Running in my new cam shaft...

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Zwap

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Running in my new flat tappet mild Lunati 213/220 @ .050 kit incl. lifters, new stamped steel rockers and new pushrods, about .055 preload.
Cam riched lubed with the Lunati lube that came with the cam.

10w/30w oil with a bottle of cam break in oil add.
Oil primed 2 turns crank cycle, set the timing about 12-14 deg BTC, primed the carb with enough petrol, water in the cooler with the cap off to get rid of air pockets and start it up, it took about 10 second cranking before it starts.

Up to a good 2.000-2.500 rpm and it runs quiet and solid with about 50 psi oil pressure, the temp rises but I didn't manage to put the cap on the cooler until it overheated, that was about 4-5 minutes from start. Stop the engine but as I've did adjust the idle too high it dieseled for about 5-10 seconds until I put a towel over the carb to stop the engine.

I let it cool down for about 30 minutes, filled the cooler up and put on the cap.
Cranked about another 10 sec before it starts.
Up to a good 2.000-2.500 rpm, now the temp was OK and I run it for another 10 minutes until the exhaust was so hot that it began to smoke and smell more than I like, safe things first, and I shut it off to let it cool down for another 30 minutes.

Start it up and run it another 10 minutes with ok cooling teperature but the exhaust was real hot and shut it off.

Lunati says 20 minutes total of breaking in this cam and lifters, and togheter I'm up to about 25 minutes, do you think the cam is breaked in and safe to run on idle after new oil and filter, or should I give it another 10 minutes to morrow to be shure?

I'm not that popular in the neighborhood after today :)
 
I would say you're good. New cam break in on a completely fresh engine can be tricky especially with the cooling system. It has to be bled of air where as the fuel system and the basic timing/ ignition stays pretty constant through the first 20 min.
 
Common overheating issue usually caused by not enough timing during break in.

If you do this again, get it started, up to rpm and twist in 34-38 degrees of timing. That will usually help with hot exhaust and overheating.

See how it runs at normal idle rpm and try driving it.
 
Thanks all!!!
I was a bit worried about the issues and if it would ruin the break in, but now I feel alot calmer, this was my first cam break in on an old V8.
 
Started it up today to check ignition timing etc. checked the manifold vacuum with a gauge and before the new camshaft I had about 20Hg at idle (stock 252/252 2bbl cam), now it's only about 15-16Hg (Lunati description of the cam says about 19Hg), is it a normal drop of 4-5Hg whith the new 256/262 cam shaft?
 
What is your idle timing? Advancing the timing will bring the vacuum up.
On my 440 with Lunati cam I had to set idle advance to 22 degrees to get 15 inches of vacuum.
The vacuum might go up a bit once rings are broken in.
 
You did degree your new cam, right?

Is your idle speed the same as it was before? As already noted, bigger cams need more initial timing also.

Going from 252 to 256 duration @.050 will drop the vacuum a little. Doubt you'd get 19" at idle though, even in a 440. As another data point my 451 with 272 duration pulls 7" vac at 1100 rpm, and 22 initial timing...
 
Ok, to clarify, it's a 383 and the stock cam shaft was 252/252 advertised duration and the new one is 256/262 advertised duration.
The engine is not rebuild but the heads are.
What I did was changed the cam shaft, new timing chain and gears, went from 516 to 916 heads (both closed chambers but 915 has 1.74" exhaust valves), new lifters, 0.050-0.060 preload, new stamped steel rocker arms.

Yes I did degree the new cam:
Question about how to degree my cam

Idle timing @ 20 deg
Idle speed 800 rpm
Idle vacuum 15-16" (used to be 19-20" with the old setup)

I had to adjust up the idle adjustment screw to get the same idle speed and leaned idle fuel mix after the new cam (checked with O2 sensor).

The cam is just broken in and I haven't been able to drive tha car yet, it's snowing here right now...
 
Zwap said:
Ok, then I should accept the drop of vacuum?
Click to expand...
Tune it to get the best you can and, of course, that is all you can do. Goes without saying but, check for vacuum leaks.
 
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