I am confused..please advise.
I always thought the thicker oil like Castrol 20W-50 would show a higher oil pressure reading than a thinner viscosity, such as
10W-30 but the thinner oil may actual flow more volume. . At 2200 miles I am considering switching from the 20W-50 to the Mobil 1 15W-50 in my 351W . The Mobil 1 seems much thinner in texture.

Oil
 

The cheapest Insurance you can buy (no sales pitch for the sensitive) is to change your oil frequently. Every time I change oil in a race motor, I cut open the filter and look in the folds for metal. The pan won't show what you really need to see.

Jam
 

Thick oil if you race and turn high oil temps and high rpm. It will give you the protection. If you have a street car and a 351 built with modern hydraulic or roller, lighter than what you are using could be better. It will take less time to get to proper temp and your car will feel faster. Drag guys use light weight oil for a run on the street. The crank has to work harder to turn thick oil. If you are not running over 7000 rpm, I would go lighter. Check with your engine builder.

Just a thought -

If 5W-30 and 20W-50 both yield the same oil pressure in your engine, it could be that more of the thicker oil is being routed through the bypass.

Cobras have a lot of extra plumbing for the oil to pass through (cooler and associated lines), heavier oils may not want to make the trip. If so, you will have the usual extra wear from less oil being pumped to the usual places (cams, rockers, rings) as well as the wear to the components driving the oil pump which has to work harder to push the heavier oil.

When I went from 20W-50 to 5W-30 (Mobil1) my oil pressure went up!

Bob

Ah: I bought Mobile 1: No wonder it was .59 cents a quart at Bob's Bait, TV repair and Auto Performance store! Going back to get Mobil1! Should have suspected sumpthin'-cb

Location?
 

Bob's Bait and TV wouldn't happen to be in Alabama would it?;) :LOL:

Rick

yep: but they got a real nice new track over there: Barber. Headed over Sat fo lappin' day. What prompted me to start this whole thread. cb

Switched from 20W-50 Castrol to 15W-50 Mobil 1.
I wanted to try lighter but this was the advice of the engine builder. He said 10W-40 Mobil 1 is good for the cooler temps.
No doubt the cooler Mobil 1 flowed thinner than even the heated Castrol . My idle pressure was close and ..yes...may have risen to 65 from 62 psi. I have crossed over !

Oils Amsoil etc
 

Cobra427, Amsoil is probably one of the best oils around, but I find them hard to believe with all their claims, as always being better than any other oil know to man - period!!!!!! Bull***t

A lot of engine builders say dont use synthetic but use that oil, when you see the makeup of the oil its normally synthetic based. Using mono grades has its problems in fact they are rubbish for the road or even track sometimes, this is what happenend to me:

My 650bhp injected, dry sumped Cobra came with Valvoline 50 racing monograde, you would go down the road on a cold day oil pressure would start at about 80psi it then would drop down to 35 when hot, this is just cruising, and you had to go through a great carefull warming up process (which I normally do) I then tried Synracing 15/40 Valvoline not much better, and they say this oil can be used on the road as well. The was a engine shop in town with a van which had Valvoline is the best oil on it for advertising - not!!!

I decided to go back to Castrol RS Synthetic 10w/60, oil pressure was 70psi cold and 60psi HOT HOT even when I left the oil cooler cover on and temperature went to 260F it still had 60PSI. All this proves it that the above Castrol oil is temperature stable, and they recommend it for road and racing!
I am not suggesting its a better lubricant than other oils.

I cant comment on Nascar or other types of racing where the vehicles are doing a continuous 7000-8000 rpm, but I would imagine Castrol and most other oil manufactureres have an oil to suit. The most important thing is to change oil at recommended intervals, and for a Cobra which might only see a few thousand miles a year, then once a year would be sufficient, and if you are like me once the car gets used it always gets a decent warm run.

Why is it that Amsoil is always challenging other oil makers to do these oil comparison tests, which are on the internet, and Amsoil is ALWAYS better, in fact anything Amway/Amsoil does is always better, and better quality than anyone else. DO THEY HAVE THE LEASE ON BEING THE BEST AND ALWAYS HAVE THE BEST TECHNOLOGY?

Ant, the not so gullible Cobra owner!