Run on issue

[Grimmy 312]

I'm having a problem with my hot xflow running on after I cut ign . I'm told its got 10.5-1 comp and im running 10* static timing . the question is if I run a colder spark plug will its stop the run on ? Or any other ideas ?

[Grimmy 312]

Sorry for the double post ! Other thread can be taken down .

[slydog 7,873]

Umm sort of bud total timing needs to come back and or turn it off in gear and drag the clutch a tad.Besides that doe's it have a MSD or aftermarket ignition? If so time for a TFI dizzy bro...

[n00bus m@x1mus 465]

You could try richening up your idle a tad aswell. Some times your plugs can glow with a lean mix and cause run on

[Grimmy 312]

I'll richen it up a bit at idle n see if it helps , it seems that if I let it idle for 10sec or so it stops easier . I don't have any msd yet but to have a few tfi dizzys . I'm looking to lock the timing but not sure how to go about it .

[slydog 7,873]

Well you lock the timing with a TFI dizzy and a MSD Street fire for under $200.Stop talking about it,stay off the piss for a week and stop skidding tyres and just buy one and wire it up.It will transform the car I promise.

 

Besides that the run can be unburnt carbon or it could be too much cyl pressure with a small cam.I use to just turn my ute off by dragging the clutch a little.Did it for around 4-5 years so it can't hurt em too much.

[Grimmy 312]

It's a fresh engine , run for less than 3hours lol so carbon is out and the cam is a fair size . I'll have the msd by the end of the month . I got a button clutch so it's a bit violent wen I let it out but if that's wat needs to happen then ill have to deal with it

[bear351c 10,270]

Harmonic balancer slipped ?? Try 8* or 12 * degrees, see if it goes away.

[Grimmy 312]

SFI race series , so I hope not

[bear351c 10,270]

Cool.!  Just checkin' 

[gerg 10,871]

10.5:1 is pretty big for a Crossy, so any hot spots will ignite fuel more easily. What plugs are you running now? If you're running NGK BP5s or similar, maybe 6 is the go.

 

Even the standard Crossys have some sort of shutoff solenoid, both the Strommy (base idle) and the Webber (idle fuel shutoff) so there's an issue even at stock compression. I think it's the long stroke/small chamber design. I'm assuming you've got some sort of Holley on there. Maybe you need something like this to kill the motor.

 

Ignition timing has nothing to do with running on. You flick the key off, and no spark is produced, so ignition timing means nothing once that happens.

[Clevo120Y 815]

I agree with Greg, what head have you got on it? The C2 if the quench wings tip isn't layed back and smoothed can be a hot spot.

[Grimmy 312]

I'm running NGK R bp5's atm , I'll try 6's and see wat happens . I've got a modded 650dp on it , and its a c2 cast head but its been ported and chambers cc'd out to 55

[Clevo120Y 815]

Try the plugs for sure, go for a run then shut if off straight away and have a look at the plugs that are in there now to determine if some are too hot and running lean, if idling for a while improves it then that tells me that the idle fuel is enough to start cooling down the chamber, I think you are running lean at part and wot, if you have a laser thermometer go for a spin then pop the bonnet and measure the header pipes, you will probably find that 1 and 6 are much hotter which indicates that those 2 pots are running lean, you may have to up the main jets by a couple or use smaller hsab's if you carb is setup for that. Xflows are a bugger that without a modified and flow tested intake manifold pots 3 and 4 will have to run a little rich to keep 1 and 6 from being lean.

Hope you get it sorted

[TF_250 398]

mine did this also changed the plugs from 5's to 7's and instant fix