Alternator and Tension Pulley assembly problem. can you Help?

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Not a real E Type
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Alternator and Tension Pulley assembly problem. can you Help?

Post by Not a real E Type » Tue Apr 16, 2019 3:44 pm

Hi there, I have joined this forum as I have come into possession of a car that is powered by a Rover V8. I have driven this car for the past ten years or so but only now do I have to do any work to it. This is my first post.

The drive belt has, for the last couple of years been a bit noisy and it's easy to see why. The home made alternator cradle is very flimsy and broken. But when I look at the set up of the alternator and the tension pulley, it's clear the tension pulley is not under any tension and the alternator is moved back and forth on an arm to provide the tension. The need to replace the alternator cradle has led me to the conclusion I must look to set this system up properly. Question-Am I right in assuming that the alternator should be fixed and the tension pulley does all of the work?
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In the lower picture, I have already started to dismantle the alternator set up. The arm pointing skyward from the centre of the tension pulley is that which was attached to the alternator housing and providing the tension. I hope maybe someone can offer some advice.

Chris Riley.
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DEVONMAN
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Re: Alternator and Tension Pulley assembly problem. can you Help?

Post by DEVONMAN » Tue Apr 16, 2019 4:20 pm

To answer your first question, when a tensioner is in the system , the alternator is normally fixed in one position and the tensioner takes up any slack. Ideally the tensioner should be on the returning belt side of the crank pulley and not on the pull side. If positioned on the pull side, the pull from the crank pulley will cause the tensioner to give a little and the full belt force will not be transmitted to the various items such as the water pump and the alternator and some slip may occur.
1950 A40 Devon Hotrod with 5.0 twin turbo RV8. (10 things to make you smile)
EDIS8 wasted spark, Holley Injection.
Been as far as the Moon and back in 54 year of driving. Same Car, 5 engine upgrades !!!


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richyb66
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Re: Alternator and Tension Pulley assembly problem. can you Help?

Post by richyb66 » Tue Apr 16, 2019 4:29 pm

You really want a sprung tensioner with a multi vee belt. Alternator should be mounted solid.

What is the black plastic pulley top right driving? I used the standard 4.6 sprung tensioner and moved it from underneath the alternator (where it clashed with the steering shaft and moved it to the front of the LH cylinder head mounted on a thick aluminium spacer

Standard 4.6
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My set up
2016-03-30-619.JPG
The redundant area on the bottom of the alternator bracket was then chopped off,

Not a real E Type
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Re: Alternator and Tension Pulley assembly problem. can you Help?

Post by Not a real E Type » Tue Apr 16, 2019 5:46 pm

Thanks Devonman and richyb66. Devonman has confirmed what I had hoped might be the case. That is a very helpful answer, especially concerning the placement of the tension pulley. As you can see in my picture, the top pulley, which is the spring tensioner, is not actually working correctly and acting only as an idler pulley. The tension has thus far been provided by pulling the alternator back and locking it into position. I think the engine belonging to richeyb66 looks fantastic and that setup is simple and clearly very effective.

Thankyou both for some very useful and inspirational help. I'll post again when I get my head around rebuilding the alternator cradle and how I might best position and fix the sprung pulley.

Cheers, Chris Riley.

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