EA81 pinging constantly!

Subydoug · Post by **Subydoug** » Thu Jul 17, 2014 9:01 am

You can get a little piece of buildup in a cylinder that gets hot. Then what happens is part way thru the combustion, just after the sparkplug has fired, the hot buildup also ignites the charge creating a sudden spike of pressure, bit like a car dieseling.

Chances are the carby is tuned fine. If the motor is getting on the the KM's then its possible that is coincidentally started happening when you put the new carby on.

Perhaps you could try spraying some water into the intake while its running? Cylinder heads with a blown headgasket are the cleanest! Maybe before an oil change though.

Regards

Doug

steptoe · Post by **steptoe** » Thu Jul 17, 2014 3:01 pm

pour brake fluid down carby throat while keeping the revs up was the decoke of choice of th 50's and 60's. Wicked lethal smoke out the back end ....

Silverbullet · Post by **Silverbullet** » Thu Jul 17, 2014 6:00 pm

Well there must have been a reason a video like this pops up in my subscriptions on YT the week before...best done after a long hot drive he says, so maybe I'll squirt some water down there with a large syringe (dad works at a zoo so we have these things

) don't want to drop too much in by accident. Not keen on the brake fluid idea Jonno don't know how the neighbours would like it

https://www.youtube.com/watch?v=KFtp_jmLF3k

steptoe · Post by **steptoe** » Thu Jul 17, 2014 6:41 pm

that was the next bit I left out - go do it on your own somwhere. At least it burns - I wouldna try squirting water darn there !

YouTube · Post by **El_Freddo** » Tue Jul 22, 2014 12:19 am

I've got to try this water trick with Sunnie the Brumby...

Cheers

Bennie

Silverbullet · Post by **Silverbullet** » Tue Jul 22, 2014 6:27 pm

Did the water trick; 50ccs overall squirted in bit by bit followed by a good rev. Could be placebo effect but it seemed to drive slightly better (a bit like how a car drives after you've taken it for a long blast up the freeway) but pinging still there.

Pinging still getting slightly worse/louder every day. Today was a bit warmer (maybe 18 degrees instead of 13) and pinged the worst. Doesn't really do it when accelerating, just at that point where you lift off slightly to maintain a certain speed or when squeezing the pedal gently to speed up a tiny bit. Even does it downhill as well as uphill

Swung the timing round to 12 degrees BTDC, made it worse. Back to 6 degrees and it's still there. So I can only think it must be fuel related...yet it smells rich most of the time

Really need an exhaust gas analyzer to see what's really going on.

Post by **TOONGA** » Tue Jul 22, 2014 8:01 pm

Silverbullet wrote: Pinging still getting slightly worse/louder every day. Today was a bit warmer (maybe 18 degrees instead of 13) and pinged the worst.

How old is your radiator?

How old is your thermostat?

I don't think I ever got an answer to the "normal temp range" question... My vortex pings its head off when it runs hotter than it should.

If your brumby runs any hotter than the first white mark on the temp gauge, consider that as hot. It should sit just below that first mark.

TOONGA

Silverbullet · Post by **Silverbullet** » Tue Jul 22, 2014 8:41 pm

TOONGA wrote:How old is your radiator?

How old is your thermostat?

I don't think I ever got an answer to the "normal temp range" question... My vortex pings its head off when it runs hotter than it should.

If your brumby runs any hotter than the first white mark on the temp gauge, consider that as hot. It should sit just below that first mark.

TOONGA

Radiator could be quite a few years old. Thermostat was brand new when I put the Weber on. I can't put an exact degrees number on the operating temp, but it is usually between 1/4 to 1/2 way on the temp guage. Only gets towards 1/2 when sitting at lights for a while, never goes above half even though my thermo fan switch is broke. Should mention the engine never pings when the choke is on, as soon as it reaches "operating temp" and the choke disengages the pinging starts.

A little story from last week: temp gauge was sitting at half way on the drive in to work (about 4 degrees ambient) and then suddenly fell to zero

Thinking I'd dropped all coolant I hurredly pulled over to find the wire had disconnected from the sensor in the T-stat housing. Plugged it back and and good as gold...even indicated cooler than it was before it fell off

Adding credence to the theory of never trusting the temp gauge. Perhaps a cheap digital thermometer dangling in the coolant would be a better indicator of operating temps. Cue Jonno...

steptoe · Post by **steptoe** » Tue Jul 22, 2014 9:24 pm

Cue Jonno...fits in ncely

I reckon the engine metal temp unit is great - no watr leaks to be had, still not gonna fix your pinging. Spend next weeks pay on a Willy special exhaust - you won't hear any pinging then - problem solved

Brumby Kid · Post by **Brumby Kid** » Wed Jul 23, 2014 2:35 pm

My new RS Liberty rally car has an EJ20G and HKS Turbo. The guy who installed it put a digital aftermarket Temp gauge in. The sensor is installed in the top radiator hose, you cut about 2" out of it and slip the hose over each end, with hose clamps of course and it's all good.

Now for this pinging
A good tune would never go astray, however are you absolutely sure it is pinging?
I wouldn't be surprised if it is the gearbox insides, uni joint, or spigot bearing. Mine does exactly the same thing at the same time and its not pinging. Thought Spigot bearing but replaced with clutch so unlikely that its that. I know my uni's are screwed as well as the gearbox, I get a lot of backlash in it as well :/

Cheers Cam

Silverbullet · Post by **Silverbullet** » Fri Jul 25, 2014 6:58 pm

That radiator hose probe idea is a good one, I remember seeing that one ages ago thanks for reminding me

Yes I'm absolutely sure its pinging/detonation. If it was something mechanical I think it would make the noise more constantly and not depending on throttle position as it is now, and it gets worse if I change the ignition timing. Also if I let it ping and do nothing to prevent it, it slowly gets louder and louder until I step on it and chuck some more fuel in. The gearbox was a low km one out of a wreck less than 12 months ago and it's the best 4 speed box I've ever had; smooth gear changes, quiet, easy reverse and not much slop in the shifter. Spigot bearing and throwout bearing were replaced with the gearbox, just the worn heavy clutch cable to fix now.

Had a brain wave on the way home; maybe my fuel pressure regulator is causing some mischief? It doesn't have any graduations to say how much pressure it's putting out so I just adjusted it to "that looks about right" and left it. Never caused any problems before though.

Brumby Kid · Post by **Brumby Kid** » Fri Jul 25, 2014 9:12 pm

That does sound like it would be pinging if it changes with timing. Blackwood Dyno tune (repco authorised) charge $140 ish an hour for the dyno. They did an alright job and have an exhaust gas analyser. Might be worth seeing what you can find out

Cheers Cam

Subydoug · Post by **Subydoug** » Sat Jul 26, 2014 12:21 am

The situation you describe is when the engine is running off of your idle and progressive jets. Try winding your idle mixture screw out half a turn and see if the behavior changes. If your jets are close to right and you have done your idle settings correctly your mixture screw will be around 2 winds out. If its more then 3 turns out your progressive jet is going to be lean. I found that a 55 primary idle jet was about spot on. Be confident that your throttle stop is as closed as it can get while maintaining proper idle speed. If you have a vacuum gauge it makes it really easy to set the mixture. Your trying to achieve the highest vacuum you can at your preferred idle speed. If your idle speed changes after you adjust the mixture, readjust the throttle stop and then reset your mixture screw. If you do all this and your mixture screw is within that 1 3/4 to 2 1/2 turns out range you can be pretty confident that its pretty darn close to bang on. best done straight after a drive while the engine is at running temp.

Other things that pop into my head, make sure your choke plate is opening fully, and I mean fully, straight up and down, no angle at all.

Regards

Doug

steptoe · Post by **steptoe** » Sat Jul 26, 2014 7:59 am

Silverbullet wrote:
Doesn't really do it when accelerating, just at that point where you lift off slightly to maintain a certain speed or when squeezing the pedal gently to speed up a tiny bit. Even does it downhill as well as uphill

Looking for an edible hat, or a new term - gnignip ? coz this noise sounds to be happening just when your 'pinging' does not fit with my experiences of pinging detonation. It sorta fits with Y pipe inner tube cracks on L Series . Is it tapwater or rainwater in the cooling system ? I believe rainwater is freshest over in Adelaide

Just compiling your Subaru odities - end float, wayward washers, mystery cam/dizzy gear mashing - now this !!

YouTube · Post by **El_Freddo** » Sun Aug 03, 2014 7:06 pm

I've done the water trick - now the test will be the cold start tomorrow. I find it pings more now but does seem to idle better. Following Cliff's advice, I still need to adjust the choke as it doesn't fully open, there's a bit of play in there.

The worst part is that I can't for the life of me find the mixture screw

I swear I've seen it before but can't find it now. With that said I didn't take the air cleaner off as I couldn't be bothered and didn't think it necessary either.

I want to check the mixture screw to see what it's set at as Sunnie the Brumby seems to be suffering the detonation on light throttle too - it's only very mild but it's definitely there

Can anyone help out with the location of the mixture screw location? It's an '89 model subaru targa top with stock carb.

Cheers

Bennie

Silverbullet · Post by **Silverbullet** » Sun Aug 03, 2014 8:57 pm

The stock carb idle mix screw should be on the front somewhere, near the idle speed screw which is on the main throttle shaft. You would need to take the air box off to see and access it properly.

Couldn't be Y piper inner pipes rattling Jonno, it has a custom made exhaust right through from the heads which is less than 1 year old.

I'm convinced my issue is the carb running lean. For some reason, it's slowly gone lean over time since I installed it and I wouldn't have a clue why. It would have to be one of the jets since changing the mix screw had no effect. I'm planning on taking it to a tune up place with a dyno and exhaust analyzer, there's a place near me that has experience with Webers that can get the tune just right. Might be a bit different to the hot rods and custom cars they're used to

Nubaru · Post by **Nubaru** » Sun Aug 03, 2014 9:51 pm

Hi, I came into this thread/post on the interest of pinging - and the detection of.

Waay back, a magazine article on making your own knock sensor circuit from a VN Commodore ECU and its knock sensor. I have the beginnings of this - a knock sensor that just bolts to the block has two wires I believe and was from a Falcon 4.0 six.

Without chasing an ECU, wondering if anyone knows how to make something of the knock sensor?? ECU 5 V in I suspect, so a USB lighter socket converter would be employed and connected to which wire and what would come out the other wire, knock or no knock ?

Is there anyone with auto electrical experience that could rattle off some basics? Could help me monitor an attempt to run low octane fuel and achieve leanest burn and monitor knock on a prehistoric carburettor EA81. Good application for the man above

Silverbullet · Post by **Silverbullet** » Sat Aug 09, 2014 3:29 pm

Sorry Nubaru couldn't help you there; that kind of electrical work might as well be black magic to me

A little update on this evolving story:
Earlier this week I discovered (when trying to get to work in the dark on a Monday morning, the coldest August night in 120 years) That the ignition lead where it connects to the ignition coil was completely corroded, nothing left of the male terminal inside the lead and the female socket in the coil was completely crystallized with blue and green crap. Really annoyed and confused since the leads were 6 months old at most but anyway I decided to get a new coil and heard good things about the MSD blaster. Available on fleabay for around $70
http://www.ebay.com.au/itm/201123622368 ... 1497.l2649

Installed it today with a new ignition lead and gapped the plugs to 1mm, took it for a run. On 98RON fuel with timing still at about 3 degrees BTDC there was no difference in performance but pinging was noticeably reduced in fact I struggled to hear any. So in a daring mood I put the timing to 10 degrees BTDC, trying to see if I could notice the difference when running 98RON fuel. Again struggled to hear pinging when driving normally. However there was a gain in performance, so I went for a WOT take off from stationary and with WOT at the higher revs it pings very badly, sometimes.

So I'm still thinking this is partly a carbie issue, but the new higher performance coil with clean contacts has helped somewhat. Today I was only driving on relatively flat roads in the local area, I will leave the timing at 10 degrees this week or until I hear the pinging return up hills etc.

Venom · Post by **Venom** » Sat Aug 09, 2014 3:51 pm

A bit of dialectric grease will help with corrosion. I put some on all of my spark plug ends, electrical connections etc. Helps them slide on and off easier too

Post by **TOONGA** » Sat Aug 09, 2014 4:54 pm

Try moving your timing back from 10 degrees to 8 or 6, remembering the sticker under the bonnet says 6 degrees + or -2, as well you can get some subaru upper engine cleaner and give that a whirl. don't bother with ebay it is cheaper at the subaru dealer

TOONGA