oil type & viscosity for Roush 427 sb (351)

[Rich Roy]

What oil to run in a Roush 427 (351) small block? Roush dealer said Valvoline racing 20-50w; others say Valvoline racing 10-30w? I have noticed with the 10-30 the idle psi is about 5 lbs less. This is when street driving & engine temp is up to normal......? What are your comments?

 

[Jim Rosenthal]

Along this line, what is the minimum viscosity oil I should run in my GT40 and Cobra SBF engines? I am thinking about switching to synthetic in these engines- better lubrication and lasts longer, in cars I don't drive often. For decades I was used to just running thick oil like 20W-50- lately I've been reading and wonder whether I have been barking up the wrong tree all these years.....not trying to start up an oil war, but I AM curious....

 

[Cliff Beer]

There's a LOT of information out there on this topic, and a s-load of debate. There are some very smart people on the subject as well who can comment (I'm not one of them). However, it seems to me the overall trends are the following:

1. OEMs are recommending lower viscosity oils in new cars. I believe this is due to a trend towards smaller tolerances in OEM products as a result of better machine tools which are more precise.

2. Oils are improving. A better oil can lubricate well while being of a lower viscosity at the same time.

3. Shift towards better fuel economy. Lower viscosity oils help to improve fuel consumption.

Given the above, I'm using more 10/30 or even 5/30 oils now than I did 20 years ago (10/40 or even 20/50 back then). I'm not looking for better fuel economy, I'm driving more modern machinery now and pouring in a better oil than 20 years ago....at least that's my assumption.

I don't know nothin' really, just guessing here.

 

[Mark]

I thought Roush recommends only using there line of oil and filters.

 

[Seymour Snerd]

Just looked at the Roush web site ROUSH Performance Engines and there appears to be absolutely nothing for technical support documents. Website definitely controlled by the sales guys.

Perhaps when you buy one of their engines you get an owner's manual (?). IAE, if I were an owner and had this question I would call or e-mail Roush.

 

[DaveM]

Rich,
The official recommendation from Roush is 10-30 for the 427R or SR. It's in the paperwork you get with the engine. For track use you'll need higher weight to keep adequate pressure with high temps. I use 15-40 as a compromise since I do 2-3 track days/year. 20-50 is probably fine for heavy track use, but too thick for street use.

 

[Rich Roy]

Dave: My engine came through the Reno outlet; was absent of "any" papers. I did call with the engine # and they faxed me the run/spec sheet done at the time of the dyno but that has no oil info on it anywhere. The dealer/owner in Reno said 20/50 Valoline racing. But others I have talked with when doing some bench racing the last few years are using 10-30 like you stated above for mostly street use. Thanks for everybody's imput. I'am filling'er up with 10-30 w..................Forever Ford!

 

[Rich E.]

Personally I'm running Valvoline 20w 50 VR1. Has a higher concentration of ZDDP. Engine builder recommended it. Currently running it in two different LS7's and my 351 based 427 in the GT40. I'm completely happy with it. No problems whatsoever.