Belt replacement

[Ctmangrum]

So I may not using the search option correctly, but im sure somewhere on here is a tutorial on how to change the belt on a 1976 Ford 351M engine.

[bud37]

So I am curious.....what belt are you referring to ? Got any pics of this ?

[Ctmangrum]

Ill post a pic this week. I want to call it the serpentine but not sure if that's what its called on a marine engine

[km1125]

I'd be surprised if a 1976 motor would have a serpentine belt. Back then they were almost exclusively just V-belts. However, a previous owner could have made modifications to change it over to a serpentine belt system.

Is this for all the accessories on the front (water pump, alternator raw water pump)? Is there only one belt?

[Ctmangrum]

Yes. That's why im calling it a serpentine. Looking for any insight.

[tomschauer]

As KM mentioned, a 1976 351M would have had a v belt or belts, not a serpentine belt. If you have a serpentine belt, there is a good chance it was repowered with a newer engine, or at least a serpentine belt kit.
The belts, v or serpentine are pretty easy to change. Take a pick of the routing of the belt before removal. Take the belt to an auto parts store and get a replacement and put the new one on.

[Phrancus]

QR_BBPOST Ill post a pic this week. I want to call it the serpentine but not sure if that's what its called on a marine engine

that would be a sea serpent.

[Ctmangrum]

So I guess im asking how to get the belt off. On a car, you have the pulley that you can adjust to loosen the belt, take it off, then install the new one. Is there a pulley or flywheel that adjusts for belt removal?

[Ctmangrum]

Oh, and it has not been repowered

[km1125]

The one thing to figure out on the serpentine belt is whether or not it used a spring tensioner. One of the idler pulleys would be spring-loaded and you can pivot that spring loaded pulley to take tension off the belt, so just having the right tool to take that tension off is all you need.

Some systems will also have a bolt "locking down" that spring-loaded pulley from moving. So, once the "spring-loaded" pulley sets the tension, the bolt locks it in place. Without this bolt, the spring constantly pulls on the belt so any stretch or wear in the belt is compensated. However, with the spring-loaded pulley able to move you can also set up vibrations in the belt which could cause it to come off (which is why some use a bolt to lock down that pulley from moving once tension is set).

Still others use the "old school" way of tensioning the belt with a bolt adjustment. YOU need to set the tension and you normally do that with a tool that clips on the edge of the belt and it indicates how much tension is on the belt itself. This is actually the best way, but also means the belt may need readjustment after stretch or wear. You also set the belt tension for a used belt less than a new belt (because the initial stretch and wear on a new belt happens quickly). The adjustment mechanism can be one of the idler pulleys, or it can be one of the accessories, like the alternator. The last engine I did one of these one, it was the alternator that you used to adjust the belt tension.