synthetic oil
12-13-2016, 03:38 PM
#1
Racer
Thread Starter
synthetic oil
i want to run synthetic oil in my built 350 engine. All the old timers
tell me not to run synthetic oil as my motor will start leaking?
what would be the worst case scenerio if i just put synthetic oil in my
motor and see what happens? can i go back to regular oil if the synthetic
oil starts to leak? thanks for any insights. Has anyone just changed
over to synthetic oil? what happened and did u notice anything different
about the way your motor performed or the way it ran? thanks
tell me not to run synthetic oil as my motor will start leaking?
what would be the worst case scenerio if i just put synthetic oil in my
motor and see what happens? can i go back to regular oil if the synthetic
oil starts to leak? thanks for any insights. Has anyone just changed
over to synthetic oil? what happened and did u notice anything different
about the way your motor performed or the way it ran? thanks
12-13-2016, 03:58 PM
#2
Le Mans Master
When I had my 1st 54 Corvette with the original Blue Flame Six the car did leak Transmission fluid even after it was rebuilt but for the motor itself it did not leak a drop of oil. Being slick thinking synthetic oil would be better for the block and all the parts inside I changed to a synthetic oil. Now you have to realize that back then the Blue Flame Six did not have an oil filter so I did not have to buy one, but when I started the motor and with in 5 to 8 min. I had an oil leak. No I didn't I had several oil leaks. So I did the smart thing and drained all the synthetic oil out and let it drain for 24 hours and put back in 10 W 30 and it still leaked in several places. I drove the car about 10 miles and pulled in the garage and still leaking. Then back to changing the oil again. This went on if I remember right 4 oil changes before the motor stopped leaking oil. From then on all I ever used was 10 W 30 in the car and never had an oil leak again. Now would I use synthetic oil in an older motor??? HELL NO. 
But you do what you want. These older motors were not machined like the newer motor are and the thicker oil helped keep them from leaking and the synthetic oil being so slick and thin it will find a place to leak out if there is one and there are plenty on the older motors. There is my $0.02.worth. 
But you do what you want. These older motors were not machined like the newer motor are and the thicker oil helped keep them from leaking and the synthetic oil being so slick and thin it will find a place to leak out if there is one and there are plenty on the older motors. There is my $0.02.worth.
Last edited by Mike Terry; 12-13-2016 at 03:59 PM.
12-13-2016, 05:16 PM
#3
Race Director
Member Since: Jun 2006
Location: Inverness FL
Posts: 17,891
Received 727 Likes
on
621 Posts
St. Jude Donor '07
my story...
my new ZZ4 crate engine used about 1/2qt+ between 3,000 mile oil changes, I switched to 10w30 synthetic and didn't used a drop on a 10,000 mile trip...
I now use synthetic in EVERYTHING I own...
try it, it won't hurt a thing...
Bill
my new ZZ4 crate engine used about 1/2qt+ between 3,000 mile oil changes, I switched to 10w30 synthetic and didn't used a drop on a 10,000 mile trip...
I now use synthetic in EVERYTHING I own...
try it, it won't hurt a thing...
Bill
Last edited by wmf62; 12-13-2016 at 05:17 PM.
The following users liked this post:
ArmchairArchitect (11-05-2018)
12-13-2016, 05:21 PM
#4
Team Owner
More urban myth. If synthetic oil makes your engine leak it had issues to start with...
12-13-2016, 06:29 PM
#5
Race Director
Member Since: Apr 2015
Location: Fresno California
Posts: 17,505
Received 3,443 Likes
on
2,113 Posts
Use the synthetic, by all means. Synthetic flows better than dino oil, due to the polymer chains being all the same size (think of a room where only golfballs are on the floor). Dino oil has polymer chains with different size molecules (think of a room with BB's, marbles, golfballs, basketballs, etc. on the floor). So, if you have a poorly sealed engine to begin with, synthetic will more easily pass through the faulty seals. If you have a nicely sealed engine that doesn't leak, no issues. I use synthetic in my 4x4, because it stays in a liquid state at much higher temps than dino oil. This may be a life-saver if I need to get out of the desert with a defective cooling system out in the middle of nowhere. Synthetic is good stuff, and has better 'cling' than dino oil too, so it tends to stay on surfaces a long time. Something to consider if your car sits for a few weeks between fire-ups. Oil on the bearings and cylinder walls at start up is a good thing.
12-13-2016, 11:05 PM
#6
Drifting
I can't believe that old myth is still a thing after what, 25 years now?
Those old timers you are listening to are filling your head with complete non-sense.
What you should be doing is your own research on grades, basestocks, and additives of different synthetic oils.
https://www.bobistheoilguy.com/forums/ubbthreads.php
Those old timers you are listening to are filling your head with complete non-sense.
What you should be doing is your own research on grades, basestocks, and additives of different synthetic oils.
https://www.bobistheoilguy.com/forums/ubbthreads.php
Last edited by 92GTA; 12-13-2016 at 11:07 PM.
The following users liked this post:
ArmchairArchitect (11-05-2018)
12-13-2016, 11:40 PM
#7
Safety Car
Member Since: Jan 2000
Location: Poway CA
Posts: 4,845
Received 1,295 Likes
on
560 Posts
2023 C1 of the Year Finalist - Unmodified
2022 C1 of the Year Finalist - Unmodified
2021 C1 of the Year Finalist - Unmodified
2019 C1 of Year Finalist (stock)
2016 C1 of Year Finalist
Like most wives tales, it has a truthful origin.
Something in dino-oil causes seals and gaskets to swell.
It's not that the synthetic CAUSED leaks.. rather, the seals would shrink without being exposed to dino-oil, thus creating leaks.
Around 2003, changes were made in synthetic oil, including Mobile 1. They added a "synthetic ester" to simulate the seal-swelling effect that dino-oil has.
I switched to Mobile1 15W-50 in my motor (1970 LT-1, never rebuilt) 2 years ago. No leaks.
Motor oil is like religion (!).. Do your own research and reading.. and make the decision right for you!
Something in dino-oil causes seals and gaskets to swell.
It's not that the synthetic CAUSED leaks.. rather, the seals would shrink without being exposed to dino-oil, thus creating leaks.
Around 2003, changes were made in synthetic oil, including Mobile 1. They added a "synthetic ester" to simulate the seal-swelling effect that dino-oil has.
I switched to Mobile1 15W-50 in my motor (1970 LT-1, never rebuilt) 2 years ago. No leaks.
Motor oil is like religion (!).. Do your own research and reading.. and make the decision right for you!
Last edited by SDVette; 12-14-2016 at 01:42 PM.
12-14-2016, 07:48 AM
#8
Race Director
Member Since: Jun 2006
Location: Inverness FL
Posts: 17,891
Received 727 Likes
on
621 Posts
St. Jude Donor '07
Like most wives tales, it has a truthful origin.
Something in dino-oil causes seals and gaskets to swell.
It's not that the synthetic CAUSED leaks.. rather, the seals would shrink without being exposed to dino-oil, thus creating leaks.
Around 2003, changes were made in synthetic oil, including Mobile 1. They added a "synthetic ester" to simulate the seal-swelling effect that dino-oil has.
I switched to Mobile1 15W-50 in my motor (1970 LT-1) 2 years ago. No leaks.
Motor oil is like religion (!).. Do your own research and reading.. and make the decision right for you!
Something in dino-oil causes seals and gaskets to swell.
It's not that the synthetic CAUSED leaks.. rather, the seals would shrink without being exposed to dino-oil, thus creating leaks.
Around 2003, changes were made in synthetic oil, including Mobile 1. They added a "synthetic ester" to simulate the seal-swelling effect that dino-oil has.
I switched to Mobile1 15W-50 in my motor (1970 LT-1) 2 years ago. No leaks.
Motor oil is like religion (!).. Do your own research and reading.. and make the decision right for you!
Bill
12-14-2016, 08:19 AM
#9
Drifting
If your motor leaks oil it needs a gasket. I have used Amsoil synthetic oils since it came on the market many years ago and never had a problem. I also use Amsoil in my Muncie transmission in my Chevelle and put on over a 100,000 miles with no problems. I have run Amsoil in my Corvette motor and transmission now for over 50,000 miles no problems.
Dave
Dave
12-14-2016, 08:20 AM
#10
Le Mans Master
Member Since: Mar 2010
Location: The Golden Triangle, Florida
Posts: 6,200
Received 1,581 Likes
on
818 Posts
2023 C2 of the Year Finalist - Unmodified
St. Jude Donor '20-'21-'22-'23-'24
I've been using Mobil 1 15W-50 in my original 50 year old engine since I've owned the car. The only leak I've had was a drip from the oil drain plug. Replaced the plug and no more leak.
Steve
Steve
12-14-2016, 09:18 AM
#11
Team Owner
Mobil 15W-50W flowed through the veins of my '61 for ten years and my '63 for the last 3 years... I did put a rear main seal in the 63 (just worn out) and no leaks since.
12-14-2016, 09:19 AM
#12
Drifting
We rebuilt my small block in 1990. Started with conventional 10W40. Did a quick oil and filter change with the same type at 50+ miles to make sure any assembly lube was drained. Then drove easy (up shifting and down shifting) for about 700-800 miles. At that point I changed again and switched to Mobil1 15W-50. Annual oil and filter changes ever since and have experienced no oil leaks.....
12-14-2016, 10:22 AM
#13
Race Director
Member Since: Apr 2015
Location: Fresno California
Posts: 17,505
Received 3,443 Likes
on
2,113 Posts
If you're changing your synthetic oil annually, I hope you're driving 10,000-15,000 miles a year...otherwise you're throwing money away.
12-14-2016, 10:52 AM
#14
Drifting
12-14-2016, 11:23 AM
#15
Race Director
Member Since: Apr 1999
Location: Beverly Hills/Pine Ridge Florida
Posts: 10,733
Received 561 Likes
on
349 Posts
I usually stay out of these oil threads, but............ FWIW...
I have a 327/250 HP engine from a full size Chevy in my 37 Chevy street rod.
I have a sticky lifter... #7 exhaust.
Played with adjustments, etc.
I ran both Marvel Mystery Oil and Sea Foam in the dinosaur oil I had been using. (NOT at the same time
)
Recently, I put Mobil 1 5/30 in it, along with a bottle of Rislone.
Long story short... I have no leaks with the synthetic. I've put only 50 driving miles on it, but it has about 2 hours of idling time on it.
I still use dinosaur oil in my 63 Corvette and 56 Chevy.
I have a 327/250 HP engine from a full size Chevy in my 37 Chevy street rod.
I have a sticky lifter... #7 exhaust.
Played with adjustments, etc.
I ran both Marvel Mystery Oil and Sea Foam in the dinosaur oil I had been using. (NOT at the same time
) Recently, I put Mobil 1 5/30 in it, along with a bottle of Rislone.
Long story short... I have no leaks with the synthetic. I've put only 50 driving miles on it, but it has about 2 hours of idling time on it.
I still use dinosaur oil in my 63 Corvette and 56 Chevy.
12-14-2016, 01:41 PM
#16
Le Mans Master
Like most wives tales, it has a truthful origin.
Something in dino-oil causes seals and gaskets to swell.
It's not that the synthetic CAUSED leaks.. rather, the seals would shrink without being exposed to dino-oil, thus creating leaks.
Around 2003, changes were made in synthetic oil, including Mobile 1. They added a "synthetic ester" to simulate the seal-swelling effect that dino-oil has.
I switched to Mobile1 15W-50 in my motor (1970 LT-1) 2 years ago. No leaks.
Motor oil is like religion (!).. Do your own research and reading.. and make the decision right for you!
Something in dino-oil causes seals and gaskets to swell.
It's not that the synthetic CAUSED leaks.. rather, the seals would shrink without being exposed to dino-oil, thus creating leaks.
Around 2003, changes were made in synthetic oil, including Mobile 1. They added a "synthetic ester" to simulate the seal-swelling effect that dino-oil has.
I switched to Mobile1 15W-50 in my motor (1970 LT-1) 2 years ago. No leaks.
Motor oil is like religion (!).. Do your own research and reading.. and make the decision right for you!
When I put Mobile 1 in my '64 way back when, it caused it to leak. I got a couple cases back then so I live with it.