pinking

[EdT]

I admit it.. I sometimes stick cheapo 95 in the car when tottling around the shops. I know.. I know..

Anyhow, filled up with BP Ultimate this morning, so gave it some beans when nice and warm. Surprised to hear a little pinking at higher revs; is this to be expected, or does the car need a tune up, or something else?

Ed

[lazyitus]

I think there is an element of pinking in most Griff 500's. Particularly if they have covered 50,000 miles plus.

I know it can be caused by 95ron fuel and I never personally use it.

I wouldn't worry too much about it myself, just keep a keen ear on it and make sure it doesn't get noticeably louder.

[Gerjo]

It could be a blocked fuel filter (has it been changed recently?) or dodgy fuel pressure regulator.
I would be careful with pinking, very harmful for the engine.

[steve-V8s]

I would be very worried if I heard any pinking at all. Thinking back to my Mk1 Cortina days all three of them suffered pinking and also fairly regularly blew holes in the pistons. Didn’t connect the two at the time or realise I was setting the timing a bit too advanced. Pinking can be very destructive, very quickly damaging the pistons, heads and valves.

[clive f]

mine had the fuel regulator replaced, now no problems.

[rev-erend]

Ed,

Unless there is a reason for it - like block fuel filter then you really need to have the timing changed by just a few degrees.

You can readjust a Griff to run on 95 but you will loose quite a few ponies.

When I had mine - I just used 95 when 8 was unavailable.

Just a get me home / next station job. Don't put too much in.

[unclemark123]

my car pinks like crazy on 98 ron, ive had the timing checked and it still does it so i tried 95. works absolutly fine, no pinking and no noticable loss in performance, plus its cheaper :-)

[Big Ashy]

unclemark123 said:

my car pinks like crazy on 98 ron, ive had the timing checked and it still does it so i tried 95. works absolutly fine, no pinking and no noticable loss in performance, plus its cheaper :-)

Thats bizarre and doesn`t make sense at all, weird!

[GreenV8S]

unclemark123 said:

my car pinks like crazy on 98 ron, ive had the timing checked and it still does it so i tried 95. works absolutly fine, no pinking and no noticable loss in performance, plus its cheaper :-)

I don't know what 'check' you think they did, but if the engine is mechanically OK and the fuelling is about right then pinking is almost certainly caused by too much ignition advance for the octane you're using. Lowering the octane would only make things worse, and retarding the ignition would be the obvious fix.

[EdT]

apart from a re-tune (or a new engnine) are there any other fixes? Booking the car in for a mini service before Xmas, like to get it back in tip top form
Ed

[unclemark123]

GreenV8S said:

unclemark123 said:

my car pinks like crazy on 98 ron, ive had the timing checked and it still does it so i tried 95. works absolutly fine, no pinking and no noticable loss in performance, plus its cheaper :-)

I don't know what 'check' you think they did, but if the engine is mechanically OK and the fuelling is about right then pinking is almost certainly caused by too much ignition advance for the octane you're using. Lowering the octane would only make things worse, and retarding the ignition would be the obvious fix.

i had it checked twice at penninsula last year. they even reccomended running on 95. it made 304 bhp on the rollers this year so cant be that bad

[v8 racing]

unclemark123 said:

GreenV8S said:

unclemark123 said:

my car pinks like crazy on 98 ron, ive had the timing checked and it still does it so i tried 95. works absolutly fine, no pinking and no noticable loss in performance, plus its cheaper :-)

I don't know what 'check' you think they did, but if the engine is mechanically OK and the fuelling is about right then pinking is almost certainly caused by too much ignition advance for the octane you're using. Lowering the octane would only make things worse, and retarding the ignition would be the obvious fix.

i had it checked twice at penninsula last year. they even reccomended running on 95. it made 304 bhp on the rollers this year so cant be that bad

I have to agree with green v8s on this one!! there is no possible way i can think of that 95 will make an engine stand more detination than 98, as mentioned by pete, pinking is to much advance for a given octane of fuel and heat in the combustion chamber, spooooky!!

[spend]

Couldn't that strange phenomena have something to with unusual advance curves on the dizzy? Would have thought it would result in horrible idling though.

Dave

[Pupp]

v8 racing said:

unclemark123 said:

GreenV8S said:

unclemark123 said:

my car pinks like crazy on 98 ron, ive had the timing checked and it still does it so i tried 95. works absolutly fine, no pinking and no noticable loss in performance, plus its cheaper :-)

I don't know what 'check' you think they did, but if the engine is mechanically OK and the fuelling is about right then pinking is almost certainly caused by too much ignition advance for the octane you're using. Lowering the octane would only make things worse, and retarding the ignition would be the obvious fix.

i had it checked twice at penninsula last year. they even reccomended running on 95. it made 304 bhp on the rollers this year so cant be that bad

I have to agree with green v8s on this one!! there is no possible way i can think of that 95 will make an engine stand more detination than 98, as mentioned by pete, pinking is to much advance for a given octane of fuel and heat in the combustion chamber, spooooky!!

Might be the variance between different 'brands' if the fuel has come from different suppliers, I certainly wouldn't treat the pump label as being a reliable indicator of the fuel quality. Alternatively, the burn characteristics on some of the super unleadeds are noticeably different...much faster flame front from ignition plus no knock sensor might = pinking. Or could be increasing temperature in the combustion chamber just enough to induce detonation if it's otherwise on the threshold of knocking anyway. Can see loads of possiblities tbh

[rev-erend]

v8 racing said:

unclemark123 said:

GreenV8S said:

unclemark123 said:

my car pinks like crazy on 98 ron, ive had the timing checked and it still does it so i tried 95. works absolutly fine, no pinking and no noticable loss in performance, plus its cheaper :-)

I don't know what 'check' you think they did, but if the engine is mechanically OK and the fuelling is about right then pinking is almost certainly caused by too much ignition advance for the octane you're using. Lowering the octane would only make things worse, and retarding the ignition would be the obvious fix.

i had it checked twice at penninsula last year. they even reccomended running on 95. it made 304 bhp on the rollers this year so cant be that bad

I have to agree with green v8s on this one!! there is no possible way i can think of that 95 will make an engine stand more detination than 98, as mentioned by pete, pinking is to much advance for a given octane of fuel and heat in the combustion chamber, spooooky!!

As with all tests - the conditions have to be the same.

If for instance :

The petrol at the station was actually 95 and not 98 as labeled ..

Heat in the engine bay - 98 tested in summer, 95 in winter .. would make a huge difference.

If 98 was tried with too much advance.. the 95 tried with ignition retarded after a service..

[GreenV8S]

rev-erend said:

If 98 was tried with too much advance.. the 95 tried with ignition retarded after a service..

That's the most likely explanation I can see i.e. that the timing was retarded to prevent pinking (hence the advice that it should be OK to use lower octane fuel now).

[v8 racing]

rev-erend said:

v8 racing said:

unclemark123 said:

GreenV8S said:

unclemark123 said:

my car pinks like crazy on 98 ron, ive had the timing checked and it still does it so i tried 95. works absolutly fine, no pinking and no noticable loss in performance, plus its cheaper :-)

I don't know what 'check' you think they did, but if the engine is mechanically OK and the fuelling is about right then pinking is almost certainly caused by too much ignition advance for the octane you're using. Lowering the octane would only make things worse, and retarding the ignition would be the obvious fix.

i had it checked twice at penninsula last year. they even reccomended running on 95. it made 304 bhp on the rollers this year so cant be that bad

I have to agree with green v8s on this one!! there is no possible way i can think of that 95 will make an engine stand more detination than 98, as mentioned by pete, pinking is to much advance for a given octane of fuel and heat in the combustion chamber, spooooky!!

As with all tests - the conditions have to be the same.

If for instance :

The petrol at the station was actually 95 and not 98 as labeled ..

Heat in the engine bay - 98 tested in summer, 95 in winter .. would make a huge difference.

If 98 was tried with too much advance.. the 95 tried with ignition retarded after a service..

This goes without saying really, you cant compare shell 98 to tesco's 95, it has to be from the same brand, other wise you could end up saying yes it pinks on 98 when i am towing my horse box but not on 95 on cruising around, thanks for pointing that out rev i should have been clearer, but if a car on 98 pinks there is NO WAY it is not going to pink on 95 if all conditions are the same.

[TeaVR]

Are you sure it's pinking? Could it be something else e.g. leaky manifolds?