Thread: 3.9 misfiring at high revs

Just to jump in on this thread, Mike, thanks for the info on how to check the stretch on the timing chain. I suspect mine is worn, being most likely original and over 200k old.
What sort of degrees movement is classified as worn-to-pretty-much-buggered?

Thanks,
Richard.

Originally Posted by Richard93Vogue

J
What sort of degrees movement is classified as worn-to-pretty-much-buggered?

Thanks,
Richard.

At 200k .... It will be stretched .... You would not notice 1 or 2 degrees ...
but after those numbers ....


My first ride 90 RRC .... 240k ..... a small popping noise of the inlet valve, at idle, could be heard at the air filter box end ... Chain was stretched 6 degrees ... I changed it and gained HP (gained original factory HP)

Had a Disco V8 ... 220K .... and it was stretched 9 degrees ...... Changed that 1 also ....



So go figure on where your suppose to set the dizzy timing, as that is also floating (Example ... set to 6 ... chain float retards 6 = Timing at TDC) ..

.... Also a stretched chain means that your inlet & exhaust valves are opening / closing + & - degrees (earlier / later) ... which can lead to burnt valves


Cheers
Mike

I have personally found the landrover ignition modules to be unreliable, with rather odd problems (random misfiring idle/or higher revs) . This includes brand new modules I have purchased to chase problems with oddly behaving ignitions! I think its not a coincidence that they are not in widespread use with other makes and models of the era (not like the sprinkling around of the good old 008 for hall effect systems or the BIM 024 for induction systems) .

There is no better recommendation than Bee-Uteys recipe for a module/coil upgrade (thankyou for suggesting it and documenting it by the way). Did it on mine and runs much smoother, no more gremlins. The cost for the module and a spare was about 10$ from a random wrecker, and the coil was about 5$ to match it.

did you check your fuel pressure ?

could be the pump or regulator.

well i never found out what the propblem ended up being. now ill never know either

oil pressure light came on tonight, 1 minute the noise was horrendous, 2 minutes more and engine siezed

so devistated

had such an awesome day all day offroading and it made it into the driveway only by chance tnoight

dunno whether to strip down and sell, or put another motor in it

time will tell

davo

Bugger...sorry to hear that!

Originally Posted by D3V1L

..........dunno whether to strip down and sell, or put another motor in it...........

That's pretty rough Davo, still I've seen a couple of V8s come and go on eBay and the like for a few hundred bucks if you want to get it going again on a budget.

Or if your pockets are a little deeper.....a nice 5.0 V8 or a 2.7TDV6 transplant instead?

if i put another motor in, it would be a 5 litre




davo