Engine break in without a tachometer

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Righty Tighty

Blame it on the dog
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Hey all, apologies if this has already been posted, I searched but couldn’t find anything.

I’m getting ready to fire up my 318LA after rebuilding it, and my car doesn’t have a tach. I have hydraulic flat tappet lifters. I do have an aftermarket tach, but I really don’t want to fuss with installing it right now. How crucial is it that I stick to 2500 RPM during the break in period? Can I apply some light throttle and stick to it for the 20 minutes and be good?
 
id run a temporary signal wire and run power and ground from the battery and let the tach lay on the fender. Just a couple wires and maybe a min or two of your time.
 
I'd at least install the tach temporarily and place it on the windshield so you can see it. I've done many break ins and you have no other indicator as to what RPM your at.
 
Thanks, I’m glad I asked. I likely would’ve just “winged it” and throttled up to what I thought sounded like 2500.

Also, I’ve switched from points ignition to electronic with a module. Do I still go to the coil, or do I go straight to the ignition module? I’ve seen some contradicting information.
 
the last 2 engines I broke in I didn't use a tach. if you have ran an engine enough times between 2 and 3000 rpms, you kind of develop a sense of where it's at by the sound. what is the most critical is having good break in oil and plenty of ZDDP
 
you can get a dwell tach from many sources, auto parts stores, ebay etc 20-40 bucks.

if you have a tach you can use alligator clips and temporarily hook it up.

do you really want to risk your engine one a little hassle!
 
you don't STICK to any RPM. That's why a tach IS THAT important. You vary engine speed 2500 and above. I usually vary it between 2500 and 4000. The oil splash to the camshaft lobes is what's important. Have your timing light ALREADY hooked up and ready. As soon as it busts off, get the idle about 3000 and put the timing on about 35* at 3000 RPM. This will assure the timing is not retarded. That's probably the number one mistake people make and retarded timing will make a new engine run HOT right off the bat.

There's NO WAY IN HELL I'd try to break one in without a tach. I don't care what some forum gurus say. It's that important.

Do you want to do this all over again?
 
I wonder if Joe Bonamassa just decides he's so good that he Tunes his guitar by ear and goes out there winging it every bite while the rest of the band uses an electric tuner.
I'll save y'all the wondering.. He doesn't

I think it's not really an issue with a stock type cam to just wing it , more than likely people end up low like 1900 rpm...anyway.
 
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I wonder if Joe Bonamassa just decides he's so good that he Tunes his guitar by ear and goes out there qinging it every bite while the rest of the band uses an electric tuner.
I'll save y'all the wondering.. He doesn't

I think it's not really an issue with a stock type cam to just wing it , more than likely people end up low like 1900 rpm...anyway.
Full throttle valve float is at around 6000 depending on how the engine was built. Around half throttle is 3000. Not rocket science unless you make it that way. Ever heard of a cam fail because it was broke in at 2750 and not 3000? Ya, me either. Joe doesn't tune his own guitar anyway. He hires it done. And when you play the Blues it is not tuned or played to perfect pitch!
 
Full throttle valve float is at around 6000 depending on how the engine was built. Around half throttle is 3000. Not rocket science unless you make it that way. Ever heard of a cam fail because it was broke in at 2750 and not 3000? Ya, me either. Joe doesn't tune his own guitar anyway. He hires it done. And when you play the Blues it is not tuned to perfect pitch!


They are tuned, and if they aren't...those chords sound fkd up. You cant bend your way through a real song, unless you're noodling a string or 2.
1900 to 2200
Then it was 3000
Then i heard from people 3000 was too high and 2000-2600 was where it was at.

It's all gusty with opinions.

I've broke them in every way mentioned.
Splitting hairs.
 
Thanks for all the input. I do have a tach/dwell meter, and I suppose hooking that up would be just as easy as temporarily hooking up the tach I have. And honestly I didn't even think about temporarily hooking up the tach until you guys mentioned it.

Have your timing light ALREADY hooked up and ready. As soon as it busts off, get the idle about 3000 and put the timing on about 35* at 3000 RPM.

Rusty, this sounds like I'm gonna need someone to start it for me while I'm at the engine with the timing light - a two man job. Is that right?
 
Thanks for all the input. I do have a tach/dwell meter, and I suppose hooking that up would be just as easy as temporarily hooking up the tach I have. And honestly I didn't even think about temporarily hooking up the tach until you guys mentioned it.



Rusty, this sounds like I'm gonna need someone to start it for me while I'm at the engine with the timing light - a two man job. Is that right?

Unless you have a remote starter switch......as you should already own doing this type work.

AND IF YOU GET ONE.......be ESPECIALLY CAREFUL because using a remote starter switch can KILL THE **** OUT OF YOU. Since it completely bypasses any type of neutral safety or starter bypass circuit, it can crank in ANY gear selection and in gear with a manual OR automatic......so BE SURE she's in neutral. We've grown to love you around here and we'd hate to see a RightyTighty sammich. That would SUCK.
 
Hold the pickles, please!!

Hmm, a remote starter switch. Didn't think of that. And it looks like they're darn cheap, too. In any event, I think Pops will be around for the first start anyway, being a momentous occasion and all. I think I'll have him start it while I look under the hood.

I've done it by ear many times. Not rocket science, c'mon boys.

I'm sure it can be done successfully by ear, especially by an experienced mechanic and someone who's done it before. This is uncharted territory for me though.
 
Hold the pickles, please!!

Hmm, a remote starter switch. Didn't think of that. And it looks like they're darn cheap, too. In any event, I think Pops will be around for the first start anyway, being a momentous occasion and all. I think I'll have him start it while I look under the hood.



I'm sure it can be done successfully by ear, especially by an experienced mechanic and someone who's done it before. This is uncharted territory for me though.

It pays to have a second person, regardless.
 
I swear my wife has more experience breaking in cams than most people I know LOL even when I have her run the drill on the oil pump and I turn the crank she says oh there it is! Knowing when the drill speeds up a little bit that it's oiling one side. She'll start the engine and let me work the throttle and get the idol turned way up. She watches the temperature gauge in the oil gauge and reports... Sometimes I'll invite a friend over who knows what they're doing. Most guys don't want to miss an engine break in...
 
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Since it completely bypasses any type of neutral safety or starter bypass circuit, it can crank in ANY gear selection and in gear with a manual OR automatic

Rusty, your cautions of safety are something we all tend to overlook BUT...

My NSS provides power to where the yellow (IIRC) wire (67 Dart with a 273) on the starter relay goes and mimics the start cir of the ignition switch. it still relies on the NSS for ground to activate the relay.

Not trying to be a dick just want to be sure I'm not missing something, later years do it different?. ( IIRC old Fords use a positive side NNS)


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you don't STICK to any RPM. That's why a tach IS THAT important. You vary engine speed 2500 and above. I usually vary it between 2500 and 4000. The oil splash to the camshaft lobes is what's important. Have your timing light ALREADY hooked up and ready. As soon as it busts off, get the idle about 3000 and put the timing on about 35* at 3000 RPM. This will assure the timing is not retarded. That's probably the number one mistake people make and retarded timing will make a new engine run HOT right off the bat.

There's NO WAY IN HELL I'd try to break one in without a tach. I don't care what some forum gurus say. It's that important.

Do you want to do this all over again?
I'm far from a forum guru, I've already been told so, but I still know what I'm doing LOL
I've never lost a cam or shredded metal by not using a tach or a timing light. I break them in on the floor of a garage with open headers running between 2 and 3000 rpms for up to 40 minutes sometimes. the neighbors love me ! lol
 
I'm far from a forum guru, I've already been told so, but I still know what I'm doing LOL
I've never lost a cam or shredded metal by not using a tach or a timing light. I break them in on the floor of a garage with open headers running between 2 and 3000 rpms for up to 40 minutes sometimes. the neighbors love me ! lol

Well sure you can do it without one. BUT he's never done this before. Does he know what 2500 RPM sounds like? I don't know. So my best advice is to hook the tach up. I wouldn't let three wires stop me. JMO.
 
I used to have a tach mounted on the firewall at all times. it's nice when you're under their tuning and adjusting and being able to see exactly what's going on. If I ever run into another junker tack I might put one under there again...
 
Does he know what 2500 RPM sounds like? I don't know.

I’m not quite sure I’d know, either. My Tacoma that I’ve put 270,000 miles on? You can bet I’d be able to hear a frog fart under the hood while driving down the freeway. But I’ve never heard this engine run, and like Rusty said, I’ve never broken in an engine.

Someday I hope to have the experience to be able to do it by ear, and I tip my hat to the folks here that do have that experience. That’s what makes FABO so great.
 
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