What oil to use when starting a fresh motor? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**ScottH** · 09-21-2004, 03:07 AM

What is the best oil, weight, etc. to use to break in a newly rebuilt engine? Any suggestions are appreciated.

Thanks.

68w/sbc406 · 09-21-2004, 03:08 AM

i used castrol gtx 10-40

Longhorn Man · 09-21-2004, 03:33 AM

As long as it is detergent, and non-synthetic.

**ScottH** · 09-21-2004, 03:37 AM

I thought I remembered someone saying a straight weight is best for breakin, but wasn't sure.

incoma · 09-21-2004, 03:42 AM

I always use 30W for the first hour, then swap to 10/40. I do this just to clean the engine out.

*1972C10* · 09-21-2004, 05:15 AM

I put 6 quarts of valoline 10W40 in mine and change it out at 500 miles then 3000 from then on.

I only overfill the engine by a quart the first time for break in.

**'68OrangeSunshine** · 09-21-2004, 08:57 AM

I'm breaking in my new 292 with 6 quarts of Napa straight 30 SAE non-detergent for the first 100 miles, then switching to detergent 30 weight. I will also add the 8 oz bottle of GM break-in oil (EOS).

mrein3 · 09-21-2004, 01:04 PM

Quote:

Originally Posted by '68OrangeSunshine

I'm breaking in my new 292 with 6 quarts of Napa straight 30 SAE non-detergent for the first 100 miles, then switching to detergent 30 weight. I will also add the 8 oz bottle of GM break-in oil (EOS).

That is what I was always told. Straight 30, non-detergent for cam break-in and 50 miles after that. Then switch to detergent straight 30. I then dump that at 500 more miles and switch to 10-30 for the rest of the engines life.

**lolife99** · 09-21-2004, 01:10 PM

Gm's EOS (engine oil suppliment) with your normal weight oil.

Joe67 · 09-21-2004, 01:34 PM

I've heard it is best to use dino oil on a new engine, but then again the Corvette and exotics use Mobil 1 from the start with no issues

bigjimzlll · 09-21-2004, 02:35 PM

Quote:

Originally Posted by 67c10step

I've heard it is best to use dino oil on a new engine, but then again the Corvette and exotics use Mobil 1 from the start with no issues

vettes have roller cams. , I use store brand 30 weight and EOS//for the first 20 miles or 20 minuts,which ever comes first..then mobile one synthetic. If the rings are not seated by the time the cam is broke in..somethings wrong

inline6Bill · 09-21-2004, 05:10 PM

Valvoline 30 wt with GM Engine oil supplement for the first 50 miles/50 minutes. 30 wt Valvoline, changed again @500 miles, 1500, then every 2000 to 3000 miles thereafter. One engine I have done this to just ticked over 150,000 since the rebuild. Can't complain about that.

**FRENCHBLUE72** · 09-23-2004, 12:19 AM

10 W 30 Valvoline Never Had A Failure Yet???

gonebad2 · 09-23-2004, 07:47 AM

Is there much value in using the GM EOS ? I have purchased several GM crate motors in the past and have been forced to purchase it when I purchase the crate motor by the GM parts guy. He says you won't get the warranty if you don't buy it. I have always dumped it in with the oil during the break in period. Just wondering??

sbc350gearhead · 10-04-2004, 07:42 PM

Never use a ND oil in a modern engine. They don't generally have the anti-wear and anti corrosion additives necessary to fully protect your engine. GM's EOS is loaded with anti wear agents, which may offset this to some extent........but there is just no reason to use a ND oil. Some very old engines with rope seals are not compatible with detergent oils, but these engines are few are far between.

09-21-2004, 03:07 AM	#1
ScottH Senior Member Join Date: Sep 2002 Location: Hampstead, NC Posts: 8,187	What oil to use when starting a fresh motor? What is the best oil, weight, etc. to use to break in a newly rebuilt engine? Any suggestions are appreciated. Thanks.

09-21-2004, 03:08 AM	#2
68w/sbc406 Got Light Emitting Diode? Join Date: Apr 2004 Location: Newberg, OR Posts: 2,485	i used castrol gtx 10-40 __________________ 1968 1/2 ton 2wd lwb 6 lug disc and bags up front. Next c notch and rear bags '02 Chevy Silverado LT ext cab short bed 2WD 5/7 drop on 22's(the family car) 1993 Cherokee work ride/weekend wheeler

09-21-2004, 08:57 AM	#7
'68OrangeSunshine Senior Member Join Date: Feb 2002 Location: Tucson, AZ USA Posts: 7,189	I'm breaking in my new 292 with 6 quarts of Napa straight 30 SAE non-detergent for the first 100 miles, then switching to detergent 30 weight. I will also add the 8 oz bottle of GM break-in oil (EOS). __________________ Every 25 years I like to rebuild that 292, whether it needs it or not.

09-21-2004, 01:10 PM	#9
lolife99 67-72 parts collector,… Join Date: Nov 2002 Location: Mid-MO Posts: 22,691	Gm's EOS (engine oil suppliment) with your normal weight oil. __________________ Keith Convert to disc brakes. http://67-72chevytrucks.com/vboard/s...d.php?t=444823

09-21-2004, 01:34 PM	#10
Joe67 67 is sold Join Date: Apr 2001 Location: Troy, Michigan Posts: 6,738	I've heard it is best to use dino oil on a new engine, but then again the Corvette and exotics use Mobil 1 from the start with no issues __________________ Joe - Formerly 67c10step ------------------------------- 1967 Chevy Stepside - ECE 4/6, fuelcell, 5lug - SOLD gr8lakes - My ebay auctions Click here to order forum apparel :: Click here to become a subscribing member

09-21-2004, 03:33 AM	#3
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	As long as it is detergent, and non-synthetic.

09-21-2004, 03:37 AM	#4
ScottH Senior Member Join Date: Sep 2002 Location: Hampstead, NC Posts: 8,187	I thought I remembered someone saying a straight weight is best for breakin, but wasn't sure.

09-21-2004, 03:42 AM	#5
incoma Registered User Join Date: Mar 2004 Location: Lexington, KY Posts: 865	I always use 30W for the first hour, then swap to 10/40. I do this just to clean the engine out.

09-21-2004, 05:15 AM	#6
1972C10 Account Suspended Join Date: Dec 2003 Location: Texas Posts: 2,686	I put 6 quarts of valoline 10W40 in mine and change it out at 500 miles then 3000 from then on. I only overfill the engine by a quart the first time for break in.

09-21-2004, 05:10 PM	#12
inline6Bill A classic GM kinda guy Join Date: Mar 2004 Location: Phoenix, Arizona Posts: 296	Valvoline 30 wt with GM Engine oil supplement for the first 50 miles/50 minutes. 30 wt Valvoline, changed again @500 miles, 1500, then every 2000 to 3000 miles thereafter. One engine I have done this to just ticked over 150,000 since the rebuild. Can't complain about that. __________________ Old school rap music: a dual exhausted GM 6 with no mufflers. "If you can find a better vehicle, buy it" Lee Iacocca, Chrysler commercials of the '80s. "I did. They are called Classic GM pickups !!!"

09-23-2004, 12:19 AM	#13
FRENCHBLUE72 PROJECT 7DEUCE Join Date: Dec 2002 Location: GRANTS PASS OR Posts: 21,594	10 W 30 Valvoline Never Had A Failure Yet??? __________________ GO BIG GREEN GO DUCKS MEMBER #6377 72 k-5 daily driver 6'' lift 35'' 350-350-205 slowly getting rust free. Project "7DEUCE" check out my build http://67-72chevytrucks.com/vboard/s...d.php?t=267665 Tim Powell..R.I.P EastSideLowlife..... R.I.P..

09-23-2004, 07:47 AM	#14
gonebad2 Merciless Butcher Join Date: Oct 2003 Location: CC Nevada Posts: 1,447	Is there much value in using the GM EOS ? I have purchased several GM crate motors in the past and have been forced to purchase it when I purchase the crate motor by the GM parts guy. He says you won't get the warranty if you don't buy it. I have always dumped it in with the oil during the break in period. Just wondering?? __________________ Your Bought And Sold....I Got Your Soul!

10-04-2004, 07:42 PM	#15
sbc350gearhead Registered User Join Date: Mar 2003 Location: Columbus Ohio Posts: 1,413	Never use a ND oil in a modern engine. They don't generally have the anti-wear and anti corrosion additives necessary to fully protect your engine. GM's EOS is loaded with anti wear agents, which may offset this to some extent........but there is just no reason to use a ND oil. Some very old engines with rope seals are not compatible with detergent oils, but these engines are few are far between.



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