Duplex chain conversion

[JamesRTab]

I am currently rebuilding a 1098 engine and I'm considering fitting a duplex timing chain conversion as my standard chain and gears are completely worn out, but I'm not sure whether I need a different (deeper) timing chain cover?

Also the gearbox on my car is for a 948 is there any problems fitting it to the 1098?

[Declan_Burns]

Yes, you need a deeper timing chain cover. Duplex chains can also rattle with wear. An alternative is to fit a new single row chain and sprockets and the tensioner from a mini. It's slightly more expensive but just as easy. It also has an advantage of having the timing marks visible from within the engine bay.[frame][/frame][frame][/frame]
To mount the tensioner:[frame][/frame]
Part nos.
http://www.minispares.com
Timing chain cover incl. lip seal : CAM4904
Tensioner kit: MSSK051
Improved seal:12G2625

[cadetchris]

no you dont need a deeper timing chain cover, only if you decide to put a timing chain tensioner on it, then you need a different cover.
however fitting a duplex is easy as cake.
whip off the cover and the the gears.
remove the two bolts behind the lower gear and countersink the holes with a drill bit roughly the same size as the two countersunk screws supplied in the kit.
fit the screws and then reset the timing marks (as per the manual, its very very very important you do that right, if not the you'll bugger the timing up totally and the engine will run like a bag of spanners, if you can get it to run at all)
fit the new gears and chain (following the manual again)
new gasket for the cover and refit.
reattach all bits the where needed to be removed before (pulley and crank nut thingy and fan blades)

enjoy after that

[JamesRTab]

Thank you for your post Declan but the mini alternative is too expensive for me, the cost of the engine parts already is pretty high, and being a student with not much money I'm trying to keep parts cost down. The only reason I was thinking of the duplex kit was because I thought it would last a bit longer, but unless I can get a cheap cover I suppose inst really cost effective

[JamesRTab]

sorry I posted the last message before I checked again. I'm guessing you are talking about the kit supplied by ESM and Bull Motif (unless there are more that sell it)

[dellerie]

this is my 948 engine. its fitted with a duplex and a 1098 cover. very easy job that takes 30 mins. make sure you 'countersink' the 2 bottom bolt holes, so that when you use brake drum screws, they sit flush with the front plate.

don't forget your flat oil thrower. don't use the dish one.

[JamesRTab]

OK thanks for the help

[bmcecosse]

Yes - you absolutely DO NOT need a deeper cover - in any case - there isn't one! The later Mini covers often rub horribly on duplex gears unless 'adjusted' with a heavy hammer..... Duplex really isn't necessary unless fitting fancy high lift cam and double valve springs. The Mini single chain with tensioner is a FAR better modification. Get the parts off a scrap Mini - and if you can - grab a crankcase damper at the same time ! Of course - the early 948 timing case with felt seal is a truly useless thing and if that's what you have - take the opportunity to get rid of it. Easiest use of the 948 box will be to use the 948 backplate and flywheel/clutchon the 1098 engine and then it will definitely fit without any problems.