ls3 GMPP Crate motor first start

[Vegas69]

You have enough opinions to choke a horse here. If you want to I say do it! BUT, I'd pull off the belt to limit your risk of compromising the water pump seal.

[DRJDVM's '69]

I filled mine with straight water and pressure tested it.... fixed a few small leaks....
Cycled the fuel pump with the front line in a can, got the air out any trash in my lines post filter.... then hooked up to the rails and cycled pump again and looked for leaks...
You wont hurt anything by doing it the other way, but other than hearing it run for 20 seconds I don't see the point....I'd rather have it be able to run for a longer time so I can go over the entire thing....let the cooling system build pressure etc.... there are plenty of things that you may not know about until its been running for at least a few minutes and even more once its at full temp...

I get not having EVERYTHING installed...... but by doing it this way all you really know is that you can get it to run....which is good.... but lots of other info will still be unknown until it runs for a longer time

To each his own.... nothing wrong with either way.....

[RdHuggr68]

We did not start my LS3 just to hear it run, we were just at a point where we wanted to make sure everything was good before continuing on. Front drive wasn't installed, it probably was only 12 seconds of runtime. No issues. Finished build, drove he car about 400 miles was run on a dyno. Then changed oil, cut the filter in half to make sure no surprises were in it. HP and torque were great for a stock 525 LS3

[XLexusTech]

Just to provide some additional context.

The plan was for the bodyshop to prep the firewall and dash and paint. Then return the car back to me to drop the engine back in. I was going to plumb wire and fire to work out kinks , leaks ect.. so that I was not crawling all over a freshly painted car.... then return the car to bodyshop to complete the paint work.

When I received the car back the first time.. the work that was done was not acceptable... I was asked to just drop the motor in and send it back so the "we can make this right" this turned into a 3+ year Body shop prison situation worthy of its own thread of lessons learned...

Resulting in, the car being fully painted without ever being fired.. so now I am in the exact position I DID NOT want to be in... I freshly painted car yet to be be fired where leaks and ghost issues could be a reality..

we live... we learn..

[dhutton]

I first fire freshly painted cars all the time. LS start ups are generally trouble free. Prime the fuel and oil pressure, turn the key and they start. Make sure your hose clamps and AN fittings are tight and you should be fine imho.

Don