[RARON455]

Maybe someone can answer a question for me, My uncle is a big influence on my performance decisions, but he has a full race car, and is a Chevy man, I drive my bird on the street mainly and take it to the track on weekends. He is recommending me to lock my distributor out eliminating advance and run total timing at all times, I have a complete MSD system the distributor is the pro-billet and only has the mechanical advance no vacuum, I see that it is fairly easy to do this with this distributor and it was built with this option. Would it be advisable to lock the distributor out completely and eliminate any advance? Would this compromise streetability, or cause overheating issues? Any advice or experience will be appreciated.

[tom s]

I did one for the dyno,I really dont think it will be streetable.Try to think about starting your car when hot with 36 degrees lead.Tom

[screamingchief]

Locking out distributors is mostly a race mod used for big cam equipped cars that rarely see the RPM's where a mechanical advance is operational (under 3000 or so RPM's).

But exceptions abound.

Locking out the distributor and using a timing computer is one option for street use.

These timing computers are often more reliable and consistent than a mechanical advance that can be affected by numerous outside influences.

And most timing computers offer options like start retard and switch activated retard among other pluses.

MSD has some really nice timing computers,a fixed unit,an analog adjustable unit (knobs),and a full digital programable unit that can do most anything.

HTH.

[guccieng]

if your car lives at idle and wot, yes. if not, no way!

[b-man]

I was out yesterday visiting Serge, one of the local PY members. I took a ride in his early '70s Ventura, it has a nice 455 with E-heads, RPM intake, 950 Holley and a 250/260-ish degree solid cam. It is capable of low-11s or so in the 1/4 mile.

We drove it around a bit and had a little fun, it has a locked HEI distributor set a 38 degrees. Drove fine out on the street, no issues, just nice and smooth running with all the advance in at idle. Ran nice and cool too.

We didn't try to start it after it was hot, never shut it off before putting it back in the garage. Any hot starting issues that might occur would be easily solved with a coil cut-off switch to let the engine crank without fighting against the 38 degrees of advance, but I don't think it was an issue with this particular car.

[RARON455]

anyone else?

[RobbMc]

There's a good chance the engine will kick back during starting, especially when hot. This can be hard on starters and ring gears.

Rather than locking the advance out, try adjusting the mechanical advance so that the distributor only produces 16 or 20 degrees of advance. Then you can run 16 to 20 degrees of initial advance at idle which will make the engine crisper just off idle (compared to the stock initial of about 8 or 10 degrees) but without risking kick back during starting. Might be a good compromise for a street car.

[Steve C.]

Some MSD boxes have starting retard features built into them.
I have been running locked timing for years, I presume the gas milage is effected some, but its not a daily driver so what the heck. And on a very rare occasion in our HOT Texas summer heat I've had a heat soak issue if I tried to start the car soon after running it hard. But I just opened the hood and waited a short time. Here in Texas the blend of gas, winter or summer, makes a differance. Insulating the carb from the intake manifold and insulating the fuel lines before the carb will help the situation.

[Skip Fix]

Or just use a really fast centrifical curve all in by 1000 or so. Give you the start retard and full advance most of the time.

[Half-Inch Stud]

Lock-out for High Compression Street sounds risque to me.

I gots LOW compression and it seems to run per 12.89 signature with 30initial and 30 total. Malfunctioning ADV setup helped get that data.
It was on Ported Vac while Street drivin, but I pulled the hose for the runs due to stuck ADV weights.

Seems the practical idea (per Geoff, the Aussie) is for me to run Manifold Vac ADV with oh say 16initial. That would help starting, idle, MPG,and 60foots might be as-good or better. Top-end same.

[GoatRider]

I think this is the part you want:

http://store.summitracing.com/partde...5&autoview=sku

A bit pricy (and one more thing that could fail) for a mostly street car IMO. But if you suspect an ignition curve problem at the track and really wanted to lock the distributor advance, this thing is made to plug right into your MSD system.

Good luck,

John