sudden rattle under acceleration

[kissncrate]

My 1275 engined 2 door has been smooth as silk recently then pulling away from a roundabout today she suddenly started rattling under load. Tickover has gone slow (so that she stalled a couple of times) but once cruising at 50 she's fine again. If it was a cylinder not firing it wouldnt smooth out would it? I'm supposed to be going to France with her on Friday - major frustration/embarrasment! My regular knowledgeable mechanic who usually steps in at this point is away as its the holidays.... Help?!

[bmcecosse]

Plenty of oil in the sump? Is the oil pressure good? Obviously the big possible problem is big-ends rattling. Or was it just the light 'tinkle' of pinking ?? Could be the vacuum advance in the dizzy has failed....and/or the mechanical advance has stuck fullly advanced - which could happen if a spring has come off or broken.

[kissncrate]

Plenty of oil in the sump? Is the oil pressure good? Obviously the big possible problem is big-ends rattling. Or was it just the light 'tinkle' of pinking ?? Could be the vacuum advance in the dizzy has failed....and/or the mechanical advance has stuck fullly advanced - which could happen if a spring has come off or broken.

I'll check the oil tomorrow morning. It's a proper rattle not pinking but what puzzles me is that its a commercially refurbished engine thats been fully serviced and only done about 12000 miles since (out of warranty of course!)
Chris

[simmitc]

Check compression - the sound you described could be a head gasket. Unlikely as it goes smooth, but important to check given the symptoms and planned journey.

[bmcecosse]

If it comes on acceleration and is a 'proper rattle' I'm afraid it is the death rattle of the crankshaft........... You do need an oil pressure gauge to make a judgment. " Commercially refurbished " could mean new big end shells and rings - and a coat of paint....

[kissncrate]

Check compression - the sound you described could be a head gasket. Unlikely as it goes smooth, but important to check given the symptoms and planned journey.

Thanks. I'll add it to the list of possibilities...

[kissncrate]

If it comes on acceleration and is a 'proper rattle' I'm afraid it is the death rattle of the crankshaft........... You do need an oil pressure gauge to make a judgment. " Commercially refurbished " could mean new big end shells and rings - and a coat of paint....

Hmm. Possible as the work was done before she came into my possession and I've learned not to set too much store by any work done by the restorer I bought it via.

[kennatt]

Well ,there is a massive difference between one mans idea of an engine rebuild and anothers,but it may not be the shaft,needs an oil pressure check before anything else. Any bets on how long the mod takes to use the edit button

[bmcecosse]

Of with the sump for a look at the centre main and a big-end or two.....

[JOWETTJAVELIN]

Of with the sump for a look at the centre main and a big-end or two.....

May be a bit drastic at this stage for a chap who wants to go to France in it.

We need more info: is this a tinny sound, or a loud hammering/banging sound? Regular or intermittent? Did it start suddenly and if so, when?

Have you checked the oil level daily or at least before and after a long run?

[bmcecosse]

Sump off is 20 minutes at most - then another 5 mins to drop the caps...... All will be revealed.

[bmcecosse]

I would not even run the engine with a 'rattle'.....

[JOWETTJAVELIN]

Aye but we do not know the mechanical capabilities of this chap... when I was packing shim in the bearings I had it down to a fine art ~ 30 mins tops.

The 1275 is a durable engine at the bottom end but not if it has been allowed to run out of oil.

[les]

Roy I do think you exaggerate the speed in which these jobs can be done in. It takes 1/2 hour to open the garage doors and get the tools ready, let alone jack the car and prepare. Then maybe make a start and probably need to get another spanner or such!
Ok if you have an assistant who has the engine cleaned and on a stand waiting to hand you the tools and mop your brow, but in the real world-----

[bmcecosse]

I assume car available and ready to go. Drive it up ramps - slide under with 7/16" AF socket on speed brace - and whizz round undoing the screws.....dropping them in a wee tin. Then wiggle the sump and down it drops! Then access a big end with 9/16" AF socket on ratchet and short extension.... To get at the main would mean dropping the intake filter (hands up -I admit I had forgotten that...) - but not a huge job. Then 5/8" AF socket for the main bolts. Simples !!

[simmitc]

So are we assuming that the sump is already dry, or will you be balancing it full of oil

[bmcecosse]

It's only 4 litres of oil - just keep it in the sump!

[JOWETTJAVELIN]

Something for you to demonstrate at the National, I think, bmce.

[les]

Ever heard of Sods law, Roy?

[bmcecosse]

If the 'national' (???) is in Ecosseland I could do so easily!