fresh rebuild: which oil.....mineral or syntheitic

[alilley]

i am not trying to start a new what oil is better thread here by no means. all that i am wanting to know is on a fresh rebuilt engine (fresh bearings and bore) which is going to better for the break in period. if it helps any i am going to be running your standard mineral oil in it, mobil 15 40 as i can get it as a really good rate plus that is what i run in my suburban, firebird, lawn mowers, and my semi. i have never had any issues out of it. the only reason i am asking which one to go with is i am debatin between the standard or they syn oil in the boat. so which is better in a new motor situation

 

[Bondo]

Re: fresh rebuild: which oil.....mineral or syntheitic

all that i am wanting to know is on a fresh rebuilt engine (fresh bearings and bore)

Ayuh,... Roller cam, or flat tappet,..??

Most all the motors I rebuild, I break-in with straight 30W mineral oil for the 1st 20 hours...
Then switch to Whatever oil ya wanta run...

 

[alilley]

Re: fresh rebuild: which oil.....mineral or syntheitic

sorry forgot about that part i am tearing into it this weekend. i am pretty sure that it will be a zflat tappet considering the block wa made between 66 and 72

 

[mkast]

Re: fresh rebuild: which oil.....mineral or syntheitic

I suggest you do not use synthetic oil for break -in.
Most oil on today's market don't have enough zinc incorporated, no longer needed, to break-in new/rebuilt engines. Several oil companies now sell break-in oil. Speed shops, some auto parts stores and of course the Internet sell it.

 

[HT32BSX115]

Re: fresh rebuild: which oil.....mineral or syntheitic

Any good 15W40 diesel type oil is good for break-in too.......


[FINALLY AN OIL THREAD!!! It's been so long!!!]

 

[Desertsky]

Re: fresh rebuild: which oil.....mineral or syntheitic

You can use any API rated oil you like and there will be virtually no difference as far as breakin is concerned. With an older technology engine, such as the older V8s, you may want to use a cheaper oil for a short time and then drain it. Newer tech engines, and rebuilds using new tech parts, don't need it. Many high performance car engines are coming factory filled with full synthetic oils. Also, most of what you would call mineral oils have a high percentage of synthetic components to them because old mineral base stocks can't pass the newer API testing.

 

[daysawasten]

Re: fresh rebuild: which oil.....mineral or syntheitic

Dont run synthetic on a new rebuild . Its to slipery and wont stick to the cyl walls for the rings to seat. New engines can run syn oil but old engines like mineral oil. I never run syn in anything ,its to expensive and the mineral oil today is 100 times better than 10 years ago. I have never lost an engine because of oil.I saw a rebuilt car run syn to early and it spun the bearings and tore the crank.

 

[HT32BSX115]

Re: fresh rebuild: which oil.....mineral or syntheitic

Its to slipery and wont stick to the cyl walls for the rings to seat.

That makes no sense....I know engine rebuilders that use oil mixed with WD-40 "half & half" when installing pistons and OTHERS that install their pistons DRY SO THE RINGS WILL SEAT.

Dont run synthetic on a new rebuild

But, GM, BMW, VW and others "factory-fill" their new cars with synthetic.............


.

I saw a rebuilt car run syn to early and it spun the bearings and tore the crank.

And that one "example" leads you to believe it was due to the synthetic?

I have never lost an engine because of oil

Um......see your quote above.............. Most here have never seen an marine engine fail due to oil either........(except-LACK OF)


Sorry to "jump" on your post......I just disagree with everything you said.......


Cheers,



Rick

 

[jopes]

Re: fresh rebuild: which oil.....mineral or syntheitic

With the way new oils have gone, you really should upgrade to a roller cam any way possible. your engine will last much longer with them. I got a roller cam upgrade coming in my 350 I just ordered because of this.

 

[proshadetree]

Re: fresh rebuild: which oil.....mineral or syntheitic

Engine will break in fine with synthetic oil, but why would you want to? you need to change it after the first 10 to 15 hours anyway.

 

[alilley]

Re: fresh rebuild: which oil.....mineral or syntheitic

With the way new oils have gone, you really should upgrade to a roller cam any way possible. your engine will last much longer with them. I got a roller cam upgrade coming in my 350 I just ordered because of this.

if i can go to a roller cam i would but i do not think one is offerd for the motor that i am rebuilding since it is a 2.5 (153 block is dated between '66-'72). I can see the advantages of a roller cam in a v8 or a hi proformance motor but that is not what i am after here. yes there are shops taking this motor and cranking out over 500 hp (a shop in kansas city) but once again not what i am trying to do here all i am after is geting this boat back on the water. the reason i started this thred was to find out (if i sescide to run syn oil)which i should break it in on.


--- about the comment about teh spon bearing and it taking out a crank cuz of running syn oil i see that very unlikely i would almost put money on it if you could find out what happened there i would jsut about say it was over reved, oil pump failed, or it was ran out of oil that is the only time i have ever heard of a motorspinning a bearing of any kind

 

[Bigdave196]

Re: fresh rebuild: which oil.....mineral or syntheitic

Break in oil.....cheapest 30W out there. We have always assembled out motors with a 50-50 mix of Marvals Mystery Oil and Lucas Oil ($20 and its cheap insurance), and saturated the parts in it during assembly. That always insured that everything was "slippery" on initial start up and stayed that way until oil reached the required areas. Also to prevent disaster we usually disconected the coil from the dist and cranked it for 15 seconds to pre lube the motor and make sure pressure was where it needed to be prior to starting then re-hooked it up and it fired over.
After 10-15 "EASY" hours, aka lower rpms and not WOT accellerations, we change our oil out and replaced the filter. Then run anything you want.
Oils today are so close that its almost preference. 20 years ago, Mobile-1 was far superior, not any more. I wouldnt reccomend 15-40w in a boat, but like Bond-O's signature block says. "Any Grease is Better,..... Than No Grease at All......." So run what you want to.

 

[daysawasten]

Re: fresh rebuild: which oil.....mineral or syntheitic

Go put a "factory BMW" car engine in your boat and put synthetic it then!!!!! A "new engine" is built alot different than the old ,there oil system is totaly different.Any engine builder puts wd40 in the oil to break should be rebuilding door hinges instead. I hope you put wd40 in your oil.

Thanks for

 

[Don S]

Re: fresh rebuild: which oil.....mineral or syntheitic

Go put a "factory BMW" car engine in your boat and put synthetic it then!!!!! A "new engine" is built alot different than the old ,there oil system is totaly different.Any engine builder puts wd40 in the oil to break should be rebuilding door hinges instead. I hope you put wd40 in your oil.

Thanks for

Now that's just plain scarry

 

[HT32BSX115]

Re: fresh rebuild: which oil.....mineral or syntheitic

Go put a "factory BMW" car engine in your boat and put synthetic it then!!!!! A "new engine" is built alot different than the old ,there oil system is totaly different.Any engine builder puts wd40 in the oil to break should be rebuilding door hinges instead. I hope you put wd40 in your oil.

Thanks for

Hmm, maybe you should read my post a little more carefully.....I didn't say he put WD40 in the break-in oil, I said he uses it 50/50 when installing pistons....... (weren't we talking about ring break-in?) One would assume that means coating the pistons/cyl walls with the mixture for piston installation I guess......

YOU SAID:

Dont run synthetic on a new rebuild . Its to slipery and wont stick to the cyl walls for the rings to seat.

And by the way, MANY engine manufacturers (not just BMW) "factory fill" synthetic oil in their new engines.

I'll agree with proshadetree though. There'd be no reason to use it since you're going to change it in several hours anyway, after "breakin"


And there's that little thing of marine engines not "needing" to use synthetic at all........ (Merc recommends against it altogether ....except their own 25W40)


Yeah.........I thought that was scary too!

 

[daysawasten]

Re: fresh rebuild: which oil.....mineral or syntheitic

To H32, Merc's oil is a synthetic blend (big difference),I guess you should read that more carefully, How many engines have you rebuilt ? Why would anybody put wd40 (wd stands fo water dispersion) on cly walls, you need oil on the walls for lubrication not to run dry. Dont be scared ,..........just build a few engines before you give advice!

 

[HT32BSX115]

Re: fresh rebuild: which oil.....mineral or syntheitic

I watched a pretty good engine rebuilder install pistons dry. He said the rings break in immediately. Evidently they did. All of his rebuilds not only ran fine but didn't burn oil either. (ever) I guess the rings did break in right away........

Now, while I could never bring myself to put them in dry, I did do the "regular" motor oil/wd40 mix on pistons/rings during installation. Not because I thought WD40 was some sort of (Water Displacing) special sauce. It isn't.

WD40 is a marketing name. Like Marvel Mystery Oil. Marketing names don't really mean anything. It's just naptha mixed with light oil. I just had it available. It also worked just fine. The rings broke in nicely and my rebuilds don't burn oil either. (and my rebuilds include automotive and reciprocating aircraft engines)

It's not rocket surgery. And you don't need a magic wand either....

Your way may work just fine.....but it's not the only way.....


This is way off the OP's question......

Sorry for the thread hijack...