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1098 - Marina - MG Metro conversion

Posted: Wed Sep 02, 2009 2:04 am
by kiwimc
Greetings minor enthusiasts from the other side of the world.

My morry steeds are a '59 4 door in near original condition and a '67 van currently awaiting reassembly after a bare-metal respray. You can't rush these things, but after 11 years (a family and house building) I am starting to get excited about putting it back together again.
It is powered by a "1300 Super" marina conversion. My research suggests this has the same cam and head as a spridget (correct me if I'm wrong), but the advantage of a single carb. Indeed, there was a vast improvement upon performing the re-power from 1098cc.
NZ never imported the Ital (so no Minor - Ital conversions over here), but in my garage tantalisingly sits an MG Metro engine.

My questions are:
1. Can I expect any problems transplanting the A+ head (alloy rocker cover, big carb and nice manifolds) onto my Marina block?

2. Anecdotally the MG Metro cam is the ultimate blend of performance and usability. Should I transplant it too? Any technical hitches to expect?

3. Out of interest, what is the difference below the head between Marina (which I have) and Ital (which I don't)?

4. The rest of my transmission is a reconditioned 1098 gearbox and standard (I believe) rear diff. If I'm not 'silly' can I enjoy the extra horsepower without snapping anything?

The Marina conversion I performed myself. For such a 'straight-forward' transplant there sure were a lot of little things to do. Most things I was prepared for, the two that caught me out were the constantly meshed starter in ring gear (luckily discovered before firing up) and the new bell-housing locater dowel larger than the original hole.

I'm sure the answers to some, perhaps all these questions are in the 100 000 forum postings, but there are not enough hours in the day to read them all...<br>Image<br>

Posted: Wed Sep 02, 2009 7:59 am
by RobThomas
1. Bolts straight on. You'll possibly find that it doesn't have a water bypass stub that mates to the waterpump. Either drill and tap a stub pipe into the head or block the one on the waterpump.

2. Cam is good. Watch that you don't have the duplex chain sprockets fouling on the timing cover. Quite a few different variations available and ensure you have a breather there. Countersink the 2 screws that hold the front plate onto the block just below the bottom chain sprocket. Sticky-out bolts on single chain, countersunk on Duplex.

3. Block is OK but the main bearing caps are different. Much machining required plus the drilling for the oilpump pick-up pipe is not tapped. Hard work but still possible if no Marina/Itals to be found. Quite a few MG Midget experts in the Antips do this to Metro engines.

4. Should be OK. I've never broken one.

Posted: Wed Sep 02, 2009 8:29 am
by bmcecosse
Welcome to the forum! Great looking cars. The MG head may be no different although it will sport double springs! Later MG Metros just used the standard small valve head - to be 'unleaded'. Only the earlier 'leaded' engines had the larger inlet valve. Both heads benefit greatly from some work in the valve throats - especially down the exhaust throats where the gases have to turn the sharp corner. Use the MG water pump if the head has no bypass connection - and simply drill 1 x 1/8" hole in the rim of the thermostat to allow ater to circulate during warm-up. The MG cam is magnificent - be sure to use the correct oil pump to match it - and take the cam followers (in correct order) over with the cam - although do inspect them carefully and reject any with pitting. The MG Metro doesn't have (or need) a 'duplex' timing chain - it does have the proper rubber tensioner version of the single chain, and if your engine doesn't have this then transpant it over. The Metro crank is obviously no use to you, and the block will need loads of work to modify it - mainly the rear main bearing where it has no 'seal'. MG Metro pistons are slightly taller and give a higher compression ratio - you could consider transplanting them. The larger carb and inlet manifold are excellent, the exhaust manifold can be used if you can fabricate up a system to match and fit the Minor - but probably easier to use a manifold intended for the Minor. A lower (numerically) final drive ratio makes a huge improvement - 3.7 is the best, but 3.9 is a close second. Source from Spridgets !

Posted: Wed Sep 02, 2009 10:03 am
by Peetee
The Marina and Ital blocks are a bit of a misnomer. Technically speaking the difference is A and A+. The change happened around about the same time as the change from Marina to Ital although as with any model change there was some production run-out from one to the other.
The engines can be distinguished by the casting of the block itself. A is plain A+ ribbed. The A+ is reputedly a stronger unit although, by now, condition of an individual unit, whichever it be, is of more significance.
Oh and here's a useful thread:
http://www.morrisminoroc.co.uk/index.ph ... tal+marina