View Full Version : Changing alternator belt

01-27-2003, 12:04 PM
1. Changing alternator belt?

Can you please give me procedures on changing the alternator belt, and any tools necessary, on a crusader 454. It seems that my alternator belt is behind the another belt which has to be removed first in order to get at the alternators belt. I have a buildup of black residue coming off the alternator area and I figure I should change it now and know how to change it in the event of an emergency. Any help would be greatly appreciated.

Date: 18:25 on 09-24-2001

premium member in standard member. 2. Re:Changing alternator belt?

I can't help you w/ the belt change but have a suggestion once you get started.
As you pointed out, getting a new belt on is a real PITA. On my last Shammy, some smart mechanic had put a spare belt on the engine block in the install position, but had used wire ties to hold it against the block and out of the way. Thus if/when the installed belt failed, the spare belt could be installed very quickly by simply cutting the wire ties, loosening the alt. bracket, and pulling it over the pulleys. Then all you had to do was snug it up and be on your way. No hoses to be removed or other time consuming tasks.

On this boat the belt did fail, but I was back up and running in about 10 min saving me about 20 min. of cursing in rough seas working on an overheated engine (your mileage may vary). And I admit it, I am a wimp. I do get seasick w/ my head in the bilge for any time at all.

What a great idea. Wish I had thought of it first.


Date: 10:28 on 09-25-2001

3. Re:Changing alternator belt?

Lep can you help?
My bad, I should have explained my situation a little better. There are two belts, one belt turning the starter and maybe a water pump and the other belt turning the alternator. No hoses are in the way. In order to change the alternator's the previous belt mentioned above must be removed first. Now all that seems to be a complete PITA. My question I guess is there a bracket on the starter that is similar to the alt. bracket that needs to be loosened first?
That "smart mechanics" idea seems to be a very good one. But if that belt is strapped up against the engine will engine heat damage the belt in any way?(may be a silly question since a lot of friction is created while its spinning in it pulleys).

Date: 17:56 on 09-25-2001

premium member in standard member. 4. Re:Changing alternator belt?

Geoff - I saw this thread and didn't reply because I never have actually seen a 454 in a Shamrock, thus could offer no real relevant insights into the job.
I do however own a classic Vette with the 454 engine. Its got every option known to man as original equipment and to run them all, it uses FOUR (Or is it five?) different belts. Its a full day's work to change 'em, so I can empathize with your problem.

O.K., so let's see. You say that to change out the alternator belt you have to change a STARTER belt? That can't be right. Believe me, no engine known to man has a belt to the starter. What I THINK you mean is that to change the alternator belt you have to first remove the belt that goes around the crank pulley, then the circulating pump pully, then the RW pump. While I've never worked on a Crusader, I'll bet that's the setup. What else could it be? So usually, you have to loosen the RW pump to give the belt enough slack to enable you to slip off the belt and access the second belt, which I bet goes around the lower pully (Crank), the circulating pump, and then the alternator. Take another look and see if I'm right.

If that's correct, look closely at the RW pump and you should see 2 bolts (Probably 1/2" heads), loosen those and the pump should pivot toward the engine's center on one of them. This will create enough slack to get that belt off.

Now a word about black dust on the front of the engine. This is NORMAL on a marine engine, new belts or old. The reason you see that dust on a marine engine and not on an automotive engine is that the pullies tend to develop slight surface rust in the belt grooves and this slightly erode the belts and this is the dust that you see, nicely distributed about the engine's front. It happens on EVERY marine engine, without exception, unless you are truely Bucks-up and have semi-custom machined aluminum or stainless pulleys on her. I watch my belts like a hawk, and while I have to wipe the dust off maybe once a month, I have the same belts on her for about the past 5 seasons (about 125 - 150 hours per season) with really a minimal amount of actual belt-thickness erosion. I keep a spare set of belts on the boat and do not look forward to having to change one on a nasty January afternoon while rocking in a nice 3-5' roll, but I just don't think that's gonna happen. They look fine with no evidence of cracking or fatigue of any type.

End Part 1

Date: 09:43 on 09-26-2001

premium member in standard member. 5. Re:Changing alternator belt?

Part 2
Oh yeah, one other cause of that dust is a possible pulley misalignment. This happens in hot rod automobiles quite frequently as guys swap engines and components, looking for an "Edge." The belt will ride on one side of the pulley more than the other and throw some black dust. This situation usually doesn't last too long in a Hotrod though, because a misaligned pulley will usually throw the belt at high rpm, meaning something over 5500. Since we never see that kind of engine speed in a boat, the belt won't get thrown, but will shed some dust. You might want to invest a few moments visually sighting across the front of the engine and look to see if the belt is nice and square to the engine or if there's a slight angular "Kick" to one leg of the belts. A few washers in front of or behind the guilty component will bring it into square alignment.

I had a '70 Plymouth Duster 340 many years ago that had this problem, and since it was a 4-spd and was built in a time that cars actually had some compression and horses, it just LOVED to rev. Used to pull second on that Hurst shifter so hard that it actually put a dent in the no-frills vinyl bench seat. In fact once I actually pulled the shifter right out of the floor, broke the aluminum mount off the trans case and had to limp 30 miles home at about 20mph, stuck in second. Nice. My girlfriend hated that car, but I loved it. Anyway, when I first bought her, I lost many a street race because the damn belt would fly off at the top of first. It was the misaligned pulleys and a few hours of inspection/correction solved the problem. No issues after that, except the car rotted away faster than I could apply the bondo. Chrylser never could build cars that were the equal of thier excellent engines. My next ride was a Vette and I've never been without one ever since. Oh yeah, the girlfriend liked the Vette a WHOLE lot more. Shallow bitch, I dumped her. ;-}

rgds, Leprechaun

Date: 09:43 on 09-26-2001

premium member in standard member. 6. Re:Changing alternator belt?

Regarding the engine heat effect on belts: Over time the engine heat will 'heat form' the belt making it want to take the form of its position against the block. Thus when installing the belt, you have to overcome its new memory which is no longer round. But I don't think the belt will suffer any breakdown. My belt sure worked when I needed it to work and my guess is that it had been on the engine 9 years b/f it got used.
You can always change the belt out once back to port if belt breakdown is a concern.

Since you have to remove a belt to get to the back belt, this idea makes even more sense. It really isn't much fun to be doing engine work in 3 ft seas. Ask me how I know that. Any tricks that will save time should be considered.

I think Lep is right on target w/ the dust off the belt. A little dust is no great concern if the belt passes all other visual inspections.

Lep, as preventive maintenance, how often do you change out your belt(s)?


Date: 10:06 on 09-26-2001

premium member in standard member. 7. Re:Changing alternator belt?

I dunno. I bought the boat in '95 and changed all the belts at that time. Those belts are still on there and look fine to me. I guess if you are a bit on the anal side with maintenance then every 4 seasons would be fine. If I was picking a job to be anal about, I look at all the rubber water hoses first. I just changed all mine out and while not super-expensive, it was not cheap, but the old ones were more funky than I originally thought.
Based on what I saw the past two weekends working on my fuel tanks, I would recommend everbody pulls the upright gunnel cover over the 1&1/2" fuel-fill hose and give it a GOOD eye-balling. Mine were so shot it was a wonder they weren't dripping fuel. They actually fell apart when I was pulling on them to get them off the deck fill. Yuck.

rgds, Leprechaun