oil difference
Thread Starter
Pro
Joined: Aug 2003
Posts: 635
Likes: 1
From: cincinnati oh
oil difference
ok. i know we have beat this to death. but serious question here. i switched from synthetic 10w 40 to regular 20w 50 and my engine seems less aggressive. now i know some of you are thinking, bogus, but seems like it is kinda sluggish a bit and doesnt rev as high as easily. am i nuts. perhaps. but think i am going to switch back. i know if it is not broke, dont fix it. thought about a bit heavier for summer driving heat to protect engine. dumb maybe.
Burning Brakes
Joined: Jun 2005
Posts: 978
Likes: 1
From: Scranton Pennsylvania
I've always thought that conventional oil was more than adequate for older engines. I have however used synthetic in my wife's Cadilac's and Lexus. Only had my 63 a few years and I use Castol 10-40 with no problems. I thought that using synthetic in an older engine would increase the possibility of leaks. Anyway, you are absolutely correct, if it ain't broke, don't fix it. Go back to your original oil. Enjoy the ride!!
Thread Starter
Pro
Joined: Aug 2003
Posts: 635
Likes: 1
From: cincinnati oh
many thanks
always used mobil 1, but castrol is right there. considering a blend. just thought that it was wierd. i mean, never thought oil would make a difference. shows my ignorance. a nice compliment from a car that is wayyyy nicer than mine.
Burning Brakes
Joined: Aug 2005
Posts: 1,133
Likes: 2
From: Corona CA
The heavier oil could indeed make some difference in the spin up of the motor, and could cost you 5-10HP, but your butt dyno would have to be pretty sensitive. It is also possible your oil level is a bit high or the windage parts are not in the motor causing windage loses which maybe be more extreme in the thicker oil...maybe to be point of aerated oil causing minor lifter collapse and thus more power loss. All that is kinda extreme but it is 'possible' though not likely.
Last edited by macdarren; Jul 8, 2007 at 01:21 AM.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Safety Car
Joined: Feb 2003
Posts: 4,068
Likes: 27
From: St. Joseph Mo
Only leak it has is the drain plug, it needs a new gasket.
Edit: A small block has none of the following.
Push rod tubes 2 x 12 = 24
Rocker studs ...............12
Oil cooler rubber donuts...2
Oil cooler adaptor gasket..1
Total ..........................39
Last edited by 67L36Driver; Jul 8, 2007 at 11:23 PM.
Race Director
Joined: Feb 2004
Posts: 11,030
Likes: 2,587
From: Del Boca Vista FL
You are correct. Synthetics do not "cause" leaks. They simply clean out areas where there had been a build up of crud where oil could not pass through and allow oil to now pass through those areas that were previously closed off due to the build up of that crud and escape from the engine.
Don't get me wrong as I LOVE synthetic oil and use it in all my vehicles.
Rich
Thread Starter
Pro
Joined: Aug 2003
Posts: 635
Likes: 1
From: cincinnati oh
agreed.
mispoke. entirely. they are not the cause. but they do expose more leaks. for the reasons stated. have had many cars that have had conventional and once i switch over to synthetic, i get some leakage. it was not showing overfill and it was not severe, i just noticed it. so, last night i drained it and mobile 1 10w40 back in. engine happy again. spools up much quicker and easier. i can mostly hear the difference out of the chambered exhaust. now, is anyone else having trouble doing a thread search? i am getting no results even typing in something like oil.
Melting Slicks
Joined: Jan 2003
Posts: 2,817
Likes: 21
From: Somerset, NJ
I use a standard 10w30 in my C-2 and 10w40 in my C-3. I am using 5w30 in my Street Rod being it is a later model GM Crate motor calling for it. If the motor doesn't have much mileage say after a rebuild I would use 10/30. Either the 10w30 or 10w40 one will do the trick in these cars. The jury is still out on the synthetic as far as I am concerned. Being in the business nothing has convinced me from what I see everyday that it is any better.
