| Author | Message | ||
     Lee R. Byrd (Mobile) Member Username: Mobile Post Number: 77 Registered: 07-2003 |
I searched the Disco Tech archives back 6-months and could not find any truly useful info. on this subject. I checked with landrover and they want $15 per plug and were rather unpleasant. I called AB and they want $9 per plug. I remembered reading something about NGK crossovers but could only find info for DI's. So, does anyone have any suggestions for plugs so I don't get screwed without a smile or vasoline. | ||
| Matt Anderson (Disco01) Member Username: Disco01 Post Number: 203 Registered: 10-2003 |
Rover Connection lists the champion plugs for $33 for a set of eight for a D2. Atlantic British has them listed for $2.75 a RN12YC and $2.49 for a RN11YC. Both will work in a D2 apparently I dont know the difference. They also list a Bosch plug for $4.95, but there has been some negative talk of Bosch plugs on the board if I recall. British Pacific has the double platinum plug you mention above for $9.31. I dont know if the double platinum is necessary, so hopefully someone else who has tried both will chime in. | ||
| Richard Garza (Rgarza) Member Username: Rgarza Post Number: 51 Registered: 05-2003 |
OEM is champion spark plug. You can get those at autozone. I think you are better off with the oem plugs. I changed my plugs and my gas mileage increased at least by 20%. | ||
| Lee R. Byrd (Mobile) Member Username: Mobile Post Number: 78 Registered: 07-2003 |
I called AB, GB and a few others; they all listed for around $9 each. The RN11YC is a copper plug rather than the OEM double platinum. I think the OEM plug is RN11YPBP or something like that. I was curious if anyone out there knew of a cross-reference for the OEM double platinum plug. Without that cross-reference I would rather use the stock ones and just pay the extra money. Does anyone know if the gap can be increased beyond .040 when using magnacore 8mm wires? | ||
| Matt Anderson (Disco01) Member Username: Disco01 Post Number: 206 Registered: 10-2003 |
I am not sure, but I think the platinum in the plugs has to do with how long they last and less to do with how they ignite. Before you take the leap why don't you wait and see if anyone else knows. I would keep the gap at factory specs. | ||
| Lee R. Byrd (Mobile) Member Username: Mobile Post Number: 79 Registered: 07-2003 |
That is the reason they have the platinum plugs. They cost more but last longer. | ||
| Matt Anderson (Disco01) Member Username: Disco01 Post Number: 209 Registered: 10-2003 |
Ok, but do they last 3 times as long???? Plug replacement is so easy I dont see why to pay the extra money for them as long as they will run the same, and considering they are both the same design just different material why shouldnt they? | ||
| Geoff 93 RRC (Geoff) Member Username: Geoff Post Number: 237 Registered: 11-2002 |
The RN12YC runs a little hotter than the RN11YC. As long as you don't tow a lot you're probably fine with the 12's. This means the electrode extends deeper into the combustion chamber. They will be better for the engine in the winter months. Platinums last longer and help the vehicle meet 100K emissions requirements. I'd just go to Autozone and get the Champion OEM or let their computer suggest and OEM equivalent. | ||
| Lee R. Byrd (Mobile) Member Username: Mobile Post Number: 80 Registered: 07-2003 |
Matt: Non-platinums are supposed to be replaced at 15k and the double-platinums are to be replaced every 30k miles (I assume single platinums last 22.5k).There is a significant difference in price. The double platinums are ~2x the price of single platinum and ~3x the price of copper. Using the prices from AB the plugs cost: copper ($2.75) ($1.47/(k miles)), platinum ($4.95) ($1.76/(k miles)), double platinum ($8.75) ($2.33/(k miles)). The copper plugs are more economical. I realize plugs generally last longer than the suggested service intervals thus increasing the economy of the copper plugs. I am doing all of my own services and would like to follow the service manual in this case. The main reason I think I will use OEM is the lack of an identical or nearly identical cross-referenced plug, decreased under hood labor time, and money already spent on other parts. I do thank you for your thoughts and time. You have some very valid points. If I were just replacing the plugs I would likely go with copper. Since I am forking out a lot of time and $ for other parts to do a 60k service, and then some, the extra $48 does not seem that bad at the moment. Geoff: Thank you for the description of the heat range and all. The local parts guys I talked to didn't know enough about the heat ranges to make a sugggestion. Some places did not even have a listing for the Disco II. Do you know if the deeper combustion chamber extension will cause any negative effects in 100+ degree F. weather? Unfortunately, champion does not sell the OEM to anyone other than LRNA. Champion struck a deal with LRNA so they could screw DII owners who want OEM spark plugs. All of the local parts stores have the DI plugs recommended for the DII. Autozone even tried to convince me they were an upgrade! The prices for OEM plugs per set of eight cost a bit under $20 more than single-platinum computer suggested plugs at most stores. I did not know the double platinums had anything to do with emmissions laws. In Alabama we have relaxed emmissions laws. Those we do have aren't enforced! If the plugs do affect emmisions, they should help keep the O2 sensors cleaner longer... Good to Know  Thanks for your explanations, time and thought. | ||
| Geoff 93 RRC (Geoff) Member Username: Geoff Post Number: 239 Registered: 11-2002 |
Cars and some trucks had to meet a federal mandate to have reliable emissions for 100K starting a few years ago. That's why we get platinum plugs and stainless exhaust even on Chevy's now. The issue with a hotter plug is that they can cause preignition and detonation - which can burn a hole in the aluminum piston under sustained high load. I don't know if the 12's could ever get hot enough to do this and on www.robisonservice.com (for instance) they recommend them over the 11's. I have the 12's in my Rangie. On the other hand colder plugs can foul easier. If you live in Alabama (warmish climate) and don't do a lot of short trips where the engine barely warms up, then the colder 11's are probably fine. The other issue with plugs is their electrical resistence. On our Trooper for instance a non-OEM spec plug can cause the computer to think its misfiring. Not sure how sensitive the D1 or D2 is to this. I have *heard* that plugs with out of spec resistence on the Trooper can lead to premature coil failure. | ||
| Lee R. Byrd (Mobile) Member Username: Mobile Post Number: 82 Registered: 07-2003 |
Geoff: I looked at the Robinson service site and talked to them yesterday. They said the DII should use the expensive plug. Their website states they prefer the heat range of the 12 to the 11 on the pre-bosch ems engines. I have decided to go with the stock plugs. I was initially shocked at the price. After much searching, a direct crossover could not be found. By the time I got done searching I was no longer sticker shocked by the cost of the plugs. I figured that I bought an expensive, to me, import and would use the factory plugs. $72 without sales tax is not that bad. I would like to say thanx to everyone that contributed to this post. I Hope y'all have a nice week. |
