Throwing belts/ alignment question

Discussion in 'Engine Topic' started by rocket dawg, Aug 11, 2019.

  1. rocket dawg

    rocket dawg Veteran Member

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    I have a 400 Chevy engine in my car ( 79 trans am) . I have 76 camaro power steering brackets mounted to the stock pontiac power steering pump. The pumps are identical. The power steering brackets have to be shimmed out 3/8th of an inch to get the pulleys to line up. Also had to shim the alternator back in towards the engine. I eye balled them best I could. At high rev's it'll pitch a belt as it did yesterday, both belts. Luck I wasnt too far from home and coasted a bunch. Belts seem to stretch alot. Maybe because the alignment is off? Any tips on getting these pulleys lined up other than basic eye ballin? thanks
     
  2. Zspoiler

    Zspoiler Veteran Member

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    I use a straight edge to line up my belts and some good quality belts and deep groove pulleys if you are going buzz it high and quickly.
     
  3. jbloake

    jbloake Veteran Member

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    Sounds to me you have a mixture of Pontiac & Chev on there if you need to shim. Use a set of Chevy pulleys & brackets on that 400 and you should be good for alignment .
     
  4. rocket dawg

    rocket dawg Veteran Member

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    The pulley on the harmonic balancer and the water pump pulley are from the 400 engine as in 1979 Scotsdale 4X4 K10. All the other brackets are from a 76 camaro donor car. I removed a couple of shims yesterday and they look perfect, Test ride this afternoon and then a re-tension of the belts.
     
  5. jeff swisher

    jeff swisher Veteran Member

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    I began tossing V belts off back in the early 1990's.
    New belts were the issue.
    My old belts and some old ones I got off cars at the salvage yard would stay on.
    I went to Goodyear Lube and picked up a $25 V belt they said had a lifetime warranty.
    Tossed it at 7000 rpm also.
    I went to Fleck bearing and got some industrial V belt Not cloth covered either .
    They stayed on.
    But they quit making the correct width ones and I was out of luck.
    It was not an issue with them lasting as much as it was people buying my cars and I would have to build another and go through the belt thing again.

    I gave up about 10 years ago and built a serpentine system and have not tossed any belts.
    The solid V belts are the ones I had good luck with. If you could get a good solis one in the correct width
    Cogged V belts toss right off no matter the brand.

    I have read many had great luck with Dayco belts when they had belt tossing issues.
     
  6. 80sz

    80sz Veteran Member

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    Put a 2’ level on crank face to
    Check them
     
  7. QUAKE_WARS

    QUAKE_WARS Veteran Member

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  8. G72Zed

    G72Zed Veteran Member

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    Along with the great points that zspoiler and 80sz made, you can also use a laser level to get them very close to perfect.

    A few other things that can help is you can go down in diameter on the driver (crank) to slow things down, but go with the same dia. on the water pump to keep the ratio at 1:1 (in most cases). The other thing I found worked very well was to triangulate the Alt pulley location by way of a lower Alt. mount (if able), shortening that leading section is the major culprit to belt toss on the Alt/WP setup.

    The pic I included shows the setup I use today, the belts are still the same ones from 2014, just like new, no fraying, and are cogged,(Napa Premium XL 25-7390 and 7320, your application will vary) never tossed a belt in 20k+miles, and I spin it 7,200+ rpm regularly and quickly , the other engines I work on are chipped at 7,600 and the BBC's are 8,200+, cogged Vbelts, no tossing if setup right.

    hope this helps you out

    pic1.jpg
     
  9. Green hornet

    Green hornet Veteran Member

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    Not only do you need to make sure the pulleys line up but you need to make sure each one is square. If one is out of square it not going to help the issue.
     
  10. rocket dawg

    rocket dawg Veteran Member

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    I used a straight edge and even thought they look straight, they are off. Just the P/S is off. The laser idea is a good one too.
     

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