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Unread 07-08-2008, 05:07 PM
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The above info is a relief to me as I poured some good ol 20-50w into the newly rebuilt MGB engine after the rebuild. Now to continue on in our reading the author tells a little bit more about breaking in engines and some suggestions on what oil is proper.

Quote:
Now for the latest report:

#1 Castrol GTX 20W-50 is still good for our cars after break-in! 10W-40, 10W-30 and other grades are NOT good. Absolute NOT GOOD for any oil (Any Brand) that is marked “Energy Conserving” in the API “Donut” on the bottle, these oils are so low with ZDDP or other additives that they will destroy our cams. Virtually all “Diesel” rated oils are acceptable.

#2 Castrol HD 30 is a very good oil for break-in of new motors. This oil has one of the largest concentrations of ZDDP and Moly to conserve our cams and tappets.

#3 Only an unusual Castrol Syntec 20W-50 approaches the levels of protection we need when we look to the better synthetic lubricants. We are attempting to get this oil but will be using Redline 10W-40 or 10W-30 as these are lighter weights for better performance, flow volume, less drag and has the additive package we need.



#4 The trend today is to lighter weight oils to decrease drag, which increases mileage. Most of these seem to be the “Energy Conservation” oils that we cannot use.

#5 Redline oil and others are suggesting a 3,000-mile break-in for new engines! Proper seating of rings, with today’s lubricants is taking that long to properly seal. Shifting to synthetics before that time will just burn a lot of oil and not run as well as hoped.

#6 The “Energy Conservation“ trend was first lead by automakers to increase mileage numbers and secondly because the ZDDP and other chemicals degrade the catalytic converter after extended miles, increasing pollution. We don’t have catalytic converters and the mileage gains are not that significant for most of us.

For you science buffs: ZDDP is a single polar molecule that is attracted to Iron based metals. The one polar end tends to “Stand” the molecule up on the metal surface that it is bonded to by heat and friction. This forms a sacrificial layer to protect the base metal of the cam and tappet from contacting each other. Only at very high pressures on a flat tappet cam is this necessary because the oil is squeezed/wiped from the surface. This high pressure is also present on the gudgeon pin (wrist pin) in diesel engines, therefore the need for ZDDP in diesel engines.

Second part of the equation is Molybdenum disulfide (Moly). The moly bonds to the zinc adding an additional, very slippery, sacrificial layer to the metal. I found out that too much of the moly will create problems; lack of this material reduces the effectiveness of the ZDDP. The percentage, by weight is from .01 to .02%, not much, but necessary.

Latest conclusions: Running our older, broken in engines on Castrol 20W-50 GTX is ok. Break in a new engine for 3,000 miles on HD 30 Castrol.

New engines (after break-in) and fairly low mileage engines will do best with the Redline 10W- 40 or 10W-30 synthetic.
I pretty much agree with everything said here. I wouldn't post it if I thought differently. Redline oil is top of the line as well as Royal Purple. I have seen independent proof showing how bad ass Royal Purple is and I'll be sticking with that brand in my more expensive engines. Redline is very popular with a lot of racers and I don't argue against it at all.
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