Going Back to points!

A

andrew muir

Club Member
Hi
I suspect my pertronix has started to play up again.
Car runs beautifully all the way to 5500 then starts to miss won't rev.
Pretty sure it is electrical, feels like hitting a limiter.
I think I shall go back to original coil first then if still problems, will go back to points.
Timing is spot on and after doing a plug chop plugs are a light chocolate brown so are about right.
Fuel filter has been relaced and is still very clean.
Its not what I really want to do but, seems pertronix just not up to the job.
Open to sugestions though.
Andrew
:(
 
Andrew, I was having a similar problem a month or so ago. I had recently had a 280ZX dizzy fitted and a brand new coil. Same as you with the problem at around 5500rpm. It didn't have a problem revving all the way to the top, however, when it was in neutral just revving it up. I changed all the HT leads for a nice new set from MJP and it ran sweetly again. Only cost about £55 I think. I also changed the plugs from BPR6ES to BPR6ES-11. A slightly larger gap I'm told.
 
Good point from Matt, your ht leads may run fine up to a point but if damaged may be arcing out under high load.
 
I have almost new plugs NGK BPR6ES-11
The HT leads are all fairly new NGK 7mm (blue ones) so should be ok.
The car wont run passed 5500rpm in neatral under low load, starts to missfire badly after 5500 runs fine up to that.
99% sure its ignition issue, will check advance again, but doubt it some how.
Could coil be failing under load??
New battery last year and this has planty of charge by the way, voltmeter indicates charging with volts going up to about 14.5 v approx.
Andrew
 
Just thought i'd throw in a contribution,may be worthwhile ruling out visually if you have ******/intermittent ignition barrel contacts not letting full voltage under heavy load, (total shot in the dark!,)had a couple of motors with similar symptoms.
 
Last edited by a moderator:
If you can make it to Jonathan's Lakeland Motor Museum meet on the 20th May you're welcome to try my HT leads & coil etc. They're silicone blue 8mm Taylor Spiro Pro's & a Crane PS40 coil all working spot on.
 
running 1.1mm plug gaps will increase your chances of high end misfire. only reason for bigger plug gaps is to efficiently burn weak (modern) mixtures!
 
just noticed the r in the plug type as well. so you are running resistive leads and plugs? not needed! why not stick with the intended BP6ES?
 
Hi
You can read my mind, I was thinking that as well, becauase 6 cyl engine suffer lack of dwell at high rpms and large gaps at plug are more difficult to fire, going to put old plugs back in to try. Have heard others with problems with R plugs as well.
Many thanks to confirming my suspicions.
Or a better coil may help faster charge discharge times.
Andrew

amocrace said:
running 1.1mm plug gaps will increase your chances of high end misfire. only reason for bigger plug gaps is to efficiently burn weak (modern) mixtures!
Click to expand...
 
Thanks for the offer Ray, but hope to get this sorted before that, as off to SPA on the 24th May.
Cheers Andrew
:cheers:

ray100 said:
If you can make it to Jonathan's Lakeland Motor Museum meet on the 20th May you're welcome to try my HT leads & coil etc. They're silicone blue 8mm Taylor Spiro Pro's & a Crane PS40 coil all working spot on.
Click to expand...
 
Just put in the old plugs NGK bp6es. Now even worse car won't rev passed 4500 and missfires really badly. I must admit the car also seemed a bit less crisp lower down around 2500 as well.
This has surprised me and, next stage is to try the original datsun coil.
Getting a bit fustrated by all of this. Any more idea anyone?
Andrew

andrew muir said:
Hi
You can read my mind, I was thinking that as well, becauase 6 cyl engine suffer lack of dwell at high rpms and large gaps at plug are more difficult to fire, going to put old plugs back in to try. Have heard others with problems with R plugs as well.
Many thanks to confirming my suspicions.
Or a better coil may help faster charge discharge times.
Andrew
Click to expand...
 
Does your dizzy use vacuum advance? If so, try testing it's still holding suction. A tube over it and give it a suck lol!
 
Hi Matt
Have tested the advance mechs all working well, vacume moves fine and checked with timing light , 35 degress advance, total.

Will check tomorrow again if i get the chance, it seems strange that the old plugs would make such a difference as they have smaller gaps. Makes me think the ignition is marginal. Will install old coil and resistor tomorrow.
Cheers
Andrew
 
I think that you're supposed to run plugs with the bigger gap when using an electronic ignition setup. I can't remember, did you say that it couldn't be fuel starvation?
 
Hi Matt
I have checked the fuel situation with clear hoses attached to float bowls after blipping throttle and running at various throttle settings the chamber levels barely moved. Also fitted new fuel filter. This is still clean.
No 99% sure ignition issue.
Changing spark plugs changes the way the car ran quite significantly so indicating ignition issue.

It could be mechanical diizzy issue but tracking down a ZX dizzy seems impossible in the short term. It seems to run on points ok.
I read on another forum of a guy with the same issues.
Will change to original coil today to see what happens.
:cheers:
 
check out all the other little things to do with the distributer system. I did have a very similar problem once before when it was all standard 240 ignition and dizzy. I changed the ballast resistor and that little stringy looking wire under the cap. Worked ok then after that. It was causing a very weak spark at the plug. It might be worth putting a 'Wanted' add in the classifieds for a 280 dizzy. From what I hear, they're about the most reliable unit out there. But expect to pay up to £150 I guess......
 
Well it is my birthday today and to add to my joy I have cracked the ignition problem.:thumbs:
I firstly put in the new plugs with 1.1 mm gap, car ran better ok till 5500rpm

I then tried doing a run with the lights on car runs bad only now reving to 4600rpm
switching lights off immediately makes car rev back to 5500rpm.

The battery is only a year old and is sitting at 12.6 volts this goes up to 13.8 volts with engine at tickover, but when at tickover and lights on voltage drops back to 12.8 volts.
So I believe the flamethrower 3 ohm coil is not getting enough voltage to run correctly!

Put old original coil back in with ballast resistor engine now runs to over 6000 even if lights are on. Although the volt gauge does not rise up much when the the engine is revved and lights on.

I think I may have a couple of issues
1, the wiring may be in need of replacing to the coil
2 the alternator should be replaced with a higher output model
3 the pertronics needs a ballasted coil to work with an old engine which may have a slight drop in voltage under electrical load.

Now looking for a possible replacement for the stock coil but will have to be a ballasted 1.5ohm coil, any sugestions?

Or should I redo the wiring to the coil, I would require a good wiring diagram as the Hynes one I have is useless?

Or should I try and find an alternative alternator
Thanks to all who posted advice
Andrew

:cheers:
 
You must log in or register to reply here.
Back
Top