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MG MGB Technical - Engine Oil Choice ?

Hi guys,

I wonder if anybody has any experience with modern oils in an MGB engine (competition or racing experience?). I have always used the old Castrol 20W50, but i have rebuild the engine and there are newer oils that should probably work better with less friction etc (15W40 or 10W40?).

I know this is a controversial question, likely to get "stick to the manual" response, but I am looking for some recent real world experience and want to know if anybody has tried them satisfactorily?

Thanks in advance,
Corneliu
corneliu

Corneliu,

I've tried Mobil 1 15/50 with no noticebly increase in mpg so back with 20/50.

Paul
Paul

A lot of people on this board have reported good results with synthetic oils, such as Mobil 1 or Castrol Syntec.

When I bought my car three years ago, the PO had been using Syntec. However, I like to change my oil once in the spring, before I begin driving the car a lot, and once in the fall before I put her to bed for the winter. That just got too expensive with Syntec, so I switched back to Castrol GTX 20/50. I decided that I wasn't making use of the extended mileage capabilities of the synthetic, so why pay the premium price for it?

I believe that almost any good-quality oil will provide more than adequate protection, as long as it is changed frequently and the engine is not abused. To me, the frequency of the oil changes is more important than which lubricant is used.
Paul Noble

Corneliu,

I just had my 74 1/2 "B" engine rebuilt by Kent Prather of Prather Racing here in the U.S. He builds engines for people all over the country and is well thought of. He reccomends Kendall or Havoline 20W50. I use the Kendall and it seems to hold up well. I have driven the car in some very high (98F) temperatures, and the oil pressure holds well.

Cheers, Doug
Douglas Keene

Corneliu,
I am currently racing an MGB. I am using 5-50 Syntec and I am very pleased with it.
Leland Bradley

Low viscosity oils for modern engines are not good for older design engines with larger bearing clearances, and they shouldn't be used as an excuse to extend oil change intervals either, neither is good for the engine. Stick with the Castrol, but I can't get 20W/50 anymore, nor the very good 15W/50 that replaced it, only 15W/40 which does seem about the same. Castrol also make a GTX Magnatec for older engines if you insist on shelling out loads more dosh, even more than at first sight as the cans only contain 4.5L instead of 5L.
Paul Hunt

There was recently a long thread on this subject on the BBS - it provided a good range of informed opinion. The point that I noted was that it is not recommended to initially use synthetic oil in a new or rebuilt engine since it delays bedding in.
B.J. Quartermaine

Doug: how about a report on your engine? what mods did Prather do and what are the dyno results? Do you have any performance figures (0-60 etc.)and what's it like to drive? We are always interested in performance enhancement results here. Thanks
Terry

Terry,

I'm not a racer, just drive the car on the street. The block was bored .040 over, a mild grind on the existing Crane cam, and a little milling of the head. The head already had the larger intake valves. Also went to the doble timing chain.

Don't have any data, but the engine runs great, and is considereably quicker than before the rebuild.

Cheers, Doug


Douglas Keene

This thread was discussed between 14/08/2002 and 17/08/2002

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