Crane ignition question

[tosoutherncars]

Hi all,

Well, the headers and the DGV are on. Time for spark...

For the Crane Fireball (XR700, their basic system) am I better using a distributor with a mechanical advance, or vacuum? (I think I have one of each) Or is the advance disconnected? I must admit, I haven't read the manual yet, I'm a little fuzzy on how the whole thing works.

-D

 

[blkcorvair]

Ive had that same setup on mine with the stock vacum advance for a while now. No problems here. I did cut some 1/2" long pieces of fuel hose and used them as spaces behind the ignition unit to absorb some of the vibration (In theory) And added an electronic Tach. Heres some pics of some of teh work.

Heres a pic of the breather header & dgx setup Ive been running

 

[tosoutherncars]

Gah! That's great! But it gives me more questions...

1) I see you're running a ballast resistor... ceramic? Was the stock one not the right resistance value?

2) Why mount the carb in that direction and have the throttle running all the way around the engine bay? I was assuming that having it 180 degrees the other way around would be easiest...

3) Where did you pick up the vacuum for your advance? Straight off the carb? It's the black tube that runs over the valve cover?

-D

 

[blkcorvair]

Much of this stuff did come installed as I bought the car, I just made some tweaks to work out the bugs. New Ceramic resitor yes. (Not sure if the values were the same. Never had the stock one but i could test it.) Vacum picks up right at bottom of carb if your 180 degrees around than the vacum would in sense pickup on the other side. It is thew black hose over the valve cover.

-scott

 

[RonMacPherson]

A suggestion, in the future if you are looking for little mounts similar, but solid rubber with studs on each end. Head for your Mercedes parts people. Benz used a little rubber spacer with studs for lots of things.

Fuel pump mounts, air filter housing mounts. etc.

Over the years.

 

[tosoutherncars]

I was going to try mounting the unit with double-sided tape, actually! I'd rather not drill any holes if I don't have to. Hopefully that will hold... Just above the w/shield wiper motor, so it's nice and close to the rest of the system.

Just got in from gutting my spare distributor and installing the optical switch. NEXT QUESTION - the advance plate only moves about 5 degrees when vacuum is applied. Is that about as far as it should go? (this is for the stock Lucas distributor with vacuum advance, obviously.)

-D

 

[tosoutherncars]

Scott, you're just running an electic fan? How's that working for you?

 

[blkcorvair]

Electric fan has been no prob. but it is 12" (cut lower shroud to squeeze it in, Also keep in mind, I run an oil cooler, wrapped header and have an addition bike radiator piped into the old heater core hoses tucked under the front wing. Use a thermostat with the wire node that fits within the hose but also ran a bypass switch to the dash. Alway comes on at 165-175.

 

[Morris]

I don't know anything about the DVG, but on a stock carb, vac advance does not kick in until about 1/8 throttle on the '79. I believe this is the same for the '78. On the stock carb, this is accomplished by setting the vacuum pick up just in front of the throttle when it is closed.

 

[RickB]

Scott did you put any other fans on, like on the aux rad or the oil cooler?

BTW I blew the doors off an aggressive driver in a BMW this morning on the way to work. That felt good, me in my old time 78 MG... Him in his little Bavarian street rod. Ha!

I'm sure he got a good look at that new exhaust unit on Frank /bcforum/images/%%GRAEMLIN_URL%%/wink.gif

 

[jlaird]

I knew it, it's much faster with that exhaust.

 

[RickB]

heheheh... I don't know about that but you know you've been passed by something...

 

[tosoutherncars]

Atta boy Rick, standing up for the LBC crowd!

Why is it always the BMW drivers? I smoked some repressed yuppie in a 325, driving my VW Rabbit a little while back. Sure, it's small and old... but a 1.8L and no smog gear on a light little car with a five-speed... that thing hauls.

-D

 

[tosoutherncars]

I don't know anything about the DVG, but on a stock carb, vac advance does not kick in until about 1/8 throttle on the '79. I believe this is the same for the '78. On the stock carb, this is accomplished by setting the vacuum pick up just in front of the throttle when it is closed.

Any idea how far it moves, once it engages? I've only got a few degrees... maybe 1/4" of motion or so, on the advance plate.

-D

 

[Morris]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Any idea how far it moves, once it engages? I've only got a few degrees... maybe 1/4" of motion or so, on the advance plate.[/QUOTE]

Not much as I recall. My advance is now computer controlled, so I pulled all that junk off. Are you testing with a vacuum pump? Does the diaphram hold air? Does the advance plate move freely? If so, your vacuum advance is probably okay.

Vacuum advance is not super critical and mainly effects economy, polution, and (IMHO) off idle power. Someone will probably disagree with that last statement, but that has been my experience.

What is really critical is correct centrifugal (weighted) advance. That's pretty hard to test without fancy smchancy equipment. What a lot of the guys do is set their advance at high RPM. Unless your dizzy is totally whack, your advance should be "all-in" at around 3000-3500 rpm. At those revs, you should be advancing roughly 30-34 degrees. If you set your timing at those high revs, then check your idle timing. If it is waaaaaaay off. odds are your dizzy is smoked. (BTW, if you do set your timing like this, make sure you disconnect your vacuum advance).

Ultimately, you want to run your car at the max advance you can without causing pinging. Unless you have access to a rolling road, this can take a lot of trial and error.


Sorry if I overexplained this... I just needed to "escape" from work for a few minutes.

 

[blkcorvair]

Rick no other fans, they are located behind the makeshift grilles that cover the obnoxious signal cutouts.