35th camaro

Had a 402 built,they said that they build them on the loose side, shop told me that my ls1 oil pump ported and shimed would be fine. what grade of oil should i run. 10w40, 20w50 or ???, what brand do you's use. i was using 5w30 mobile synth. i only run the car in summer.

G Engines

I would break it in on 10w 30 conventional and you can run a 20w50 for some added oil pressure. Valvoline VR1 is a great race oil that you can run more than 500 mile with.

35th camaro

thats what i had in mind, should i see a little more pressure with the 20w50, has anybody seen the difference?

jmdgto

i run 20w 50w in my 408 that G Engines built. it has a high volume oil pump. i am thinking to switching to 10w 40.

tom falco

I use 15-40 and thats all we use in my shop.

Jimbo'sZO6

iTrader: (1)

I have been running Rotella T 15w40 in my 416 since day one with no issues at all. Now at 4k miles I'm thinking of going with a synthetic, not sure which one yet. All of the good quality diesel engine oils have a high ZDDP content which is very good for engine break-in. Alot of hi-po engine builders recommend this oil for break-in.

Jimbo

35th camaro

is it ok to keep using that deisel oil 15/40 even after brake in periode?

35th camaro

jmdgto why are you considering going to 10/40?

tom falco

The 15-40 oils do not have zync in it any more. The epa pulled their crap and with the 07 enission standards on new trucks you cant have zync oils. The cat wont tollerate it. But not to worry 15-40 is fine because our engines have roller cams. Basically zync is meant for high friction areas like cam to lifter contact on flat tappet cams. You can buy EOS supplament from your chevy store or buy ZDDP on line. Never run a 10-40 oil in anything. Rule of thumb is the broader the numbers the less oil the oil has. example 10-30 is a higher oil content to chemical viscosity modifiers. 10-40 has more chemical modifiers then oil. We do run synthetics but got away from it because of the wild cams and profiles we run.

rpmauto

iTrader: (14)

I switched from 10w30 vr1 to 20w50 vr1 and have over 15psi better at hot idle. Motor was set up a little loose. I like the vr1 stuff because of the zddp. (off road use only)

35th camaro

i was looking at castrol synth 20/50 after the engine is broken in.

2 fast 2000

iTrader: (4)

Never run 10-40?? Are you crazy?? You got to come with something different than that for a excuse for not running 10-40. I've ran 10-40 royal purple for the last 6 years with no problems. There is not to much difference between 10-30 and 10-40 anyways. Not enough to make a statement about.

JimSwan

iTrader: (3)

i ran 10w-40 royal purple in only 2 motors both went through rod bearings with in 5 months i hate royal purple and will never use it, i had both motors for 3 years same setup as soon as i use royal purple they had problems and thats the only time ive had problems, that oil is junk and a waste ive heard countless bad things about royal purple have gone thru 2 motors thanx to royal purple, i use ams oil , full synth race oil and never had a problem.

tom falco

Ok a fiew years ago GM sent out a service bullitin about using 10-40. Once again an oil cant conform to a flow rating of a broad viscosity without VM modifiers. The broader the number 10-40 10-50 the more VM modifiers. And less oil. In the summer I run straight 30 in my engine. 10-40 is a very poor choice for a high performance engine. Tom
.

JimSwan

iTrader: (3)

yea same here ether 10w30 for winter and 15w-40 summer or straight 30 depending on the brand, use to use vr1 sraight 30 but im liking the ams oil and 15w-40

Pwebbz28

iTrader: (31)

Go with something the EPA doesnt regulate like it does shelf oil. I was told by my builder to use redline or amsoil.

2 fast 2000

iTrader: (4)

I was told you shouldn't be switching back and forth from heavier to thin motor oil. I was told it was very bad for the piston ring wear.

2 fast 2000

iTrader: (4)

My guess is you had maintenance issues with your ride, because I never had a problem out of Royal purple. Specialy being the fact you went through 2 rod bearings in 5 months. No doubt Amsoil is great but I love royal purple. The only oil that ever gave me any problems was redline.

tom falco

So then why do people run multi vis oils??????

There seems to be a lot of mistery about oils. First the W rating on any oil represents a winter oil. An SAE rating is a summer oil and is recommended for temps higher than 45* The service manual explains that. Most engines manuals will not recommend W oils in higher temps with sustained speeds. Changing viscosity will not hurt your engine. But running a multi vis oil in high ambient temps at sustained speeds is a NO NO. For a 4 cylinder grocery getter is fine. But not on a high output engine with high HP. Just my $.02

mebuildit

I find it strange to run multi viscosity oils for break in. I have always used straight weight oil for break in 30w. Once you get some time on the engine, do a leakdown on all of the cylinders to make sure everything has been seated in.
Only after everything looks good on the gages, that is when I switch over to synthetic.
Just my .02¢