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MG MGB Technical - Which oil to use in new engine?

What weight and oil brand do you guys use? I am about to put in a fresh engine and wonder if I should stick with the Castrol 20W50 that I have been using for years.
Todd

Todd-
Castrol 20W/50 is still the best petroleum-based oil for the MGB. I use synthetic Mobil 1 with great results. It doesn't thin out at high temperatures or thicken up at low temperatures. However, it's useless as a break-in oil. For that you should use a non-detergebt oil and change both it and the oilfilter every 500 miles for the first 2000 miles. I also use the K&N Performance Gold oilfilter.
Steve S.

I am also a fan of Mobil 1, but I would caution not to break in a new motor on it. The rings won't seat. For your reference, there's plenty in the archives on breaking in a freshly rebuilt motor.
Steve Mc

Stick with Castrol GTX 20W50. It's what most of us use. It works just fine as a break-in oil (no further discussion needed on this one...really). It works great as an every day oil for your B. It works great. Aside from beer, it's the only thing I buy by the case.
Barry Kindig

Steve S,

there's a local engine builder that uses an additive to break in engines with mobil 1....i'll find out what it is and post it.


I understand that it is original fill on corvettes -they must be using an additive to break in those engines.

I use mobil 1 15-40 year round.

rn
RN Lipow

I have just broken in a brand new engine and followed the builders instructions --break in on 30 weight non detergent ( I used Shell 30ND ). Change oil and filter at 500 miles and am now using 20W50 Castrol. I have over 2500 miles on engine and not burnt a drop of oil --so rings have seated nicely and engine hums like a British clock.
Gil Price

This thread was discussed between 10/06/2002 and 11/06/2002

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.