2200 engine pinking

G

gosnell

New Member
Hi all jst a bit of extra info please, The car has been pinking badly so I checked the timing with a gunsun super strobe and found that the car was firing at abot 12deg BTD, So I have now adjusted to 8 deg but I am still getting pinking?. I bit of past history it took about a year to get the car to run correct and what was found was the cam timing was out by abot 3/4 the width of the locking key and also it was found to have a dodgy rota (thanks richardUK), since these items were replaced the car drives like stink ( tech Term) apart from the pinking. I use a engine booster/ lead replacement but I am not too keen on retarding more to 6 or 4 deg.

John
 
Hi John,
It may not be the best policy, but I now totally ignore readings from a timing light and adjust entirely on the basis of pinking. I.e. find a setting where it's as close to pinking as possible without actually doing so.

Not sure that you have the terminology the right way round there. Going from 12deg BTD to 6deg BTD is advancing, isn't it?
 
Willy Eckerslyke said:
Not sure that you have the terminology the right way round there. Going from 12deg BTD to 6deg BTD is advancing, isn't it?
Click to expand...

No, 12beforeTDC occurs before 6BTDC so moving from the former to the latter position is retarding the timing.

For the OP I'd check the mixture setting and if that's OK (not too weak) then I'd retard it further gradually using the vernier and then when it gets to a point where the pinking is gone, or acceptable, check the timing with the strobe again to see where you are, and TBH as the 2000's are set at 4BTDC (SC's) I wouldn't be too concerned if it was that, or anything in advance of TDC really. If it's worse than that then you need to look for another cause for the problem.
 
bear in mind that 4 cyl cars have a reputation for the timing marks being well out from reality. Either start by checking the veracity of TDC or adopt the other suggestion and retard until pinking stops!

Chris
 
harveyp6 said:
Willy Eckerslyke said:
Not sure that you have the terminology the right way round there. Going from 12deg BTD to 6deg BTD is advancing, isn't it?
Click to expand...
No, 12beforeTDC occurs before 6BTDC so moving from the former to the latter position is retarding the timing.
Click to expand...
Thanks Harvey, that was making my brane hurt. Just as well the vernier is marked with an A and R, or I'd have come unstuck!
 
In addition to the advice already given, if your ignition timing and fuel/air mixture is set up correctly, perhaps another thing to check is your valve timing? This is quite quick and easy to do.

Also, another consideration might be carbon build up in the cylinders and piston heads which can cause hot spots and increase compression which in turn leads to the pre-ignition "pinking". Do you know when your engine last had a de-coke? Rather than remove the head for a de-coke, you could try something like Redex or similar to try removing any carbon build up. It is a quick and cheap thing to try that might point you in the right direction.

On Chris's point about the 4 timing marks possibly being incorrect, maybe you could find TDC on no. 1 cylinder and see if this corresponds to the TDC marked on the pulley? If there is a difference you could factor this in when setiing 8 BTDC?
 
As I said at the begining of this thread the cam timing was out by about 3/4 of the width of the locking key, at that time the engine would only run with the timing at 2deg A TDC but after changing the cam timing and the fitting of the red type rota the car runs great apart from the pinking, But I will retard the timing from 8 deg BTD now, and see how far I need to adjust Possibly 4-6 will do it.


John
 
Sorry John. When I said valve timing, I was really thinking about the inlet and exhaust valve clearances (0.010" on inlet and 0.014" on exhaust). For example, if the exhaust valve clearances are less than 0.013-0.015", they will tend to close too early at the end of the exhaust stroke leaving residual hot exhaust gas in the cylinders. On the following induction stroke, the extra heat in the cylinder may tend to cause the pinking :?:

It was just a thought, as I once had problems with pinking and erratic tickover at idle (though engine was OK at speed). My valve clearances were almost all out of tolerance with the exhaust once being especially bad (down to about 0.009" IIRC). Getting them all in tolerance made a huge difference.
 
Im going into hospital soon, so I will get it checked as and when I think that it was a v good idea.

John
 
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