New 450 SEL owner...questions

[1980sel]

So I just got a very clean 1980 SEL and I have a couple of questions....my first question is I went to adjust the belts as they were all pretty loose..everything went fine until I restart it and it's making a godawful sound..shut it off and discover that the alternator fan is rubbing on the bracket...for now the belt is readjusted loose and it's ok but even with this adjustment there's barley enough of a gap to see light between the pulley and bracket...I'm wondering if someone installed the wrong alternator...mine has the big enclosed fan vs just a small open to the elements fan. My second question is I need the check valve and tube that goes from the front of the right head to the air cleaner tube...tube is stripped and valve is in pieces...exhaust flows through this tube..I can't find either anywhere and for now just plan on JB Welding a later models check valve onto the tube as the tube is already trashed. Thanks for any advice you guys can give.

[adamb]

For the first part of your question, it might be easier if you post some close up pictures. Clearly, there should be no rubbing after correct alternator belt tension adjustment. Also consider replacing the belt if it looks worn. It's cheap and a new one won't snap like mine did recently.

[John Hubertz]

It isn't uncommon for people to fit a later-model alternator to the W116 as lots of them fit the mounting bolts - but I wouldn't worry too much as long as you have some adjustment range.

On older cars belts tend to stretch over time - you could remove the belt (i know, it is a chore), and take it to any old-school auto parts store like NAPA (in the USA), and they have a tool to measure the existing belt.  Buy one just a bit smaller in total diameter (the tool has marks to tell you the belt size).

Be sure the width is correct for original belts, not just the belt you took in to check.  Sometimes belts wear down on the sides and ride too deeply in the pulley, which also can cause excessive adjustment.

Here's how I would proceed.

1.  Remove belt
2.  Go to parts store, and compare the original to a brand new correct belt... if it is a bit smaller, buy it.  If the length appears about the same, then buy one slightly smaller.  If the width is worn down but they are about the same length, buy the original one.

The last time i ran into this problem was on a 300 D - I'd put an alternator on with a slightly smaller pulley.  It took me two trips to the parts store to get just the right belt... so if you live more than a few blocks away I'd recommend buying two or three belts of slightly different lengths, and just return the ones that you don't use.  It saves a lot of running back and forth for different belts.

[ptashek]

On older cars belts tend to stretch over time - you could remove the belt (i know, it is a chore), and take it to any old-school auto parts store like NAPA (in the USA), and they have a tool to measure the existing belt.  Buy one just a bit smaller in total diameter (the tool has marks to tell you the belt size)

That, or you can pm me with your chassis and engine numbers and I'll pull the belt sizes out of the EPC for you tomorrow. I'm more than certain some of the folks here know the sizes by heart too.

[1980sel]

Thanks guys but it's not so much the size of the belt that's the problem..even with the belt removed there's just a very small gap between alt pulley and bracket no matter how i adjust it...there's one sweet spot that it won't hit and it runs fine like that but the belt is too loose for my taste....

[oversize]

Sounds to me like someone's changed the alternator, or modified the brackets.  Without a pic there's no way of telling.

[1980sel]

I'll try to get a pic up in the next few days...

[John Hubertz]

If it ain't broke....

[Hemersam]

"If it ain't broke, don't fix it" was one of the hardest lessons to learn for me. I still have the urge to ignore it from time to time.
Hemersam

[1980sel]

Just a quick update...did a basic tune up...plugs cap rotor and air filter..and managed to track down a good used check valve and tube..running much smoother and quiter without the massive exhaust leak.....

[WGB]

1) is it the correct alternator and is it mounted correctly.
2) Is it the correct alternator body
3) Is it the correct pulley and fan
4) some other combination of the above
5) Are your alternator bearings worn

You may have to shim out either the alternator body vs bracket or place a washer between fan and shaft of alternator.
You may be able to very gently bend each fan blade on the alternator 2 mm or so to give you clearance but make sure you do it evenly.

Just make sure you have the correct pulley and that is is in reasonable alignment to the other pulleys so that the belt is running straight.

Bill