, Ha!

Stu Fox

[Stuart F.]

Re: Alternator Alignment 1963 327/250HP

I don't mean to step on anyone's toes or insult the private owner application of a redundant belt; however, as belts will stretch with use, it could become too loose and throw off taking the main belt with it. I too like the peace of mind having my idler belt. I know how critical that water pump can be when you are "red lining". The alternator not nearly so.

I lived through the era of 389 Pontiacs with reverse cooling and only one drive belt for the pump and alternator. They were prone to throwing that belt at high RPM's, and you would get instant overheat. They depended on the pump to circulate the coolant as they had no natural convection flow (heat rising, cool dropping, etc.).

Stu Fox

[Jim L.]

Re: Alternator Alignment 1963 327/250HP

I don't mean to step on anyone's toes or insult the private owner application of a redundant belt;

No offense taken. We all have our individually well-reasoned ways of doing things. The addition of that belt is one of mine.

however, as belts will stretch with use, it could become too loose and throw off taking the main belt with it.

I wouldn't be so bold as to argue that this couldn't happen. I will, however, note that it hasn't happened and speculate that the odds of it doing so are pretty small.

If the engine in my '63 sees anything over about 3300 RPM, then I'm driving like a wild man. IOW, I don't perceive the environment in which that redundant belt lives to be particularly stressful.

However.....

The engine in my vintage road racer runs a similar belt arrangement, except with the deep groove pulleys, and sees repeated high RPM as a routine matter. I've never thrown a belt and never broken a belt in thousands of racing miles.

Checking belt condition and tension is one of my mandatory steps in preparing the car for the next event; I've never noticed the development of any slop in the redundant belt.

Jim

[Jim T.]

Re: Alternator Alignment 1963 327/250HP

Stuart------


I'm not Jim but I think I can answer the question. One does not tension this kind of a belt (unless one uses it with an idler pulley). A belt which encompasses only the water pump and crankshaft pullies is called a "captive" or "captured" belt. These were actually used in PRODUCTION on MANY Corvettes from about 1965. For this type of belt to function properly, it must be of an exact length---it can't be 1/8" too long or 1/8" too short.

How does one install such a belt? With difficulty!. There are several ways to do it and I have found the easiest is to unbolt the crank pulley, install the belt on the appropriate groove (usually, the innermost groove), and pull the pulley down so that the indexing center ring on the rear of the pulley snaps into the center orifice on the balancer. Then, rotate the pulley as required to align the pulley bolt holes and install the bolts.

My 68 327/350 with no power steering has the captive belt. With the recent water pump change it made me realize that the way the fan clutch is attached to the waterpump is different from my 70. My 68 uses bolts from the fan clutch to the water pump. Makes installation line up of the pulleys with the captured belt a little frustrating. My 70 with all power and air, no caputred belt uses studs in the water pump and the installations of nuts to secure the fan clutch to the assembly. What does your 69 have?
If I have to do a water pump change again on the 68 I will consider going to studs and nuts to make installation easier.