February 12, 2009 -- It seems we are
constantly changing brands of oil or recommending a new mix of
lubricants. Actually, oil and fuel have become a source of major concern
for the last 5-6 years, so we are always researching and testing new
products. If you read my article from 2007, you have our basis of
concern. Itís not the good old days when you could trust Kendall GT1 to
get the job done.
We have 3 different types of engines we work with.
The flat tappet engine like the MGís, the overhead camís like the Miataís,
and the rotary engines.
Flat tappet engines need 1600 ppm of zinc. Race flat
tappet engines need to be around 2000 (2500 for break in). We use Brad
Penn, Red Line, and Torco oils here. The Brad Penn has 1500 ppm of zddp.
Any oil with an energy-conserving label has a level less than 800 ppm.
Valvoline VR1 is around 1200 and we have heard good reports on it, but it
is only best when using 20W-50.
Check out the product Cam-Shield (www.cam-shield.com).
We tested Cam-Shield and it does indeed do what they claim. Each ľ ounce
of cam shield per quart adds 800 ppm of zddp, which is zinc and
phosphorus. So, street flat tappet engines can use any oil with ľ ounce
of cam shield added or Brad Penn straight. Racing flat tappet engines
need Brad Penn with ľ ounce of cam shield added. Brad Penn is working on
a 15W-40 racing oil but for now only carry 10W-30 and 20W-50. We have
always said to change the oil before every race weekend when you check
your valves hot and race prep your car. Simply mix the two weights for
colder weather then use straight 20W-50 for the summer months.
The Miata engines with their overhead cams and
lighter spring pressures donít have any of these issues, so a good racing
oil is fine in a 15W-40 weight. The rotary engines obviously donít have
cams so a good 15W-50 is great for rotary engine bearings.
Thanks for listening and being as concerned as we are
that your Prather Racing engine will continue to perform as it did on the