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 Posted: 05-11-2008 09:50 pm
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D.Drake
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I have my 73 MkI  back on the road (almost) !
I have changed the timing belt sevearl times over the years ,but with out a guage it is by guess and by golly .
Someone on the list recommended that you  could estimate  the tension by twisting the belt 45 degrees  between the alternator pulley and intake cam .
I tried this and the belt is whining (too tight)
Anyone have a technique that they feel gives them a good result without using a Burroughs Gauge .

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 Posted: 05-11-2008 10:10 pm
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D.Drake
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I just rediscovered the old Message archive ,and found that the locationI chose to twist  ,between the dizzy pulley and Intake was not right .Should have been between the exhaust pulley and Crank
Also a recommendation of 3/8 " deflection between the dizzy pulley and Intake was recommended .
I just hate having to keep readjustingthe timing belt  because I have to remove the alternator to access the rear tensioner nut .I really should have changed to the newer style tensioner ;-(

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 Posted: 07-05-2008 11:39 pm
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Steve Jarvis
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Since I don't have the device to measure the belt tension (or know where to get one) I wanted to understand the process. Do you mean that the belt should be able to be pushed in 3/8" from the resting position? How much pressure are you using?

Thanks

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 Posted: 07-06-2008 03:26 pm
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John Finch
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Try finding a Burroughs or Robinair guage on ebay or google. Model numbers that are known to work for the Lotus 907 are (Burroughs) BT-33-86J, BT-33-73F and Robinair 10240. I found the Robinair on Ebay for about $25.00. Takes all the guess work out for cheap. Best of Luck.

Last edited on 07-06-2008 03:27 pm by John Finch

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 Posted: 07-06-2008 03:55 pm
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Greg Fletcher
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I lived for years without a belt tensioner gauge, so don't feel did like you must have one. As John mentions, it does take the guess work out of it.

One way to check the belt tension: place a metal straight edge on the belt from the distributor pulley to the intake cam pulley. Get an ink pen and mark your thumb nail with a mark 1/4 inch and 3/8 inch from the end of your nail. While holding the straight edge with one hand, push the belt down with your thumb as far as it will go in the center. The belt should deflect between 5/16 and 3/8 when adjusted to 95 pounds.

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 Posted: 07-18-2008 03:29 am
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dwalls1
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Thanks Greg! Used this trick this week when I replaced my belt and idler bearings. First checked the old belt and found it within spec, then used it on the new one and got it dialed right in. Or should I say "nailed it".

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 Posted: 07-19-2008 07:19 pm
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Steve Jarvis
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I just tightened the belt up from about +1/2" of play to 5/16". Seems to be fairly easy. I did do it differently than the manual and did not remove the fan. Seems you can loosen the alternator and get in from that direction also.

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 Posted: 07-19-2008 08:56 pm
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dwalls1
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My fan is extended towards the radiator due to it's having had A/C installed, so that clearance is not an issue. I am in the process of moving the fan back against the pulley to make room for a fan shroud. Problem is cutting the extra sheave and length off the crank pulley as the original pulleys are NLA. Anyone out there have a stock pulley I could releave them of?

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