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MG MGB Technical - 18gh to 18v

I have a 1980 LE with 18v engine and has overdrive transmission. I am rebuilding a 1969 gh with the intentions of installing it in the LE. Questions...........

Will the front plate and front cover from the 18v bolt on to gh motor?

Do I need to use the back plate as well for transmission and starter mounting.

Can I get by without oil cooler and use the bypass tube from the 18v.

Thank you

P Harrington

Can't comment on the rest, but you can certainly do away with the oil cooler. With modern oils, I'm convinced you don't need it and with it run the risk of overcooling. I've been running my '69 without one for some time now....

BTW, I'm using a bypass hose but would like to find a bypass metal line, if you happen to have an extra! ;-)
Rob Edwards

The rear plate is the same on both engines, but the front plates will need to be switched. There may be some surfaces, on the front of the '69 block, that may need to be filed down a little to allow proper seating of the front plate. RAY
rjm RAY

The GH motor is precisely the one I am also rebuilding. Your are right Ray, the back plate is the same, but the front plate, I presume you mean the timing chain cover will be different as the GH engine uses a duplex chain, whereas later 18V engines went to simplex ( single row.? ) Am I right? I have not started stripping yet to find out! It also has double valve springs i have seen that already. My 18V has single springs, if you are going to higher revolutions you will probably want double springs, to avoid valve bounce and other associated nasties! Mike
J.M. Doust

Thanks guys,

Just to clarify, the 18v front plate ( that the engine mounts attach to ) will accept the timing chain cover from the GH motor.

P Harrington

The oil cooler was originally optional, and as long as you can accept lower oil pressures in hot weather or hard use then it will be fine without. I'm convinced the factory started fitting it as standard to allay owners fears regarding oil pressure, even though the same thing happens when stuck in traffic regardless.
PaulH Solihull

As an addition to this thread, I am running my GT without an oil cooler here in Queensland. I have not noticed any actual drop in oil pressure. On start-up the pressure shoots up very quickly to 60 or 70 lbs per square inch, and when warm, settles to around 60 or a little below. As the revs rise though, up goes the pressure, so I am happy. Peter Burgess does mention that overcooling the oil is not good, as draws more power( pump works harder), and actually causes more wear. Still I would like to put an oil cooler back on when the car is supercharged, but intend to use a thermostat. Where can I get one of these, and how would it fit? PS, of late the weather in Queensland is actually cold and very wet, just like Europe being very cold and snowy, what is happening to the worlds climate? Mike
J.M. Doust

5 years ago I purchased my oil cooler thermostat and stainless steel hose kit from Moss. It works extremely well and the engine warms almost instantly. I felt that, like you, with a supercharged engine the oil cooler was a goo bit of insurance. The kit is manufactured in England by Mogul. RAY
rjm RAY

Front plates are different, front timing cover is the same duplex and simplex chains are interchangeable under the one cover. The only difference in front covers from my experience is one has the provision for the later type oil seal and the older one is for the felt type seal and perhaps the timing marks for the front pulley. If they are different in other ways I have never noticed.

Oil cooler is terrific, only had one a couple of years but makes a big difference to when the temps climb. Here in Melbourne we can get Summer temps in the mid 30's to low 40's. I used to panic getting stuck in traffic that the car would over heat. With the oil cooler, it gets hot still but seems to be able to sustain it. It was either a new ally rad or the oil cooler. Oil cooler made the diff.

A J Ogilvie

Just to mention that the timing marks are in different positions on the two engines.

Ste Brown

I advise changing the frony engine plate. If you don't,you will find the "round" engine mounts in the LE won't accept the older front plate.
JR Ross

This thread was discussed between 16/12/2010 and 24/12/2010

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