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Hard starting and pinging


MrTougéTka

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Gidday guys, I'm having ongoing problems with my little 4k kp bugeye. 

To save a long story...  I'll try generalise this as much as i can. 

I've been battling pinging issues and now hard starting(also won't idle on its own) 

So far I've replaced coil, spark plugs(twice) leads, rebuilt the carb, replaced manifold gasket with a one piece(slight vacuum leak from coby headers) 

I got the motor to run without pinging after i ripped the dizzy out and shifted it around.  but the timing was way too advanced so i pulled it out again to restart the process. Which made it worse, it won't idle on its own and the pinging is back. 

I'm certain I've lined up the dizzy to correct base timing. 

Also another problem is the points. I can't set them with a wide enough gap(i set them to 0.45) but they keep closing almost shut. I think the cam might be worn down, has slight up and down play too) 

 

What is the correct way to install the dizzy if it has been installed back in the wrong way? 

Fixing the carb did help with the pinging at first but it slowly came back. 

Would low compression cause pinging? What elsw could cause it to ping its head off? 

I hope you guys can understand, wrote this out in a bit of a rush. 

The car runs bloody well other than the pinging, bogs a tiny bit when taking off also. 

Edited by MrTougéTka
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usually pinging is a result of too much compression, or too much timing or not enough fuel / too much air.. usually.
It may actually be preignition, which is slightly different from pinging (detonation), where a hot spot in the combustion chamber ignites the mixture when it gets to a certain compression, the hot spot acts like a spark plug thats constantly lit like a glow plug.

Q1 Is it pinging only under load .. (if so but the pinging goes away once rpm increases, then suspect base timing as the cause)
Q2 is the manifold vacuum advance hooked up and functioning? (if not, the base timing would have to be set quite high for a smooth idle, which will ping its head off under load)
Q3. how do the spark plugs look after a hard drive? (if white, then go and check your power valve piston in ur carby float cover again)

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18 hours ago, rebuilder86 said:

usually pinging is a result of too much compression, or too much timing or not enough fuel / too much air.. usually.
It may actually be preignition, which is slightly different from pinging (detonation), where a hot spot in the combustion chamber ignites the mixture when it gets to a certain compression, the hot spot acts like a spark plug thats constantly lit like a glow plug.

Q1 Is it pinging only under load .. (if so but the pinging goes away once rpm increases, then suspect base timing as the cause)
Q2 is the manifold vacuum advance hooked up and functioning? (if not, the base timing would have to be set quite high for a smooth idle, which will ping its head off under load)
Q3. how do the spark plugs look after a hard drive? (if white, then go and check your power valve piston in ur carby float cover again)

It pings the entire time it runs, but definitely worse under load. 

Yes I'm certain the manifold vaccum  was hooked up. 

Plugs are Quite fouled and black looking. 

Alright I'll double check the carby and see if the float isn't stuck or the power valve is working properly. 

 

Cheers mate, i don't go on the forum much due to work, so if i don't reply fast I'm not being ignorant 

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ok if its pinging at idle, something is seriously wrong mechanically, there is just not enough mixture to detonate audibly at idle in a normal engine.
So before you continue looking for detonation causes, i suggest just making absolutely sure you arent hearing an exhaust leak, which commonly tricks people into thinking they have pinging or valve train noise. You may be well experienced and are certain that it is detonation, but I myself have been fooled into misinterpreting an exhaust leak at the manifold as a combustion problem and i advise others to second question themselves. 
That said, if its not banging at idle, but every other part of the PRM and/or load range, then sure, start looking at carby.
Black plugs may just be oil fouling so I'm not going to rule out running too lean yet.
Speaking of which, if theres enough oil carbon deposits in there, u could be developing a pre-ignition hotspot, another thing to consider.
Or of course, it could jsut be the most obvious thing, which is the timing marks are wrong haha.

Edited by rebuilder86
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1 hour ago, rebuilder86 said:

ok if its pinging at idle, something is seriously wrong mechanically, there is just not enough mixture to detonate audibly at idle in a normal engine.
So before you continue looking for detonation causes, i suggest just making absolutely sure you arent hearing an exhaust leak, which commonly tricks people into thinking they have pinging or valve train noise. You may be well experienced and are certain that it is detonation, but I myself have been fooled into misinterpreting an exhaust leak at the manifold as a combustion problem and i advise others to second question themselves. 
That said, if its not banging at idle, but every other part of the PRM and/or load range, then sure, start looking at carby.
Black plugs may just be oil fouling so I'm not going to rule out running too lean yet.
Speaking of which, if theres enough oil carbon deposits in there, u could be developing a pre-ignition hotspot, another thing to consider.
Or of course, it could jsut be the most obvious thing, which is the timing marks are wrong haha.

It used to have one. The new gasket stopped the pinging for a couple of weeks, then it came back lol 

Maybe the exhaust mani keeps getting loose from vibration? Theres hardly any mounts for th3 exhaust system as far as i can see

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Quote

The new gasket stopped the pinging for a couple of weeks, then it came back lol 

that doesn't sound like pinging...   Get a timing light over it, that would be best.

Also, stick a piece of wire down a spark plug hole and check your TDC on the gilmore, just to make sure.

Then set the timing on the crank to 10deg BTDC and turn the dizzy with the ignition on until you see a spark as the points open. Lock the dizzy there and try it.

That works, but a timing light is better.

Once you're sure the timing is OK then chase other problems, like the manifold.  Don't use the 2-piece exhaust gaskets, get a 1-piece, clean out all the threads & its best to put the manifold on w/o the exhaust pipe on it. A pain, but it seats much better as the pipe can twist against the bolts you are doing up. Check the exhaust manifold face with a straight edge too, they get a bit bent. Not much you can do if its misaligned as the carb manifold usually refuses to come apart with those 4 bolts shearing off.

https://www.rollaclub.com/board/topic/27374-one-piece-manifold-gasket-who-makes-them-4k/

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yeh the manifold nuts on mine need to be re tightened about twice every year. hahah dodgy as right?
i was previously scared of stripping the female aluminium stud threads in the head so FOOT TIGHT is about where I would stop.
But then i kept finding the nuts loose. so now i even ignore the 21 foot pounds in the manual and rattle gun the shit out it with my bosch cordless 18v which apparently puts out 185 Nm of torque.
So lets just say , worst case, i put 100 nm into it, it still comes loose about twice a year.
Id say it has somethign to do with the thickness of the manifold gaskets. they have a lot of give.

Edited by rebuilder86
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10 hours ago, altezzaclub said:

that doesn't sound like pinging...   Get a timing light over it, that would be best.

Also, stick a piece of wire down a spark plug hole and check your TDC on the gilmore, just to make sure.

Then set the timing on the crank to 10deg BTDC and turn the dizzy with the ignition on until you see a spark as the points open. Lock the dizzy there and try it.

That works, but a timing light is better.

Once you're sure the timing is OK then chase other problems, like the manifold.  Don't use the 2-piece exhaust gaskets, get a 1-piece, clean out all the threads & its best to put the manifold on w/o the exhaust pipe on it. A pain, but it seats much better as the pipe can twist against the bolts you are doing up. Check the exhaust manifold face with a straight edge too, they get a bit bent. Not much you can do if its misaligned as the carb manifold usually refuses to come apart with those 4 bolts shearing off.

https://www.rollaclub.com/board/topic/27374-one-piece-manifold-gasket-who-makes-them-4k/

I shall try that this weekend! Thank you so much brotha! I just need to redo all the timing points from scratch so i know its a decent enough base to go off. 

 

Its definitely the manifold, I'll try to disconnect the manifold from thr rest of the system then bolt it on, should do the trick. 

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