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 Post subject: Paranoid about belt tension?
PostPosted: Mon Oct 06, 2014 5:42 pm 
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So initially when I bought my 944, I tried to find the best ways to do each repair job, whilst also saving the most money. One cost saving measure I risked, was not to bother with a belt tensioning tool. I was given some good pro tips on how to judge belt tension specifically on the 944.

My first belt change went great - for a year, until an idler bolt fell out and snapped the balance belt: http://forums.tipec.net/viewtopic.php?f=25&t=15727&p=105388#p105388

I obviously did not tension the balance belt tight enough after that, as it slipped a few teeth only a few months later. I did check the timing belt tension whilst I was in there.

Then yesterday whilst doing a general service, I noticed a belt slapping noise coming from the belt covers. It's hard to tell only by hand, but the timing belt seemed quite loose and was oscillating up and down in the section from the camshaft to the water pump. I also read last night that you can get a very rough idea of tension by trying to turn the water pump pulley by hand on a cold engine. I could not turn it this morning when cold, so I presume my tension is ok?

The balance belt will just turn 180 degrees in it's longest run.

In a state of concern last night, I panic bought the Arnworx tool.

Is that belt slapping noise normal? Idlers to belts position are good: turning freely but not obstructing the belts.

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'85 944 mostly working
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 Post subject: Re: Paranoid about belt tension?
PostPosted: Mon Oct 06, 2014 6:14 pm 
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You have to check the belts and re tension if necessary after 500-1000m running. Search for Van's guides on youtube if you need help.


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 Post subject: Re: Paranoid about belt tension?
PostPosted: Mon Oct 06, 2014 6:22 pm 
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I've heard a Porsche mechanic say " a quarter twist then no more than half an inch of waggle..." which I interpreted to read that finger pressure to twist 90 degrees and a half inch of lateral play...

My S2 has an auto tensioning main belt, but I tensioned the balance belt like this and it's been fine...

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 Post subject: Re: Paranoid about belt tension?
PostPosted: Mon Oct 06, 2014 9:25 pm 
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I too have "got away with it" for almost 3 years now on the timing belt, and I did check it after 1000 miles, but it seemed fine. I suppose the only way to really be sure, is to wait until the Arnworx arrives.

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Alex.
'85 944 mostly working
'83 924 "Yin Yang" cheap track car with another member
'01 Vauxhall Combo diesel van for camping, working, and moving slowly

Computer Problems: At your WITS End? http://www.witscomputers.co.uk


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 Post subject: Re: Paranoid about belt tension?
PostPosted: Tue Oct 07, 2014 6:55 am 
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I have an Arnworx kit here which I lend to members so no excuse. Personally I normally set them up by feel & then check using the Krikit. I'm normally a fraction tight which on new belts is fine. As others have said they need around 1500-2000 miles to bed in & then need rechecking.
In fact I would probably sell my Arnworx kit & Krikit tensioner as I don't use it any more, any one interested?

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 Post subject: Re: Paranoid about belt tension?
PostPosted: Tue Oct 07, 2014 8:27 am 
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tr7v8 wrote:
I have an Arnworx kit here which I lend to members so no excuse. Personally I normally set them up by feel & then check using the Krikit. I'm normally a fraction tight which on new belts is fine. As others have said they need around 1500-2000 miles to bed in & then need rechecking.
In fact I would probably sell my Arnworx kit & Krikit tensioner as I don't use it any more, any one interested?


Bugger. Well at least I have the latest version coming my way.

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Alex.
'85 944 mostly working
'83 924 "Yin Yang" cheap track car with another member
'01 Vauxhall Combo diesel van for camping, working, and moving slowly

Computer Problems: At your WITS End? http://www.witscomputers.co.uk


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 Post subject: Re: Paranoid about belt tension?
PostPosted: Tue Oct 07, 2014 9:38 am 
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The 20+ year old spring loaded tensioner may be good enough, or it may over tension the belt which could knock out the waterpump bearing prematurely. Personally I want to know how tight the timing belt is when the block and head are up to temp...


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 Post subject: Re: Paranoid about belt tension?
PostPosted: Wed Oct 08, 2014 11:00 am 
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tr7v8 wrote:
I have an Arnworx kit here which I lend to members so no excuse. Personally I normally set them up by feel & then check using the Krikit. I'm normally a fraction tight which on new belts is fine. As others have said they need around 1500-2000 miles to bed in & then need rechecking.
In fact I would probably sell my Arnworx kit & Krikit tensioner as I don't use it any more, any one interested?


No idea if I really need these but how much? - while I go research what they are :D


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 Post subject: Re: Paranoid about belt tension?
PostPosted: Wed Oct 08, 2014 11:59 am 
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I have the Arnworx kit with the two spanners & the flywheel lock, the latter is essential. The dial gauge & all the little bits are there as well. I also have a Krikit which is the neat little Gates tensioner checker. I'd be looking at £100 plus P & P (it is heavy!) for the lot.

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http://tipec.net/region_southeastlondon.php

2018 Mitsubishi Outlander PHEV
2005 Porsche Cayenne S SOLD
2000 Jeep Grand Cherokee SOLD
2010 Mazda MX5 Mk3.5 2.0 Sport Tech SOLD
2000 Porsche Boxster S SOLD
1987 Porsche 944
2019 Abarth 595C


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