13 replies to this topic

[belche23]

Right I've got to the point where I'm going to order the timing chain.

The question is do I just buy a new single timing chain or buy the duplex kit? It's going to be a road car 1330cc engine with sw5 came.

If I go with the duplex timing chain is there anything else I need or do?

Thanks

Dean

[nicklouse]

how are you timing the cam in?

[belche23]

Same as mini mania on you tude with Offset keys

[tiger99]

With any highly developed engine a duplex chain is advisable. Good idea on fairly basic engines too, as they last longer.

You probably know about the need to countersink the two holes for the 1/4" UNF screws at the bottom of the engine endplate. Best to use Allen head, but Philips (or confusingly and incompatibly, Pozi) may be supplied as they are the same as brake drum screws.

You probably also know that some timing covers need a bit of attention to avoid fouling the chain.

As above, you may need a means of adjusting the valve timing, unless it comes out exactly right.

Apart from that, there is no downside.

[nicklouse]

Same as mini mania on you tude with Offset keys

Sure?

So you will buy new duplex cogs and not bother to get adjustable ones?

I would always use duplex by the way.

[skoughi]

I used a simplex IWIS chain on my reasonably standard 1330, what's everyone's thoughts on this setup? OK up to a certain level of tune maybe? At least I've only got about 50% friction of the duplex!

[Cooperman]

A duplex should last longer than a simplex and is better in high revving engines.
There are mixed feelings about the tensioner with a duplex.
I don't fit one with a duplex especially with high revving engines as I have seen one which broke up and another which was about to. However, other builders always fit one.

[Spider]

Simplex or duplex - a new chain also means new sprockets.

 

If it's a road going car, fit a duplex for longer life, about 3 times that you'll get from Simplex.

 

<Edit: Be aware if going from Simplex to Duplex, there's two 1/4" UNF Bolts you need to replace with Countersunk types and you'll need to Countersink the holes. It can all be done 'in car'. If you need to buy a countersinking bit the angle of the countersink for these screws, being UNF is odd-ball at 82⁰, though often you can get away with a 90⁰ type, but best to get the right one if you can, or sharpen an old drill to the right angle >

Edited by Moke Spider, 02 September 2016 - 08:11 PM.

[AlexMozza]

With my 1330 running a SW5 cam, I bought a swiftune vernier duplex chain set at the same time.

No need to run a tensioner with it either.

[Guess-Works.com]

 

Same as mini mania on you tude with Offset keys

Sure?

So you will buy new duplex cogs and not bother to get adjustable ones?

I would always use duplex by the way.

 

 

I use offset keys, once set what is the likelihood that you are going to change the cam timing? With race/competition applications, yes I can understand the need as a slight tweek to cam timing can change the torque/power attributes of an engine therefore making it more suitable to one track/application as the need requires... On a road car, most people want to fit the engine and be done with it...

 

PS...

I don't fit a tensioner either... they are not designed for duplex gears, and no production mini was ever fitted with a duplex and tensioner. Like cooperman, I've seen them split in two down the middle.

Edited by Guess-Works.com, 03 September 2016 - 08:14 AM.

[John Gervais]

Simplex or duplex - a new chain also means new sprockets.

 

If it's a road going car, fit a duplex for longer life, about 3 times that you'll get from Simplex.

 

<Edit: Be aware if going from Simplex to Duplex, there's two 1/4" UNF Bolts you need to replace with Countersunk types and you'll need to Countersink the holes. It can all be done 'in car'. If you need to buy a countersinking bit the angle of the countersink for these screws, being UNF is odd-ball at 82⁰, though often you can get away with a 90⁰ type, but best to get the right one if you can, or sharpen an old drill to the right angle >

 

Glad I found this thread - 

 

I'm currently trying to figure out what I'll need to fix a pesky oil leak and had thought I'd replace my current AE duplex chain with the IWIS or the 2H4905EVO from MiniSpares, using the sprockets I have.

 

Is this not possible?  

 

f I changed sprockets, then I'd probably need a handful of different Woodruff keys and shims, wouldn't I?  

 

Or would the new timing gear slide right on and be good to go?

 

Unfortunately, I won't have the luxury of dismantling the engine, examining and then ordering parts, as I need to find someone with a garage I can borrow to remove the engine for a cross-pin diff install.  So, my purchases need to be planned in advance - while it's out, fix the oil leak from somewhere around the timing cover, replace the water pump etc... 

[Spider]

 

Simplex or duplex - a new chain also means new sprockets.

 

If it's a road going car, fit a duplex for longer life, about 3 times that you'll get from Simplex.

 

<Edit: Be aware if going from Simplex to Duplex, there's two 1/4" UNF Bolts you need to replace with Countersunk types and you'll need to Countersink the holes. It can all be done 'in car'. If you need to buy a countersinking bit the angle of the countersink for these screws, being UNF is odd-ball at 82⁰, though often you can get away with a 90⁰ type, but best to get the right one if you can, or sharpen an old drill to the right angle >

 

Glad I found this thread - 

 

I'm currently trying to figure out what I'll need to fix a pesky oil leak and had thought I'd replace my current AE duplex chain with the IWIS or the 2H4905EVO from MiniSpares, using the sprockets I have.

 

Is this not possible?  

 

f I changed sprockets, then I'd probably need a handful of different Woodruff keys and shims, wouldn't I?  

 

Or would the new timing gear slide right on and be good to go?

 

Unfortunately, I won't have the luxury of dismantling the engine, examining and then ordering parts, as I need to find someone with a garage I can borrow to remove the engine for a cross-pin diff install.  So, my purchases need to be planned in advance - while it's out, fix the oil leak from somewhere around the timing cover, replace the water pump etc... 

 

 

Sorry, I'm just having a little trouble understanding your post here exactly, however as a chain wears, it gets longer and so the actual chain pitch (that is the distance between the links) also increases. Given that the Chain and Sprockets are 3/8" Pitch, as that 3/8" pitch of the chain increases it no longer will 'line up' correctly with the Sprockets. It is true that they 'wear together' to a point, however note that the pitch of the Sprockets is also increased.

 

So, fitting a New Chain to worn Sprockets will load the leading Sprocket Teeth, instead of loading about 90⁰ the way around the leading side of the Sprocket and this ill wear the Chain in very fast order. In Practice, this also further accelerates wear to the Sprockets too.

 

Just fitting a new chain alone is false economy.

 

If your engine has a higher CR or is tuned, then yes, I would recommend checking and correcting Cam Timing, even if only fitting a new chain. The Keyways between Sprockets are rarely indexed at the same angle.

 

You could buy a few keys, say 2, 4, 6 and 8⁰ ones and that will realistically cover anything or purchase a Vernier Sprocket.

 

You won't have to remove nor dismantle the engine to check and set the Cam Timing, it can be done in situ.

 

 

[John Gervais]

Cool - that makes sense, no different than a bicycle chain.

 

Best to do it right, so new sprockets it is.  I've just ordered a Rollmaster CS8000 timing chain set.

 

Thanks for helping!

[John Gervais]

And just ordered a KAD viscous crankshaft damper -