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MG MGA - Serious engine problem

I was out for a run this afternoon - running along in 4th gear (4,500 rpm), good oil pressure and engine temperature spot on when there was a sudden loss of power and an almighty clattering from the engine!! It sounds pretty terminal.

I've done about 100 miles since completing my start of summer service (engine, gearbox and axle oil change, filters, plugs etc.). When the recovery guy came out to tow me home we noticed the oil filter was not on that tight and was leaking a bit of oil under pressure when the engine was running. On checking the oil level I had lost some, but the dipstick was still reading above the minimum mark and I still have oil pressure.

I fear a big end has gone (or something like that) and I now face an expensive engine rebuild. No doubt the garage will give me the bad news when they check things over next week. One nagging doubt though, could a slightly loose oil filter canister (the OE type not a modern screw in cateridge) cause oil stavation and serious damage to the engine or is it just coincidence? My A is a 1600 Mk1 and has done about 3,000 miles since a total nut and bolt rebuild in the early 90's.

I would really welcome any thoughts/views/consolation in my hour of misery from the many experts who contribute here.

Thanks, Peter
P Wright

You won't really find out what has happened until you start to dismantle - however it could be something as simple as the timing chain jumping off the sprocket - happened to my midget and also to my son's Metro .
It is possible that a leak from the oil filter could cause a drop in oil pressure but you would probably have noticed that drop before the engine went bang.
Hope it not a big or small end that has broken and damaged the bores - good luck - Cam
Cam Cunningham

Cam, thanks for the thoughts. As you say, I'll have to wait and see - will let you know. Peter
P Wright

P Wright, -- Loss of power along with the noise indicates loss of combustion pressure on one cylinder. I presume from your brief description that it did keep running until you shut it off. With no other information to go on my best guess would be it dropped the head off an exhaust valve, punched a hole in a piston, and dinged the valve seat slightly. Been there a couple of times.

This is usually not a terribly expensive repair, assuming you can buy one matching piston, and a new valve and some gaskets. No machining required (maybe), just R&R the head and oil pan to pull a con-rod, change a piston, and (if lucky) lap in a new valve to clean up the valve seat. Cross your fingers, it might be worse.
Barney Gaylord

Barney - Yes, it kept running. Thanks you for input (despite my brief explanation), helpful as ever. I have not had a chance to follow up on things this week so I'm hoping to get someone to look at it properly next week. I'll update here when I find out more. R, Peter
P Wright

This thread was discussed between 08/06/2008 and 14/06/2008

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