EA81 pinging constantly!

Silverbullet · Post by **Silverbullet** » Mon Jul 07, 2014 7:46 pm

Here we go again, it's that time of the month

The time where my Brumby decides to develop some ridiculous issue that is nigh-on un-solvable.

Since the Weber swap on my EA81 with an L series intake it has been running like a dream, never ever pinged and had more power. Hardly had to touch the baseline settings on the Weber, Jets seemed right first go etc etc. Ever since the swap I have only used 98 RON fuel.

Now all of a sudden it is pinging its heads off, constantly. In 2nd, 3rd, 4th at certain rev ranges it will start rattling. 3rd gear at 50 km/h, 4th at 60 km/h and even at 90 km/h on a straight flat road with no load it will start rattling. Only way to stop it is to back off and slow down, down shift or if I put my foot down and drown the bastard it stops rattling until you slow back down to the speed limit.

So my mind turned straight to ignition timing; I suspected my old dizzy was dodgy for a while so replaced it with a rebuilt unit, new ignition module, set the timing to 8 degrees BTDC and it made the pinging worse yes worse

Then because stomping on the pedal and squirting more fuel in it seems to stop the rattle, I thought maybe it's running lean because of a developed vacuum leak; checked all hoses and they are tight, no leaks. The nuts holding the carbie down were not as tight as they were so I nipped them up a bit, no difference. And so the other question is, am I causing engine damage by driving it like this? What damage does pinging actually create?

It's just that time of the month again where my ute decides it's been running too well, and makes its own problems out of thin air

Post by **TOONGA** » Mon Jul 07, 2014 8:03 pm

Have you tried the timing at 6 degrees?

does your motor have blue rocker covers or black rocker covers?

Have you tried 95 ron or 91 ron fuel?

What gap do you have on your spark plugs?

Is your vacuum advance hooked up properly?

When did you last do the valve clearances?

Is your engine running in the "normal" temperature range?

As for damage ... it is pre-detonation which means the fuel is exploding while the piston is coming up to top dead centre. The long term effects are big end bearing damage and everything else above them damage.

TOONGA

YouTube · Post by **El_Freddo** » Mon Jul 07, 2014 9:12 pm

Check valve clearances.

Check oil filler cap.

Blocked fuel jet leaning out the fuel mix?

Try driving on recirculate with your climate control. If this does the trick you've got a dud fresh air vacuum diaphragm, it's located behind the glovebox. I've just replaced the one on Sunnie the Brumby. But I didn't have detonation.

Hope one of the above in either post works

Cheers

Bennie

Silverbullet · Post by **Silverbullet** » Mon Jul 07, 2014 9:51 pm

TOONGA wrote:Have you tried the timing at 6 degrees?

does your motor have blue rocker covers or black rocker covers?

Have you tried 95 ron or 91 ron fuel?

What gap do you have on your spark plugs?

Is your vacuum advance hooked up properly?

When did you last do the valve clearances?

Is your engine running in the "normal" temperature range?

As for damage ... it is pre-detonation which means the fuel is exploding while the piston is coming up to top dead centre. The long term effects are big end bearing damage and everything else above them damage.

TOONGA

1. Haven't put the timing to 6 degrees, I thought this would make the problem worse, will try it.

2. Blue rocker covers, solid lifters

3. Did put half a tank of 95 in a few weeks ago, that was before this problem started though.

4. Spark plug gap .8mm, checked them last week and plugs were text book tan colour.

5. Vac advance hooked directly to the ported vac point on the Weber, same as the Hitachi was.

6. Re-did the valve clearances about 3500 k's ago, they had barely moved since the last time I did them but I do have a few that are making some noise right now. .010" intake .040" exhaust.

Bennie, oil filler cap?

Blocked jet I guess a possibility, would be pretty bad luck though to block a brand new carbie within 6 months. As for the interior vacuum, it isn't connected at the moment.

Guess I'm checking the clearances again, the book says every 20,000k's seems like I'm doing them every 5000

steptoe · Post by **steptoe** » Mon Jul 07, 2014 10:23 pm

grease yer nipples ? Is it really detonation pinging (or pinking as some would like to call it - dressmaking term though

) or is it tailshaft ping, ting, tinging ? Maybe you need to run the twin port in before it goes in the 'bullet ?

YouTube · Post by **El_Freddo** » Mon Jul 07, 2014 11:21 pm

Yep, oil cap - if it's loose it'll rattle much like the sound of detonation. If you can twist it easily it needs its clamping tabs bent in a bit or the rubber seal replaced.

If it's a heat thing the detonation would still be there with harder acceleration. To me it sounds like a fuelling issue. Did you buy fuel from a dodgy servo recently or know of any bad fuel batches around?

Jets can get clogged at any stage if you've got a dirty fuel system.

Cheers

Bennie

Subydoug · Post by **Subydoug** » Tue Jul 08, 2014 9:01 am

As jonno said, check your tailshaft. Just lay under the car and forcefully twist the backlash back and forth. They make a racket if the UJ's are worn. Easy and cheap to replace.

Your engine shouldnt be pinging like that. I got shaved heads and run about 10 btdc. Only time I really get pinging is low rpm, high load and only with std unleaded and it varies from tank to tank. If your worried that it may be lean you can just adjust your slow speed screw out a half turn. This will richen your mixtures across most of the throttle range, down side being a rich stinky eye stinging idle.

Id also recommend plugging your advance into a non-ported supply. Your car will idle better and run cooler. It will also bump your RPM up a bit allowing you to close your butterfly a touch more.

Regards

Doug

steptoe · Post by **steptoe** » Tue Jul 08, 2014 1:01 pm

To test MY 4WD tailshafts (2WD are hard to find

) I'd find a dead quiet street in industrial arae after hours with nice incline so to roll with engine and radio off to hear ting ting, see dry reddish brown rusty stuff about the unijoints also a tell tale. wap the 'bullets with the ute ?

Silverbullet · Post by **Silverbullet** » Tue Jul 08, 2014 6:32 pm

Quite certain it is engine detonation not tailshaft or other rattles. I've heard enough pinging from an EA81 to know what it sounds like

Dodgy fuel did cross my mind, but I don't empty the tank completely between top ups so it's hard to get a definite difference between batches. Always use the same servo. Doug I've had this carbie/dizzy setup plugged into manifold vac once before, un-drivable!

No power, sounded like arse, exhaust rattled like all hell but you run yours on manifold vac? Strange how it can be so different between cars.

Anyway today I quickly whipped out the timing light and adjusted to 6 degrees BTDC after work (thunder storm and hail quickly closing in) when it was properly warmed up and everything as hot as it gets. A quick run round the block and I couldn't hear any pinging, will see what it's like tomorrow.

Oh and for whoever asked about temperature range, with the EA82 manifold it runs slightly warmer than stock setup but still well below half way on the gauge.

YouTube · Post by **El_Freddo** » Tue Jul 08, 2014 6:54 pm

Somethings to investigate/consider:

- age/condition of leads and plugs and
- compression of each cylinder

That could reveal a couple of things that might explain what's going on.

Cheers

Bennie

Subydoug · Post by **Subydoug** » Tue Jul 08, 2014 7:56 pm

Hmmm, did you plug the hole in the weber when it was straight vac? Vacuum advance is only really for emissions so you shouldnt lose power.

The giveaway for rattly tailshaft is like jonno said, rolling to a stop you can here it clacking.

What RPM are you setting the timing at?

Regards

Doug

Post by **TOONGA** » Tue Jul 08, 2014 8:36 pm

I was just looking at a diagram for a 32/36, are you using the vaccum advance port or the ported vacuum source?

the vacuum advance port will have no suction at idle, while the ported vacuum source will have vacuum (mormally used for EGR etc) and will advance your vacuum timing as far as it will go.

TOONGA

Silverbullet · Post by **Silverbullet** » Tue Jul 08, 2014 9:17 pm

Yeah Doug had that one plugged when not in use. Setting the timing at idle/800rpm with the vac advance disconnected/plugged. No rattles when rolling to a stop, only a very strange sound from the rear that sounds like rubber squeaking up against something...another story

I'm using the vacuum advance port on the front of the carby as suggested in the instruction sheets that came with the Weber. This is a ported vacuum source since it only supplies vacuum when the butterfly is opened past a certain point. Everywhere I've read (except here) says vacuum advance on any dizzy should only be ported, theory being you don't want the advance mechanism to operate at idle. Only when driving do you want the advance mech to kick in to compensate for the change in RPM's.

steptoe · Post by **steptoe** » Tue Jul 08, 2014 10:14 pm

yeah, then you gotta ask those same sources why it is suggested the vac advance be disconnected and plugged up to get true timing values DBTDC @ xxxrpm. Most often idle speed and timing changes between vac advance hooked up and hole bunged.

Good that you got rid of the noise anyway.

Subydoug · Post by **Subydoug** » Wed Jul 09, 2014 8:50 am

Ah, the rubber squeak during deceleratng, I had that too. In my case it was the exhaust bracket thats inside the passenger side rear wheel well. I just welded it back up and it was gone.

There is no problem with letting the car run at higher ignition timing during idle. Everyone has different opinions about everything though. I get the best results with a non-ported supply to the vac advance.

Regards

Doug

Silverbullet · Post by **Silverbullet** » Wed Jul 09, 2014 5:30 pm

Couldn't hear a thing on the way to work due to the amount of rain beating down on everything...on the way home I got almost all the way home without hearing a rattle but before I got too excited, going up a long shallow hill in 4th at 60, squeezed the throttle a little bit and heard the faintest of rattles, disappeared very quickly.

Well since I couldn't hear anything for so long and the rattle that is left is so faint, I'll leave it at that until it gets worse again.

Silverbullet · Post by **Silverbullet** » Tue Jul 15, 2014 6:07 pm

And it's back, gotten worse every day until now it's back how it was. Checked timing and it hasn't moved from 6 degrees. Sheesh I dunno, maybe a vacuum leak as the idle seems a tiny bit up and down, but I've never had a vac leak cause detonation. On the old setup I drove around for an hour with a 6mm ID vac hose disconnected and only noticed when I realized there was a loud hissing sound coming from the engine bay

Getting the exhaust gas analyzed was on the to do list when I did the Weber swap to get tuning right, maybe I should get on with it now. Wonder what will happen if I move the timing the other way and advance it to 12 degrees or so.

Subydoug · Post by **Subydoug** » Tue Jul 15, 2014 8:15 pm

Have you tried some form of cylinder treatment? Mayhaps the weber has been running a little bit richer then the old hitachi and you now have a small chunk of carbon which is causing a bit of preignition in one cylinder. Short of pulling the heads off and sandblasting them I donno what to try, but maybe someone else has had success with a particular product.

Regards

Doug

steptoe · Post by **steptoe** » Tue Jul 15, 2014 11:04 pm

With the vehicle firmly up against an immovable object, handbrake on hard, wheels chocked, give the engine a few revs to say 3000rpm and watch the timing marks as they advance along the flywheel. Se if they creep up or fly to max, see if you can then estimate how much advance the dizzy has in it...add your own marks for beyond 20 DBTDC with white out - for a better understanding of the advance.

Silverbullet · Post by **Silverbullet** » Wed Jul 16, 2014 11:06 pm

Will try Jonno.

Doug, I didn't know carbon deposits could cause detonation. If it was running rich enough to do that though the spark plugs wouldn't look as good as they do? Still perfect tan colour.

Found a place that still tunes carbies, also has a dyno and gas analyzing equipment...now I'm tempted to see what this Weber can do with a professional tune