when I was at Autozone they listed two types of Bosch Platinum +4s for the Disco II ... extended tip and regular tip. They were out of the regular ones so I bought the extended tips, but wanted to check if it is OK to use them? I won't be putting them in until I replace my valve cover gaskets, and plan to do the Magnecor wires and the thermostat at the same time.

Also, before I do the above should I do the engine flush with ATF and the Seafoam or wait until after the valve cover gaskets are replaced?

Thanks,
Mark

 

With the design of the cyclinder and the way the plug goes into it I wouldnt think that the lenght of the plug would matter. I wouldnt use those plugs anyway, the plug goes in the compression chamber sideways and the open tip design of the +4 plugs only helps the ignition of the fuel/air mixture if it goes in through the top of the combustion chamber. Like on a multi-valve overhead cam engine like a Toyota, Honda, Mitsubishi etc.
I use Denso Iridium plugs and I love them. Much smoother idle than platnum and better fuel economy too.
But if you want to use platinum then just use regular Bosch Platinum plugs.
As far as the ATF flush, depending on the mileage of your truck, unless you are prepared and willing to remove the oilpan and clean out the oil pump pick up tube I wouldnt do it.All that sludge breaks loose and can clog the oil pick up.
Others have also had problems with lifter noise after a ATF flush because sludge clogs the hydrolic lifter and it runs dry. I would just switch to full synthetic, it has more detergants and will clean as you drive.
Others will have different opinions, but this is mine.

 

If I remember right the correct plug number is an 8814.
I have never seen or heard of any one using an extended plug in a Rover and wouldn't suggest it.
As for the other stuff, it really won't be a difference in the engine result whether you put the pligs in first or after the treatment.
By the way, don't forget to put some anti seize on the plug threads.
What are you using for plug wires, the Plus 4's love lots of voltage. I ran my last set for a little over 65,000 mile with great results, then decided to try the new Bosch Fusion to see if they are actually any better.

 

Wires are 8mm Magnecor, I will be putting them in at the same time as the other stuff listed above.

BTW, Disco Mike (anyone else familiar with compression test readings) - could you take a look at my post below and let me know if my numbers look OK? Thanks!

https://landroverforums.com/m_48098/tm.htm

 

Your compression is good for that mileage.
Send me your e-mail address and I'll send you some picture of my 99 doing it's thing off road in Colorado and Death Valley

 

so you aim the plug's gap to the ex valve in an 8v head(2v), so 4 electrodes makes that impossible, the spark is always shrouded w/the flame having to work it's way around all that plug

 

Sorry, I don't know if this is a question or a general statement, either way I am not sure what your are saying.

 

Not a significant factor. Aircraft spark plugs (high power and heat) have 4 electrodes too. Far more important in aluminum heads is proper spark plug torque.

Dave

 

i just thnk an open gap plug(side gap-) is an improvement over a std plug, we use them sometimes in high compression(10.5-1) 8v turbo 4's running ton's of boost(25psi+, giving an actual CR of 25-1 or so), and a plat4 would be going in the wrong direction, esp when a side gap can handle such high combustion pressures

i am just missing the benifit of the plat4 over any other plug avail


just some plug theory from one who has worked on very few dom v8's

 

benflynn

I agree with you, I dont see the benifit either. If the plug came in from the top of the head between the valves, like on a Honda or Mitsubishi then I could understand.
I use Iridium plugs which are better than standard plugs. But I think it all boils down to personal preferance.