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Belt Drive
https://www.ausmini.com/forums/viewtopic.php?f=2&t=11902		 Page 1 of 1
Author:  slide [ Fri Oct 07, 2005 9:35 am ]
Post subject:  Belt Drive
Anyone using a belt drive instead of timing gears? Is it worth the effort and expense? Does it reduce noise by much? Is it any more or less reliable than an ST duplex set?

Slide
Author:  TheMiniMan [ Fri Oct 07, 2005 9:54 am ]
Post subject: 
we havbe fitted literally hundreds of these things over the years, & they are basically the same weght as a duplex chain set up,,,they are a tad quieter,,, do tend to keep cam timing more acurate & it`s easier to change the belt than a chain.

BUT,,,i personally don`t like them much really,,,if you get a seal problem & oil spills all over the belt, then ,,,well,,,ouch,,,pretty pennys are going down the drain if it`s left long enough to strip the belt of all it`s teeth & smash some pistons into valves

YUK!!!

Fast fours & rotarys race mini experienced this a few years ago & it wasn`t a pretty picture

they`re ok,,,but if you do fit one, then make sure you keep an eye on any oil leaks, & also, if the belt strips it`s teeth off, then you`d probly need to make a tool to hold the cam pulley to be able to remove the retaining nut from the cam pulley, as there`s no way of holding the pulley to undo the nut once the belt has stripped, just a thought for you to have tinkering around in your head :-)
Author:  drmini in aust [ Fri Oct 07, 2005 10:11 am ]
Post subject: 
I like them as there's no stretch, so less timing scatter.
I've run one for 10 years now. No problems. I change belt every 40,000 miles... :wink: After that distance the teeth still look new. There's no tensioner on the outside of the belt so it doesn't flex itself to death like OHC belts do. :wink: ps. I know this as I was once a Fiat man.... :?

If I see an oil leak before 40,000 miles, I change the seal.
The steel gear sprockets are easily bruised though- you need to ensure you don't mark them with pullers etc or they can chew the belt teeth.

Belts for these (052R190) all used to be made in Italy, but lately production has shifted to China.. :shock:

I thought the Chinese belts felt a bit too loose last time, so brought some Kevlar race ones in from www.minimania.com - they cost me about $75 each, landed. They are supposed to be good for 50,000+ miles.
Author:  Mick [ Fri Oct 07, 2005 11:01 am ]
Post subject: 
I fitted a Mini Spares belt drive in 1995, and could not stop the bugger from leaking oil, I replaced the seal around the camshaft twice and it still leaked despit my most careful efforts to fit it. I also found the Mini Spares vernier type belt drive quite difficult to set accurately, the pinned type might have been a better choice.

I gave up on the bugger because of the oil leak and sold it on. I later heard that you needed to fit a second oil seal next to the first prevent this. I wish I had bought another brand.....

But this was 10 years ago, they might have picked up their game by now.
Author:  drmini in aust [ Fri Oct 07, 2005 11:43 am ]
Post subject: 
Mick,
Mine is the original `Triger' one, plain pulley, not vernier. Was in an S motor I bought.
I use an offset key. Once set it never needs adjusting anyway.
Only seal problem I found was the crank one can go hard with high mileage and drip a little- but the belt stayed dry.
Never a problem with the big seal on the cam. :wink:

I'd buy another if they weren't so dear.... :cry:
Author:  Mick [ Fri Oct 07, 2005 12:12 pm ]
Post subject: 
Yeah I would have loved for it to be a success on this engine. It was a fully balanced lightened and fully 'Vizarded' Cooper 998 engine with a very, very, very nice 295 head (is this the right number for a cooper 998 head) fitted to my shadow blue and white 63 cooper. Wow what a machine.

It was great without the belt as well, but it still dissapointed me as it was a bit of a star item in my view. I did get some scatter once the double row chain was on, but the chain was new and might have gotten worse over time.

I wish I had kept that 998, you really learn the attractions of a small bore engine with a machine like that..
Author:  tainted [ Fri Oct 07, 2005 8:34 pm ]
Post subject: 
Tech reason behind belt drives, on 'A' series, short distance, chain will streatch up to 15thou, belt will only streatch up to 5thou, thus keeping your timing more acuate longer, unless you like dickin around with ya engine all the time.

There was noted on ebay yesterday a belt kit for an A series sprite, same thing, the current price then as $99 bucks, didn't check too much cause I got one, so check there if your interested, probable still available, and is a fairly simple job to install.
Author:  drmini in aust [ Fri Oct 07, 2005 10:43 pm ]
Post subject: 
Chain (single or duplex) will stretch a damn sight more than 15 thou... why, the new ones they sell for Minis now are slacker than that when new! And far worse after a few thousand miles..

Get one out of the box, bend it sideways and you'll agree. Except for the Iwis one, they are a POS. They just don't make 'em like they used to. Mr Renold would turn in his grave... :lol:

ps. I have worked with transmission chains for 40+ years, so I know a good 'un when I see it. :wink:
Author:  tainted [ Fri Oct 07, 2005 11:08 pm ]
Post subject: 
I aint going to argue, I do know chains stretch further than belts, this fact still eludes most people, steel stretching further the rubber composite. The 15thou I mentioned, I think, was an average length growth on a simplex chain during an average (?) life, and yest chains do stretch, especially with a lot of side ways movement.
Author:  drmini in aust [ Sat Oct 08, 2005 7:06 am ]
Post subject: 
The steel in chain doesn't `stretch', what happens is, the pins & bushes wear. Nowadays they are sloppy when new. And there are about 52 of 'em.... doesn't take much to get 1mm (.040") of chain slack... :x :lol:

:idea: Wrap it around the cam sprocket and squeeze it tight, then see if you can lift a roller away from the sprocket at the opposite side. I bet you can, even with most new chain... :wink:
Author:  Fat80y [ Sat Oct 08, 2005 3:52 pm ]
Post subject: 
So Doc you're saying there's not much point upgrading to a duplex from a single these days, and if you really want your cam timing spot on belt is the way to go?
Author:  Lillee [ Sun Oct 09, 2005 12:53 am ]
Post subject: 
If you are building a new performance engine and can find a cheap belt drive kit, buy it. Otherwise a good double row chain is more than adequate. If you are running a 2 row now and not planning to rebuild, don't bother about belt timing.

IMO bottom line, for a highly tuned engine where you are chasing for as much HP as possible (every horse you can get is worth the expense for you) then certainly a belt drive would be the way to go. On a more relatively stock engine where 1-2 degrees of cam timing slack is not going to make any significant difference then bugger it, stick to a properly setup 2row chain.

Belt drive kits are not cheap full stop. The bang for buck increase in hp by keeping the timing right throughout the engine's life is not as good as say if you were to invest this money into a proper head porting job which you can gain 10%+ HP total for relatively the same price...
Author:  Fat80y [ Sun Oct 09, 2005 9:47 am ]
Post subject: 
Double row it is then.
Author:  TheMiniMan [ Sun Oct 09, 2005 6:51 pm ]
Post subject: 
yeah 68del has got it,,,a cheap belt drive in "like new" nick, then ok,,,Maybe if you`re chasing every milliscule of oomph & then you can lighten it a little while you` re there too, then oky doky as well, sweet, But!!!.....

the average Joe just can`t go past a good "quality" duplex really
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