synthetic oil and rebuilt engines?

[DR BOOST]

here's my problem.

engine rebuilt about 3500 miles ago
normal oil pressure was 28 at hot idle and 60 at cruise
on the highway i saw the pressure at 45....30 minutes later it was at 40. i shut off the motor. the next day i started it up and it was 15 at idle with a faint rattle above 2500 rpm

i decided to pull the motor and check the bearings. the rods are perfect and the mains are down to the copper.

a reputed engine builder told me that this is common with rebuilt buick V6's and synthetic oil. i had switched to synthetic oil about 2 weeks prior.

has anyone else come across situations like this?


why it so hard to keep buicks alive? i feel like putting velcro on my engine mounts so i can freshen the bottom end every other week



surej

 

[turbo nasty]

The guy that told you about the bearings this sounds fishy. I have 118k on the stock motor and still running strong never been pulled.

The specs for a small bock build up does not apply to the buick, it's a different beast.

Call duttweiler, jack merkel, lou's auto, etc and ask about the bearings in the Buicks you will see the guy (bearings) is off kilter.

 

[jastrckl]

For the first 6,000 or so of a rebuild, I'd use dino oil. That's not a buick motor thing that's something I'd do for any motor. But what do I know.

 

[turbodave231]

On a new engine, I prefer to use a non-syn 10W-30 for initial startup. I change the oil after a few hours of run time to get the debris (left from the rebuild process) out of the oil pan. No matter how careful you are on rebuild, there will be some debris.

I then switch to 10W-30 Mobil One and a PF52 filter. Three years and hundreds of 11 sec passes later and all my bearings look great. (I pull the pan and inspect them every year)

I have always used Clevite 77 P series bearings in my Stock block engines and have had very good sucess with them. I suspect your engine may not have been setup with the correct bearing clearances on the mains or you have a problem with debris in the oiling system. Did you flush your oil cooler?

The part about Synthetics causing the problem is pure BS!!

 

[Chris McDade]

I just pulled my motor and after 5000 miles and about 50-60 10 second passes Im showing very little copper on some of the rod bearings and none on the main bearings. I would say that there is something wrong with the rebuild. I would confront them about it.

Good Luck

 

[The Radius Kid]

Originally posted by DR BOOST
here's my problem.

engine rebuilt about 3500 miles ago
normal oil pressure was 28 at hot idle and 60 at cruise
on the highway i saw the pressure at 45....30 minutes later it was at 40. i shut off the motor. the next day i started it up and it was 15 at idle with a faint rattle above 2500 rpm

i decided to pull the motor and check the bearings. the rods are perfect and the mains are down to the copper.

a reputed engine builder told me that this is common with rebuilt buick V6's and synthetic oil. i had switched to synthetic oil about 2 weeks prior.

has anyone else come across situations like this?


why it so hard to keep buicks alive? i feel like putting velcro on my engine mounts so i can freshen the bottom end every other week



surej

Go give the lying,SOS a good kick in the butt.
That's gotta be the lamest excuse I've ever heard.
Unless you did something wrong[it doesn't sound like it],it sounds like he goofed.

 

[DR BOOST]

thanks for the reponses.

what are some of the causes of wiped mains? coolant has never been in the oil

im here pulling out my hair trying to figure out what happened.

surej

 

[87gnand00ws6]

What they said,

On a rebuilt motor you want to use a non synthetic, 10w30/10w40 wichever you prefer, Havoline and castrol are my favorite non synthetics. I however have never needed to rebuild my gn, but after doing the timming chain and flushing the oil and doing the valve springs etc. i ran on havoline for the first 2 oil change, switched back to mobile one 15w50, synthetic is great though. I love it.

 

[V6UnderPressure]

Hey Surej, I told you to use the Prasad Bearings, But did you listen? NooooooooOOOOOOO!

Scott

 

[clean86]

Surej, IMHO you can't keep that thing alive because you BEAT THE SNOT OUT OF IT!!!.

Just kidding bud, like we talked about the other day, I think the mains where set up wrong. It should have taken out the rods first if it was from you 2 ton foot. Call him on it!! You know how I feel about reputed engine builders!!
Jeromy

 

[DR BOOST]

ttt

 

[6PacktoGo]

The only real problems with synthetic oils are not really problems.

First off, synthetic oil will sometimes prevent new rings from seating on fresh engines. Use a 20W50 or 30W good quality mineral based oil for the first 3K miles, changing it every 1K, and then switch to synthetic oil.

Second, synthetic oil will find every weak seal in an older engine and escape through it. If you have even a slight oil leak on mineral based oil, you'll have a big leak with synthetic oil.


Third, in some cases, we've seen synthetic oil combine with poor quality lifters or worn lifters to kill a cam. The reason is that lifters are SUPPOSED to have a crown on the face (it is a 360" radius if you really want to know), but the poor quality lifters we've seen, and worn lifters also, do not have that full crown. Without the crown on the lifter, the taper of the lobe will not make the lifter spin. If a lifter stops spinning, it will soon destroy itself and the cam. Synthetic oil is so slick that we have seen it allow the lifters to stop spinning if the crown is not there.

None of those problems are actually a fault of the oil.

Regarding your main bearing failure, synthetic oil did not cause it. Since the rod bearings are fine, oil starvation is not a problem. I'd say there is likely a problem with the machine work. Hard to say without actually seeing and measuring the parts in question.

 

[V6UnderPressure]

HEY ILBCNU6, I think Surej had all the work done by Pete. But I could be wrong. Correct me on this if I am wrong Surej.

Scott

 

[gnsrule]

Hey Surej, It was funny you said this....
While I was at a reputable rebuilder and talking about your motor in question, a kid brought his motor in in a box, same stuff, wiped bearings. When we asked what oil he used, there was silence...untill he said synthetic....then we all startd lafing our ass's off.
Ive never run syn in anything before, and have never had an oil related problem...EVER
I run 20/50 no synthetic in my 87, and thats what im gonna run in the 86. $0.89 a quart, nothing but the best in my motor.
Good luck....
BTW, was that you at the shop or Prasad that day, i dont remember
Good Luck

 

[Ken H]

DR BOOST, if you don't mind me asking, what kind of pistons were you running in your rebuilt engine. Just curious as I have experienced the same problem as you in the past.

Thanks, Ken

 

[V6UnderPressure]

Originally posted by gnsrule
Hey Surej, It was funny you said this....
While I was at a reputable rebuilder and talking about your motor in question, a kid brought his motor in in a box, same stuff, wiped bearings. When we asked what oil he used, there was silence...untill he said synthetic....then we all startd lafing our ass's off.
Ive never run syn in anything before, and have never had an oil related problem...EVER
I run 20/50 no synthetic in my 87, and thats what im gonna run in the 86. $0.89 a quart, nothing but the best in my motor.
Good luck....
BTW, was that you at the shop or Prasad that day, i dont remember
Good Luck

Hey gnsrule, what brand oil did you use?

 

[aperrego]

So what is the best oil out there?

 

[DR BOOST]

trw forged with lightweight pins

surej

 

[gnsrule]

Scott, Ive been runnin Castrol 20/50 mineral oil for the last 14 yrs in the 87. Granted, thats only 42k on it, but still, no problems yet. I get 18 psi at idle and about 60 at rpm. Thats a stock cover w/ a hi volume kit, added about 8 yrs ago along w/ a external filter (ie: turbo saver).
BTW, a buddy just calld me tellin me his Harley w/ a big bore kit, cam, S&S carb, etc is puffin out the rear cylinder. After talkin for a bit, i ask what oil hes runnin, he tells me syn. Hmmmmm, I dont know Harley's, but it sure is coinsedence that its synthetic.
Like i said, I'll stick w/ good old 0.89 cents a quart, nuthin but the best for my motor.

 

[turbosam6]

aperrego-

WEAK dude, you so bogarted my avatar. You should change it, I had it first.