Custom Motor Build -- Conventional over Synthetic?

[BillyTheKid]

Originally Posted By: Jim Allen
I think the old "dino-only for break-in" is a hangover from the old days. Back before the new honing techniques they use now, ring seating was a big issue and a really slippery oil could slow or stop that process. Might still be true for some of the behind-the-times machine shops out there so it could be an "it depends" answer. For myself, if I plan on running a short break-in OCI, I prefer not to dump high dollar syn, so I might use a dino for that reason. Since many new engines start with syn in the crankcase, I think that puts paid to the notion that dino is "needed" for break-in in all cases.


I am pretty sure you are correct with what you are saying, however, from a personal standpoint, I dump oil very quick after it is fired up and run for a short time/miles. During break-in is when most of the break-in materials will be present, so why spend on expensive oil for that when it will be dumped? I dump the oil early on new cars I have bought, and I certainly do this when building a performance engine. I am into the motorcycle race scene more than cars, but this is the same guideline and my builder does from a personal standpoint, and we have much success with it. Oils are expensive enough, so I will not be breaking in with $9 plus per quart stuff only to be dumped right out.

 

[ThatGuyOverThere]

I realize I'm late to the party...did not expect my thread to cause this much discussion.

The motor is about to be put together this weekend and I will break in it as per manufacturer specs. The manufacturer specifically recommends 10w40 and says that it is because of the tolerances that the motor is built to.

I'm not debating the break in procedure or oil. They recommend Valvoline 10w40 like this:

1. Start up the motor, let it idle to operating temp.
2. Change oil, change filter.
3. Drive it easy, varying RPMs up to 4000, try to avoid cruising (constant RPM). No more than 3/4 throttle. 400 mile break in period.
4. Change oil, change filter, and go on with your life.

I apologize if I didn't make it clear. My confusion is on to the part where the manufacturer recommends 10w40 NON-synthetic for normal use. This is a high horsepower street engine. It will be driven daily through every season. It also sees a fair amount of track duty (1/4 mile passes and some road racing).

The manufacturer specifically states NOT to use synthetic in the motor, ever. Anyone know why this could be?

I used to run Redline oil but now that I am looking to use Valvoline 10w40 conventional, the cost is much lower. I'm thinking I could just use conventional and change the oil every 3000 miles or even sooner, maybe 2000 miles.

What do you guys think?

EDIT: This is a roller cam motor Ford Modular motor (2005-2009 mustang).

 

[aquariuscsm]

Stick with what your builder says,Valvoline 10W40. It`s an excellent oil,cheap at Walmart,and he (the engine builder) definitely knows what`s best.

 

[Jim Allen]

Yes, go with what the builder says to keep whatever warranty you have intact... but it's a waste of oil and filters IMO.

If the builder uses a modicum of sanitary engine building practice and good machining, there should be no need for that many oil/filter changes... especially on a roller cam engine (flat tappet engine shed more metal during break-in). I would wonder how they made the determination of what to do. Old custom or some objective testing, i.e oil analysis and particle counts, etc. Anyway, the oil is cheap but I just abhor waste.

No synthetic? No rhyme or reason to it. I have interviewed shop son why they do that and in the cases where they could give an answer other than "because that's the way we've always done it, it was because some old timer tried syns back in the '70s or '80s, something unexpected happened and from that point syns were evil. I would love to have a shop give me a reason that makes sense.

Your proposed 3K interval is too low. You should be able to run at least 5K, unless this will be a track car. Search DNewton3's posts. He just did a statistical study and also highlighted an SAE Paper done by FoMoCo and one of the things that came up was that oils need some time to lay down a protective barrier coating. That can take up to 3000 miles but between the point of the oil being first installed and that barrier point, wear is actually HIGHER with the new oil than it is with the old and wear is LESS with used oil than new.

 

[ThatGuyOverThere]

Originally Posted By: Jim Allen
Yes, go with what the builder says to keep whatever warranty you have intact... but it's a waste of oil and filters IMO.

If the builder uses a modicum of sanitary engine building practice and good machining, there should be no need for that many oil/filter changes... especially on a roller cam engine (flat tappet engine shed more metal during break-in). I would wonder how they made the determination of what to do. Old custom or some objective testing, i.e oil analysis and particle counts, etc. Anyway, the oil is cheap but I just abhor waste.

No synthetic? No rhyme or reason to it. I have interviewed shop son why they do that and in the cases where they could give an answer other than "because that's the way we've always done it, it was because some old timer tried syns back in the '70s or '80s, something unexpected happened and from that point syns were evil. I would love to have a shop give me a reason that makes sense.

Your proposed 3K interval is too low. You should be able to run at least 5K, unless this will be a track car. Search DNewton3's posts. He just did a statistical study and also highlighted an SAE Paper done by FoMoCo and one of the things that came up was that oils need some time to lay down a protective barrier coating. That can take up to 3000 miles but between the point of the oil being first installed and that barrier point, wear is actually HIGHER with the new oil than it is with the old and wear is LESS with used oil than new.


That's interesting, thanks for your input. Here's the way I see it. I did question the engine builders and they couldn't really give me a good answer other than "blablabla designed with tolerances that require 10w40 non-synthetic".

For the purposes of the 1 year warranty, I'll do what they say and run the 10w40 conventional. I'll break it in like they say. And during my normal oil changes, I'll have the oil analysed as I go along. If everything looks good, I see no reason to move to a synthetic.

I'll sample the oil at 2500 and 5000 miles before changing it. Is there any flaw to my methodology?

 

[mechtech2]

Guy -

With a brand new engine of uncertain build,I wouldn't think of going 5k on the oil.
It's not worth it to me, in the long run.
We all know many people will do this with their new Mom n Pop cars, but what is gained? $20 over the life of the car?

This is why I would use dino for the first fill - why waste full synth for no benefit at a short [like 2k] fill?

Car mfrs used to test run all their engines. They often used Propane on a test stand. It's tough to verify how each and every one does this now.

 

[ThatGuyOverThere]

Thanks for the advice mechtech. I will try 3000miles and see what happens.

 

[Ben99GT]

On the back of the installation sheet that Total Seal provides with every ring set they sell it states, "During engine break-in, use petroleum based motor oils only. Synthetic oils may be used after the break-in cycle is complete"

FWIW

 

[Volvohead]

Originally Posted By: Malo83

I would stick with the engine builders recommendations, none of the so called experts on this board turned any wrenches on the engine,

Best statement on this thread.

On a field rebuild, you do exactly what the rebuilder recommends. It's not a new long block.

I used to break in my rebuilds on a straight 30. But if this guy says 10w-40, you use a 10w-40.

 

[Ben99GT]

Total Seal FAQ:

QUESTION:
Can I break my engine in on synthetic oil?

ANSWER:
Though we have seen it done successfully on occasion we do not recommend it. We have seen the best and most consistent results breaking the engine in on light viscosity conventional oil. Synthetics can be used after completing the break-in process.

Total Seal on seating their rings:

Ring Seating

When first starting your engine to ensure proper ring seating, do not allow the engine to idle for long periods at a time. It is a good idea to mildly load the engine as soon as you can. Highway driving is a good way to properly seat the rings quickly. Do not idle the engine as idling does not break in any engine. Total Seal ® DOES NOT recommend the use of synthetic oils during break-in. After 2000-3000 miles on the street, or one night racing on the track, the rings should be adequately seated so that any oil you prefer can then be used.

With an aftermarket engine, built using aftermarket parts, just do what the engine builder and/or parts manufacturers suggest.

 

[ThatGuyOverThere]

Thanks for the responses everyone!

 

[ThatGuyOverThere]

So I asked the engine builder some more. They said I need to use 10w40 conventional to maintain proper oil pressure for the variable cam timing to work. They said synthetic could make the VCT not work correctly.

I have no idea how true this is, what do you guys think?

On top of this....I have the VCT locked out anyway...

 

[BillyTheKid]

I call [censored] on the oil pressure synthetic vs conventional.

I also am a believer you need to break the engine in harder after a rebuild, I don't follow the nurse it at this many rpm or speed, then do this after that time, etc.

 

[SteveSRT8]

Easy break in is a recipe for more blow by, less power, and shorter engine life.

And I also call complete baloney on the VCT nonsense. Almost every mfgr has them now and they work well on virtually ANY oil.

 

[Propflux01]

If the guys says 10w-40, well, why not. AS for his reasoning, IMHO, Total B-S