my first cam break in

-
M

MoparOrNokar

HammerTime
Joined
Aug 17, 2014
Messages
218
Reaction score
20
Location
Flint, Michigan
Finally today is the day that i get to hear my new engine come to life. This will be my first cam break in. Ive read alot and watched lots of videos. Still very nervous. I have alot invested and quite frankly i dont have the funds to start all over lol. Im looking for any pointers from the old timers amd experienced guys. I wont be firing until this afternoon. Still have a few more things to button up. I will have the garden hose there to spray the rad if the temp gets up. Im also going to run a box fan on the grill. This is a comletely new setup so i dont know how its going to react. Thanks in advance guys. Ive gotten alot of help from this community along the way and i appreciate everything guys
 
Make sure you have a known 'good' carb, so it will fire and run.

Box fan in front of rad. Hose handy. Something to watch the RPM's tach inside or one hooked up under the hood. Double check everything before you fire, oil level, coolant level etc. Leave the distributor loose enough so if you have to turn it some to get it to smooth out, you can.

It would help immensely if you have a second person there to check for leaks etc while doing the break-in.

Fire it and bring it up to 2000-2500 RPM and vary between the two for a minimum of 20 minutes.

Good luck!
 
good break in oil is a must - 2000 rpm for 20min with an occasional throttle "rip/blip" - mufflers on for back pressure.. IF you have an issue -leak, whatever - shut it down, fix the issue and restart -- if this happens, keep track of run time - 20min is total time - cumulative.
 
Have you primed the oiling system? I do that as a matter of habit on every engine I can.

Fill up the carb primary bowl with fuel through the vent tube so it has plenty of fuel to get started quickly. Be careful not to slop it all down into the carb.

Set the timing in the distributor by visually lining up the reluctor point and gap while the crank timing mark is set on the desired base timing; that should get you close on timing to start.

What valve springs do you have? And what oil are you using?
 
I had a 426 hemi rebuilt by Ray Barton and the day he was going to run it on the dyno I was in attendance. His son fired the engine, it idled, was checked for leeks and immediately started a full pull, up to 6000 rpm. I turned to Ray and said I thought you needed to break in a rebuilt engine @ 2000 RPM for twenty minutes? He smiled and said we just broke it in.
 
What Scampmike said, make sure you have a good oil in there and make sure it has zinc. Most of the newer oils don't have zinc and you will wipe out your cam lobes. You can buy it separately and add it to all the autozone sold stuff later. Good luck
 
Thanks guys. Yes i primed the engine with a drill. Showed 75 psi. Engine currently has venom breakin oil in it. Not sure on the spring poundage but the engine builder told me it would be fine to break in. The builder just rebuilt the carb for me so that should be top notch. What would a good initial timing to start at?
 
Well my opinion on the whole deal is you already know exactly what to do. I'm sure you've primed the oil and I'm sure you are going to start it as fast as you can and maybe even go so far as to put a little trickle of gas in the carburetor to get it to just definitely fire right away leaving the distributor a little loose so you can twist the timing make it run better.

So my advice is to enjoy it and have fun because it doesn't happen everyday and it probably won't happen again for a while especially being your own.
:thumbsup:
 
HemiMark said:
I had a 426 hemi rebuilt by Ray Barton and the day he was going to run it on the dyno I was in attendance. His son fired the engine, it idled, was checked for leeks and immediately started a full pull, up to 6000 rpm. I turned to Ray and said I thought you needed to break in a rebuilt engine @ 2000 RPM for twenty minutes? He smiled and said we just broke it in.
Click to expand...
yep
 
I think a lot of the 'crucial break in' stuff is either from a)cheap cam cores that are going to wipe eventually, or b) cheap oil, lack of initial lube (pre-oiler, cam lube etc)

I'm more in line with the way hemimark says his motor got done. I fire it up, make sure I have good pressure, no obvious leaks (I pressure test cooling system before firing the motor) get the motor running decently then drive around for 10-15 minutes.
 
I put a check list on my windshield to remind me to check stuf during my 30 minutes. It's easy to forget stuff when you're amped up during break in. Also keep a fire extinguisher near by. Hopefully you won't need it.
 
HemiMark said:
I had a 426 hemi rebuilt by Ray Barton and the day he was going to run it on the dyno I was in attendance. His son fired the engine, it idled, was checked for leeks and immediately started a full pull, up to 6000 rpm. I turned to Ray and said I thought you needed to break in a rebuilt engine @ 2000 RPM for twenty minutes? He smiled and said we just broke it in.
Click to expand...

I kinda agree with this. The '20-30 minutes at 2,000 rpm' procedure is so the cam companies cover their ***. Say you wipe a lobe and then call the cam company, first thing they ask is whether you followed the break in procedure. No? Sorry, you're S.O.L. But hey, we have the exact same cam waiting to ship, what was your credit card number again?

What kind of cam is it? The general idea with a flat tappet cam that uses dual valve springs is to remove the inner springs before the break in to reduce the spring pressure on the cam. They get re-installed after the break in.

Also, if you have a FT cam, make sure the lifters rotate in their bore when you turn the motor over. Mark an edge with a marker and watch it while you rotate the motor.

If you have a solid cam, set the lash a little looser, maybe a few thousandths.

I recently broke in an engine on the dyno, because I was nervous like the O.P.. I did it because I liked the idea of a controlled environment where things are right in front of you, it's easier to spot problems right away.

The one big advantage of the dyno is the cooling system. The dyno has a tank and the water is fed right into the water pump inlet without a t-stat. If you're doing it in the car, you're on your own.

Make sure you used the lube provided with the cam and some sort of assembly lube on the bearings. Like said, the oil system must be primed so you need the tool for that. Probably best to have a gauge on the sending unit tap so you can get an idea of what the pressure looks like when you spin the pump up.

Make sure the initial timing is set before you fire it. #1 on compression stroke, distributor rotor pointing towards the #1 intake, rotor tip on the leading edge of the cylinder tower on the distributor cap. If you have a marked balancer then it's easy to set the initial but if you don't put a timing tape on it. Once you get it running then take a look at the total if you have a quick advance curve to make sure it's not way off.

I also agree with the carb aspect. If you have a known good unit, put that on, make sure it's ready to go - float levels, fuel in the bowls etc.

If it's all set up right, it should fire right up. The cams get wiped when you have trouble starting it up, like if you have to crank it over and over or if the tune is all whacked when you get it started.
 
12-15 degrees advanced - I am RIGHT behind you - just put carb on it today - I set my initial timing to 12 degrees advanced. I doubt it makes any difference as you already have oil in it - I went with Joe Gibbs DRIVEN BR and plan to use JG oil afterward too..
 
Last edited:
Got it done guys. Have 1 small oil leak at the back of the intake easy fix though. Still was able to finish the break in. 10w30 holds 50psi at 1300rpm hot. Thanks for all your help fellas
 
glad ya got it done. Not as "scary" as it may seem. Mild lift cams and springs help make it a success.
 
You must log in or register to reply here.
-

Back
Top