998 plug leads do not fit?
 

I could be missing something really obvious here but...

After starting to put together my 998 project I was under the impression that apart from length all the 748 to 998 plug leads are the same fitment at the spark plug end. Thing is when I try and fit some of my 996 leads to the 998 motor they won't stay on the plug. I have to push them past the point of sealing on the cam cover and this sprung load pops them off the plug.

All the advertised ones on the bay look the same so what am I missing?

:confused: :confused: :confused:

Spark plug ends? Have you fitted new plugs?

Correct plugs fitted Ant. Its as if the rubber part is to short. I can push the cap onto the plug but it will not stay on?????

You checked the ends though, right?

It may be that the plug body (the white ceramic) is too thick so it can't push down enough?

Are you using the same plugs as before? If not it might be worth comparing.

Aren't the Testastretta plugs the next size down on those in a 996, C's and not D's

Yep smaller plug on the thread Kev but same connection. Gonna go and compare the length with the 996 ones later today

Definitely two different leads. The difference is around 5 mm longer for the 998 and the seal shape at the top is different. Reckon I can mod the 996 ones to get the motor up and running but looks like new ones long term. DOH

:)

Not sure if its the same issue but I had a problem when I put a 998S testa motor into my 748R chassis after my 748R engine let go.

The plug leads wouldn't go onto the plugs.

Using some silicone lube, we managed to get the leads to push further through the long rubber tube-end thus meaning the metal connector was further into the rubber (and closer to the plug cap).

Worked fine after that

Yep that's the problem. I cured it with of all things a sharpened 748 inner fork spacer. Put the plug lead inside it and then in the hydraulic press at work snipped about 2 mm off. Trimmed it down perfect. Now a beautiful water tight fit. :)