Hello guys,
Tomorrow is the big day, I'll break-in the new cam and we will see how this guy performs.

I've researched a lot around the break-in process and I'm pretty confident it will go fine, now my only lasting question is about the timing I should set during break-in.

Later I will plug the vacuum figure out all the settings and get the curve right, but during break-in I just want to set a good timing for 2000 rpm with the vacuum on and everything.
I don't want to have too much and get to pinging during break-in but also don't want to be too little and see my headers go cherry red. What should be a good number? 40*? 50*? All the way till pinging then a tad back?

And what about the electric choke? Should I let it do its magic or just click it open?

Thanks,
Fábio.

 

I'd plug the vacumn and set the timing to 36 degrees btdc in by 2,700 and then hook the vacumn back up.

 

I got this new StreetFire HEI distrib from MSD and I'm not sure how it's curve looks like. From the little info there is on the instruction sheets it seems that the vacumn can add 22* to it. Wouldn't it throw me around 58* way out of the magic 52*?
I'm really afraid of messing up my break-in.

Thanks,
Fábio.

 

I just broke in my XE268H this way and still have not connected the vacuum advance. This weekend I plan to take detailed vac readings, measure for the full curve and dial in the VA. I would not use VA at all for your breakin.

 

Plug vacuum advance. Set initial timing for 7 to 10* btdc. Set timing mark on compression and hook up timing light. Turn key to on position. Slowly rotate distributer body until timing light flashes. Lock down distributer and she should fire right up. Put a fan in front of radiator because break in generates a lot of heat. Dial in timing curve later.

 

Ok I'm confused. I have to break in a new 383 in a week and don't want to screw it up. How am I suppose to drop the stock distributor into a fresh motor and set initial timing on the stock points distributor without starting the car?

 

Seems that Jeff has a great way of doing it, turn your engine until the 10* mark on the harmonic damper, then with the ignition on but the engine off twist the dist until the timing gun blinks.

I did by eye looking into pics of the dist before I disassembled the engine.

By the way Jeff was also right about it generating lots of heat. Seems that the electric fan+aluminum rad setup that I have is great to cool down a stationary car during 800rpm idle but dont even get close to be effective cooling a stationary car turning 2500+rpm.

I had to stop the process twice beacause of overheating, the first time was 5 minutes in, but because of the new temp sender that I put in that seems to be the wrong one for the stock vette gauge, after calling Scott for emotional support(thanks Scott) I got it back up took out some advance and used my IR gun to read the temp. It went on for another 10 minutes or so until the temp raised to 220* measured on the upper hose and the 15?psi rad cap started squirting boiling water then I shut it down.

Due to lack of helpers I blocked the throtle open which made shuting off the engine really not funny with scarry sounds and backfires, I do not recomend that, get a helper on the throtle and when you shut it off cut the ignition and the throttle.

All said and done I think it went fine, it fired up right away, no leaks, no pinging, no back fires, no misses, the new headers pipes and exhaust sound really smooth.

Tomorrow I'll change the oil and filter again, retorque intake and exhaust, check spark plugs for mixture, see if the push rods are still spining, check dynamic compression, dial in the timing, idle mixture, idle rpm, and drive it around.

Thanks a lot guys for the support.
Fábio.

 

get a plainjane simple continuity "test light" that runs on 12vdc. Set points gap w/feeler gage ... on bench if you want. Verify #1 cyl is at TDC ... then very slightly reverse motor so it's at about 10*-15* BEFORE TDC. Install/Drop distributor in so rotor is at or very near position to fire # 1 plug. Do NOT connect hi-tension coil wire from coil to center dist cap. Turn ignition to RUN. Connect test lamp to Negative side of points, the other side to separate ground. Gently rotate dist back & forth noting how lamp turns off & on as points open & close. Note just that position where lamp is flickering. Lock dist down into that flickering position. Again, confirm rotor is in #1 cyl fire position. Turn ignition OFF. Replace hi-tension coil wire. Connect a timing light in preparation for initial engine run. As soon as motor starts, recheck timing & adjust as needed.

I've also set points gap & points timing on the side of the road with only a matchbook flap to set gap ... and a cellophane pak-wrapper betwixt points as substitute for the flickering lamp ... just as cellophane can be pulled from points is about where a lamp'll flicker. I didn't invent that method ... I learned it from a much older gent.

 

Thanks Jeff and jackson!

I haven't done a engine break in in 20 years so I'm very rusty. I do have a friends industrial fan lined up for cooling so I'm good there. The cam that HBR Competition Engines here in Vegas put in is a custom grind from Custom Cams Inc and something about the way they are ground allows for a relatively easy break in at 1500 RPM's for 20 minutes. I don't have any junk header so I have to do the deed with my freshly ceramic coated Hooker sidepipes. If I can get it fired, steady 1500 RPM's for 20 minutes and not get the headers too hot I think I'll be good.

 

Oil and filter were awesomely clean, intake and water pupmp both lost their torque dramatically, had to take carb and dist out to retorque everything, spark plugs looked just as new, probably that wasn't long enough for them to get the magic tan, pushrods are still spinning(knock on wood), dynamic compression is at 180 psi, exacly where we wanted it to be, I'm having trouble with my timing light so I roughtly set it to 12* initial and will run that vacumn advance for now. Vacumn on idle is around 17, and the new exhaust sounds great.

Tomorrow we will have a test drive with the tops off
Thanks a lot Scott, Mako, Lars, and all the guys for all the help during this project, this comunity rocks!.

Next stop: rear end...

Fábio.

 

Well... It sounds great but I think I already said that.
The surprise is that the old iron heads, stock exhaust, wiped cam, and stock distributor had more humpf on the lower rpms than the new setup

It really wakes up at 4000 rpm where it gets much better, I'll start reading Lars papers on tuning and see if I can get more juice out of this guy at bottom end.

I already got the distrib vacumn advance set to go all out on lower vacumn as this cam generates less vacumn than my stock one, it got slightly better. After that I have replaced the carb's spring for the secondaries with the long yellow one for the same reason but haven't tested it yet. You will definetely see more posts on this

Fábio.

 

Set it to 8-10 degrees BTDC.

You can static set your inital timing with an old (but working) spark plug.

1) Remove the distributor cap

2) Take the number one plug wire off the number one plug and insert your old spark plug in the boot.

3) Turn the engine by hand to the position that both the harmonic is at 8-10 degrees BTDC and the rotor is pointing toward the number one position if the cap were installed.

4) Loosen the bolt that holds the distributor clamp-down bracket.

5) Turn the ignition key to the "On" position

6) Ground the plug (away from the carb)

7) With your other hand, rotate the distributor back and forth while watching your grounded plug. Stop rotating at the exact position when the plug fires.

8) Turn the ignition key off. (You shouldn't leave the key in the "on" position any longer than necessary if you have either a resistor or resistor wire to your coil. Things can get warm. But this procedure takes less than 30 seconds).

9) Button it up, fire it up.

Good luck!