List:
Ah, the great oil debate....
As an automotive engineer (albeit an electrical one), here's what I've
learned from both the racing and engineering communities.
Without question, the greatest wear to an engine and its bearings, and a
challenge to the oil is during cold starting & operation. There's no oil
pressure, and the oil's run back down in the pan. You're rubbing metal
against metal, and that's when wear is the greatest on the bearings and all
the engine components.
In a racing engine, there are certainly benefits to be derived from lower
parasitic losses from friction and viscosity. However, there's also a cost
trade-off depending on how often you're going to change the oil. While
synthetic oil will certainly last longer before breaking down, I strongly
recommend you change oil FAR sooner than that. Synthetic oil is going to do
nothing about the minute particles of bearing and other material floating
around in there that can wear and damage the bearing surfaces.
THus, my engine builder recommends and I agree that you change the oil
frequently. Modern standard oils (like Valvoline racing, which is what I
use), are certainly up to the challenge in my engine, and cost less than
synthetic. So, I change the oil and filter after EVERY race weekend. I know
some guys run the same oil all season, but I firmly believe that is just
asking for trouble. How will you know if you've broken pieces off of valve
springs, or bearings if you don't check it regularly??
We went over 100 hours (I have an hourmeter installed) before the first
rebuild on my nearly 200HP Lotus Twin Cam by doing this religiously. And, I
regularly turned it to 9,000 rpm. On the second freshening, I found pieces
of a valve spring in the filter and the oil at 50 hours. By checking this
after each weekend, I caught it before it grew into a BIG, EXPENSIVE problem.
I do use synthetic lubricants in the tranny and rear end. I was going
through a set of ring & pinion gears every season. We switched to Torco
synthetic, and added a drain plug so I can easily change it (which I also do
EVERY race weekend), and I've now gone more than 3 seasons on the same R&P.
So, while there's no debate that synthetic will hold up to higher temps, last
longer before breaking down, and provide 1 or 2% more power from reduced
frictional losses, I still can't justify the cost based on the fact that I
believe changing it OFTEN is the best insurance to keeping the engine
together.
There, I'm done now...
Myles H. Kitchen
1965 Lotus Cortina Mk1 #1228
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