Gday,

An evil heavy knocking sound is coming from my engine when I open up the accelerator a bit, about the time that the secondarys should start to crack open. I bought a timing light on the way home and it checks out ok at idle, 6 degrees as far as I can tell. When I put a few revvs on her though the timing advances a lot, like a good 50 to 60mm on the wheel...I think its advancing, its heading anticlockwise.

I removed the vac advance hose from the dizzy and blocked it. I took it for a drive and it seemed a LITTLE bit better but still running like crap. I noticed that even with the vac advance hose removed the timing stil seemed to advance with more revs, is this supposed to happen?

Also to adjust timing all you have to do is loosen the 12.5 - 13mm bolt at the bottom and rotate the dizzy as a whole? Mine was real tight and wouldnt budge...

The idle is very rough but I have taken all 8 plugs off one by one and the idle got the same amount worse every time....WARNING: DO NOT tale a lead off while touching the body with your other hand. Had a stuffed heartbeat for a few seconds. I was p****d off that my girl is running bad and didnt think what I was doing.

I have checked all of the plugs (new), points (new and ok as far as I can tell), dizzy cap (new), and leads (new). Im not sure how to test leads, when I put an ohmeter over then it read infinity so I used my insulation tester (Im a sparky so I have those lying around) at 250 and 1000v and they tested 0Ohms so I take it theyre ok. Lifters have been replaced at the same time as the rest of the ign system 1500km ago.

I did fill up 1/3 tank with BP Ultimate 98 today as I normally do, may just be crappy fuel. The pinging/tapping didnt start untill a couple of hours after I filled up and during those 2 hours I would have been driving for about an hour in total.

This is also the first time I have run the car since I installed an electronic rust protection system, I checked it out and theyre are no shorts, I have also disconnected it since the problem developed.

I hope Ive given enough info. I'll be topping up with some new fuel tonight to see if it makes any difference.

Thanks

i hope for your sake it isn't a conrod or main bearing as the clevo had a common habit with the mains .how is the oil pressure ? is it flucksurewaiting.sorry about spelling

If it started just after you filled up then it sounds like bad fuel.
Happened to me many times with my clevo, top up with fuel and it would ping it's a*** out.
The distributor has mechanical advance aswell as vacuum so yes it's meant to do that.

I'd go and top up with some premium and then take it for a run and see how it goes.

Yea definitely sounds like you got a dud tank of fuel, either drain it (best in the long run - sucks for your wallet) or fill her right up with some premium/98 and go for a long drive

Could always drop in half or even a full bottle of octane boost.

lol
On another note, my clevo also knocks under hard accelleration, ever since I swapped in the single rail to replace the loader. Damn dodgy exhaust! hits on the Gearbox x-member... Time for a new exhaust.

Thanks for the help but it seems its not bad fuel as I drained the tank and filled up with fresh premo from a different place. The noise seems to be getting worse if anything. Could it be a too lean/rich fuel mixture? and what does a sticky intake valve sound like?

Looks like I'll be taking it into the mechanics tomorrow with the $3.25 I have in the bank from all this stuffing around and seeing what he reckons.

If an intake valve is sticking open she'll be choofing back through the carb... I broke an intake valve spring in my Clevo once, it sounded like a charf cutter.
It's really hard to pick a noise without actually hearing it mate, good luck at the mechanics with your $3.25 though lol.

Well shes at the mechanics now, hes 99% sure its a head gasket leaking between 2 cylenders. Hes doing a comp test tomorrow to verify it.

Im going to look at some new 4v heads that have HO valves, some kick a** springs, sleeved and seated for unleaded, blah blah, tomorrow. Just to check them out.

Thanks for the help.