Pulley Misalignment

[RIDAVIDK]

Hello All

I joined the forum last year when I got my first larger boat, a 1975 Pearson 28, with an atomic 4 engine. I had a problem with the cooling system and got some great advice that solved it.

New problems this year. I noticed that my Oberdorfer 201M pump was leaking, and I decided I would replace it, and rebuild the old one sometime in the future as a spare. I also have a problem with a loud squealing sound that is coming from the water pump area. It happens as the engine revs up, not at idle. I have read through the threads here and tried a couple of ideas. I ran the engine without the belt on at all and the squeal was gone. I tried a new belt, and the squeal was still there. Could the bad water pump be causing the noise?

While trying different things, I noticed the alternator, and water pump pulleys line up great, but the accessory drive pulley is out of alignment by at least 1/4" towards the bow. I really can't see any way to align all three. The alternator pulley would not seem to be adjustable at all. The water pump pulley could be moved forward to line up with the accessory drive pulley, but then it would not align with the alternator. Has anyone else come across this problem? Could this be the source of the squeal? Thanks in advance for your help.

[romantic comedy]

is this a FWC engine? WHere is the second pump mounted? have any pictures?

[RIDAVIDK]

The engine is FWC. I am attaching a photo. Unfortunately it is difficult to photograph, but maybe it will help. The 201M is mounted right below the alternator. It is hard to see from the picture, but at the top is the accessory drive, and you may be able to see that the belt is angled forwards. This is because the pulley on the accessory drive is about 1/4" more forwards than either the alternator or pump pulleys. There seems to be no way to adjust the position of the alternator pulley without modifying the attachment bracket. The pump pulley can be adjusted in and out along the shaft. I can line up either the top two, or the bottom two pulleys, but not all three.

David

[RIDAVIDK]

Sorry about that. The photo somehow became huge. On my laptop it is a normal size. Does anyone know how to upload it properly?

David

[ndutton]

Can you confirm which side of the bracket (on the water jacket side plate) the curved alternator adjustment arm is attached? The curved arm should be on the forward or flywheel side.

[RIDAVIDK]

Alternator bracket

It is on the forward side as shown in your photo.

David

[ndutton]

Roger that.

There's no adjustment in the auxiliary drive so the alternator and pump will have to be aligned to suit. I'd start with the alternator, get it right and finish with the pump.

The alternator bracket mounted on the head has some play. You can loosen the head nuts to get a little adjustment, then retorque. The alternator pivot bolt has play too, so much that the MMI automatic tensioner kit includes a replacement pivot bolt with bushings to keep things in alignment while the alternator is allowed to float.

[RIDAVIDK]

Alternator alteration

Thanks for the advice Neil. I think you are right, that I need to get the alternator and accessory drive pulleys lined up first. The water pump has a fair amount of room to adjust its pulley, and so can be done when the other two are good.

I have a couple of somewhat more radical ideas to adjust the alternator since it needs to move forwards about 1/4". Let me know what you think.

1)The alternator bracket is bolted to the engine on two studs. I removed the nuts and there is no play in the holes. I was thinking of removing the bracket and turning the holes into slots that would allow me to slide the alternator forwards and into alignment with the accessory pulley. I guess the alternator could possibly slide in the future, but most of the force from the belt is pulling down and wouldn't be affected by the hole being made a slot.

2) Cut, or grind away some of the shoulder on the alternator where the pivot bolt goes through(about 1/4"). It doesn't seem like this would affect anything on the alternator. I could then use washers on the pivot bolt on either side to fine tune its position.

Either method would also get it further away from the distributor cap.

David

[ndutton]

If it comes down to it I like #2 better than #1.

I'm curious why it's misaligned in the first place when it's rarely if ever mentioned on this forum. Why is yours different? In other words, be sure to address the real problem rather than a work-around band-aid remedy. I'm not suggesting your ideas are band-aid-like but rather try and determine what really caused he misalignment before you decide on a remedy.

[hanleyclifford]

Here is the pic:

[edwardc]

I would prefer #2 also.

From the picture, I can't tell what kind of alternator you have. Is it one of the original Motorolas, the 55 Amp Mando that used to be sold here, or some other 3rd party, like Balmar? The A4's mount is somewhat unusual, and most alternators don't have the right width foot to fit in the head bracket.

Is it possible that this was a custom modification to the foot of a 3rd party alt, and it wasn't quite right?

[joe_db]

I have 2 Motorolas and a Delco 10SI and I have never noticed this issue. I too would triple check everything before cutting or grinding.

[RIDAVIDK]

Thanks for the comments guys.

Neil, I have been thinking the same thing myself. Why is it not aligned. I only have two ideas. First, the alternator is not the right one and is somewhat wider than the original and therefore pushing the pulley over a little. Second, could the pulley on the accessory drive have moved to the right a bit. It is very hard to see on my boat, but it seems to be held on with a nut. Could the accessory drive move at all?

Maybe the water pump bracket is skewed somehow and causing the misalignment. I am going to change the water pump, as it was leaking, and I think I will see what the alignment looks like without the water pump in place.

Hanley, thanks for fixing my photo. What did I do wrong?

Ed, I am not at the boat now, but it is a 55 amp API alternator. I don't remember any other details, but I may be down there later today and can see what other info is on it.

[edwardc]

Ed, I am not at the boat now, but it is a 55 amp API alternator. I don't remember any other details, but I may be down there later today and can see what other info is on it.

Mando and API are the same. The company name just changed. It's the one MMI used to sell. The foot should fit perfectly, so scratch that theory.

I don't think the accy drive pulley can shift, but I suppose it's possible that someone assembled it with a washer that doesn't belong there. Really grasping at straws here.

[ndutton]

I have not had my auxiliary drive apart so I can't comment on the idea of the pulley migrating. I've never heard it mentioned on the forum though so based on that I'd vote "not likely."

edit:
This might help. I just measured the auxiliary drive off my spare engine. The dimension from the mounting face of the drive to the center of the pulley groove is 2-15/16" I'd check this before shipping spare alternators all over the place.

It would be interesting to bolt on an original Motorola 35A alternator to compare alignment as a starting point. If you don't have one, for round trip shipping cost I could loan you one of mine. Via USPS Priority Flat Rate mail you could have it before the weekend. Maybe somebody closer (I'm assuming Rhode Island from your moniker?) has a better offer.