12SecondTA

What motor oil is the best?

I have a blueprinted 76 350, balanced and all. Being assembled.

I've been told Shell Rotella T 15w40 oil is by far the best oil for brekaing in one of our motors since its made for harsh conditions and diesle motor oils have higher standards.

Clearances are tight, but nothing too tight.

Hyperutectic Pistons Moly Rings
Clevite 77 Bearings
Flat Tappet Camshaft (520/544 and 230/240 duration @.050)


Whats your best solution?

Vader

That would work just fine. I have used plain 20W for break-in. The engine usually gets quite hot during break-in, but doesn't have any real load. If you've used adequate assembly lube, there should be no cold start-up problem. Once the cam has been broken in, the oil and filter need to be changed anyway. At that point you can change to a multigrade for the next 500 miles for ring break-in. Then go straight to synthetic.

Delvac is a good product. Using a multigrade isn't necessary for break-in, and some multigrades that break down quickly under high heat will start to fail on break-in. 15W is probably as low as I'd dare go.

Breaking in a roller cammed engine is a little different, since the higher RPM operation for the first 20 minutes is not necessary to polish the cam lobes and lifters. There is no cam break-in lubricant required, so all that moly is not floating in the oil. The oil filter only has to trap any contaminants left in the engine and particles that are worn off during break-in. That oil can be left in for a couple hundred miles if you're comfortable with that - long enough for ring break-in runs.

ede

most builders won't recommend a multi weight oil. straight 20w or 30w is usually what you see recommended. i usually use pennzoil 30w with gm engine oil supplement for around 30 minutes then change oil and filter and refill with 30w for 500 more miles or so. all in all how you do the initial start up and break in are by far more important than the oil you use, as long as you use some sort of oil for the application. lot of guys i've built engines for bring me whatever they have laying around and i've/they've not had the first oil related problem.

sofakingdom

iTrader: (1)

The good thing about the Rotella (also Delo 400, and some other similar oils) is that it contains zinc additives, which are there for flat tappet cams. That's the single most important consideration for break-in oil. The newer spec auto motor oils don't have those, for environmental reasons, and because they're not needed any more since most newer cars have roller cams.

Alternatively, you could use just about any good-quality non-synthetic oil you happen to like, and add a can of GM EOS to the initial crankcase fill, to get the anti-wear additives; like ede is talking about.

If you had a roller cam, you could use the same kind of oil that you'd use for the rest of the engine's life, and it would be fine. Which could be synthetic if you chose. But, DO NOT use synthetic for flat-tappet break-in.

rx7speed

wouldn't you still want to stay away from synthetic during initial break in with the rings sir sofa?

sofakingdom

iTrader: (1)

Not really...

The rings aren't an issue. The factory has been using synthetic as the crankcase fill in new cars for many many years now. Seems to work just fine for them. Motors I've built recently with roller cams, I've used synthetic also; has worked perfect for me.

The only thing that synthetic ISN'T good for, is flat tappet cams. The problem is, it's TOO good; and at initial startup, it can lube the lifter faces so well, that the lifters don't rotate. And of course they self-destruct in short order as a result.

79_EFI_Z

It's true the factory has used synthetic in their cars, however they are also finish honing their cylinders for that application as well. This is something that most local machine shops are not set up for. I would NOT run synthetic for break in or you will never get a good ring seal. After its broke in u can run all the synthetic you want. Besides, why run the expensive stuff for break in if you are just gonna dump it right away anyhow?

vrtc350

iTrader: (1)

I have always been told that it is not good for break in because it is too good. However, no one has explained why. What other issues will it cause?

79_EFI_Z

imagine your crosshatch as a series of peaks like this:
/\/\/\/\/\/\/\/\/\/\

regular oil will knock thie peaks off like this:


/ \/ \/ \/ \/ \

which is what you want.
Synthetic will fold the peaks over like this:
.__ __ __ __ __
/| /| /| /| /| /|

covering up the gap between peaks, causing bad seal, oil consumption and blow-by.

79_EFI_Z

My diagram isnt coming out right

Hopefully it conveys what im talking about.

Gumby

That Rotella stuff comes up allot all over and some live by it but then the others sides goes into detailed specs why Rotella is only meant for low RPM apps like big rigg's, though it does have some good stuff for a break in.

Also the wet clutch debate on using it........

vrtc350

iTrader: (1)

I understand what you are saying. Thanks for explaining that.

I really like the Rotella. There is also a synthetic avialble in it as well.

ljnowell

I dont think you would have any problem at all with synthetics as far as ring seal goes. The rings will do thier job.

12SecondTA

so using rotella is a good thing? ok, i'll buy a few gallons tomorow for break in.

My darn oil pan is 8 quarts, so i'll need 9 quarts just for breakin, to use for 30 minutes, and another 9 quarts for the first 500 miles, and another 9 quarts after that. Fun stuff. Lots of money.

Wonder if i get a discount if i buy oil in bulk...

vrtc350

iTrader: (1)

rotella is what is in mine for break in. That is if I ever get it in!(installed that is). Damn thing has been finished on the stand for almost 5 months.

12SecondTA

i have a dead line, my goal is to win best of decade, at the local big car show. Which is held this september, the second saturday.

So i've got some work todo like crap. Car is gonna be orignal exterior appearance, with a modified interior, and non-stock drivetrain.

Dialed_In

iTrader: (3)

I always use straight 30 non detergent oil for break in, no loads. There is an oil out for gas motors that has the zinc additive in it. I've tried it on a few engines by itself and mixed with the 30w and it seemed to make a difference on the flat tappet cams. Less wear on the lobes and lifters after break in.

79_EFI_Z

They will do their job AFTER they seat to the crosshatch, or more specifically, when the crosshatch seats to the rings DURING break in. Synthetic won't allow it to seat properly which is what I was trying to convey in the diagram. AFTER break in synthetic is not a problem.

ljnowell

I know the point you were trying to make, but I dont believe it. Mainly because I have seen otherwise. Especially in todays world when most people use Moly Rings. The rings and crosshatch seat to each other, and it is going to happen whether you are using synthetic or not.

Dialed_In

iTrader: (3)

A lot of that has to do with how the block was honed

79_EFI_Z

Well I'm not gonna argue about it. If you don't beleive it then that's your choice, however, you did not originally ask the question, so it's up to the person who did to sift through this and decide what he wants to beleive. If you have seen otherwise then that's great, but it doesn't make my scenario false, just because you haven't seen it. Am I saying my scenario happens 100% of the time? Absolutley not. This statement IS 100% correct. Maybe you have seen more competent hone jobs done, I have seen both. So why not just err on the side of caution and use the cheap stuff. Besides, why spend extra money on something you are going to dump right away anyhow?

79_EFI_Z

Also, there was a wirite up about this in a magazine once also, I wish I could find it but I can't remember which one. It was very interesting. Maybe I'll scour the Net for it, hopefully I'll have some luck.