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Joe,
Your second picture above shows a clear mis-alignment. The alternator is setting too far forward. As you well know, the lower bracket is the "place holder" for the alternator with the upper bracket, more or less, acting as as the belt tensioner. Can you slot the two mounting holes on the lower bracker enough to allow you to relocate the alternator rearward? With your skill set, this should be an easy fix. Keep us informed.
Joe,
Your second picture above shows a clear mis-alignment. The alternator is setting too far forward. As you well know, the lower bracket is the "place holder" for the alternator with the upper bracket, more or less, acting as as the belt tensioner. Can you slot the two mounting holes on the lower bracker enough to allow you to relocate the alternator rearward? With your skill set, this should be an easy fix. Keep us informed.
this is exactly what I did to get better alignment, not 100% but again im not flipping belts.
These shots seem to indicate that the fore-aft alignment is spot on....................IF the alternator is not "yawed" of cocked toward the drivers side. I haven't been able to come up with a method with which to measure yaw yet. Ideas??
Last edited by 65tripleblack; 07-12-2018 at 03:11 PM.
Joe,
Your second picture above shows a clear mis-alignment. The alternator is setting too far forward. As you well know, the lower bracket is the "place holder" for the alternator with the upper bracket, more or less, acting as as the belt tensioner. Can you slot the two mounting holes on the lower bracker enough to allow you to relocate the alternator rearward? With your skill set, this should be an easy fix. Keep us informed.
Yes. The holes are already slotted and the alternator is at around mid-slot. I also have room to **** the alternator nose up or nose down. I can finagle it if need be. Please take a look at the next few sets of photos.
It's very easy to get an optical illusion in pictures...................parallax error, ya know.
Last edited by 65tripleblack; 07-12-2018 at 02:52 PM.
My earlier comment included the lower crank pulley. From your first set of pictures, the alt appears ahead of the pump pulley, but unless the crank and water pump are in alignment, it could be the water pump needs moving forward. If the crank and pump are in alignment (not shown in pics) that would not be the case. How does the idler belt align?
Also, once a belt rolls, you will likely never get it to track correctly. Uneven stretch if the fabric.
Hard to tell from the pictures but it looks like the alternator needs to come forward and is tipped back. I had the same problem with my 65 365 h.p. years ago and it was trial and error without a factory A.I.M. Do you have all of the correct spacers and bracket?
Page 38 may help. https://www.chicagocorvette.net/pdf/...orvette-C2.pdf
Its certainly not the cause of your problem but I think the adjustment bracket on the top of the alternator is supposed to be on the front of the alternator not the rear.
Yes. The holes are already slotted and the alternator is at around mid-slot. I also have room to **** the alternator nose up or nose down. I can finagle it if need be. Please take a look at the next few sets of photos.
It's very easy to get an optical illusion in pictures...................parallax error, ya know.
Hi Joe:
When trying to sort out belt alignment, the first thing to understand is that the front face of the balancer is *always* in the same location on all Chevy small blocks, regardless of which balancer is used. The plane established by the front face of the balancer is "ground zero" for sorting out pulley alignment. With that established, here are some things to consider:
1) Deep-groove pulleys were used on your engine. If deep-groove pulleys get mixed with standard-groove pulleys, alignment problems will result.
2) I believe your engine should have the '533 pulley on the balancer and the '245 pulley on the water pump. These are both deep-groove pulleys and they should align perfectly *IF* the hub on your water pump is in the proper location. The hub is a press fit on the shaft and it can be placed anywhere using a press. For deep-groove pulley sets, the face of the hub was placed 2-11/16" (or is it 3-11/16"?) from the mounting surface of the block. For standard-groove pulleys this distance was 1/8" less, at 2-9/16". Most water pump rebuilders split the difference and set it at 2-5/8" (which is slightly wrong for either pulley set).
3) So, your first objective should be to make sure that the '533 crank pulley and the '245 water pump pulley are in perfect alignment. If they aren't, you can shim the water pump pulley forward with one or more GM spacers (I can look up the part number if necessary). To move the water pump hub back toward the engine, you must remove the water pump, remove the backing plate, support the impeller, and use an arbor press to push the hub back on the shaft. Failure to properly support the impeller will damage the water pump.
4) Once the crank pulley and the water pump pulley are in perfect alignment, the alternator alignment is a simple matter of matching the water pump pulley. The alignment tools suggested in a previous post should work fine. I use an inexpensive laser pointer made for business presentations. I simply lay it in the water pump pulley and point it at the alternator.
5) There were at least three alternator pulleys used over the years that had different offsets. You may find that a different one would work better than the one you are using, but be sure to use a large diameter version to keep the alternator speed reasonable when you are running your engine to 7000 rpm.
6) Note that alternator alignment is not just fore and aft, but also the degree of parallelism to the crankshaft. You may need to modify your alternator bracket to get this right.
7) Lastly, my impression is that the Quanta reproduction V-belts are more stretchy than modern belts, and more likely to get tossed at high rpm. If you don't mind a non-stock appearance, I think a modern Gates belt with the "notches" in the vee will stay in the groove better. Also, as noted in a previous post, be sure to set the belt tension to the GM spec, using an inexpensive belt tension guage such as the Cricket.
First, I just ordered a Kricket belt tensioner per SWVette suggestion. I never entirely trusted the old "measure deflection at the center using thumb calibrator" method.
Next..........the water pump is an Edelbrock aluminum pump. Fairly sure I checked alignment when I installed it, but will check it against the crank pulley again. Joe, I realize that there are 2 spec'ed pressed on lengths for the hub. Unlikely that the pump was perfect out of the box. Hopefully when I re-check the hub, it can be aligned using spacers rather than having to be pressed further inward.
Next......all pulleys are deep groove and correct for 365 SHP. It uses an idler as well.
It's not easy measuring yaw and pitch of the alt. As I said earlier, it appears that the nose of the alt needs to be pitched about 5 degrees higher than it already is. The yaw angle appears to be zero as shown by the straightedge photos.
Hopefully the water pump hub is off, and that, combined with a pitch correction of the alt, and PROPER tensioning of the belt will improve things.
Pop: I hear you on the deformed belt.
Robert: I believe that the top bracket is properly located at the rear of the boss.
68Hemi: The level tells me it needs to be tipped back further another maybe 5 degrees. Fore-aft seems OK according to straight edge shots.
Last edited by 65tripleblack; 07-13-2018 at 12:03 PM.
While not stock pulleys (Below) I had alignment problems. Turn out to be water pump (not pully) I tried various pulleys with same results. It was close but needed shims to push pulley out. I don't remember how much but thousands. Kind of apple and oranges but crank, A/C, Alt, PS were all in alignment.
Its certainly not the cause of your problem but I think the adjustment bracket on the top of the alternator is supposed to be on the front of the alternator not the rear.
That particular bracket is mounted correctly...behind the boss on the alternator.
.........the water pump is an Edelbrock aluminum pump. Fairly sure I checked alignment when I installed it, but will check it against the crank pulley again. Joe, I realize that there are 2 spec'ed pressed on lengths for the hub. Unlikely that the pump was perfect out of the box. Hopefully when I re-check the hub, it can be aligned using spacers rather than having to be pressed further inward.
Hi Joe:
If you find that you need to shim the water pump pulley forward, the easiest method is to use the GM "reinforcement" that was introduced at some point as a response to cracking of the face of the water pump pulley. This part shows up in the AIM somewhere during midyear production. It's probably available from the reproduction parts suppliers and I think it is still available from GM. I have 5-pack of them and can send you a couple if you like.
As I recall, the "reinforcement" is about 1/16" thick and they are stackable.
We had the same alignment problem with my 65 350 HP. initially we tried adding shims to the lower bracket. Ultimately we moved the locating tube in the lower alternator bracket using a brass hammer. It is the tube the lower bolt passes through. It's just a press fit.
First, I decided to make a simple tool as suggested by Clem (PA Motorman) in an old thread and I have some 5/16" diameter steel rod in my garage. Once the 90 degree angle is firmly pressed into the sheave, the long straight end automatically shows the alignment of the other sheave(s) it is pointing to.
Remember that earlier I determined that the alt has to be further pitched "nose-up" by another 4-5 degrees (rough guess, or 1/2 bubble on a level). Every bit counts, apparently on a high revving engine. I'll also assume that the belt was not tensioned properly and so I'll anxiously await the KriKet belt tensioner from Gates.
Gearhead Joe's generosity is duly noted, although it appears that there is alignment between the pump and crank pulleys. Look at the next series of photos and tell me what you think. It is just soooooo close, but I'd imagine every thousandth counts when an engine is sometimes revved over 8000 RPM. The following photos show my arm pressing the 90 degree angle FIRMLY into the crank sheave, and the alt sheave. Your impressions??
Sight Line Pump/Crank Pulleys
Sight Line Pump/Crank/Alt Pulleys
90 Degree Bend Of Tool Forced Into Crank Sheave From Below
Gearhead Joe's generosity is duly noted, although it appears that there is alignment between the pump and crank pulleys. Look at the next series of photos and tell me what you think. It is just soooooo close, but I'd imagine every thousandth counts when an engine is sometimes revved over 8000 RPM. The following photos show my arm pressing the 90 degree angle FIRMLY into the crank sheave, and the alt sheave. Your impressions??
Hi Joe:
It's hard to tell from the photos whether the crank-waterpump pulley alignment is "perfect" or possibly the water pump pulley needs to come forward a smidge. You might try simply looking at the two belts installed snugly in the grooves, running parallel between the two pulleys. Having the two pulleys so close together makes it easier for the eye to discern misalignment.
In any event, the bigger problem is that the alternator pulley is not properly aligned with the water pump pulley. I'm only mentioning the crank-waterpump alignment because that alignment should be correct before you start moving the alternator. Otherwise, you risk basing your alternator alignment on an incorrect water pump pulley position.
I think that once you are certain the water pump pulley is in the right place, you should just do whatever is necessary to make the alternator align with it. You are correct that this is actually a 3-axis alignment, rather than just a simple forward/backward alignment. Since your alternator bracket is not stock, it may simply need some modification or possible replacement.
It's hard to tell from the photos whether the crank-waterpump pulley alignment is "perfect" or possibly the water pump pulley needs to come forward a smidge. You might try simply looking at the two belts installed snugly in the grooves, running parallel between the two pulleys. Having the two pulleys so close together makes it easier for the eye to discern misalignment.
In any event, the bigger problem is that the alternator pulley is not properly aligned with the water pump pulley. I'm only mentioning the crank-waterpump alignment because that alignment should be correct before you start moving the alternator. Otherwise, you risk basing your alternator alignment on an incorrect water pump pulley position.
I think that once you are certain the water pump pulley is in the right place, you should just do whatever is necessary to make the alternator align with it. You are correct that this is actually a 3-axis alignment, rather than just a simple forward/backward alignment. Since your alternator bracket is not stock, it may simply need some modification or possible replacement.
I'll let you know if I can use the hub stiffener (shim). It's possible that the pump pulley can come forward another 1/16". Yup, and 3 axis alignment is best done with very expensive laser technology and precision equipment, which is why my first post inquired about tool rental or foolproof methods of measurement. Perhaps you can design a tool for me.........cheap. Fore and aft is easy to do using crude tools. Pitch and yaw not so much...........and I think pitch and yaw of the alt can be dialed in better. BTW: the idler belt is the original 18 YO Quanta wrapped belt that sustained a cut when I threw the alt belt the first time at the track. Never a problem with it. I don't recall re-tensioning the alt belt after I replaced it last year, and that might be part of the reason it rolled over.
I will do a more thorough alignment over the next few days and report back if anything of interest turns up.
07-12-2018, 11:18 AM
Fore and aft is easy to do using crude tools. Pitch and yaw not so much...........and I think pitch and yaw of the alt can be dialed in better. BTW: the idler belt is the original 18 YO Quanta wrapped belt that sustained a cut when I threw the alt belt the first time at the track. Never a problem with it. I don't recall re-tensioning the alt belt after I replaced it last year, and that might be part of the reason it rolled over.