7 Things To Know Before Starting A New Engine For The First Time

I can tell by the smile on your face that you just got your new engine back from the machine shop. It has taken a while to get everything you wanted, but there it is, the mill for your hot rod. Now you just need to get it in the car, and then fire it up. That sounds easy enough, but is it really that simple? To some extent, yes. But there are a few things you need to do before starting a new engine and bringing that beast to life.

Let’s face it, you have sunk a boatload of money into this engine. That means you need to make sure you don’t destroy it on your first attempt to start it. Since I like to help people, I thought it would be a good idea to offer some sage advice to those wanting to know what should be done to and for an engine before the fires are lit for the first time.

The Big Fill

When it comes to engine oil, do not cheap out and buy the inexpensive store-brand 10W-30 found in the department store. I can’t stress enough that quality break-in oil is paramount to keeping things happy when starting a new engine and after the first fire-up. But what is break-in oil? Break-in oils are — in the minds of an untold number of professionals — mandatory to the long life of a newly rebuilt or crate engine. A break-in oil is formulated to protect new camshafts, lifters, pistons, cylinders, and rotating assemblies from wear that occurs during the first start-up.

start your new engine

The days of using any motor oil during break-in are gone. Now, a dedicated break-in oil should always be used in a new engine.

A break-in oil, like Driven Racing Oil’s BR oils, is formulated for use ONLY during break-in and offers improved protection over traditional non-detergent oils. A quality break-in oil features a refined mineral oil and Zinc Dialkyldithiophosphates (ZDDP). While the mineral oil helps with the break-in (especially with flat-tappet camshafts), ZDDP is an anti-wear additive that helps protect new metal components during break-in.

For best results, you should use a break-in oil like BR30 or 40 for the first 30 mins of initial engine start-up. After that timeframe, drain the oil and install a new filter. Once that is done, Driven suggests you add its GP-1 Conventional Break-In Motor Oil and run the engine for another 300 to 400 miles until the engine achieves break-in. It is also recommended you purchase enough break-in oil for two oil changes. EXAMPLE: your engine needs six quarts to fill, you need to purchase 12 quarts of break-in oil. I know this sounds like an expensive proposition, but how much will it cost if you need to rebuild your engine again?

This is just a personal preference, but I would not start your new engine without a mechanical oil pressure gauge attached. I know the technology associated with electric gauges has improved exponentially, but for break-in, I want mechanical.

All Primed And Everywhere To Go

It’s no secret you never want to try starting a new engine when the bearings are dry. I am sure your engine builder used an assembly lube when he built the engine, but it is still a good idea to prime the oil pump before you start your new engine. You will need to do this before you install the distributor. An oil pump primer is not expensive, and you can even rent them at some parts stores. I even made one from an old point-style distributor. With the primer shaft installed in the oil pump, run the pump with a drill motor long enough to fill the oil filter and get oil through the entire engine. This usually takes a couple of minutes to do. You can also watch the oil pressure gauge to be sure you are making pressure.

start your new engine

An oil priming shaft is something every enthusiast should have. I made this one from an old point-style distributor.

Time For Timing

Once you have primed the pump, you need to install your distributor and find Top Dead Center (TDC) for the number one cylinder. Finding this and the proper position for the number one spark plug wire is fairly easy. One way is to remove all the spark plugs, and with your finger covering the number one spark plug hole (driver’s side front), have someone turn the engine over with the starter. Removing all of the spark plugs allows the engine to spin freely without compression and helps keep wear to a minimum during this process.

When you feel compression starting to push your finger away, stop and rotate the engine by hand until the timing mark is at 10 to 12 degrees Before-Top-Dead-Center (BTDC). Another method requires the removal of the driver’s side valve cover. For this method, with the valve cover off, turn the engine over until both valves of the number one cylinder are closed. That will put your piston at TDC.

You will need to find top-dead-center of the number one cylinder before you install the distributor. I actually set the timing between 10 and 12 degrees BTDC before I slide the distributor into place.

With the engine at TDC, use a small piece of tape or a marker to mark the position of the number one plug wire on the distributor cap. Next, place a small mark on the distributor housing to correlate with your number one plug wire position. This will help to position the distributor when you mesh it with the camshaft and help you get the vacuum advance pointing where it should. Although the distributor doesn’t care which lug is used for the number one cylinder, distributor positioning does matter, because if the vacuum canister is pointed too far forward or backward, the canister could make contact with the engine as you try to set timing. This could keep you from setting it where the engine needs it.

When you install the distributor, the oil pump driveshaft rarely matches up with the position of the distributor gear. When dropping the distributor into position, find the spot where gear mesh with the camshaft will allow you to set the distributor so your number one cylinder mark will be aligned. Remember, as you drop the distributor into place, it will rotate slightly because the cam and distributor gears are not straight-cut (the rotor will move with the curve of the gears).

When you are comfortable you have the gears meshed as needed, rotate the engine to bring the distributor stem in alignment with the oil pump driveshaft groove, and the distributor will fall into place. When the distributor is in place. Rotate the engine to ensure timing is as needed. With the number one piston at TDC, the rotor in the distributor should be pointed at or slightly before the number one plug terminal in the distributor cap.

Fuel For Fire

Let me go on record as saying you should never use starting fluid and never pour raw fuel down the venturi of the carburetor when starting a new engine. If your engine has a carburetor and a mechanical fuel pump, it will take a lot of engine cranking to get fuel to the fuel pump and into the carburetor bowls. Excessive cranking (with the spark plugs installed) is not beneficial to the engine. Starting fluid contains ether, which can actually wipe the oils off of your already vulnerable cylinder walls. What’s more, if the engine backfires, this can cause a large eyebrow-removing fireball.

start your new engine

If you are running a carburetor, you can prime it by pouring a couple of ounces of fuel down the vent tube of the carburetor. I have done this with an eye dropper or even a turkey baster with a small hose attached. This will ensure the engine is able to spray gasoline when the throttle is operated.

Fire In The Hole

It is usually a good idea to have some buddies around when starting a new engine. One can watch gauges and another look for leaks while you work the throttle and check timing. If you followed all the steps cited, the engine should come to life and only need minor tweaking to begin break-in. If it requires excessive cranking, something else is wrong (check for fuel, air, and spark).

Quick Tip

I only use water in the cooling system during the initial startup. If I do have any water leaks, having only water leak out is less expensive than antifreeze. You can always drain the water and add a 50/50 mix of antifreeze and distilled water immediately after the break-in.

Running On

Here is where people run into problems when starting a new engine. During the actual break-in, when using a flat tappet cam, as soon as the engine is running, bring the RPM up to 1,700 to 2,000 and set the throttle to hold that RPM for 15 to 20 minutes. This will help ensure proper flat-tappet camshaft break-in. Do not get the engine running and immediately shut it down unless you notice something is wrong. Also, do not let the engine idle and do not continuously rev the engine.

As soon as the engine is running, check the oil pressure gauge to be sure there is sufficient pressure. Listen for any odd sounds and check for any fuel leaks. If there are no leaks or strange sounds, and you have good oil pressure, let it run. Watch the temperature gauge. I usually place a fan in front of the car just to help with cooling. I should have mentioned this before you started the engine, but it might be a good idea to do the initial start-up outside of the garage.

During initial startup, there will be a lot of smoke coming off of the exhaust manifolds or headers, especially if you have coated them. You will also notice blue smoke coming out of the tailpipes. This is normal and should clear up as the rings seat.

start your new engine

Piston rings need to experience a load in order to break in. If you are interested in more information about the proper way to break-in piston rings, check out the video below.

There you go, you have successfully and safely gotten your new engine up and running. However, you are not finished yet. Once the engine is timed, broken in, and ready to hit the road, you need to do a quick post-break-in check of everything.

start your new engine

After everything is broken-in and the engine has cooled, be sure to go around and check all of your fasteners. Retighten as needed.


  • Retorque all external bolts (intake, oil pan, exhaust manifolds/headers, etc.)
  • Check all fittings and hoses for leaks. Some might not appear until the next day.
  • Change the oil after 500 miles.
  • Recheck your timing marks and reset your choke and idle mixture (carburetor).
  • Now you’re ready to go. Back that classic out of the garage and put some miles on the odometer.

Starting a new engine for the first time can be a nerve-wracking ordeal. You just spent a lot of money to get the engine built, so it stands to reason you will worry about issues when you first start it. Hopefully, this outline will help alleviate some of your concerns and you’ll have a happy and healthy running engine that will be in your car for many miles of highway cruising.

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About the author

Randy Bolig

Randy Bolig has been working on cars and has been involved in the hobby ever since he bought his first car when he was only 14 years old. His passion for performance got him noticed by many locals, and he began helping them modify their vehicles.
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