First start with new cam/ heads won't stay running

[4speed68rt]

Let it rip!! Stress test.

 

[Myasylum]

I saw a You Tube video with a Honda motorcycle (a different beast I know) but they did a test. They rebuilt two engine exactly the same. One engine they babied a broke in according to what was suggested. The other, they went straight to redline and beat the you know what out of it. After like 300 mi (can remember exactly) they took the engine apart and spec'd everything out and saw no difference with either engine!
However your talking a Honda engine Vs a old sloppy 70's engine. Might be a different story with these old V8's? Idk? Still interesting though.

 

[Myasylum]

Well then the rings are already seated then. You may be rebuilding the bottom end soon though.

Yea... I'm aware of that. I don't plan on beating it up too much though. I hoping it last a little awhile.

 

[Myasylum]

Well, I was ready to go on my first drive... I put it in reverse, died. Put it in Drive, died. Used both feet gave it more gas to keep it running with my other foot on the brake put it in gear engine started to stumble moved a few feet... died.
I gave up. Going to bed. I don't know what this is now?
Runs great at idle though. Sounds awesome like angry bees, but it dies.
Ugh.. good night.

 

[69 Sleeper Bee]

Hang in there !

 

[Geoff 2]

New start up runs very hot. Many possibilities & needs to be fixed before driving, but most likely:
- air in the coolant, needs purging of the air.
- retarded ign timing.

 

[gtxrt]

Well, I was ready to go on my first drive... I put it in reverse, died. Put it in Drive, died. Used both feet gave it more gas to keep it running with my other foot on the brake put it in gear engine started to stumble moved a few feet... died.
I gave up. Going to bed. I don't know what this is now?
Runs great at idle though. Sounds awesome like angry bees, but it dies.
Ugh.. good night.

what is the camshaft specs. did you check for vacuum leaks.

 

[Myasylum]

It's a Lunati 703 cam.
I didn't notice any leaks, however I was more frustrated yesterday than anything. I'll have to look again. I am running at about 12-15 degrees advanced.

cam specs:
Lunati 10230703LK Lunati Voodoo Cam and Lifter Kits | Summit Racing

 

[Moparnocar]

It's a Lunati 703 cam.
I didn't notice any leaks, however I was more frustrated yesterday than anything. I'll have to look again. I am running at about 12-15 degrees advanced.

cam specs:
Lunati 10230703LK Lunati Voodoo Cam and Lifter Kits | Summit Racing

You may need more intitial advance, went through the same thing with a 284/484. W more advance, you can back the carb down to the idle slots. However, the dist needs to be modified to not go over 36-38 degrees total

 

[Myasylum]

Yea, it's to stock distributor too. I didn't want to change to much at once and cause to many problems
What really sucks is that I'll be gone for 4 days so I can't check anything till then.

 

[padam]

I think that’s a pretty aggressive cam.
You have some tuning to do.

 

[gtxrt]

I think that’s a pretty aggressive cam.
You have some tuning to do.

it is about 2 sizes over the HP magnum stock cam, but being fast ramp it has less advertise duration to .050 duration which is a help.

 

[padam]

it is about 2 sizes over the HP magnum stock cam, but being fast ramp it has less advertise duration to .050 duration which is a help.

Two really big sizes, depending on his CI

 

[4speed68rt]

Make sure that you have some good high octane gas that is fresh. Set the timing correctly. Make sure there is no vacuum leaks.

 

[Crackedback]

Next time you do this cam break in stuff. IGNORE the idle timing number.

Get the thing started, run it up to 2500 rpm and put 35-40 of timing in it. That will keep the temps down. Total timing doesn't really matter as the engine has ZERO Load on it.

Setting idle timing at 10 degrees and having it run at 2K RPM it might have 20-26 timing in it depending on distributor and that will cause it to run HOT with limited airflow across the radiator.

A 703 cam, I'd run more in the 16-18 range for initial timing. Limit mechanical.

 

[Geoff 2]

This^^^^^^^^^^

 

[Don Frelier]

This^^^^^^^^^^

Or even higher...

 

[1967coronet]

Also for any future break in runs.
Place a large electric house fan or squirrel cage fan blowing into the radiator.

 

[Don Frelier]

No hood and a mist from a garden hose in front takes away a bunch of heat.

 

[68-500]

Before you mess with the timing. Hook vacuum advance to manifold vacuum instead of ported vacuum at the carb. It maybe just the bump in advance you need with that cam.