MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

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 Midget and Sprite Technical - Engine rattle on start up

My 1500 engine rattles badly on initial start up when it's been standing for a couple of days without being run. It only rattles for about a second or two, I presume until the oil gets round. It seems to be coming from the rockers although I cannot be certain it's not the little ends. It's fine and quiet after the initial start up and if I run it every day it's not as bad.

I'm thinking the oil is draining from the rockers back in to the sump when the engine is switched off but can't work out why or how to correct it. I'm keeping my fingers crossed that it's nothing too serious.
Eamonn Spencer

Not draining from the rockers, rather from the oil fi9lter. The filter drainback valve is dead or missing. New filter, possibly of a different spec or brand.
Noise is rod bearings without oil.

FRM
FR Millmore

I recently bought a new oil filter from MGOC and I asked about anti drian back and got the reploy that its a std filter they would supply.

When I looked it doesn't have anything to prevent oil drianing out - I think there should be a flap of some sort - can anyone confirm this and where to get one...?
John Barber

I use NAPA Gold filters on my 1500, and the anti-drainback fitting... a rubber ring just inside the holes in the base... is standard equipment. That's where you'll see the drainback prevention, anyway.

-:G:-
Gryf Ketcherside

As a temporary work-around, you could try spinning the engine around without the choke, such that it spins for ~3 secs or so without starting... this will help by pumping the oil around...

A
Anthony Cutler

Mine was doing that - because it had run its big end bearings.

I hope its not that for you though.

Have you checked what oil pressure you are getting when the engine gets to temp?

C L Carter

Thanks guys, I've tried spinning the engine without the choke and this seems to reduce the noise but does not eliminate it. I suppose the easiest (and cheapest) starting point is the filter, It's due a service anyway. I may be burying my head in the sand a little, but surely if it was the big or little ends going, i'd get the noise all of the time?
Eamonn Spencer

yes, just bear in mind there's more to a full service than an oil change and that some new parts are so poorly made you're better off clean up and keeping some existing parts as the new ones can introduce faults

as we've not had it for a while - the Driver's Handbook lists all that goes into a proper service and tells you how to do it
Nigel Atkins

When I bought my 1500 midget about 11 years ago, it had been running before I arrived to check it over so I couldn't tell if it was OK at start up or not, noise wise.
The oil pressure was fine though.

The next day though it gave the rattle noise on first start, but after that during that day the oil pressure remained fine and the engine ran perfectly well, and started quietly thereafter.

The next day, same rattles.

I then fitted an oil cooler and while at it I put on a remote housing for the filter so that it would hang vertically to prevent oil draining from it overnight. (I had already tried a filter with the rubber "non drain" flaps which made no difference).

The noise was still apparent after the fitting of the cooler and remote housing for the filter.

I then changed the big end bearing shells and thrust washers but that didn't help either, start up noise wise, which could mean the crank journals are worn, but the oil pressure is nominal at speed and idle which would tend to disprove that.

I then changed to using Halfords "Classic" oil and I haven't heard the rattles since.

Of course it could just be me, or my particular engine, or some other strange intervention, and it may not work for anyone else.

But it did for me.

I have done about 35000 miles since I first heard the rattles, and they probably had been there for a long time prior to that but I didn't own the car, and about 5000miles since I changed the bearings.

I do tend to keep the revs below 3000 as the engine looks so weak inside I don't like to over-stress it.

It is a characteristic of these engines, that some have a dry start rattle due to oil drain back, and that particular oil seems to lessen the effect.
JB Anderson

This thread was discussed between 18/05/2012 and 21/05/2012

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.