97 3.9 Disco rough running

Hi everyone.

Been looking at threads in here and can't really find anything that sounds the same as my problem..

My disco all of a sudden started running rough the other day.. It starts fine and runs fine up until the engine is up to full temperature and is under load, still idle's fine and seems to rev easy enough,
So when its under load (normal road driving) and over about 2k rev's she sound like she's misfiring..
checked the distributor cap (which is new) and it was slightly twisted, twisted back and problems still there, everything under the bonnet is relatively new.. plugs, leads, rotor arm, filters, oil.. ect..

Only thing is she got slightly hot after some fun off-roading.. blocked radiator.. it was just into the red when we got to a garage to wash it out.. not losing any coolent either nor is it contaminated with oil..

Any idea's? i'm stumped!

Check you timing with a strobe.

Cheers mate.. was thinking about that.. 98k on the clock so probably would benefit from a new chain aswell

Might be worth checking alternator output and also coolant temperature thermistor.

Timing chain won't affect timing as such, just affects changeover from load to unload and can get slack when at part throttle, but it definitely won't affect timing that much to make it run very badly, unless there is not enough advance set there anyway.

Aim for 6 degrees btdc at warm tickover. I ran about 10 degrees.

@ classic kev, think you might be on something there mate.. she is getting a bit stubborn to start.. but she always does.. just cranks over quite slowly now.. might add a couple of new earth straps to help her.

@ Mr Noisy, cheers mate.. i'll check her with the strobe when I get home.. just need to get of this Rig first

Update* Now running perfect, vaacum advance a wee bit sticky.. well actually dizzy was more of a fish bowl than a dizzy!
Back fire turned out to be a big hole in the down pipe.... which completely broke away doing 70 on the dualler, Aberdeen got a very unwelcome wakening that morning as I drove home..
4 ht leads broke when removed *mental note* only buy genuine LR!
Now the beast thunders on!

Safe!!

DissyV8 said:

4 ht leads broke when removed *mental note* only buy genuine LR!
Now the beast thunders on!

Click to expand...

Yeah that might cause a bit of rough running! BTW only buy genuine parts.

classic kev said:

Yeah that might cause a bit of rough running! BTW only buy genuine parts.

Click to expand...

Cheers Kev, aye all of £40 for the genuine LR leads! She performed seemlessly offroading the other week..
Just need to remove the viscous fan now to stop it sucking in mud and blocking the rad!

Be warned, mine used to get too warm when I had electric fans fitted. Viscous only for me now, it's too easy to overheat these things as it is and at the time I was using a brand new HD 4 row radiator and still couldn't combat the temps when things for real hot...

Mr Noisy said:

Be warned, mine used to get too warm when I had electric fans fitted. Viscous only for me now, it's too easy to overheat these things as it is and at the time I was using a brand new HD 4 row radiator and still couldn't combat the temps when things for real hot...

Click to expand...

Appreciate the words of advice Noisy, looking at putting in twin 13" kenlowe's and the x-eng thermostatic switch kit.. will be keeping the viscous in the boot for any emergency situations though! Just a bit fed up with getting chocked up every time I touch deep mud..
Ooh and just thinking.. what do think is the average life of the water pump on the RV8 is?

I do not find the fan causes too much radiator trouble, if the rad is going to get caked its going to get caked anyway.

I think i had twin 12" fans and fitted a thermo switch in the thermostat housing.

Maybe my fans we kicking in a bit late, not sure, but I like to keep my coolant around 80 degrees now to be nice and safe. Can't remember what temp the switch was at but it was an OEM switch designed for cars with AC and I remember it was the cooler of the two options available.

Also after my second set of fans packed up from water ingress into the bearings I finally gave up and accepted the viscous was a better, safer, cheaper, more reliable option - I just used to remove it when wading deep water.

Plenty of advice available over here anyway, I would also advise you try it if you wish, it certainly was nice running electric, but it just didn't work out for me 18 months down the line

Cheers