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2500 6 cylinder megajolt trigger wheel


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On 2/5/2021 at 1:51 PM, Ian2000t said:

Looks like you can still get the WR7DTC from a Porsche shop at a decent price:

https://www.design911.co.uk/fu/prod2069/Porsche-928GTS-and-968-Spark-Plug-WR7DTC/#2069

I did use WR78's in my Mini years ago, but they didn't seem to play nice, so went back to NGK. I also tried to stay away from Bosch plugs, as the Beetle used to fowl them up once and that was the end of them - switching to NGK plugs fixed the issue completely.

Although these days I keep getting NGK's fail in the Mini - seems like once they get a bit flooded they quickly seem to crap out after. Maybe not as well made as they once were?

What gap do you use with the WR7DTC? I will probably give these a try if you have good results with them!

WARNING!!
 

DO NOT order WR7DTC from this site. I just received 10 x WR7DC+, which are single electrode, from them. 

Called them and they advised that these have superseded the WR7DTC, which are no longer available. So, I'm sending them back for a refund.

 

Looking around, I think the options I have are:

 

WR6DTC - Bosch resistor triple electrode, but a cooler heat rating (6 rather than 7).

W7LTCR - Bosch triple electrode, same heat rating as WR7DTC. Not sure if it's resistive though? It's not according to the Bosch chart, but the Green Spark Plug finder shows this when you've filtered to just resistive plugs.....

WR78 - Bosch resister for electrode, same heat rating as the WR7DTC.

 

From what I can tell, the heat ratings go the other way for Bosch, so a "6" in Bosch would be more like a "7" in NGK. I'm running NGK 5's at the moment, with no pinking, so I think an NGK 7, or Bosch 6 would too cool for my engine?

 

 

BoschNGKPlugs.png

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I abandoned NGKs some years ago for exactly this reason. Once they’ve got wet they are dead and nothing brings them back. First discovered in a modern (Nissan Primera GT) though I didn’t realise the p

Hi Ian, and welcome. I'm a big fan of distributorless ignition though I've always used it as part of a full engine management system using Megasquirt ECU rather than Megajolt. For both my 2L

Perfect, thanks! All sorted now! 

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eBay certainly has WR7LTC plugs listed, I wonder if that is what you found with a mislabelling?

As far as I can see, the LTC projects further into the chamber than the DTC version, so question is will it clear the piston/valves?

Phil

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The "R" in WR indicates resistive.

I think I mentioned the WR7DTC were getting harder to find. The equivalent 6 is likely to be similar as they are part of the same product series and anyway I've found the 7 works fine so would be reluctant to change.  It was a fluke - we've had several Golf GTIs over the years and they are the listed OE plug for them.  As well used set found their way into my Herald years ago as an emergency measure and when I swapped back I noticed an unexpected decline in performance.  That was in the early 90s.  Been using them ever since.

Anyway, I'd reckon the WR78s are probably your best bet as they are a current model and get good reports (from Roger) though I've not tried them myself yet.  That's what I'll buy next time I need a set.

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Bespoke trigger wheel turned up today. Fits great! 

Stated making the crank sensor bracket, going to use the Ford Explorer sensor I think as it will mount sturdier than the Ford Fiesta one I have. 

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Looks good. I was thinking how clever/brave you’d been getting holes drilled before offering it up with the sensor in place, then I noticed you’ve been even smarter and slotted the holes :biggrin:

 

PS. Who did the trigger wheel for you?  Friend is looking at options for his Stage (TV8)....

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Yeh, i thought I would struggle to get things mounted up exactly, so i asked for a slotted design.

Used this guy on ebay:

https://www.ebay.co.uk/itm/184637204188

 

I chose one of his standard trigger wheels and then asked him to enlarge the centre to 32mm to allow the crank bolt and socket to fit inside it, and to add the slots in 2" pcd to mount where the fan used to (central non rubberised part of the damper). Another reason for slots is that the 4 bolt holes aren't square, it's actually a rectangular pattern. 

Had to do some drawings for him, and he got it bang on. Can't complain for £28 delivered! Would definitely use again! 

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Right, I'm at the starting phase now, but not going great! 

What firing order should i have the plugs connected in? I used the "Datsun 240" diagram off autosport site, but all I'm getting is a few pops through the carbs..! 

How can I tell if the MJ is picking up the crank sensor input properly? And is there anyway to tell if I'm getting the right firing order at the plugs? 

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Hooo, this old chestnut.  As you are getting popping and banging I would say it is working and the plug leads are wrong. I’ve played this game a few times - have never got them right first time.

First thing is that the plug leads need to be paired on the coils

1-6
2-5
3-4

Thats the easy bit. Then you have get the coil firing order right. This can be done either by swapping plug lead pairs from coil to coil or by swapping the LT earth wires around.

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16 minutes ago, Nick Jones said:

Hooo, this old chestnut.  As you are getting popping and banging I would say it is working and the plug leads are wrong. I’ve played this game a few times - have never got them right first time.

First thing is that the plug leads need to be paired on the coils

1-6
2-5
3-4

Thats the easy bit. Then you have get the coil firing order right. This can be done either by swapping plug lead pairs from coil to coil or by swapping the LT earth wires around.

Think we posted at the same time, but got it working now! I basically did what you said there - got them paired and then tried swapping until it started! 

Now just got to figure out why it stays on when I switch the ignition off. Think I had that with the Mini years ago... 

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1 hour ago, Ian2000t said:

Think we posted at the same time, but got it working now! I basically did what you said there - got them paired and then tried swapping until it started! 

Now just got to figure out why it stays on when I switch the ignition off. Think I had that with the Mini years ago... 

Hello Ian

               It is a feed from the ignition waring light you need to fit a diode in circuit (I have forgotten where!) but someone will post it on here

Roger

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I have just had the same problems as you have had, first with the plug leads needing changing around and then engine not stopping when switched off. I hopefully have sorted this by fitting a diode in the circuit from alternator  to the warning light. I used a SR5100 5A 100V Schottky Germanium Rectifier Diode 5 Amp, sourced on the Internet auction site. My car is converted from dynamo to alternator with the regulator control box removed and the smaller wires for the ignition light circuit are joined together at this point, so I fitted the diode here. Seems to work fine, engine stops when  asked to and the ignition light still functions correctly.

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Congrats on the birth of your new ignition. :smile:

Others have beaten me to the reason (and cure) for the non-stopping issue. This afflicted my PI, which came as a surprise as it never was an issue with the Vitesse.

Nick

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Thanks! 

With the diode, does it go in between the alternator to ignition light then? 

You know, I think I did a worse bodge on the Mini way back. I think I added a resistor before the switching relay feed, so it usually saw around 8v, and after switch off saw 2v, which was low enough for it to deactivate! 

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On 2/21/2021 at 11:24 AM, Jdowson said:

Yes the diode fits in between the alternator and the warning light. The banded end on the diode connects to the alternator side.

John

Perfect, thanks! All sorted now! 

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