just got my dui dist. in and was wondering what plugs were best to use. i am running ngk right now. its a 74 f engine.
spark plug with dui (2 Viewers)
- Thread starter mwalls54
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This is an open question. I've worked in an autoparts store and everyone thinks their plugs are the best. I have use bosh?? spelling doesn't look right... and I've use champion truck plugs. I would avoid the $.99 plugs for sure. If you get some in the $2+ range you are probably going to be happy with them. The only person you can trust to give you a good idea on plugs... is yourself by trying different types.
I've use the bosh plat and the champion truck plugs. The plats have the electrode surounded by ceramic so it disapates heat much better and doesn't loose it's gap over time as much as many. I've pulled plugs out after 50k with some and had .075 gap, and done the same with bosh and it has been closer to the .050 or less. So I guess my vote is bosh.
TC
I've use the bosh plat and the champion truck plugs. The plats have the electrode surounded by ceramic so it disapates heat much better and doesn't loose it's gap over time as much as many. I've pulled plugs out after 50k with some and had .075 gap, and done the same with bosh and it has been closer to the .050 or less. So I guess my vote is bosh.
TC
I've not had good luck with Champions. Don't know why, but they seemed to develop a miss during idle.
Now I use the Denso plugs or NGK.
Now I use the Denso plugs or NGK.
I'm using the stock plugs with my DUI distrubutor (NGK or Denso, not sure which brand) in a 72 F motor. Plugs are gapped at around .055, which is what DUI recommends. Motor runs great. Make sure your plug wires are in good shape to get the full benefits of the new distributor.
Brian
Brian
NGK BPR5 EY. R is for resistor type (used in cars with modern electronics, not necessary for a cruiser but won't affect it either, and they're more common than non resistor I think), Y is for split electrode. 5 is heat range 5 (factory recommended); higher number is a cooler plug (meaning it distributes more heat to the block instead of the combustion chamber); lower number is a hotter plug. One reason to use hotter plug is if you oil foul plugs a lot, to try to burn the oil off the electrodes. One reason to use cooler plug is if your engine PINGS, or pre ignition, which means too much compression and/or heat (assuming timing is correct); cooler plug will lower heat in combustion chamber and MAY decrease pinging . Word.
{Rant mode on}
There is no reason to run a longer plug gap than the .039 that the factory recommends. A longer gap will require a higher voltage to jump the gap, leading to lower reliability ignition and increased wear on the plugs, rotor, cap and break down of the insulation.
All you need is sufficient spark to ignite the air/fuel mix and anything more is waste. Racing engines may require a higher voltage to ignite the mix because of the large air fuel charge in supercharged engines and because of the high compression, but you aren't going to ever run into this situation in a 2F.
If high voltage spark did anything beneficial, then all the factories would use them. Just because racing engines need a higher voltage ignition doesn't mean that adding a high voltage ignition will turn a 2F into a racing engine.
{/Rant mode off}
There, I feel better.
There is no reason to run a longer plug gap than the .039 that the factory recommends. A longer gap will require a higher voltage to jump the gap, leading to lower reliability ignition and increased wear on the plugs, rotor, cap and break down of the insulation.
All you need is sufficient spark to ignite the air/fuel mix and anything more is waste. Racing engines may require a higher voltage to ignite the mix because of the large air fuel charge in supercharged engines and because of the high compression, but you aren't going to ever run into this situation in a 2F.
If high voltage spark did anything beneficial, then all the factories would use them. Just because racing engines need a higher voltage ignition doesn't mean that adding a high voltage ignition will turn a 2F into a racing engine.
{/Rant mode off}
There, I feel better.
- Thread starter
- #8
the dui instructions say to gap between .050 and .055 never said this was going to be a race engine. my race engine i run a gap of .030 and thats in a chevy ls1 that has one coil per plug. I hate points dist. and wanted electronic and this was the best replacement i have found
thanks for the info i have ngk plugs and going to get new ngk's with the new set up.
thanks for the info i have ngk plugs and going to get new ngk's with the new set up.
The GM HEI system, which includes the DUI distributor/coil combination, means "High Energy Ignition". The factory recommended plug gap in HEI equipped vehicles was .060" when the system was introduced. It was heavily advertized as being beneficial to everything that ails. The thick wires were needed to insulate the high voltage coil output. Nothing much has changed and the recommended plug gap for HEI systems is still higher than that for lower output ignition systems including the stock Toyota. If you use a DUI distributor also use a large plug gap. Not for racing but because it's got the juice to jump the gap efficiently.
By the way Doc, resistive plugs control the electrical noise transmitted by the system as radio frequency interference. Use them so your enemies in the next lane won't shoot you first because their radios crackle when you are nearby..
By the way Doc, resistive plugs control the electrical noise transmitted by the system as radio frequency interference. Use them so your enemies in the next lane won't shoot you first because their radios crackle when you are nearby.
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