13 Steps To Ensure You Don't Blow up Your Engine During Initial Start-Up

When ranking automotive thrills, starting an engine for the first time has to be near the top of the list. Will it start? Will it leak? Will it run well? Will it keep running? What’s that noise? Why is that so red? What’s that smell? 

If all goes well, the uncertainty soon bleeds away, leaving nothing less than euphoria as the realization of a job well done sets in. A thrill indeed.

Unless something goes wrong. Not only does this type of failure bring about immense frustration, but it can also have a devastating effect on the wallet. Sometimes failures are inevitable—the results of bad parts or botched installations. An incorrectly mounted 50-cent gasket, for example, is capable of wrecking hundreds or even thousands of dollars in reciprocating assembly components. Often, however, these issues can be prevented.

Following a methodical start-up procedure can minimize the amount of damage that failures cause. Having made hundreds of first-time starts, we’ve developed a course of action that has kept us out of trouble many times. We always break in an engine with the same oil we plan to use throughout its life. For an older engine like this Triumph, we go with 20W50 Castrol GTX. While most of our start-ups go perfectly, this one didn’t. A massive oil leak kept drama at the forefront, but it showed why a solid procedure can be so important. Here’s how we do it.

Step 1:

We begin our start-up procedure by adjusting the valves. We use the procedure outlined in the factory manual, but we follow our cam maker’s recommendations if we’re running an aftermarket piece.

Step 2:

Next, we pull all the spark plugs and check the compression. Ideally all the numbers should be identical, but it’s fine as long as they’re within 10 percent of each other. If any cylinder is radically low, we readjust the valves for that cylinder, then check again. 

Don’t panic if the reading remains low, as we often find that an offending valve will seat within the first few seconds of start-up. We do listen carefully during this process, however, to make sure there isn’t excessive valve noise or evidence of poor running, which indicates a dropped cylinder. 

Step 3:

With the spark plugs still out, we crank the engine with the starter until we get oil pressure. Some engines allow you to prime the oil pump to achieve oil pressure sooner.  Either way, the process usually takes 30-45 seconds. If we end up waiting significantly longer, something is wrong and we stop the procedure until we find the problem. 

Once we have oil pressure, we look for oil leaks, then double-check the oil level. Once the oil filter, passages and cooler lines have had an opportunity to fill, we usually find ourselves down a quart or more.

Step 4:

Now we can reinstall the spark plugs and connect their wires. We always triple-check the plug wires: We ensure that they are not only in the correct order, but in the correct direction, too—clockwise or counterclockwise at the distributor. 

Then we position the distributor, using our best guess to select a timing setting that will start the engine. If we’re in doubt, we static time the engine.

Step 5:

A multi-carb engine like this one adds an extra step, as we need to adjust each of the idle screws the same amount. In this case, we went in two-and-a-half-turn increments. If you’re working on an injected car, in theory you can skip this step.

Step 6:

Now we double-check all the fluids: oil, gas and coolant. We always squeeze the top radiator hose to make sure it’s full of coolant. Even if the radiator looks full, air bubbles might be hiding in the upper hose.

If we find or even suspect any bubbles, we remove the radiator cap and squeeze the top hose to release this excess air. Then we refill the radiator and repeat the procedure as necessary.

Step 7:

Before starting the engine, we make sure that the brakes and clutch work. Why? In case we need to move the car right away. For this same reason, we also place the car on its tires instead of jack stands. We take these precautions mainly because of fire risk; if a fire erupts, we want to be able to quickly roll the car outdoors so it doesn’t take the garage down with it. In fact, we usually work with the car outside or just inside an open garage door. This also keeps the fumes from overwhelming us. 

Time for the moment of truth: With an assistant nearby and ready with a fire extinguisher, we start the car. If we’ve done everything correctly, the car should come to life almost instantly. 

Once our car is running, our assistant holds the engine at about 2000 rpm while we adjust the idle. The cam and lifters rely on splash oiling, which is especially important as they bed in. We then keep the engine running at 2000 rpm for about 20 minutes.

Step 8:

Here’s another step for those running carburetors or individual throttle bodies: Make sure the individual units are balanced. The old hose-in-the-ear method works well here, as matched carbs will produce matched tones.

Step 9:

We then double-check that the ignition timing is correct. If we change it, we again set the idle to hold the engine at 2000 rpm.

Step 10:

Abort, abort! We always check a newly fired engine for leaks, and we found a pretty large one this time. It sprouted at the rear of the engine, so we immediately turned off the car to investigate.

While we feared rear main seal trouble—this would mean having to remove the engine or gearbox—the problem turned out to be a missing oil passage plug. Once installed, we fired the engine back up and worked on bedding the cam and lifters.

Step 11:

Using a digital pyrometer, we constantly monitor temperatures. We find this tool to be indispensable for engine start-ups—spending about $30 to $100 allows you to effectively monitor an engine as well as other parts of a car. 

In this case, we use the pyrometer to keep tabs on the temperature of the coolant as well as the engine block and cylinder head. We like to watch the temperature of these areas rise to about 180 to 200 degrees—if the engine doesn’t get any hotter than that, we’re a go.

With pyrometer in hand, we also check the engine’s thermostat at this stage. If the thermostat opens when the coolant reaches the appropriate temperature, we move on to the next step. If the thermostat doesn’t open on cue, then we have something to fix.

Step 12:

Once we ensure that the cooling system is working properly, we start monitoring the exhaust temps. We mainly look for consistency, as all ports should hover around 350 degrees. 

You can also do some brief diagnostic work here. A cool exhaust port is a quick sign that one cylinder isn’t firing, and a port above 800 degrees is a sign that the mixture is off—either too rich or too lean.

After monitoring the exhaust for about 20 minutes, we turn off the engine so that we can retorque the head and readjust the valves. We often perform another compression check as well. Once that’s taken care of, we start the engine, set the idle down to about 800 rpm, and get ready for our first test drive.

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Comments
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APEowner
APEowner Dork
9/21/20 9:32 a.m.

Great article.    With one exception that's the procedure I've been using for decades. 

The exception is that I no longer crank the engine to get oil pressure.  Performance engines always get pre-lubed just before first fire and standard engines do if it doesn't require a bunch of mucking about.  If I can't prime the system I just fire it up.  The theory is that the slow cranking without pressure wipes the pre-lube off before pressure is built up whereas starting the engine gets pressure almost instantly. 

I've never done a real study to see if my theory is correct but my street engines generally last  a couple 100k miles after first start using that technique.

One should, of course use their engine builders first fire procedure if they didn't build it themselves.

MadScientistMatt
MadScientistMatt PowerDork
9/21/20 10:24 a.m.

Good timing; I'm about to get my Dart's engine back together.

Paul_VR6 (Forum Supporter)
Paul_VR6 (Forum Supporter) Dork
9/21/20 11:48 a.m.

Is there a hack score we should be calculating like points/13? Because I am at 3/13 at best cool for any modernish car many don't apply. The check oil (I never run engines with coolant at first), make sure oil gets pressure with fuel disabled, and let it rip. If it starts and will hold at 2k on throttle and no leaks after about a minute, button the rest up and hit the dyno.

David S. Wallens
David S. Wallens Editorial Director
9/21/20 12:23 p.m.

In reply to Paul_VR6 (Forum Supporter) :

I like the hack score idea. So, can anyone beat 3/13? Do we have a 2/13?

jimbbski
jimbbski SuperDork
9/21/20 12:28 p.m.

The last rebuild engine I started I had everything set up, spun the oil pump with a drill motor, installed the dist. and after adding a bit of fuel down the carb. my buddy turned the key. That engine didn't even turn over more than 1/4 revolution before firing up and running at a fast idle. Well just until the carb ran out of fuel.  I  had plumbed the mechanical fuel pump backwards!  

300zxfreak
300zxfreak Reader
9/21/20 12:34 p.m.

I have been told several times to stick a hose in my ear, but I had no idea this is what they were referring to. ...........or were they ??

Vigo (Forum Supporter)
Vigo (Forum Supporter) MegaDork
9/21/20 2:12 p.m.

E36 M3, you want a hack score? TWICE I have installed engines that wouldn't complete a full revolution! As in, i put a bar on the crank, spun it some amount of degrees less than 360, installed it, and then found out it wouldn't actually make it all the way around!!! I can't remember what one of them was, but the other one was because mud daubers had crawled all the way down the intake manifold through an open intake valve and built a mud nest in the cylinder. I blew almost all of it out the spark plug hole after discovering that, but it turned out my one cranking attempt had lodged a small pebble into the quench pad of the head and the piston wouldn't go over TDC (just as well, with a rock in there..) so i ended up having to pull the head, remove pebble, smooth out that spot a bit, and reassemble.. sigh... After that i made sure to plug EVERY HOLE THAT LEADS ANYWHERE IMPORTANT. The amount of silliness that bugs have caused me on cars is just outrageous. My old turbo caravan even has a dead scorpion curled up INSIDE the fuel gauge in the instrument cluster. Country livin'...

californiamilleghia
californiamilleghia SuperDork
9/21/20 2:24 p.m.

How many times have you taken a fresh motor apart and  looked at the bearings and seen a lot of junk in them even after running only a few minutes , 

Cleaning all the oil galleries  is sometimes almost impossible to do unless you take out the oil galley plugs which are a dead end for the gunk to hide , 

not sure about other engines  , but air cooled VW motors  need these pulled out and tapped for allen head plugs , 

I would also add check the oil filter that its tight.......and if possible fill it with oil before you put it on.....

Shaun
Shaun Dork
9/21/20 6:47 p.m.
Vigo (Forum Supporter) said:

E36 M3, you want a hack score? TWICE I have installed engines that wouldn't complete a full revolution! As in, i put a bar on the crank, spun it some amount of degrees less than 360, installed it, and then found out it wouldn't actually make it all the way around!!! I can't remember what one of them was, but the other one was because mud daubers had crawled all the way down the intake manifold through an open intake valve and built a mud nest in the cylinder. I blew almost all of it out the spark plug hole after discovering that, but it turned out my one cranking attempt had lodged a small pebble into the quench pad of the head and the piston wouldn't go over TDC (just as well, with a rock in there..) so i ended up having to pull the head, remove pebble, smooth out that spot a bit, and reassemble.. sigh... After that i made sure to plug EVERY HOLE THAT LEADS ANYWHERE IMPORTANT. The amount of silliness that bugs have caused me on cars is just outrageous. My old turbo caravan even has a dead scorpion curled up INSIDE the fuel gauge in the instrument cluster. Country livin'...

I just found the beginnings of a mouse apartment right up on the throttle plate of an engine that has been sitting 2 weeks.  I took the air filter box off as part of deer strike repair and wow that was fast. Every hole...no matter how short the time...

David S. Wallens
David S. Wallens Editorial Director
9/22/20 1:37 p.m.

In reply to Vigo (Forum Supporter) :

Okay, that wins. 

jfryjfry (Forum Supporter)
jfryjfry (Forum Supporter) Dork
9/22/20 11:15 p.m.

I've never heard of doing a compression check on a new engine. All of that cranking would wipe off all of the prelube.  
 

same with cranking to raise oil pressure - I've always spun the oil pump with a drill right before.  
 

and running up to 2k (or 2500 or thereabout for 20-30 mins) is only to break in flat tappet cams only, right?


And don't forget making sure the distributor isn't 180 out is a big part of the process too  

 

Paul_VR6 (Forum Supporter)
Paul_VR6 (Forum Supporter) Dork
9/23/20 6:18 a.m.
David S. Wallens said:

In reply to Vigo (Forum Supporter) :

Okay, that wins. 

Happy for myself, but poor Vigo!

Some engines you can't spin the oil pump if it's assembled and ready to run. Also, what is a distributor? wink

P3PPY
P3PPY HalfDork
9/23/20 9:30 a.m.

In reply to Paul_VR6 (Forum Supporter) :

It's that thing you're supposed to tighten down after a hi-perf rebuild on your beauty queen 1991 5.0 otherwise it will get just enough out of time to not work right and you'll sell the whole car at a loss because you're just done messing with it and the next week the high school kid who bought it at a steal will call and tell you that your timing was off and now it's a beast.

It's that thing.

APEowner
APEowner Dork
9/23/20 11:48 a.m.
jfryjfry (Forum Supporter) said:

I've never heard of doing a compression check on a new engine. All of that cranking would wipe off all of the prelube.  
 

same with cranking to raise oil pressure - I've always spun the oil pump with a drill right before.  
 

and running up to 2k (or 2500 or thereabout for 20-30 mins) is only to break in flat tappet cams only, right?


And don't forget making sure the distributor isn't 180 out is a big part of the process too  

 

Funny, I apparently only skimmed the article.  In my head that whole section talked about a leak down test which I do on fresh engines.  I agree on the compression test.

I've got a surplus Accusump that I use to pre-lube performance engines where I can't spin the oil pump shaft.  As I said above, for stock engines I just start them.

Paul_VR6 (Forum Supporter)
Paul_VR6 (Forum Supporter) Dork
9/24/20 9:04 a.m.
P3PPY said:

In reply to Paul_VR6 (Forum Supporter) :

It's that thing.

Forgot about them, haven't had one since '99!

Vigo (Forum Supporter)
Vigo (Forum Supporter) MegaDork
9/24/20 10:43 p.m.

One time i couldn't get a 22RE i built to make oil pressure through cranking. I usually leave the spark plugs out to make the engine spin faster and put less load on the bearings, but it just.. wasn't making pressure. Took off the filter and it was dry. Yeah, i know some people fill them, i dont. Wouldn't have been able to tell it never got any oil from the pump if i had, in this case! Anyway, I ended up using a tiny tiny funnel shoved into the oil port under the filter that came up from the pump, and filled that with oil. Then i turned the engine backwards (gads!!!!!!!!) with a ratchet until the oil pump sucked it through backwards. It wouldn't go through otherwise. I figured if it wouldnt drain through and i spun it backwards id pump oil down into the pickup tube and it would hold it there as if picking up a straw out of a drink with your finger closed over the top. Anyway, did a few rounds of that until i was sure i'd back-purged the pickup tube of air, put the filter back on and cranked it... bam! Oil pressure! 

I recently rebuilt a slant six and even with the oil pump gooped up with assembly lube it still wouldn't make oil pressure at cranking speed. Did the same thing again, only this time it was easier because the oil filter adapter stands it straight up! Worked that time too.

That's the silliest thing ive had to do to get a new engine to make oil pressure.

Many engines you can actually just run the pump without cranking. I just put together a turbo 2.2 for an omni glh for someone and those drive the oil pump off the intermediate shaft which is run by the timing belt. All you have to do is spin the 18mm sprocket bolt until you get pressure, and then put the timing belt on and start it! That one made 70psi right before the harbor freight right angle drill i was using started smoking. cheeky

A long time ago i didn't want to buy an SBC priming tool so i knocked the handle off a flathead screwdriver and chucked it up in a drill and went to town. I couldn't figure out why i never got oil to the lifters/pushrods, and that's when i finally noticed that oil channel that goes across the distributor base which my screwdriver clearly didn't have.. but i won't say how long that took..

The rpm for cam break-in thing is about the fact that engines will distribute 'splash lube' in the crankcase differently at different rpms. Unless someone has run one with a hole in the side or a clear oil pan and figured out an ideal rpm to splash the most oil onto the camshaft, its probably a good idea to vary rpm up and down in the lower half of the range.  Steve Brule talked about this a little bit on a recent Engine Masters. 

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