Technical mk2 uno 45S odd timing problem

[smokeme]

long time no see to some of you.. seems like i finally met my match

just got a friends car in with an odd sound under load (sounds like pinging aka detonation/pre-ignition)
I started with the basics, checked timing belt and it was all aligned, checked ignition timing and it was way retarded (can't even see the notch, about 2cm behind 0 mark..) changed the distribuidor and same result.. the carb has also been changed, no intake leaks.. the car has no mods at all and the compression is a bit high at around 200psi..

anyone has any ideias? i'm stumped, especially on how the compression can be higher then the manual specs.. the car has 130kkm

 

[Louie Bee]

Hay a blast from the past! hows it going?

Are you sure it's the distributor from a 45 / 999? apparently the dizzy from a 60 / 1108 fire has different internals. do a search here on FF but I seem to remember it's the springs inside and may give your issue.

Wouldn’t have thought you'd find 2 Uno 60 dizzys though.

What's it like with the Vac advance blocked off?

I guess it's a proper carbed Uno, not an SPI? I found my SPI uno has issues where the ECU seems to effect the timing and idle speed so you need to reset the ECU after adjusting the timing.

I have had pinking sounds caused by other things in the past :- Speedo cable and gear linkage .

Not sure if compression is loads higher than stock. Is it more of an increase than you'd expect after a couple of head skims when doing the head gasket?

 

[Davren]

Excessive carbon deposits in the combustion chambers/piston crowns could cause pinking and high compression. Would have to be very excessive though. Perhaps the owner's been a bit over enthusiastic with the Red-X.

Dave.

 

[alexGS]

Welcome back :wave:

As you know, pinging/pre-ignition usually happens when the timing is too advanced (not when too retarded as you have). Maybe on this occasion the engine is 'dieseling' (i.e. running like a diesel!) due to the higher compression.

Valve timing can affect compression readings (the valves being closed for longer than they should be on the compression stroke). Obviously, with the distributor driven off the camshaft, valve timing affects ignition timing too.

Therefore, I suggest you take off the bottom pulley to check whether the Woodruff key is missing/sheared. Though, I guess you've been timing the camshaft off the flywheel? It's hard to say, but I think you have to check the valve timing yet again to be sure.

Also, I've had an electronic ignition module (the finned box) that was faulty and retarded the timing. Did the finned box get changed at the same time as the distributor?

-Alex

 

[smokeme]

i don't have any cars with FIRE engines that legally run at the moment

ok let's see if i can cover everything..

car is a stock carbed 999cc 8v

today i got a known good dizzy from my stockpile, ignition timing is spot on but the engine seems to hunt at idle (rpm spikes from the normal 850 to 1100 at random times) and it still pinks under load.. vaccum advance was one of the first things i had checked, the pin had been cut so it would never come on, replaced it with a new one..

either the head has been skimming to much or there's a serious carbon problem

the funny part is the owner's had it since new and says it's never blown a gasket which leaves carbon deposits as the only option..

another thing i noticed is condensation out of the exhaust at all times (even after an hour on the freeway), never seen that before, even when i removed the exhaust at the manifold there was noticiable condensation on the ground.. leakdown test didn't show anything but i never seen a FIRE do that before, i'm starting to doubt the quality of the fuel in the tank...