Cam Break in???

[kenny811]

For anyone who as built there own 4.0, when doing the cam break in how long after the motor fired (For the first time) do you let it run before you hold it up to 1800 rpms for 15 - 20 minutes? I have been told not to let it idle, start it and hold it at 1800. Then i've beet told to idle it for about 2 to 3 minutes then kick it up. I am at the point where im ready to do the cam break in.

Thanks
Kenny

 

[Motornoggin]

My machine shop told me to get in it and drive it. keeping it in the higher RPM range and shifting a lot. As soon as it fired, I hopped in and took it for a 20 minute drive. It didn't run perfect, but it ran well enough to do that. I have had no problems.

 

[kenny811]

Mine is brand new, and it took me 3 days to get it to run right, or just to idle right. The distributor ended up being bad, swapped it and it idles for about 45 seconds but it idle perfect. The break in from crane cam was 1800 rpm for 15 minutes not driving it. So I just want to see what other guys did with their break in's.

 

[Russ Pottenger]

You've been given the proper information by letting the initial run in at 1800 to 2000 rpm for the first 15 to 20 mins.
The camshaft has about .001 to .002 taper ground in the lobe. If you put a strait edge on the bottom of the lifter you will notice a slight crown. The taper in the lobe, and the crown in the lifer is supposed help the lifter spin in the lifter bore as its moving up and down. The moly lube that you coat the lobes with, and smear on the bottom of the lifters aid in this.
I also suggest using a break-in concentrate that most of the camshaft manufactures sell.
Most of them contain a high concentration of zinc dithiophosphate which further helps with the critical initial break-in period.

After the cam break-in procedure, drive it with varying the speed and the load. This will help break-in the piston rings.

 

[gradon]

X2 on Russ's post--that is how I broke my stroker in. I used Brad Penn Sae 30 break-in oil with the high% of zddp. Immediately after that 20 mins, drain oil and change filter. Use more break-in oil and change it after 500mi. Buy a magnetic drain plug and maybe a magnetic filter sleeve to keep those metal particles from moving around.

 

[kenny811]

Very Cool!!!, thank you. After I break it in I then need to install the new D44 I have for it, then install upper & lower control arms. Then I think its ready for dirt. Its seen plenty of driveway.

 

[tomcat]

Very Cool!!!, thank you. After I break it in I then need to install the new D44 I have for it, then install upper & lower control arms. Then I think its ready for dirt. Its seen plenty of driveway.

i am in the same boat as you, just broke my cam in tonight, and now have to build the D44 for the rear. a detroit locked 35 on 31's is not going to like a stroker....

 

[old_man]

I'm old school. I run 30w non-detergent for breakin. Never run synthetic to breakin a motor. I have run extra ZDP in every new build I have done since 1968. Isky cams got me started on it.

I don't tend to do the 15 minute idling breakin. I have always started it and give it 2 minutes to check for leaks, then I drive around town, never keeping the same rpms for about 20 minutes.

I change the oil to more non-detergent at about 50 miles, then at 500 miles and 1K. I can normally feel when the rings start to seat, then I give it another 200 miles and convert over to Valvoline DuraBlend.

I have 80k on my 4.7L stroker.