Suitable engine oils

[briandshepherd]

I wondered if there is any specific requirement for engine oil for my TC5124
The Brown Book suggests NOL 30, and there appears to be a number of different oils offered by suppliers as suitable for older vehicles.
Brian

[Tom Lange, MGT Repair]

You are opening up a can of worms by asking that question. There are many different kinds, brands and weights of oil out there, but 20w50 appears to be the best weight with today's oils and additives.

Beyond that, it is a matter of personal opinion and anecdote. There is much discussion about the need for extra ZDDP in our flat-tappet engines to help reduce cam and tappet wear; my personal preference in the US is either Valvoline VR-1 (which has increasaed ZDDP already) or ANY good 20w50 oil, with a bit of added ZDDP. Opinions still rage back and forth whether the ZDDP "crisis" is real or imagined, so it's up to you. There is equally-diverse and strident discussion whether Brad Pitt oils are better than Penrite, whether Valvoline is better than Castrol, a dedicated "Classic Car" oil, or Brand X.

My belief is that no matter what oil you use, most important is that your engine will last longer if you change your oil frequently. I change at the beginning of the season once my car has been on the road for a week or so, and at the end of the season, before I put it away for the Winter - and sometimes also in the middle of the summer. I have a spin-off filter adapter (highly recommended), and change the filter every time.

There is no doubt that synthetic oils lasts longer than petroleum-based oils, but the benefits appear limited. There is no indication that if we drive our cars long and hard, or seldom and briefly, synthetics really give us any advantage, when balanced against the increased cost. MG owners also tend to shy away from synthetics because anecdote says they are thinner than regular oils, and therefore cause our cars to leak a bit more.

I hope this helps.

Tom Lange
MGT Repair

[Steve Simmons]

I also use VR-1 20W-50 in most of my old cars including the TC. General wisdom says 1200-1400ppm of ZDDP is the correct level for engines like ours. I also prefer to buy an oil with ZDDP already in it rather than adding my own. Oil companies spend millions of dollars to figure out what the ideal levels of each ingredient in motor oil is, so dumping a bunch of additive into the mix doesn't seem like the best way to go unless there's no other choice.

Synthetics are superior to dino oil, but older engines don't run nearly as clean as modern ones, so despite the fact that synthetics can go 10,000 miles between oil changes, a TC can't. So in my view it's as waste of money to use expensive synthetic oils in this application.

[briandshepherd]

Thanks Tom,
Thats more or less what I suspected as I used to compete with BMC "A" Series Engines years ago and we always used 20/50 oils then and I suppose the XPAG engine is very similar if just a bit older.
Just thought I ought to ask the question before I considered changing the oil.
Brian

[Herman 5560]

Just my experience with synthetic oil in older engines. My old landrover defender ran perfectly on normal SAE30, ok here in SA we do not have the extreme temperatures' like in other places on the world, but after deciding to treat HER to an expensive blood transfusion of synthetic oil I had endless problems with the oil pump loosing its prime and like said the oil leaks increased.

[Duncan M]

Synthetic (thin) oil is the greatest thing since sliced bread for extremely cold climates. It also is great stuff for a modern engine with modern, sophisticated (clean) fuel injection, in any climate. Synthetic engine oil is not generally suggested for cars that are carbureted. Even a well set up SU carb will contaminate the oil with small amounts of fuel. Synthetic oil more prone to degradation from fuel and moisture than dino oils are.