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How long after an engine rebuild should I wait before using synthetic motor oil? I've got moly rings, and I remember reading that they take longer to seat than normal rings.

Also, what weight is best to run? A heavier oil increases oil pressure, but a lighter oil is said to reach critical enginer parts faster on startup. I'm considering trying the 0W30 Mobil 1. My car will see occasional street use to/from work during the summer (5 mile trip) and some strip action.
 

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The last time I freshened my engine I went to Total Seal Gapless rings. The top ring is moly, the 2nd is gapless.

Total Seal said to put 500 street miles or 25 dragstrip passes on the rings before changing to synthetic.

I did as they said. Straight 30W for 20 minute break in then changed the oil. Stayed with the same 30W, just wanted to get the assembly lube and any missed junk out of the engine. Ran that 30W 25 passes+ burnouts, return road, etc and then changed to Mobil 1. Used 15W50 at first then changed to 10W30. Same pressure, but figure it might free up a hp or two.

Later,

David Cole
 

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I could/should start a whole new forum on this subject, but my dyno operator and I argued deeply and long about this subject, because I always ran amzoil in my brand x nitrous machine. I wanted to run synthetic in the mustang motor. He said why? He did back to back tests (with certain synthetic oil company reps there), with various motors, and made NO noticeable difference in HP and/or TQ. The only difference was the synthetic oils would seep into the intake (reversion), and soot them up where as the ordinary oils (non synthetic), did not.
My .002.

(that's the reason I'm running Kendall 20/50 in the stang...............no problems.
 

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I run Royal Purple #11 (5w-20). I have seen several tests usng RP against petro oils , and even other synthetics and the RP always shows a power gain. Thats why almost all the really fast Stock and Super Stock guys run it. As do the majority of the sprint cars, and NASCAR guys (at least the ones who dont have a major oil sponsor).

(plus since I have been running it, my bearings look better than they ever did running any brand or weight of petro oil).

Just my .01 cents worth

PS, I figure since it is all that Cosworth uses in their motors, it's definatley good enough for my junk (by comparison).


Oh yeah, the original question, I break the cam in with straight 30 weight petro, dump it, put clean petro 30 weight in, make 5-8 passes, dump it again, then switch to the synthetic.
 

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I heard about killing an engine if changing to synthetic.
This guy said:
The stock engines are build to take mineral oil (15W 40), because the bearings have "bigger" clearance numbers than good aftermarket bearings (main and rod).
If you change in a stock engine to synthetic the bearings could wash out.

If the engine is rebuild total ( piston rings, main and rod bearings ) you are able to take synthetic oil.

gearheads, please correct me if thats wrong 1
Robert
 

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i heard a story of a certain Havoline sponsered winston cup team.they had cases of empty havoline oil bottles in the shop.they filled the bottles with royal purple #9 (0/10w,i think)to have at the races.whenever the havoline big wigs would come around after the race to get a sample of their oil for testing,the pit crew would take a couple of real havoline bottles,pour them into a container and microwave them...here's your samples mr.sponser.
 

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Just for conversation, whilst at the dyno thursday, I again asked my dyno operator, what he thought of synthetic oils.
He again basically reitterated that for severe weather problems, (i.e. cold/warm), they are great. As for making horsepower, they DO NOT increase horsepower. Unless you compare running 20-50 wt regular oil, and then changing to 10-20 (whatever), LIGHTER OIL, then, of course you will pick up something because of the less viscosity, but not because of the actual synthetic oil.
Also, synthetic oil does not burn. It makes it harder for the oil rings to 'take off/scrape' off the cylinder block. (hurting hp). Then when it does get past the rings, (a little bit always does), it gets into the combustion chamber, and basically clings/soots up the chamber. IT DOES NOT BURN like regular oils., hurting HP. Almost acting like an EGR system.
Flame suit on, but I"m just repeating what he said.
If you're running a roundie round motor, and engine temps are always above 240-250, then synthetic oils would be super. If you're living in Alaska, or some other major cold region, then synthetics would be superb for that application,(cold startups/cranking) concerns.

Also, something else I found out. MOBIL 1 is NOT a full synthetic oil. It is maybe 50/50. If it was a full synthetic, it would cost twice as much. Mobil made it basically 50/50 so they could sell it cheaper to MORE people.
bummer..............and I used to like that oil..............
 

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Everyone has their personal favorite stuff and their own beliefs about how to make horsepower. That's part of what makes our sport so great.

The engine builder I have talked to several times says he has seen as much as a 25 hp increase on a 410 ci sprint car motor when switching from Mobil 1 5-30 to Royal Purple 5-30 on back to back dyno tests. A friend of mine who has a record holding Super Stock class car also claims that synthetic, specifically RP is worth hp on the dyno even over comparable other brand synthetic oils.

I run it because I like the way my bearings look at the end of a season and they never looked as good on any petroleum based oil. And the fact the synthetic oil doesnt get foul looking since I run alchohol is also a factor.

But oil is like everything else, people have their favorites that has worked well for them, and they arent going to switch (me included).
 

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Most of what I understand revolves around the idea that Synthetics lubricate better ...

If you believe that, the benefit at the "friction points" is obvious ...

In lubricating better they assist in keeping operating temperatures in line ... (especially at the friction points)

My source on this understanding was from a fellow that built and race oil/air cooled racecar engines.
 

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it does lubricate better in all motors. as for increased hp, that is debateable. If manufacturers dont want u to use it during breakin, doesnt that answer the lubrication question? Case should be closed on that issue otherwise aftermarket and stock manufacturers would nt care. As far as the gunking up carbs and all that, i can say that i use it in every vehicle i own, stock or performance and never gunk up anything. Use it because it lubricates better and lasts longer(shouldnt be a debate here either but i know someone will argue this one). Great stuffregardless of brand(but not the blends). Just my dimes worth and opinion.
 

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If it cant be used on break in, then why do some new cars come right off the showroom floor with it?

I have heard with proper cylinder wall hone, it can be used right away. But the hone is very critical to get the rings to seat when it is used right away and most shops arent set-up to get that finite of a hone. And that is why it is best for the majority of people to break in on petro oil then switch to synthetic after the rings have had a chance to seat.
 

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I started using the synthetic (Mobil) after I worked on a turbocharged car that the oil had coked (or cooked, if you prefer) in the turbo bearing area-completely plugged it). I had read an ad and believed it when it demonstrated that synthetic would not scorch and turn to carbony stuff. I had an 85 turbo coupe that was happy with it, and I have used it ever since. I've got 212K on my 5.0 right now, and it seems OK. I also feel less guilty when I get late oil changes (I go every 5k for easy reference).
 

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Kid ...

My understanding (and I could be wrong) is that the factory rings are different than the "moly" rings we tend to normally use.

My undertanding is that the rings we use in our "HotRod" builds are harder and more difficult to break in.

Anyone with better info is welocme to chime in and clue us in better on the Synthetic Oil/ Ring Brake In issue.
 

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Well to add fuel to the fire, crane cams, msd, ford motor company, and many others that i have seen in writing will void the warranty if synthetic is used before break in. Msd will void warranty because the distributor gear and cam will not break in properly. Same with crane and ford motor is concerned with bearing and ring breakin.
 

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When firing up an engine that has been assembled with a flat tappet cam of any kind synthetic oils are a bad idea until the cam and lifters have been broke in. The lifters are designed to rotate as they go up and down the opening and closing ramps and the friction created between the lifter and lobe is what is reposible for rotating the lifter. However when synthetic oils are used often they have a lot better lubricating qualities, so much so that the lifters will not rotate properly during breaking, causing the lifter and lobe to start an irregular wear pattern and ultimately fail. That is why most cam makers specify a single grade petroleum based oil for breaking in their cams. After the breakin period is complete however, synthetic oils will work fine.
 
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