A question about oils

[skyhawg]

Hello all.. a quick question.. I'm getting ready to put oil in the motor i have just rebuilt.. I planned on using a straight 40 weight oil for breakin.. I have used other oils in the past but cant remember exactly what it was..
Which oil do you all recommend for break in??
Also I have one book that says to use a ATF fluid in the Tranny (727), the same book also says to use Dextron in a standard tranny... Another book I have says to use Dextron II in the 727... again which oil do you guys use? I have been using Dextron in it prior to rebuild but want to be sure I use the right stuff..

Sorry for such simple sounding questions.. but I would rather sound silly then screw something up..

Jim

[Tarrbabe]

I usually use the oil that I plan to run. I also change my oil after 30 minutes and look for anything odd in the oil and filter. How do you plan to break-in your engine? How long before oil change? Did you change camshaft? A race engine is often broken in differently because of clearances and style of rings.

[6 packin]

I would suggest running a step lighter oil or so during break in! Also make sure you bring it up when it fires to at least 1800-2000 RPMs for 20 minutes or so, or untill operating temp! Like babe said! These is very important when dealing with new cam and lifters. Also after the first run change the oil and check valve train and so on before you start it with the fresh oil which now should be like a 10w-40 in hot conditions ..

Happy motoring!

[dave571]

As indicated in an earlier post, straight 40 weight is too thick for break in. Way to thick.

I usually start with 5w30, 10w30 isn't bad either. Then run it in just like 6packin said. Change the oil again and carry on.

With the 40 weight you might do some brg damage. Then in 6 months it'll show up when a rod comes out the side of the engine. Then you'll do this

[skyhawg]

I will be primarly using the car as a daily driver.. and yes usually in hot conditions.. I'm in Florida.. lotsa bad traffic.. so hot conditions, and not moving very fast..
I rebuilt the entire engine.. Crank was turned down .010.. rods were resized, new pistons. pistons and rods were balanced to within a gram of each other. .. Pistons are .030 over.. so block was also honed.. new Edelbrock cam and lifters.. the one in the performer kit with the manifold.. new carter mechanical fuel pump. The MP high volume oil pump. On your guys recommendations.. a windage tray... New valve spings on all valves and I had hardened exaust seats put in and new exhaust valves. ( had some small cracks there ). Oh yeah the motor is a 400... Also on your guys recommendations I went to a 750 cfm carb (Edelbrock) and TTI headers..
I have also rebuilt my tranny and put in a TCI street fighter TC which is about 500rpm above stock...

That should have answered your set of questions to me..

So if I plan on using a 40 wt oil I should go the first 30 min or so using 30 wt.. check and change the oil and go with the 40 wt for the next 500?
How bout the tranny?

Thanks Jim

[dave571]

No.

Straight weight oil is WAY to thick for break in. In general there are no benefits to using straight weight in an automotive engine. For the most part, straight weight oils are used in air cooled applications.

Run it in, with either 5w30 or 10w30.

Then you could use 10w40 when driving in the heat. Even with that said, I wouldn't run heavier than 10w30 until you have 1000miles on it.

The new brgs ect make the clearances in the engine tighter. A thicker oil (like straight weight 30 or 40) is very difficult to push through the brgs to lube them. Since everything is "new" you want to start with a thinner oil, and only use heavy oil when the engine is broken in. Even then, only if the oil pressure drops off when hot.

As for the transmission, Dextron is fine in your transmission.

[jelsr]

I agree with the lighter oil concept, 5-30 would be fine. Just be sure to prime it before striking the flint, and keep the r's around 2K for 20-30 min as was posted earlier.

[6Cuda6]

Just as the guy's are saying...10w30 oil for break in..than i would switch up to 20w50....i wouldn't use straight weight oil, what are they using at the dealerships on new cars???it's usualy a good indication of what you'll need...

As for the trans, use TYPE "F" trans fluid...better viscosity and less slippage..if youre running a 4 gear use the standard 80-90 gear oil [stay away from the synthetic as we are experiencing problem with it]