310 - A/C belt rubbing on water pump housing

[bkahler]

I've got a real dilemma on my hands. Last fall during a routine inspection of the engine on the 310 (chevy 454) I noticed that the A/C belt was flipped in the groove. At the time I didn't do anything about it as we weren't planning on driving it until spring.

So today I decide it's time to replace the belt. I loosely install the first belt which is the A/C to Water Pump to Crank to Power Steering. While routing around the water pump I just happened to notice (by touch) that the belt seemed to be resting against the water pump outlet. I used my bore scope to take these two pictures. One picture sure seems to show the belt being deflected slightly by the water pump. The other also seems to show it touching.



Here's a couple of pictures of the Argosy motor sitting on the test stand. There is a clear separation between the belt and the water pump casting.



I know there are shims that can be used to shim the water pump pulley farther forward but they are used to align the water pump pulley with the crank pulley. I don't believe there is an alignment issue although I will try and verify that tomorrow.

The only thing I can think of is there are different castings for the 454 tall water pump and this one is just a bad casting. I do know the engine was replaced back in 2000 with a factory crate engine. I'm fairly certain the water pump on the engine right now is the one that was installed back in 2000. We broke the AC belt last spring on a trip and I replaced it while on the side of the road. The belt that I just removed because it had flipped in the groove is the belt I replaced last spring.

I'm guessing it flipped because of the rubbing against the water pump casting.

At this point the only thing I can think of doing is replacing the water pump and making sure I get one that has the same profile as the one on the Argosy 454.

Any suggestions?

Thanks!

Brad

[idroba]

This is a long shot guess so take it for what it is worth. I had a GMC motorhome with a 455 Olds engine. I was on the GMC forms at the time. Many GMC people were having issues with belts slipping, flipping and breaking.

Others found that the original GMC belt was 11 mm wide, where as many replacements were only 10 mm wide, but they were all listed as identical replacement belts. Apparently since V belts are not super common on new engines, the belt manufacturers were just substituting 10 mm belts for the 11's to reduce inventory requirements.

Put a 10 mm wide belt on a GMC 455 and you will have problems, an 11 and you won't.

The advice was for one to take a 10 mm open end wrench with you when you purchased a belt. If it fit over the belt, you were getting a 10 mm one, if it would not slip over the belt, it was 11 mm and you could buy it.

Again, no idea if there is a similar problem with the Chev 454 of that era, but there could be I would think. At least I thought I would mention it.

[bkahler]

Unfortunately in this situation a narrower belt would work in my favor. I guess I need to measure the width of the belt. According to all the specs I've seen the belts for the 454 should be 10mm wide.

If it does have an 11mm belt that would make it ride farther out of the pulley possibly enough to cause rubbing. I'll check tomorrow.

Thanks!

Brad

[ventport]

Can you get in there with a grinder and relieve the water pump casting so the belt clears?

[bkahler]

Originally Posted by ventport

Can you get in there with a grinder and relieve the water pump casting so the belt clears?

I thought about trying a grinder and I think I can get in there but it would be tight. The water pump is at least 14 years old so it might be time to bite the bullet and just replace it with one that has better clearance.

I will say I'm not exactly looking forward to tearing into that area because you have to remove the alternator, part of the power steering pump and the fan assembly. I think I'd rather have my teeth pulled...

Brad

[TG Twinkie]

In looking at the last pic. It appears the pulleys are out of alignment. Are you sure there is not a spacer missing from behind the fan cone. This would cause it to set farther back and run on the water pump.

[bkahler]

Originally Posted by TG Twinkie

In looking at the last pic. It appears the pulleys are out of alignment. Are you sure there is not a spacer missing from behind the fan cone. This would cause it to set farther back and run on the water pump.

TG, if you're referring to the 2nd picture which shows the belt as installed on the 310 you might have a piont about the pulleys. If you're referring to the very last picture which shows a new engine, those pulleys are within 1/32" of each other. That last picture is of the motor that will be installed in my Argosy motorhome.

Using a straight edge I was able to reach down around the front of the engine and as near as I can tell by touch (can't see a thing!) it may be that the water pump pulley is set about 1/8" back from the crank pulley. I had no visual way of verifying what I was feeling with the straight edge but several tries at different angles seem to produce the same result. Unfortunately the alternator pulley appears to be set back about 1/16" from the water pump pulley which would mean I have to figure out how to space the alternator pulley out far enough to line up with the crank pulley, water pump pulley and the smog pump. I didn't check the smog pump yet, I'm almost afraid to!

I'll be looking at the problem more this weekend. I do have some water pump pulley spacers and will likely try and install one to see what happens.

Brad