what viscosity on a new build? 351W/408 street

Status
Not open for further replies.
Joined
Jun 25, 2009
Messages
4,085
Location
Chicago, IL
I have a freshly built 351W/408 stroker with all of the main and rod bearing clearances set to .0028 - .003 I believe that those clearances are on the looser side of the scale. King bearings, FWIW.
The actual builder said to use 20W-50 VR1; the designer said to use 10W-30; although he added that I could use 20W-50 in the summer.

this is a street car. it is currently filled with Joe Gibbs break-in oil.
 
The problem is that 0.003" is on the absolute max side of what can be considered optimal; MOFT drops, POFP rises, and oil pressure distribution across the bearing surface becomes non-homogeneous.

Nothing wrong with VR1 here, especially in a stroker.
 
I agree with the builder (who is probably your warranty guy too....) and others that have suggested the VR1 based on those clearances.
 
I will not address viscosity; use whatever you wish.

The main objective in initial oil changes on a new vehicle (engine) is to facilitate the removal of harmful manufacturing and break-in debris for those interested in long engine life.

Mr. Jim Fitch, founder of Noria Corp. has authored a book "How to select an Oil and Filter for your Car or Truck" The above statement is from page 43. http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=How+to+select+an+oil+and+filter+for+your+car+or+truck

Table 13 on this same page Mr. Fitch outlines his RECOMMENDATIONS for the first few oil changes: 1st oil change within 100 miles of taking possession of the vehicle; 2nd oil change 1500 miles after 1st change, 3rd oil change 3K miles after 2nd, 4th and beyond at normal intervals. Go synthetic at 4th change.

If you've never heard of Mr. Fitch or Noria; I would suggest a cursory google search; his credentials are quite impressive in the world of lubricants. His book I referenced was written way back in 2003.

Jim Fitch is the CEO and a co-founder of Noria Corporation. He has a wealth of “in the trenches” experience in lubrication, oil analysis, tribology and machinery failure investigations. Over the past two decades, Jim has presented hundreds of courses on these subjects and has published more than 200 technical articles, papers and publications. He serves as a U.S. delegate to the ISO tribology and oil analysis working group, and has been awarded numerous patents. Since 2002, Jim has also been director and board member of the International Council for Machinery Lubrication. Among his specializations are motor oil and Engine Lubrication.

I mean no "slam" to anyone on this board, there are some quite knowledgeable people on here who are experts in their fields; but I would rank Mr. Fitch right up there and take his advice over most anyone on this board.

Nevertheless, it is your vehicle and you are the one who must sleep at night with your decision. Hope you enjoy your new engine.
 
I have no problem changing the oil frequently. the engine itself was $$. Roller lifters and roller rockers - so zinc should theoretically not be a concern. the builder knew this was for a street car - but I agree his build seems to be more towards race use. (loose bearing clearance, high volume Melling oil pump, larger oil pan). I've seen him race - and he wins races, period.

forged crankshaft, forged Mahle pistons, AFR heads, Quick Fuel SS 750.
 
As loose as those clearances are, I'd go 20W-50 VR-1 in a heart beat
smile.gif


I would not use the Joe Gibbs break-in oil unless you have a roller cam which I see you do ... So that might work out OK. Is the Gibbs oil 20W-50?

On an engine that was not completely engineered to use it, I would never use a full synthetic on start-up, and agree that it should only be considered after three changes. That is also common practice in marine and aviation engine rebuilds.

If you supply more info like spring pressures over the nose, cam type and MFG along with lifter selected, I might change my recommendation - but most likely not. VR-1 is the hands down most popular oil for built engines in a poll I conducted at Chevelles.com (I mostly build BBC's, but the odd SBF now and then...). It's more than 2:1 over the next most favored oil - Mobil1 ... That is with a sample base of over 200 responders. Big enough sample base for the built engine crowd
smile.gif


Unfortunately I can't buy VR-1 any longer in the Komunist Kollective of Kalifornia (KKK), so I have to drive to Reno to get it. And because of that, I am doing a lot of evaluation for built engine start-up oil. On a slightly tighter motor I would use Chevron Delo 15W-30 SD (severe duty), or SAE 30HD. But you are out there a bit, so 20W-50 makes perfect sense. And it's good down to at least freezing (32*F) so I would not sweat seasonal changes
smile.gif


If you have ready access to VR-1, just do it and your motor will be as happy as it can be
smile.gif


After you get say 2,500 miles on it, maybe switch to Mobil1 15W-50. It's also a very good oil
smile.gif
 
Last edited:
the cam is a Bullet custom grind with .565 of gross valve lift. from what I can tell, the springs are AFR 8019 with 155# at 1.810 and 412# @ 1.21
the lifters are rollers supplied by Bullet - they have their name on them, but I imagine they are sourced? The builder recommended "no synthetic".
 
Was this engine balanced and blueprinted ?

10w30 in the winter and 20w50 in the summer sounds ok.. If this engine was done correctly and it was balanced and blueprinted than the "designer" as you put it would be the person to ask.. That should be calculated into the build
 
At least a 15w-40 or better yet a 20w-50! The clearances are similar to what are used in the big block Chevrolets I have done over the years in my boat. Your engine seem like a high $$$ build. Syn isn't all it is marketed to be for every use when compared to todays "conventional" oils
 
I run the same clearance, .0025-.003" rods 'n mains in BBCs & SBCs and the big oil pumps 'n pans.
1.8/1.7 rockers on the BBCs, 1.7/1.6 SBCs, both on .340" FT. lobes with the appropriate springs.
I can still buy high SAPS CI-4 15w40 HTHS 4.4, and mono-grade high SAPS like Delo 400 SAE40 or Mobil 1640 with HTHS >4.3
I use SAE50 Duron, HTHS 5.3, instead of 20W50 in weather always above 10C or 50F.
 
Status
Not open for further replies.
Back
Top