Crane HI6 and plug gaps

[jpnovak]

I just installed a Crane HI-6 that is triggered by my previous points conversion. BTW the engine is a 2.2 E with webers. I am just curious what plug gaps I should run. I opened them to .045". I know that the MSD units call for .05-.06". Any one know a good starting point?

So far the car runs much smoother above 1500 rpm and at idle. I am having a realy problem with a BAD stumble from idle to 1500-1700. Its so bad that the car will stall if I am not careful. I am curious if the plug gap is the cause.

thanks for your help.

Jamie

[sessa]

bump

[J P Stein]

From what I've been told:

To gain full advantage of the MSD unit, a high capacity coil is necessary. Don't know about Crane, but I suspect the same is true. The coil is the gizmo that provides the voltage to jump that big gap. Stock coils are not up to the task.

I have all the MSD goodies, plus a new RS dizzy going in as part of my winter project. I am hoping for easier starts and cleaner running down low on my carbed 2.7L hot rod motor......modest ambitions....maybe the rear tires will break traction at 4K rpm rather than 5K :-).

JPIII

[jpnovak]

Well I tried some different gaps. I tried .055, .060, .040. Seems the smaller gaps work well. I think that I have weak batteries which do not allow me to run a large gap. I think this is causing the bad stumble. Either that or I have some bad Beru connectors. I do have the recommended Crane coil.

BTW, The car starts faster and my plugs have really cleaned up. I can not comment on the extra power or mileage until I get some other problems sorted.

Jamie

[RoninLB]

Sounds like carb related. Air leakage/vac leak or a carb adjustment. Hard to pinpoint without listening to eng. It's a carb eat carb fuel world

[911pcars]

jpnovak,
Among other suggestions, have you checked the engine compartment at night? The higher spark energy may be causing the plug wires to leak/crossfire if they're too old. This will be more noticeable when the engine is under a load (i.e. accelerating).

BTW, where did you end up mounting the Crane box? I know the bulkhead is a logical place, but that location isn't as accessible to adjust the rev limiter.

Sherwood Lee
http://members/rennlist.org/911pcars

[jpnovak]

I did check for arcing in the wires. Did not notice any. I first thought about the wires. the wires themselves are relatively new. maybe 1 year and 4K miles old. I just put new 8mm wire on teh old beru connectors, which measured within spec on the MM. I do wonder about a grounding arc, If you accelerate slowly it runs very smooth. If you stomp on it, it cuts out. I am still confused here

There is a small section in the manual about a miss caused by a weak battery. I assume to get higher output, there needs to be plenty of current. Since I have had problems in the past with my batteries this may be a good place to start.

I mounted the unit behind the rear seats on the firewall/seatbacks. I have no sound pad so this was easy. I also have webers with watershields. the rev limiters are very easy to reach.

[J P Stein]

Ah.....a clue.

"When you stomp on it, it cuts out"

A close look at operation of your accelerator pumps may be in order....timing (slop in the pump linkage), volume....

Distributor advance or lack there of could also cause this, but it does sound carb related.

[RoninLB]

J P is right on

[lonewolf]

question
did you have this problem before installing the hi 6?
what happen when you snap the throttle at 4000?
does this problem happen when you are in neutral as well as when you are under load. does this happen when eng is cold as well as hot.
if you snap the throttle at 1500 in neutral and the eng revs normal then your accelerator pump is ok.
what kind of muffler and is it ok
a restrickted exhaust will rev smooth with a slow foot but will not take any instant thrust.
if this happens only when driving ,first check your point gap. leave point and plug gaps stock for now and the same with carb settings . when you get the eng to rev clean all the way up then you can start messing with them. start checking grounds , especially the one between the regualtor panel and body. the charging system and a fully charged battery are critical in a sooth operation of any high output ignition
also if you look in the pamphelt that came with the ign they unlike MSD call for a specific kind of plug wire. this dosen,t sound like your problem ,but it is a variable.

thats enough to keep you going for a while
i hope that helps

[jpnovak]

OK I think I have already done most of those suggestions but here goes.

-I did not have the problem before the HI-6 installation.
-High rpms throttle snap will sometimes bog down but not stall the car.
-It is not points-I have an optical points system(Crane XR700-highly recommended)
-Accelerator pumps measure volume correctly. not the problem.
-I did not check the ground on the left fender well. I did move some wires to attach ground for HI-6
-I do have the correct wires.

I firmly beleive the problem is electrical in nature. I am not sure why but the car ran very well onthe way to work this morning. It was cool and rainy-first time in several months there is water in the air. Thanks for all the help.

Jamie

[lonewolf]

i had a similar problem .
check the ground at the regulator panel.
the miosture is helping your ground problem. (Clue)

[jpnovak]

Yes, After I posted about the ground, I had a "moment of clarification" I beleive this term was plagurized from a previous post. Looks like I have something to do at lunch today. Now did I remember to bring that 13mm wrench?