Bonneville America Forums Forums Technical Forums Performance Mods More oil talk...

Ever since I did my big bore, about 4,000 miles ago by now, I have been running straight Castrol 10-40 dino oil ($8 a gallon too). It seems to run just fine and is pretty quiet mechanically to boot. Hmm. This is with a big bore, new clutch springs and belt drive since then. No problemo.
All this talk about how synt is required I can say without a doubt is pretty much manufacturer BS. I know that the synthetic has better friction magic and all, but as far as it being required, I seriously doubt that. Action speaks volumes eeh? (that's for wojo, eeh?)
I will be trying the new Vavoline that Gary James spoke of as soon as my bike comes home from the GF's house. I have her Magna getting it all finished up so she can ride. I even put my last 4 quarts of Amsoil in her bike as a test. Mine is sitting in her garage (keys are with me though) starting to get the shakes too as it's been 80º+ the last few days, but then again, my butt doesn't mind a few days off after the long haul to Ga and back.
So, when I try the Vavoline new mc oil, I'll report back.

Less drag = less friction/heat also. Less heat means better adhesion, and less breakdown of the additives which promote adhesion, viscosity, suspension, and heat transfer. That's why they extend the change intervals with synthetics. It works better longer.

No aluminum bore, no need for syn. oil.

Going back to the early '70's, remember the problems GM had with the Vega aluminum block (without iron sleeves) and cylinder wall failure? The fix was to bore and sleeve the Vega engine (under extended warranty, no less). Finally, after the Vega was dropped, GM production-line sleeved this same 4 cyl. engine that was standard in the Monza. No syn. oil was readily available then. Seems like yesterday.....

By the way, Shell Rotella T 15-40 oil, available in gallons at Wally-Mart, would be a good choice, too, for iron sleeved engines.

For the standard aluminum bore, or aluminum big bore kits, I'd probably go with one of the syn-natural oil blends, but would change it more frequently. I'd also go up as high as I could on the oil weight, especially in the hotter areas of the country.

Remember: the oil viscosity enhancing additives tend to break down between 1000 and 2000 miles, with the oil seeking the lower viscosity rating! (This is why I'm a fan of straight weight oil, though the higher straight weights are getting harder to find at the auto parts stores. Heck most of them around here have even quit carrying racing oil. Bummer.)

Oops, almost forgot a very important point in this oil discussion! The Wiseco big bore kit uses their wonderful forged piston (YEA!!!), which has different expansion characteristics from the stock, cast piston.

All forging alloys, while stronger than any cast alloy, including hypereutectic castings, tend to have greater expansion when heated to operating temperature. This means that skirt clearance with a forged piston must be greater than with a cast piston. (If you were to put mufflers on a drag race engine, you'd scare yourself with the piston rattle before the engine gets up to temp.!)

Amyway, in a forged piston motor, I always run thicker oil over one with cast pistons - straight weight if I can find it.

Incidentally, TRW forged pistons are made with a different alloy from the "California" race pistons, such as Wiseco, JR's, Diamond, Ross, ect. This different alloy has more silicon in it, so it expands less than the other forged ones. The others are slightly stronger, though. TRW's are run with tighter skirt clearance than those other forged jobs. That's great for a hi-po street motor.

i get the valvoline racing 50 wt for my bsa at auto zone.

i use the rotella t 5/40 synthetic in my kaw voyager and it works great.

been using amsoil 20/50 and have used mobil 1 v twin oil in my speedy. like the amsoil best.

waiting to hear more on the newer valvoline mc oil. just don't know about it being non synthetic.

i guess i could cruise the bob's the oil guy site...

cat http://www.bobistheoilguy.com/

The use of synthetic oil is not all about it generating
less friction, which it does to some extent, but about
it being able to handle heat better without breaking
down. In jet engines we have used synthetic oils for many
years for this very reason. The oil in a jet is not a
multi viscosity oil and the Exxon 2380 oil that is in
common use is almost clear coming out of the can. These
oils still burn and produce a build up in the engine but
withstand heat much better. The air cooled engines run at
higher temps than do liquid cooled engines. On the Triumph
all we have is the small oil cooler up front and since
there is no oil tank, all the oil is staying in the hot
engine all the time. Remember that the oil cooler is doing
very little when you are at a stop with no air flow.

Papa - is this Shell Rotella Synthetic of which you write one and the same as the stuff that has truck, etc., recommendations on the jug? Doesn't mention bikes but says it's great for all kinds of hard working vehicles.

Dearest Pat and Members,
I had used the recommended oil for 28,000 miles then switched to Amsoil. Not much difference, other than shifting was louder with Amsoil. 800 miles ago I filled her with the new Valvoline 4stroke MC oil. So far, I like it best. Vera's motor appears to be quieter and shifting is much smoother with a lot less "clunk" in lower gears. I know that "loud valves save lives", but I like the quiet ones better. I will change it at 3,000 miles since I don't know how well it holds up. But at $3.18 at A-Zone, I don't mind the frequency. My initial response is "Buy It Now". I look forward to any studies done on this stuff, but for now I like it better that the recommended oil. I have always used Valvoline in my current and previous vehicles, since my old Volvo mechanic DEMANDED it. I am not sold yet - my 1980 Ford pickup had 287,000 miles after 10 years and the rear seal went out. Maybe Val--line is not as good as some people say.
Havoline oil was my second choice in the past - never Q'state or P'zoil.
Just Ride Safe!!!
Dennis