MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

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 MGF Technical - Thermostat and drilling

I thought I would chance my luck and post a thread not slating MGR.
Anyway the mod of drilling a 2-4mm hole in the thermostat seems to be one of the best things you can do for the K. Especially in the F. My car now warms up much the same as any other car I have owned ie slower. It is that much slower that the oil temp is getting on for between 60-90 degrees. A good balance me thinks.

Obviously no good for emmisions and the like however as pointed out it will stop the head being thermally shocked.

See I can post a non nasty MGR thread. Even better if MGR give me half the cost of a new engine I might even be nice to them.
S.laithwaite

Unfortunately, thermal cycling continues with the thermostat ring drilled Stephen - but you are absolutely right, the amplitude of the oscillations is much less - and the reason why our Motorsport racing colleagues perform this mod :o)

Money out of MGR? blood and stone are the two key words of a phrase that springs to mind... ;o)
Rob Bell

>> Even better if MGR give me half the cost of a new engine I might even be nice to them <<

I didn't get it when i needed a new one, why should you? ;-)

SF
Scarlet Fever

Hi,

I've bought a new spec Thermostat in last week from a German Elise driver. Haven't found the time to investigate finally, but it includes the new tiny extra valve which probably does a similar 'bypass'.

I'll do some pics and get back later this weekend with it.

It's as well 82°C instead of the standard 88° C.

Dieter K.

Andrew when did you replace yours and for what reason ? I will be taking the bottom end of my old one next week and will take pics when I finally discover what went wrong.

I must stress that the engine was never thrashed unless you consider the very occasional 5000 rpm excessive.
S Laithwaite

Stephen,
Do you have the K-engine manual?
what do you expect to find in the bottom end?
Will Munns

Will

I have the workshop manual for the car but not a detailed manual for the K. I really don't know what I am going to find in the bottom end. However a very quick inspection of the engine last week with the head off revealed little. That is, and I am going to shoot myself in the foot here, the head gasket was okay. No liners were split at the top anyway and no piston had a hole in them. I was suspecting one of the afore mentioned and was a little surprised not to see any of them

The symptoms of the engine failure were.


1 Loss of water, not alot as it turned out only the contents of the expansion tank.

2 Mixing of oil and water

3 Expulsion of the mixture of oil and water via the in let manifold thru to the air box. In addition further expulsion via the exhaust manifold resulting in an almighty amount of smoke.

I hope I am not coming across as somebody who thinks he knows a lot about these engines. However I am determined to find out what happened if for no other reason that this engine was treated with the upmost respect. And of course consideration to rebuilding it with new liners and pistons etc.

Oh btw the head gasket was located on steel dowels and the inlet manifold gasket was of the new type. I assume these were fitted following original HGF in 2001 mileage 29,000.

Any ideas ?











S Laithwaite

You are unlightly to find much in the bottom end, except oily bits

The Elise manual contains the K manual, it's what I used for stripdown and rebuild (note, some special 'tools' 'required' during stripdown if you decide to put it back together):

http://www.brooke-kensington.co.uk/misc/Elise%20Service%20Manual%20-%20indexed.pdf

>Expulsion of the mixture of oil and water via the in
>let manifold thru to the air box. In addition further
>expulsion via the exhaust manifold resulting in an
>almighty amount of smoke.

It could be your liners have been disturbed (see tools required!) they are gooed into place and could have been disturbed by someone moving the crank during HGF repair, this would lead to water seeping past the liner and into the oil, as the oil gets hot the water evaporates and vapor is passed thru the engine and out of the breater tubes in the head, these lead to the throttlebody, and hence the airfilter and sucked into the engine and hence the exaust manifold. Unfortunatly I don't think that you will be able to actually see the seepage without putting the head back on and pressurizing the water jacket.
Will Munns

Thank you for the reply Will.

Everything you say makes a lot of sense. The only thing is I put 60,000 miles on the car since original HGF and all was well apart from a little excessive water consumption.

You mentioned that the liners are " gooed into place ". I was fit to remove liner no 2 by hand. Is this normal As none of the rest of them would shift. Don't worry it was removed carefully.

I don't want to drift, however during the Summer I did have a bad omen when I checked the coolant and noticed an oily film on the top of the coolant. I knew then that something was going on and I suppose was waiting for the inevitable.

S Laithwaite

>You mentioned that the liners are " gooed into place ". I was fit to remove liner no 2 by hand.

I think you know where the problem was then! 8-)

It could be that the small amount of water loss was seapage past the goo, and this boiled off in the normal way (a small amount of water/petrol vapour is expected from the oil, thats why the breather pipes are there!) but over time the seapage got worse, destroying the goo and giving your symptoms.

You're mant to be careful about not moving the liners, so if you plan to reassemble then you'll need to re-goo all the liners and make up some liner clamps. As you have disturbed the liners then have a look around the bottom end, take care not to get dirt into the oil passageways or on the bearing surfaces, also make sure you keep track of which bearing shells/caps/bolts etc. fit which holes (exactly which holes)
Will Munns

Cheers Will. Very helpful info. When money permits I guess I will rebuild.
S Laithwaite

>> I've bought a new spec Thermostat in last week from a German Elise driver. Haven't found the time to investigate finally, but it includes the new tiny extra valve which probably does a similar 'bypass'. <<

Now that's interesting Dieter - what thermostat have you purchase? The new pressure sensing system? Are you planning on installing it in the MGF's standard thermostat housing?

Interesting!
Rob Bell

>I didn't get it when i needed a new one, why should you? ;-)

I did nerr neeer!
Neil W

Eh ?
S Laithwaite

This thread was discussed between 23/10/2003 and 24/10/2003

MG MGF Technical index

This thread is from the archives. Join the live MG MGF Technical BBS now