Reg Vs Synthhetic oil

[jp70deville-CLC #24151]

I'd like anyone's advice of which to use for my car..Been sitting for 14 years, 39 K on the odo. Runs fine, but cold starts are a little rough...I think that that in part might be due to the exhaust, which is on oreder to be replaced from to back.... One friend tells me to use synthetic, , the other says no way!....  Is it true that once you use synthetic, you can't go back to reg oil?  Any thought comments are much appreciated

Thanks in advance, Jeff

[jeff1956]

one word of caution.  synthetic runs very clean, but on an old engine that means it will clean all the old gunk on the inside which will lead to at very least...leaks worst it could clog something by dislodging a hunk of old hardened sludge.  i stick with dino oil on my 56.....but use synthetics in all the new stuff.

jeff

[jp70deville-CLC #24151]

Thanks Jeff...I bought the 6 qts of syn, but have been having second thoughts...I still have the receipt so I am thinking I should return it and stick to reg 'ol oil
Thanks for the reply,
Jeff

[Otto Skorzeny]

Yes jp, I would use the regular oil. It's seemed to have worked ok for the car its whole life, why change now?

If it were a newly rebuilt engine then you might consider the synthetic.

[jp70deville-CLC #24151]

Thanks Otto..
OK you both have convinced me enough!!

Jeff

[RobW]

Why 6 quarts? It should only need 5 with a filter change and 4 without.

[jp70deville-CLC #24151]

Hey Rob..I know that 4 is std..but it reccommends 5 for a filter change..just wanted one more for the sake of..I dunno whatever ..Nonetheless, I'll be taking them all back

[John Barry [CLC17027]]

I would tend to be very cautious about using synthetic oil on a vintage engine for the simple reason that those engines were engineered to use refined petroleum lubricants in the first place.  Recall that synthetics didn't become common until the late '70s/early '80s, so I'd shy away from using them on any engine older than roughly 25 years (my own sense of the matter, anyhow).

[Jim Stamper]

     In 1960 I bought my first car, at about 16, a 1942 Chevy "blackout" car. In california and no rust, not even a very old car then. In my rush to do kind things to it I changed the oil, using Union Oil's " Royal Purple Triton" I think it was called. I turned a non-detergent oil using non-smoker in to a true smoke bomb in about a day with that high detergent oil.

     So my next kindness was rings and a valve job. My high school auto shop ground the valves and got the head ready as a project, while I rolled around under the car in the sand and wind tending to the other duties. The rings went OK, I even removed the ridge at the cylinders tops, and since the car had about 80,000 military miles on it I figured I should probably remove a brass shim from each rod bearing. This I did, and finished reassembling the engine. It wouldn't start so a friend towed me and it started and actually ran pretty well after that initial startup. But at about 1500 miles #6 rod went through the left side of the block. I pulled over, saw the rod and piston bits hanging out and reached down and collected them, started the car up and drove the remaining half mile home.

     You may have guessed I had very little guidance but much enthusiasm all through that adventure, starting with learning an important lesson about old engines and new oil. ( and other lessons too)

                                                    Jim Stamper #13470

[mike mason]

Have had this synthetic v non-synthetic oil discussion (sometimes very heated) with family, friends, mechanics & shops for many many years.    Have long since converted all vehicles, new, old & race to synthetic, including drive every day 65 MGB & 50 Cad.  Results: no new smoking or leaks, higher oil pressure, lower operating temperature, smoother running. 

Wouldn't go back.
Mason

[Misfit]

I'm glad I'm not the only one Mason. I run 10W-40 full synthetic in my '59 Cadillac, my '76 Eldorado and the 2 daily drivers. The daily drivers get the 30 weight though.The '59 quit with the blow-by and oil use, is smoother and quieter.

No change in the Eldorado except at start up. It starts after a week, just like you had it running a minute ago. Smooth and quiet.

There will always be the diehards in anything you discuss. I'm pulling the engine and trans out of the '59 due to severe trans leaks. I'll go through the engine just because it's out and I can detail the engine bay at the same time.

Again, there will be Valvoline 10W-40 full synthetic going in the engine and a fully synthetic transmission fluid too.

To each his own.

MisFit

[Jim Stamper]

     I believe in synthetic oils too, but I am trying to make a distinction here between newer cars from the 60s and 70s that undoubtedly have always had detergent oils in them and consequently are likely to be very clean and sludge free inside, and older cars from the 50s on back that have been slumbering for a long time and have only known non-detergent oils. These engines, some of which don't even have oil filters, are very sludgy inside and melting that sludge loose with any sort of detergent oil is courting disaster for that engine and will likely provide a discouraging start in the old car hobby for the new guy on the block.

     Has anyone dumped synthetic oil in a long slumbering 60 year old car? I am not saying it can't be done, I just think that would be reckless. Hopefully, new people join the hobby all the time. Some have good advisers on how to go about things, others read something and take it as gospel and apply it to the wrong situation.  That was just how I got my start in cars and many costly lessons were learned.

     Carefully suit the action to be taken with your specific situation. Ask questions.    Jim

     

     

[The Tassie Devil(le)]

I may be wrong, and have been known to be on a number of occasions, but I believe that Synthetic Oils shouldn't be mixed with Petroleum-based Oils.

And, an engine should not be changed to Synthetic until it has been totally stripped down, cleaned out, and re-assembled.   This is usually done at the time of rebuilding.

Bruce.

[TJ Hopland]

So what is a synthetic blend that all the brands seem to offer then?  That would seem to be a mix?  I have been running a blend in my daily driver in the winter for a few years now.  I started out with that because it was all I could find in the 5-20 weight.  Now there is getting to be more options so I guess I could switch but its worked well so far and I resist change...

The last few machine shops I have used for projects both told me to do the first 1000 or so on regular with some cam additive then use what ever I want.   I have put synth in old crusty stuff and it did not seem to be any different than any other fresh oil or cleaning.  I believe the detergents are the same either way (assuming you are not buying non detergent oil).  As for leaks and other issues that also did not seem to change.  If it leaked and smoked before it leaked and smoked after.  Starts do seem happier with synth other than that its just the cost which in the big picture of owning and operating an car is nothing.

[jp70deville-CLC #24151]

It's funny you you overlook things

In my stupidity, in all of this time, I did not tell you all that the orig owner installed an aftermaket  FRANZT FILTER!!! Obviously, I known this for a year...He was a WWII man, and apparently saw the marvel/longevity in tank and marine engines...I cannot/still/don't/ will not tell people I put toilet paper in my Cadillac's oil filter..it's an odd concept, I'll admit and seems true on the premise....but it is one pain in the ass when I wanna work on something close to the cowl....I think she needs to go...BTW 10/40 is fine with her