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MG MGB Technical - OIL PRESSURE PROBLEM???

2 weeks ago i had my 68 bgt serviced by reputable MG garage. Had engine, gearbox, axle oil change and filter etc.

When i now start the engine the oil pressure takes maybe 2 seconds to come up. Still same as old oil pressure when it does - about 40-45 at idle and 60 driving.

I'm concerned because what used to happen was the oil pressure came up as soon as i turned the car over - instantly. Now there is this 2 second gap. I generally only use the car weekends so is standing in the week. Is this delayed oil pressure doing damage? Do you think a thinner oil has been used from last time? Is it safe to drive or am i damaging my pride and joy!?!
MIKE

Mike,
Its probably due to the oil draining out of you nice clean oil filter. dont worry.
T J Nicolson

Mike,

I started a thread on this a couple of weeks ago, check the archives. In my case, it looks like the Castrol GTX 15w/40 I used (all I could find, Castrol have stoppped making 20w/50 and 15w/50 GTX) is too thin and is draining back past the valve in the oil filter. I have tried a Unipart and a Champion filter, both the same thing - filter empty after standing for a day or so. Mine now takes 5 or 6 seconds to build up pressure as the filter fills back up.

This is certainly doing damage - change as soon as possible! I've found some Duckhams 20w/50 and will be changing to that this weekend. If I were you I would go back to the garage and get them to sort it - ask what oil they used.

Tim.
Tim Jenner

I've found out it was 20/50 oil that went in. What came out i don't know as it was in when i bought the car.

Do you think a faulty filter may have been fitted or was it just the old one was maybe clogged?

Do oils change quality by make? I have been told the new oil is Duckhams 20/50. What was recommended in MGB's originally - was it castrol?

Does anyone think the brand of oil could cause much of a difference?
MIKE

I don't think it's anything to do with the oil or the grade. 15/40 or 20/50, the problem is still there. It's entirely due to the filter IMO. Mounting the filter upside down might be a good idea for access but has left us with this problem. I reckon it's quite hard to find a filter with a decent anti-drainback valve these days. Apparently there is a Volvo brand filter that fits that seems of good quality. There were details in another thread recently. Incidentally, Duckhams 20/50 was one of the recommended oils originally.

Mike
Mike Howlett

Hi Mike
I have had this problem with both Halfords & Champion filters, it seems to be pot luck some are OK some aren't. For all a filter costs I renew it if it drains as these few seconds without oil pressure are bad for the bearings
Ron
r algie

Ref the query on oil quality. Base oils are still very much the same, but the refining processes have mproved, and definitiely the additive packages are far superior in modern oils. However, modern oils are designed for the modern cars, so look for an API SD or SE logo on the oil you use if your engine already has a reasonably high mileage.

The problem with the new filter is that it is not yet sufficiently caked to slow the drain back, and by the sound of it, your old filter would have been gummed with particulate and residue etc.

What I am looking to do on my newly rebuilt engine is find a machine shop to manufacture an insert piece to go between the filter and the housing to stop drain back, as well as to use a better quality filter, that is, a finer pore rating. If I can come with anything I will post back.

Martin.
Martin

Mike
I've been using the Bosch filter on my '79 with no draining problems also the WIX is good too
Pat
patrick bailey

I use the Car-Quest brand filter and have had no problems with drainback. It's just a rebranded Wix filter and the local British car shop had used it for sometime between the crossland and mann filters. If you have the common topload filter it should be a "short ford" style.
Jared Snider

I've just taken the Unipart GFE121 off mine and it was empty (all oil drained out). So I've now tried a Champion C102 (what I've been using for the past 4 years with no trouble) and a Unipart GFE121 with both Castrol GTX 15w/40 and Duckhams 20w/50. I've put on a replacement Unipart because I had it, just in case it was a one off, but if that doesn't work I think I'll try one of the other suggestions (Volvo filters, Fram, etc). I don't understand why this has suddenly become an issue, surely all the filter manufacturer's can't have suddenly stopped making decent drainback valves!?

Tim.
Tim Jenner

Tim
A lot of these are produced in the same factory and badged accordingly. I know there is a place in Central Illinois that makes these as do a few other places in the Far East.
In industrial filters, these are often specific to the manufacturer and are a much higher performance, but at upwards of £100 per element you would expect that! They are also tested according to ISO standards so can be compared to some extent for performance.
Automotive filters are cheap and cheerful, afterall you would baulk at paying £50 for a filter! And new vehicles costs are controlled by savings in pennies, nevermind pounds, so some of the high quality filter manufacturers like Pall and Parker etc do not get involved in the automotive business because they do not have the facilities for mass market production of cannister filters at the prices automotive makers demand.
Hence, a change in design to reduce production cost can affect a number of brands.
HTH
Martin

I don't see how a filter could be empty even with a defective anti-drainback valve. The inverted filter adapters I have seen all have a vertical standpipe in the center so only oil above the standpipe can drain out through the center. I believe the anti-drainback valve is around the outer portion of the filter and oil would drain out through the oil cooler feed hose if the drainback valve leaks. I don't know how UK cooler oil cooler hoses run but in USA cars the cooler hoses run through the radiator support panel. The filter feed hose goes UP and passes through the radiator support panel. I just checked on my 68 GT with a spirit level and where the hose passes through the support panel the hose is level with the the top of the oil filter. I don't see how oil could drain uphill. Of course, I'm assuming UK cars have the same setup. So it would appear that the filter cannot drain down any lower than the top of the standpipe unless there is an oil leak around the base of the standpipe.

Tim, I would disconnect the oil hose fron the filter adapter with engine cold and see if oil runs out of the filter and the hose. For some information on oil flow you may be interested in this article by Barney Gaylord.
http://mgaguru.com/mgtech/engine/of102.htm
Regards, Clifton

Clifton Gordon

Anyone had experience of these magnetic filters?

http://www.cambridgemotorsport.com/menu_templates/list_menu.cfm?menu_temp=oils_fuel.cfm&dep_id=11&prod_ass=1&ass_id=190

apparently last forever and just clean them when changing the oil.

can anyone vouch for these or had any problems?
worried car owner

What about non-ferrous particles?
Paul Hunt

This thread was discussed between 02/05/2003 and 07/05/2003

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