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MG MGF Technical - My 2nd HGF - More...

Hi
I'm told (I haven't seen it first hand yet) that the replacement gasket fitted 6k miles ago failed this time at no. 4 cylinder.

apparently it hadn't 'gone bigtime' but just showed traces of the moisture and definite antifreeze where it shouldn't be.

this is unusual right? Its usually near number 1 where the failure occurs?

Julian
Julian


Hi Julian,
sure the gasket is being viewed right way around ;) ? If so it is probably a "new" place for the gasket to open up to the outside world...Hopefully all 4 liners are of equal height and not disturbed during the work.
If possible let us have a pict. of the gasket.

Regards , Carl.
Carl

I will try and get a pic.

I did ask which end it had gone to make sure his idea of number 4 was the same - gearbox end apparently.

Is this the "same no. 4"?
Julian

No 4 is indeed the gearbox end. I also wonder if the head bolts were checked before reuse and if they were in spec. Having been taking an 1800 K engine to pieces yesterday which has had a recent gasket change and steel dowels, I noted that the usual area of elastomeric stripo was weakening and pending failing. I also found no signs of antifreeze and recent corrosion was clearly visible.

I also found that several of the through bolts would hand tighten right down to the end of their thread whilst 3 others were locking out outside what I regard as serviceable and all certainly right in the area of 97mm measured height between block face and underside of bolt head. This smacks to me of uneven previous tightening of the bolts and that the bolts by where the gasket was weak was also where the bolts all went to the the end of their threads.

It seems that this engine, which was running well before the accident that placed it in the second hand spares market, was probably running with under torqued bolts and so the clamping load on the engine sandwich was less than it should have been. On the other hand those three bolts that had stretched may have been so stretched before refitting last time. Whatever the many conotations of what has happened it shows that the potential for less than ideal previous work isn't accounted for enough when repeat failures occur, yet this and not any design or part quality is the cause of the second failure.

Rog
Roger Parker

This could be a inlet gasket failure on 1 or 4 . This was a recent failure on a VVC in the shop, the inlet manifold had a slight twist in the mating face coupled with a slight casting defect on the block face ,almost immpossible to see and could easily be missed ,as I did. Have the manifold face checked for alignment and reface if required and check block face, torque bolts/nuts carefully and in correct sequence, the standard VVC gasket is a bit weak,IMO, so I usually help this seal with some 'wellseal' solution.HTH
Mike.
mike

Roger, all of the stretch bolt were replaced after the failure.

I saw the gasket last night and I couldn't see anything wrong with it although I was assured that it had "gone just there - look, can't you see? Just a gnats cock but its gone". No I couldn't see it really, but I'm not used to looing at them.

Mike - I will take a pic of the gasket (which I have kept) and post it. You can pass judgement!

Julian
Julian

And another thing - having got the HG fixed late last night and re-bled this morning for safe measure, I now cannot start the car as the starter motor has gone!

bizarre coincidence or what? It frightened the life out of me too as it made a terrible noise and with all the work I've just had done on the engine I obviously feared the worst! Phew.

All ok though as that was the third thing to happen as my girlfriends window smashed on the way to work this morning.

So nothing else could possible go wrong now...
Julian


Hi Julian,
have the starter grounding cable checked at both ends. The starter is NOT grounded via the engine block but via a fairly thick black cable that is prone to corrosion at least at the boot end. This can give machinegun sound when You try to start the engine...

Regards , Carl.
Carl

Thanks Carl
I'll make sure I check that out before whipping out the engine...!

Cheers

Julian
Julian

This thread was discussed between 17/04/2002 and 19/04/2002

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