Has anyone fitted a Marina box to a Minor??

linearaudio · Post by **linearaudio** » Wed Jul 08, 2009 9:12 am

As my last post was hijacked by a discussion on diff ratios and 940 heads (no offence taken!), and only a couple of doom mongering comments (again, no offence meant, Roy!!).....
Has anyone had experience of fitting a Marina box to a Moggy?

I am interested in possible interferences, starter motor engagement, pilot bushes, clutch actuation etc. Charliemorrisminor has given me in depth info on converting a Marina box to overdrive, including gearbox mountings, so I am happy enough with that side of things, and NO! I was not about to get a shorter prop made, my initial works will be done on a donor Moggy at the local yard as a pattern!

As an aside, the white coat fits and looks the part, and I have access to a strait jacket if things go really awry

As a gesture of goodwill, I will post my experiences of fitting the 940 head and the mods needed, and if that only gives an extra ~7BHP then I'm a Dutchman (no, I'm not!).

PS: All the above was written in the best of spirits

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Post by **bmcecosse** » Wed Jul 08, 2009 12:51 pm

All I have read about - suggests you need to reduce the height of the engine by lowering the front towers - and possibly moving the engine slightly forwards too. The Minor bellhousing has a slot taken out of the top part - maybe the same can be done on Marina bellhousing to get a bit more clearance? Good luck with it - you seem to have the necessary go-ahead attitude!

Wed Jul 08, 2009 1:29 pm

certainly when fitting a marina engine, as pointed out, you lower the front tower, you also need to take the bulge off the bell housing that the start motor gear sits in.

Sorry i did not understand that you were going to trial fit everything into another moggy when i said do not get the prop made up.

If using an original marina backplate.. apparently.. things get a bit close on the chassis leg so you might need to modify the backplate in this area.

Post by **bmcecosse** » Wed Jul 08, 2009 3:57 pm

I only suggested extra 7 bhp - so as not to be accused of claiming the ridiculous! Twin carb MG1100 engine was 55 bhp - with twin SUs on horrible manifoild - and (relatively) small valve 12G295 head. The 940 conversion is 'bound' to be better than that! However - you must remember the standard 1275 engine - with most of these parts (but crucially NOT the alloy inlet manifold with NO hot-spot !!) on a larger capacity block - was only rated at 55/60 bhp depending which car it was in ! Losing the hot-spot is usually reckoned to be worth about 5 bhp.

linearaudio · Post by **linearaudio** » Wed Jul 08, 2009 4:58 pm

bmcecosse wrote:I only suggested extra 7 bhp - so as not to be accused of claiming the ridiculous! Twin carb MG1100 engine was 55 bhp - with twin SUs on horrible manifoild - and (relatively) small valve 12G295 head. The 940 conversion is 'bound' to be better than that! However - you must remember the standard 1275 engine - with most of these parts (but crucially NOT the alloy inlet manifold with NO hot-spot !!) on a larger capacity block - was only rated at 55/60 bhp depending which car it was in ! Losing the hot-spot is usually reckoned to be worth about 5 bhp.

And don't forget the RC40 exhaust- should be good for 5BHP in itself- but hang on, we're drifting from the thread AGAIN!!

Someone tell me about clutch linkages and starter meshing, also one for you Roy- what do I need to do to fit the Marina flywheel to the 1098 crank, isn't there something about hole pattern being different?

Give me a stone to get some blood out of, it would be easier (joke!!)

Post by **bmcecosse** » Wed Jul 08, 2009 5:34 pm

The RC 40 exhaust is just a name! It's no better than any other exhaust with decent bore !

Post by **superchargedfool** » Thu Jul 09, 2009 10:54 am

bmcecosse wrote:The RC 40 exhaust is just a name! It's no better than any other exhaust with decent bore !

NO.

surely not.

I have always been a believer in what people claim. I've always thought an RC40 was worth at least 10bhp. (tongue firmly in cheek).

linearaudio · Post by **linearaudio** » Thu Jul 09, 2009 12:01 pm

The advantage of the "just a name" RC40 as I see it is a much freer flowing than standard BMC system, and yet not offensively loud like some aftermarket systems are. Having heard some of the "big bore" systems on mini's with even fancier names, I am happy to not be setting car alarms off as I go down the road!
I studied exhaust acoustics a fair bit in the long distant past, regarding filtering of particular frequencies, and having spent countless hours pursuing quietness and flow for a particular engine type, I am happy to pay a small price(~£50) for an RC40 system, as opposed to an extortionate price for something with a trendier name tag and chromey tailpipe(s)!

Post by **superchargedfool** » Thu Jul 09, 2009 12:48 pm

I think we all know that big name and or big price doesn't always guarantee satisfaction.

Excuse my ignorance here but isn't an rc40 for mini's? Can you get one for a moggy then?

Post by **bmcecosse** » Thu Jul 09, 2009 1:10 pm

I just made myself a larger bore exhaust for the Traveller - using a new old stock straight through Cooper S silencer (£3 on ebay - local pick-up!) and a 3 branch manifold. It's quite loud - but not too bad - sadly though, despite keeping the silencer under the passenger's feet - I've lost the trumpet!