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MG Midget and Sprite Technical - mg midget 1500 engine rebuild

Hi all ,

ive just bought a second hand midget 1500 engine . Im looking to have it stripped down and rebuilt replacing worn out parts on the way . I'd also like the engine block dipped and repainted . Its currently fitted with an oil cooler .
I would be interested in any suggestions for slight modifications that i could have done in the process to make it a better engine .
Could anyone recommend someone to do the rebuild for me ?
Any idea of the approx cost ?

thanks

Dave
D Stratton

Get Deb to do it, the 1500 oracle!

Modifications and cost both depend on how much you are willing to spend! :-)

From what I have read I think the reliablity of the 1500 is improved by balancing everything and fitting an oil cooler (already done). Power I think can be improved simply by fitting K and N air filters and a tubular exhaust manifold.

Sure people will be along with more 'precise' advice.

I will follow this thread closely as I am considering my options for my 1500 at the moment.

Cheers,
Malcolm
M Le Chevalier

Cost would be dependent upon what you want of the engine.

For a fully spammed up 1500 in Fast Road guise with full bottom and top end modifications for reliability and longevity, and giving around 110Bhp + 95 ft.Lbs you are looking at between 2500 - 3000 GBP.

Deborah Evans

Hi Deb ,

sounds good :)

When you say fully spammed up , what modifications / extras would be done / added?
if i was just interested in the engine being restored to how it would have been straight out of the factory with maybe only slight mods for slight increase in performance /reliability then what sort of figure would i be looking at ?

The thought of having a fire breathing dragon under the bonnet sounds good but i use the midget as my main mode of transport and its mainly town driving so i dont think i would see the benefit of a full on tune

Dave
D Stratton

Fully spammed includes:

Top End:

Gas Flowed Cylinder Head with enlarged exhaust valves.
PB Inlet valve guides, Colsibro exhaust valve guides, hardened valve seats
Flowed Inlet Manifold
Tubular 4-2-1 exhaust manifold
Manifolds port matched and doweled to cylinder head.
Replacement rocker shaft, rockers and machined spacers
Uprated valve springs with correctly machined replacement spring seats
Tubular push rods
Replacement cam followers with oil drain holes
New Fast road cam (NOT a regrind)
Supply and fit camshaft bearings (as per small crank 1300 motor)
Duplex Vernier timing gear
Cylinder head top face modified to prevent oil puddling at top end
Correctly set up rocker oil feed
Cylinder Head skimmed to provide 10.5:1 CR
Carbs re-jetted to fixed jets and set up with correct needles/ram pipes/filters

Bottom End:

Strip Block and clean
Strip and replace core plugs
Crank regrind as necessary and set up for wider Big End Bearings
Oil supply to No 2 Main Bearing improved
Overbore as required
Deck block to remove bore recesses, equalise piston heights
Dynamically Balance Crank/Flywheel/Clutch/Front pulley
Lighten, Balance and polish con rods. Cx for straightness
Balance con rods end to end and overall to +/- 0.1g
Replacement pistons and rings
Replacement tri-metal Big End and Main bearings
Replacement Little Ends as required
Supply and fit ARP rod bolts, head studs, flywheel bolts
Supply uprated Main Cap fasteners
All other studs/bolts/nuts etc replaced with new.
Replace oil pump with new (angled pick up type)
Baffle sump

Sundries:
Gaskets/oil seals
Oil filter
Cx water pump and replace as necessary
Alloy engine back-plate
Clutch plate and cover
Coolant pipes (flexible)
Uprated oil low pressure switch
Oil pressure release valve and spring
Oil
OAT coolant
Fit engine
Set up static timing and basic mixture
Carry out first start up and bed cam correctly
Re-Time dynamically and adjust mixture



For a 'stock' motor you'd save on the cost of doing the cylinder head/manifolds (aside from fitting new stock valve guides and uprated valve seats)and the cost of things like vernier timing gear.

However replacement stock items eg cam shaft (if required) would cost little less than uprated types.

The bottom end work would be the same save polishing and lightening the con-rods.

The trick to reliability and longevity with a 1500 is all about putting the bottom end together well, having it all correctly balanced, and ensuring the oil system is top notch.

I do not recommend using currently available 'stock' bottom end fasteners since these are 'monkey metal' and I have seen numerous failures. Additionally Tri-Metal bearings are ESSENTIAL in the 1500.


So, for a 'stock' 1500 you'd be looking at around 1500 - 2000 GBP dependent upon what needs replaced and machined (eg re-bore/pnew pistons and rings).











Deborah Evans

Hi Deb ,

thanks for your replies . Looks like i'll be saving for the fully spammed work :)

What sort of notice would you need for me to book it in for the work ?

Dave
D Stratton

Dave,

I'm in the process of moving house just now (and between workshops).

With the other commitments I have, the earliest I could start would be around mid September.
Deborah Evans

that would give me enough time to get the readies together .Shall i contact you nearer the time to arrange ?
D Stratton

Please do :)
Deborah Evans

Deb ,

what would be the best number to contact you on ?
D Stratton

Dave,

Drop me an EMail and I'll send you the number.

Owing to the spam I get I don't want to put the phone no out here. I already get FAR too many unsolicited calls from overseas as it is!
Deborah Evans

This thread was discussed between 27/05/2011 and 06/06/2011

MG Midget and Sprite Technical index

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