• Peter S30
    7 April 2008 at 08:24 #47254

    Here is an image of the 3litre now companion of my V12. I bought it knowing about the problem with the motor, but not knowing yet how much of a problem it will be.

    The second image shows a look into the oil and water: brownish-oily in the water and white emulsion in the oil. Head gasket or crack in block or head, or the wet liners lower end seal ? :help:

    I was told that ompression of number 6 cylinder is low , I will measure how low and how the others are. I hope for a combination of wet liner seals plus head gasket. But I think the motor is ready annywhay for a complete overhaul.

    Tips on the topic welcome (repair manuals, what to avoid, specialties on this motor..)


    Attached files

    7 April 2008 at 21:17 #47256

    Hi Peter, Could be as you have said ,do you know if the head has been off. other sources valve guides .If you care to send me your email address i will try to help further John.
    woodyward@hotmail. co.uk

    Peter S30
    14 April 2008 at 20:28 #47268

    Hi John and others,

    After making an adapter for my compression tester (I was surprised by the nice little spark plug with M10 thread, like from a model plane) I have now measured compression and found from cylinder 6 to 1:
    4, 4, 8, 4, 8, 8
    Now I am going to get the workshop manual (source found) and a head gasket (good/cheap supplier?) and then try to take the head off. I do not hope to much that it is only the gasket but would be good to have it.
    Useful other tests suggested before that ? May be compression test with oil sprayed in to compare and see if low compression comes form piston rings or the head ?

    Enough questions for today

    Peter S30
    8 May 2008 at 10:51 #47342

    not a reply to myself but the continuation of the story:

    the head is now off. Don?t forget the two heating pipes to the inlet manifold ! also dont put the rope for pulling off the head around them (guess what I did) 😀

    here are some impressions from the action and a look insite. More inspection to come: the valves look quite bad and coked. The liners look ok only number 5 has some rust (because of the water in oil). Now I will make the down-holding device to the liners before turning the engine and see the other cylinders. I am tempted only to give the head to be refurbished and leave the rest of the engine.

    Impressive how little space there is for the head gasket to seal between cylinders 1/2, 3/4, 5/6 !

    Suggestions whether or not to enamel the exhaust manifold ? it looks like it originally was. Paint the inlet manifold ?

    Attached files

    Peter Reeves
    9 May 2008 at 15:00 #47343

    Hi Peter
    1. How was it getting the engine out?
    2. I would have the bores checked and if possible replace the piston rings.
    3. Yes to the head including valves, seats, seals and other part of the head.
    4. Now to me an important part. Descale flush, flush and flush again as much of the engine and other parts of the cooling system as you can. These engines are prone to running HOT!
    5. Exhaust. If I did my engine again I thing I may have the exhaust manifold bound in heat tape before putting it back in the car. It gets very hot under the bonnet and this may help cooling?? But this is open to discussion!
    6. Have a look at the front of the engine by the distributer area they are prone to leak oil change gaskets as necessary.
    7. Have a look at the water pump impellor and again clean out any sediment/scale as required

    Colin M34
    9 May 2008 at 18:57 #47344

    Hi Guys,

    Peter, good luck with your engine work.

    I would like to pick up Reevsy ‘s point about recommending the binding of the exhaust manifold with heat tape. I think this is an excellent idea! As many of you know, M45s also get a little hot under the bonnet and I have attached a photo showing how I have bound mine.

    The heat tape I used came from a company called “car builder solutions.” Their web site is http://www.nfauto.co.uk/


    Colin M35

    Attached files

    Peter Reeves
    9 May 2008 at 20:52 #47345

    Hi Collin.
    With binding your exhaust outlet as you have, did you have to put any extra shielding to the under body of the car to protect against excessive exhaust heat?


    Colin M34
    10 May 2008 at 12:21 #47346

    Hi Peter,

    I have not bothered so far, though when the restoration is complete and I start using the M45, I will keep a look out for warm passenger’s feet!

    Actually, the M45 the silencer is in quite a flow of air so I don’t think it should matter.


    Peter S30
    13 May 2008 at 06:22 #47347

    Hi, thank you for ideas and recommendations

    1. the engine is not yet out, so far I only took the head off, not shure yet, if I will take the engine out and how (removing front end of body or not, remove with gearbox or leave that in)

    2. one of the wet liners (number 4) protrudes the block by about 0.15mm (0.006inch). It is not possible to knock it in (with an aluminium block in between not to damage it). I wonder if the head gasket can compensate for this and why it is higher than the rest of the wet liners, which are all flat with the block.


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