Straight weight oil for new engine break in?

[CT8]

Originally Posted By: willistheguy
Okay okay okay!

Let's refocus here. The reason this post exists is to discuss the reasoning for using a straight weight oil for an engine rebuild. I did not give that much information about my engine build initially because this was supposed to be more of a general topic.

Here are some responses:
-I am not concerned about block/oil heaters because this is not a winter car, I just happened to finish the build near winter.
-You are right CT8, measuring is important. I'm in school for automotive. (I haven't taken my fuels/lubes course yet ). I don't want to get into the discussion of why I did what to my engine. It was calculated. I just want to discuss this threads topic.
-Some would disagree with those of you who are saying you don't need to break in a roller cam: Roller cam break in. Also from Micheal Prodemand's general break in tips (doesn't specify roller or not but roller engine vehicle was entered into prodemands vehicle search): "Breakin procedure is required when new or reground camshaft has been installed. Operate and maintain engine speed between 1500-2500 RPM for approximately 30 minutes. Procedure may vary due to manufacturer's recommendations." (I get break in is much more sensitive for flat tappets but nonetheless some say you need to do the same break in for roller cams)

Since people asked, here is more details on THIS build (I still want to focus on the straight weight oil question)
91 thunderbird 302 block, cylinder bores ball honed only
87 mustang rotating assembly + pistons
new cam bearings, rod bearings, main bearings
chrome moly piston rings (would switch to iron if I could go back)
96 explorer heads/intakes with full valve job and new springs
Trick flow stage 1 roller cam
Ford racing lifters + new pushrods
1.6 Roller rockers
Reman oil pump
Comp cams timing gear set
Chrome moly rings are the way to go.

 

[Garak]

Originally Posted By: willistheguy
-Some would disagree with those of you who are saying you don't need to break in a roller cam:

Let's put it this way. If you feel that you need to, or simply want to, break in this engine in a more conventional method, it's easy. Follow the recommended procedures using a dedicated break in lube, like the one from Amsoil, Royal Purple, Red Line, and so forth. Those will generally be roughly an SAE 30 monograde.

Contact Pablo on this board for more details on the Amsoil product, and probably best pricing. Doing this simply won't hurt anything.

 

[Jetronic]

Originally Posted By: Ducked
Originally Posted By: Jetronic
Originally Posted By: Ducked
OP, that site you linked to contains this:-

"Friction modifiers are long chain polymers similar to synthetic rubber that are ground up and blended into multi-viscosity oils. This allows the use of a thinner viscosity base oil for easier cold starting and reduced friction. As the oil heats up, the friction modifier thickens and allows the oil to behave more like a heavier viscosity oil at operating temperature."

They seem to be confusing friction modifiers and viscosity index improvers, which doesn't inspire confidence, though maybe there are some with dual-function?

I've never done a full engine rebuild, but 4WIW if I had 30W in it I'd use it.

I doubt you need to heat the oil on the stove, but if you wanted to it'd be do-able using a double boiler. It'll be hot to handle though.


I suppose a viscosity modifier is also a hydrodynamic friction modifier when you think about it.


Well yeh, but then so is oil. If you apply the term that broadly it ceases to have much meaning.

Don't like the "ground up rubber" bit much either. I'd like it even less if it was true.


Not at all. the friction in the hydrodynamic region is solely dependant on the viscosity of the oil. VM can reduce the apparent viscosity of the oil when the shear speeds get higher. monograde can't.

I'm still no fan of the shearing effect of the VM though as you risk falling out of the hydrodynamic lubrication regime. And the ground rubber is kinda true. The same material is used to make pencil erasers...

All the above isn't what the website was alluding to though, it's clear they mixed up the words friction and viscosity.

 

[userfriendly]

How do you break in an engine that has a roller cam with .530" lobe lift X 2:1 rocker ratio and 1100# open spring pressure?
Answer; You don't.

 

[supton]

Originally Posted By: userfriendly
How do you break in an engine that has a roller cam with .530" lobe lift X 2:1 rocker ratio and 1100# open spring pressure?
Answer; You don't.


?

I don't understand. If it's a new build it likely has new rings and bearings, and perhaps a newly-honed bore. Wouldn't all those surfaces need some amount of wear-in? [I know new engines have some fantastic hone jobs and it wouldn't surprise me if very little wear occurred there, but I'm not sure what occurs on older school engines.] Seems to me that there is always some amount of wear-in, even if it's trivial compared to "the old days".

 

[SteveSRT8]

Originally Posted By: userfriendly
How do you break in an engine that has a roller cam with .530" lobe lift X 2:1 rocker ratio and 1100# open spring pressure?
Answer; You don't.


Exactly. In our family owned machine shop this engine would be started up, fluids checked etc., and then taken out to some test roads for a wailing.

The rotating assembly is either right or wrong, and the rings will seat very quickly if handled correctly during the initial run in. High load, upper gears, lots of decel, about 10 minutes or so and you're done...

 

[userfriendly]

The pushrod ends are the highest loaded part in this Pro-Stock type engine with over an inch of valve lift and half a ton of valve spring pressure.
Achieving the valve lift with a high rocker ratio cuts down on the push rod flex.

 

[willistheguy]

Thanks for all the responses guys. I still don't think we have nailed the original question but I have still learned a bunch. I actually contacted Amsoil to ask them about the straight weight question and they responded with "that is what most rebuilders call for". It is starting to sound more and more like the only reason you'd use a straight weight oil for break in because people said so. Perhaps originally it was thought VII's were an additive that should be avoided in break in (for some reason or another).

Either way I broke in the new engine a few weeks ago. Since there was no true consensus here, I just used the Valvoline conventional SAE30 with ZDDP additive (because most say you don't need it but it can't hurt). I changed it after the first 50 miles. Now using Valvoline 5w30 conventional. I've got 100 miles on the engine so far. I'll be switching to full synth after first 1000 miles. It will take many more miles before I start to see any results from my break in. Probably won't have the car that long. See here to see startup/idle/rev

https://www.youtube.com/watch?v=bdgfTt52CJ0

 

[Ducked]

Originally Posted By: Jetronic
Originally Posted By: Ducked
Originally Posted By: Jetronic
Originally Posted By: Ducked
OP, that site you linked to contains this:-

"Friction modifiers are long chain polymers similar to synthetic rubber that are ground up and blended into multi-viscosity oils. This allows the use of a thinner viscosity base oil for easier cold starting and reduced friction. As the oil heats up, the friction modifier thickens and allows the oil to behave more like a heavier viscosity oil at operating temperature."

They seem to be confusing friction modifiers and viscosity index improvers, which doesn't inspire confidence, though maybe there are some with dual-function?

I've never done a full engine rebuild, but 4WIW if I had 30W in it I'd use it.

I doubt you need to heat the oil on the stove, but if you wanted to it'd be do-able using a double boiler. It'll be hot to handle though.


I suppose a viscosity modifier is also a hydrodynamic friction modifier when you think about it.


Well yeh, but then so is oil. If you apply the term that broadly it ceases to have much meaning.

Don't like the "ground up rubber" bit much either. I'd like it even less if it was true.


Not at all. the friction in the hydrodynamic region is solely dependant on the viscosity of the oil. VM can reduce the apparent viscosity of the oil when the shear speeds get higher. monograde can't.

I'm still no fan of the shearing effect of the VM though as you risk falling out of the hydrodynamic lubrication regime. And the ground rubber is kinda true. The same material is used to make pencil erasers...

All the above isn't what the website was alluding to though, it's clear they mixed up the words friction and viscosity.


"And the ground rubber is kinda true. The same material is used to make pencil erasers..." "kinda true" implies its kinda untrue as well. Depends what you mean by "same material" of course, but it could be chemically very similar and physically different.

My understanding is that the polymer extends as temperature rises and increases the viscosity. I'd be surprised if a ground up solid pencil eraser would do that reversibly, but I am often surprised.

 

[Ducked]

Originally Posted By: willistheguy
Thanks for all the responses guys. I still don't think we have nailed the original question but I have still learned a bunch.


Think we might have a clue here:-

Originally Posted By: Jetronic

VM can reduce the apparent viscosity of the oil when the shear speeds get higher. monograde can't.

I'm still no fan of the shearing effect of the VM though as you risk falling out of the hydrodynamic lubrication regime.


I'd tentatively interpret this as implying that high shear due to asperities/over-tight clearances during running-in might locally and temporarily reduce the VM viscosity to an undesirable degree, leading to excess wear (scuffing, galling, etc), and that this won't happen with a straight-grade oil.

Straight-grades are looking better all the time.

 

[FlyNavyP3]

Originally Posted By: willistheguy
Thanks for all the responses guys. I still don't think we have nailed the original question but I have still learned a bunch. I actually contacted Amsoil to ask them about the straight weight question and they responded with "that is what most rebuilders call for". It is starting to sound more and more like the only reason you'd use a straight weight oil for break in because people said so. Perhaps originally it was thought VII's were an additive that should be avoided in break in (for some reason or another).

Either way I broke in the new engine a few weeks ago. Since there was no true consensus here, I just used the Valvoline conventional SAE30 with ZDDP additive (because most say you don't need it but it can't hurt). I changed it after the first 50 miles. Now using Valvoline 5w30 conventional. I've got 100 miles on the engine so far. I'll be switching to full synth after first 1000 miles. It will take many more miles before I start to see any results from my break in. Probably won't have the car that long. See here to see startup/idle/rev

https://www.youtube.com/watch?v=bdgfTt52CJ0


Sounds good, keep an eye on oil level as recently rebuilt engines tend to use some as everything finds a home. Although I doubt you'll be driving this much in Michigan this time of year. Enjoy!

 

[BrocLuno]

Originally Posted By: willistheguy
Okay okay okay!

Let's refocus here.

I don't want to get into the discussion of why I did what to my engine. It was calculated. I just want to discuss this threads topic.

-Some would disagree with those of you who are saying you don't need to break in a roller cam ... Operate and maintain engine speed between 1500-2500 RPM for approximately 30 minutes. Procedure may vary due to manufacturer's recommendations." (I get break in is much more sensitive for flat tappets but nonetheless some say you need to do the same break in for roller cams)

Since people asked, here is more details on THIS build (I still want to focus on the straight weight oil question)
91 thunderbird 302 block, cylinder bores ball honed only
87 mustang rotating assembly + pistons
new cam bearings, rod bearings, main bearings
chrome moly piston rings (would switch to iron if I could go back)
96 explorer heads/intakes with full valve job and new springs
Trick flow stage 1 roller cam
Ford racing lifters + new pushrods
1.6 Roller rockers
Reman oil pump
Comp cams timing gear set


OK, let's focus ... You do know the reason to spin a USA V8 motor after rebuild is to oil the cam lobes? The cam is lub'd by sling oil off the spinning crank. Not enough spin, not enough oil - it's that simple. Yes flat tappet cams & lifters are more demanding, but the machine shop said do it, so do it.

The reason for SAE 30 HD is because it's all oil. There are no VII's to uncurl as the oil heats up, etc. VII's are not oil and they do not lubricate. They may carry oil molecules in their curled state. But they are not oil. They are plastics. You do not want them in a fresh metal motor scenario where there are no AW surfaces built up yet. ZDDP needs heat, pressure and time to bond and coat metal surfaces. With a fresh start you have zero in place. So you are relying 100% on the oil. At least have 100% oil to start out ...

OK, you did good firing the motor and getting the machining debris out at 50 miles. A few $ for an oil and filter change is peanuts compared to the work put in.

Your cam is not making 1,100 pounds of open pressure. It's making prolly 300~400 over the nose. The rocker ratio puts a bit more back into the lifters and the cam, but it's not terminal. And SBF's are pretty easy on cams. If the donor block showed no lifter bore wear, it's a good block so it'll be fine with the new cam. Are you running OEM Ford push rods, you don't say?

Since this is a weekend toy, it'll sit for long periods. That is not where I'd run a full synthetic. Yes it'll still have an oil film, but it will be a thin one. At best I'd run a semi-syn so you can keep a little better capillary fill between starts. You'll change oil annually and it won't have enough miles to need a syn, so why go there ...

 

[willistheguy]

Originally Posted By: BrocLuno
Originally Posted By: willistheguy

Since people asked, here is more details on THIS build (I still want to focus on the straight weight oil question)
91 thunderbird 302 block, cylinder bores ball honed only
87 mustang rotating assembly + pistons
new cam bearings, rod bearings, main bearings
chrome moly piston rings (would switch to iron if I could go back)
96 explorer heads/intakes with full valve job and new springs
Trick flow stage 1 roller cam
Ford racing lifters + new pushrods
1.6 Roller rockers
Reman oil pump
Comp cams timing gear set


The reason for SAE 30 HD is because it's all oil. There are no VII's to uncurl as the oil heats up, etc. VII's are not oil and they do not lubricate. They may carry oil molecules in their curled state. But they are not oil. They are plastics. You do not want them in a fresh metal motor scenario where there are no AW surfaces built up yet.

Are you running OEM Ford push rods, you don't say?

Since this is a weekend toy, it'll sit for long periods. That is not where I'd run a full synthetic. Yes it'll still have an oil film, but it will be a thin one. At best I'd run a semi-syn so you can keep a little better capillary fill between starts. You'll change oil annually and it won't have enough miles to need a syn, so why go there ...



What you say about VII's not being oil and not lubricating makes sense. This kind of makes me wonder why I would not run straight weight all the time? I'm not concerned about it being harder to start. I may accidentally be raising another question here though so perhaps ignore that. What did you mean by AW surfaces?

I am running Melling std. length pushrods (non-hardened because not using pushrod guide plates)

This is mostly a weekend toy yes it sits most of the time. I will consider not full synthetic, thankfully I'll have most of the winter to think about it. I'm attracted by Motorcraft semi-synth with all I hear and it being affordable. I already use Motorcraft filters.

 

[Ducked]

Originally Posted By: willistheguy

This kind of makes me wonder why I would not run straight weight all the time?


Now you're talking.

 

[BrocLuno]

You can run straight grades all the time. Folks did it for 100 years. Still a lot of trucks, and boats, and tractors out there with just 30 HD in crankcase ...

The deal is how you get to multi-grades. Cheap ones have mineral oil base solvent refined and a ton of VII's. Expensive ones have synthetic base and can pass the viscosity tests with very little VII's. It's you choice. This is where research and thinking come in.

I am a proponent of straight grades where they are appropriate. But the upper mid-west is not one of those places. Phoenix, yes.

So just use a good narrow range multi from a well known refiner and you'll be fine

 

[Garak]

Originally Posted By: Ducked
Originally Posted By: willistheguy

This kind of makes me wonder why I would not run straight weight all the time?


Now you're talking.

Spend your winter here and I'll show you why.

 

[veryHeavy]

My engine came with "roller lifters" and Honda factory-filled 0W-20 in it (synthetic). The engine has now surpassed 200,000 miles with many owners reporting 400,000 miles.

Redline SAE30 is actually a 10W-30 oil due to its synthetic nature (no VIMs, just default weight).
Perhaps try that.