MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - 948 (bored to 998) build up!

Yes, that's right - finally reassembling my new engine!

A few piccies etc will probably follow later, but have a few quick questions:

998 rods - these seem to want to fit a different way round to the regular 948 rods. Presumably not a problem? We can't find the old pistons & rods to compare them....

Also, can anyone tell me where I can get a new engine number plate (both plate & rivets) and also stamped up correctly (I believe it should be stamped from behind), as the plate has gone missing too.

Water pump - using an unleaded 998 head, so no bypass hose fitting. Which pump should I use?

And lastly - there seem to be several different types of oil filter adaptor, to take a modern filter (I've had enough of changing the old type filters) but a new type I've seen recently is simply an adaptor plate that bolts to the existing filter housing. Does anyone have any experience of these? I'm very tempted as then I can still use the angled filter housing.

Thanks! :-)
Paul H

When will it be finished (Drivable)Paul?
G Lazarus

Sadly not in time for Spridget 50, but I hope to trailer it along anyway behind the Amazon
Paul H

Spin on filters were fitted to later Sprites and minis so the housings are available either new or secondhand. Do use the 948 spacer as it makes changing filters easier.

I would guess that you use a 948 water pump. Tap the bypass 3/8 UNF and screw a cut off bolt ( with a touch of sealant ) into it to blank.
Alan Anstead

Engine number plates - pressed numbers from below + special fixings can be obtained from

Minimail
01989 720111
minimail.co.uk

Richard.
richard boobier

I've done a similar conversion to you with my 948 but don't remember any issues with the rods.

I used a 1300 water pump with the cast impeller from Mini Spares, the ones with the pressed plate ones are rubbish. The only thing to watch is that it may catch the block, a quick buzz with a grind stone should sort that.

I have also 'upgraded' to the Mini filter head, still using the 948 spacer. The only issue I had was that the pipe from the block to the header had to be bent quite a bit to get it to fit, something I'm not 100% happy with.

When the bypass is removed it's common practise to drill a few holes in the thermostat to keep water moving round the block when it's closed.
Andy Barrass

Thanks all!

Regarding the filter, I was thinking of the type that is simply an adaptor plate that replaces the canister, so that the modern filter can be fitted - like this:

http://cgi.ebay.co.uk/MG-midget-SPRITE-BMC-A-SERIES-SPIN-ON-OIL-FILTER-KIT_W0QQitemZ150231721838

Are these worth using or not?

Re: the rods, didn't know that they were offset, hence the fun & games until we realised! After that, fitting the pistons went smoothly.

Got as far as crank, piston, rods, cam & oil pump all installed. The pump that came with the SW5 cam wouldn't fit under the backplate, so part of the pump housing & also the backplate were relieved as appropriate by my brother. Would have got further but the duplex kit was missing the countersunk screws for the front plate, so couldn't go any further at the front of the engine.

Most other parts are degreased & ready for the reassembly.

A few quick questions about the head - using a factory unleaded 998 one. This only has single valve springs though - is it worth fitting the double springs from the original head?

Can the 998 head be drilled for the heater tap? There is a 2 or 3mm deep recess in the casting where the water way would be.


Paul H

for the filter, the aftermarket kit has more joints so more to leak or go wrong.
This would have been cheaper for you, and is the right part
http://tinyurl.com/67empm
David Smith(davidDOTsmithATstonesDOTcom

Paul,

For the oil filter a standard later Mini spin-off filter head, as David's eBay link shows is the simplest fit.

Richard
Richard Wale

Thanks guys!

Anyone able to advise about drilling the head for the heater valve / tap?
Paul H

Hi Paul,
I am interested in each information concerning transforming a 948 to a 998cc.
I want to modify my engine with big valves on a 12G202 head + SW5-07 cam.
But for the bore, I was asking myself about reboring the block to 998cc with hight ratio pistons. But no idea concerning the rods, the crank and the oil pump.
This engine is not for racing, just to have more torque and to be used in a Ashley Coupe MKI Midget.
laurent
laurent

Laurent 998 is 948 + 60. The blocks can be then taken out to 998 +60 which is what I have. I also have a 202 head but with 88G229 camshaft & twin 1.25 S.U.s
Rolling roas shows 62 BHP.
Alan Anstead

Thanks Alan. So I do not have to change a lot of thinks on my engine.
88G229 or if I am lucky, an MG Metro cam.
laurent
laurent

You'll also need the right conrods, depending on which type of 998 pistons you use. The original 948 rods have a pinch bolt little end, and aren't compatible with the 998 pistons. From what I was advised at the time when my engine was bored out, the original 948 rods are best binned anyway.

The oil pump I'm using came with the cam (SW5) but fouled the cover on the engine back plate (solved by removing some excess metal from both).

BTW, IIRC 948 to 998 is + 66 thou


Alan - is that wheel hp or flywheel hp?
Paul H

Somewhere I have the correct adaptor threaded unions to take oil from the banjo bolt area and run it straight through a pipe to the remote filter canister and then I have made (and have some spare) alloy blocks to take adaptors that bolt onto the block in the same way as the Midget filter assembly but just have a single 1/2BSP (?) threaded adaptor. Not easy to find the top union but the bottom union is simple to make.
[Not well described, but y'know what I mean]
Want pics?
rob multi-sheds thomas

62BHP at the flywheel..Soon to fit a sierra 5 speed gearbox.
Alan Anstead

This thread was discussed between 05/04/2008 and 07/05/2008

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.