Ping Ping Ping Knock

Guys,

I've bumped the timing on my 93 5.0 I set it by ear to the max I could run on 87 octane gas.

Normally, the temps up here in Alberta don't get too hot, and 87 octane works nice at about 70F or 20C. Lately, it got up to the high 20s low 30s (mid to high 80s) and it was knocking under WOT at about 3 grand. So I put 89 octane in it and it now pings under WOT at about 4 grand.

Apparently, temp makes a lot of difference, I assume cause the air is thinner, but what does the higher octane have to do with that? I guess when it gets this hot, I have to run 91 octane, but I'm not sure why. Anyone?

Thanks all.

BRad

"BradandBrooks" > wrote in
news:X8kHe.80332$5V4.53660@pd7tw3no:

> I've bumped the timing on my 93 5.0 I set it by ear to the max I could
> run on 87 octane gas.
>
> Normally, the temps up here in Alberta don't get too hot, and 87
> octane works nice at about 70F or 20C. Lately, it got up to the high
> 20s low 30s (mid to high 80s) and it was knocking under WOT at about 3
> grand. So I put 89 octane in it and it now pings under WOT at about 4
> grand.
>
> Apparently, temp makes a lot of difference, I assume cause the air is
> thinner, but what does the higher octane have to do with that? I
> guess when it gets this hot, I have to run 91 octane, but I'm not sure
> why. Anyone?

Normally, thin air can run higher timing. My guess is that your computer
is messing with the timing. You should look for evidence of overheating
which can cause preignition.

On Mon, 01 Aug 2005 07:26:47 GMT, "BradandBrooks"
> wrote:

<snip>
>I've bumped the timing on my 93 5.0 I set it by ear to the max I could =
>run on 87 octane gas.
>
>Normally, the temps up here in Alberta don't get too hot, and 87 octane =
>works nice at about 70F or 20C. Lately, it got up to the high 20s low =
>30s (mid to high 80s) and it was knocking under WOT at about 3 grand. So =
>I put 89 octane in it and it now pings under WOT at about 4 grand. =20
>
>Apparently, temp makes a lot of difference, I assume cause the air is =
>thinner, but what does the higher octane have to do with that? I guess =
>when it gets this hot, I have to run 91 octane, but I'm not sure why. =
>Anyone?
>
>Thanks all.
>
>BRad

The reason that you need higher octane fuels when you advance the
timing to the max is....

The lower octane fuel burns faster than the higher octane fuels thus
when a lower octane fuel is ignited at an earlier time, the fuel being
lower octane burns too quick causing an explosion before the piston
can even get to the top of the stroke. The explosion you hear is that
darned ping and if it continues to do this, eventually you will wear
into the wrist pin or the rod bearing or it can just as well put a
hole in through the top of the piston.

...Ron
--
68' Camaro RS
88' Firebird Formula
00' Mustang GT Vert

"RSCamaro" > wrote in message
...
> On Mon, 01 Aug 2005 07:26:47 GMT, "BradandBrooks"
> > wrote:
>
> <snip>
>>I've bumped the timing on my 93 5.0 I set it by ear to the max I could =
>>run on 87 octane gas.
>>
>>Normally, the temps up here in Alberta don't get too hot, and 87 octane =
>>works nice at about 70F or 20C. Lately, it got up to the high 20s low =
>>30s (mid to high 80s) and it was knocking under WOT at about 3 grand. So =
>>I put 89 octane in it and it now pings under WOT at about 4 grand. =20
>>
>>Apparently, temp makes a lot of difference, I assume cause the air is =
>>thinner, but what does the higher octane have to do with that? I guess =
>>when it gets this hot, I have to run 91 octane, but I'm not sure why. =
>>Anyone?
>>
>>Thanks all.
>>
>>BRad
>
> The reason that you need higher octane fuels when you advance the
> timing to the max is....
>
> The lower octane fuel burns faster than the higher octane fuels thus
> when a lower octane fuel is ignited at an earlier time, the fuel being
> lower octane burns too quick causing an explosion before the piston
> can even get to the top of the stroke. The explosion you hear is that
> darned ping and if it continues to do this, eventually you will wear
> into the wrist pin or the rod bearing or it can just as well put a
> hole in through the top of the piston.
>
> ...Ron
> --
> 68' Camaro RS
> 88' Firebird Formula
> 00' Mustang GT Vert

That would royally suck. Royally. And how does air temperature affect this?
When it's cold, it never pings, when it's hot, it does.

Thanks.

Brad

Jezus. Buy a cheap timing light, disconnect the spout connector, and
then set the timing correctly (and then replace the spout connector).
And since you have a 5.0 go-fast car, why put regular in it? Does it not
make sense that mid-grade would be better anyways? If you insist on
being cheap, I would strongly suggest setting the timing via a timing
light to get an accurate measurement.

If you adjusted the timing with your calibrated 'ear', you still needed
to remove the spount connector first. If you do not know what the spout
connector is, I would suggest a Haynes or Chiltons manual. Crappy Tire
sells the manuals and the timing light for decent prices.

HTH,

Chris in Calgary.

BradandBrooks wrote:
> Guys,
>
> I've bumped the timing on my 93 5.0 I set it by ear to the max I could
> run on 87 octane gas.
>
> Normally, the temps up here in Alberta don't get too hot, and 87 octane
> works nice at about 70F or 20C. Lately, it got up to the high 20s low
> 30s (mid to high 80s) and it was knocking under WOT at about 3 grand. So
> I put 89 octane in it and it now pings under WOT at about 4 grand.
>
> Apparently, temp makes a lot of difference, I assume cause the air is
> thinner, but what does the higher octane have to do with that? I guess
> when it gets this hot, I have to run 91 octane, but I'm not sure why.
> Anyone?
>
> Thanks all.
>
> BRad
>

Chris, I know how to set timing. What I want to know is why temperature
affects timing. Obviously, it must be the thinner air.... thanks.

Brad



> wrote in message news:enCHe.85117$5V4.20732@pd7tw3no...
>
> Jezus. Buy a cheap timing light, disconnect the spout connector, and then
> set the timing correctly (and then replace the spout connector). And since
> you have a 5.0 go-fast car, why put regular in it? Does it not make sense
> that mid-grade would be better anyways? If you insist on being cheap, I
> would strongly suggest setting the timing via a timing light to get an
> accurate measurement.
>
> If you adjusted the timing with your calibrated 'ear', you still needed to
> remove the spount connector first. If you do not know what the spout
> connector is, I would suggest a Haynes or Chiltons manual. Crappy Tire
> sells the manuals and the timing light for decent prices.
>
> HTH,
>
> Chris in Calgary.
>
> BradandBrooks wrote:
>> Guys,
>> I've bumped the timing on my 93 5.0 I set it by ear to the max I could
>> run on 87 octane gas.
>> Normally, the temps up here in Alberta don't get too hot, and 87 octane
>> works nice at about 70F or 20C. Lately, it got up to the high 20s low
>> 30s (mid to high 80s) and it was knocking under WOT at about 3 grand. So
>> I put 89 octane in it and it now pings under WOT at about 4 grand.
>> Apparently, temp makes a lot of difference, I assume cause the air is
>> thinner, but what does the higher octane have to do with that? I guess
>> when it gets this hot, I have to run 91 octane, but I'm not sure why.
>> Anyone?
>> Thanks all.
>> BRad
>>

On Tue, 02 Aug 2005 03:04:26 GMT, "BradandBrooks"
> wrote:


>That would royally suck. Royally. And how does air temperature affect this?
>When it's cold, it never pings, when it's hot, it does.
>
>Thanks.
>
>Brad

Sorry on the late reply, my ISP is quite suckola.

Density, the colder the air is the more dense it is, the warmer it is
the less dense it is. The colder the air, the less area it needs to
fill a given amount. Molecules close together means that you can put
more in a given space, or more air/fuel in, the less pinging out.

If you really want to learn about how temperatures work in conjunction
with air density you can probably find more information by researching
Nitrous oxide detonation an your favorite search engine. I'm in no
way an expert on the subject, there are people here that know the
physics much better than I do.

...Ron
--
68' Camaro RS
88' Firebird Formula
00' Mustang GT Vert

Well if you know how to set timing, why is your car pinging? And WHY
THE **** WOULD YOU SET YOUR TIMING 'BY EAR'. What sort of accuracy are
you hoping to get from that? Are you retarded?

BradandBrooks wrote:
> Chris, I know how to set timing. What I want to know is why temperature
> affects timing. Obviously, it must be the thinner air.... thanks.
>
> Brad
>
>
>
> > wrote in message news:enCHe.85117$5V4.20732@pd7tw3no...
>
>>Jezus. Buy a cheap timing light, disconnect the spout connector, and then
>>set the timing correctly (and then replace the spout connector). And since
>>you have a 5.0 go-fast car, why put regular in it? Does it not make sense
>>that mid-grade would be better anyways? If you insist on being cheap, I
>>would strongly suggest setting the timing via a timing light to get an
>>accurate measurement.
>>
>>If you adjusted the timing with your calibrated 'ear', you still needed to
>>remove the spount connector first. If you do not know what the spout
>>connector is, I would suggest a Haynes or Chiltons manual. Crappy Tire
>>sells the manuals and the timing light for decent prices.
>>
>>HTH,
>>
>>Chris in Calgary.
>>
>>BradandBrooks wrote:
>>
>>>Guys,
>>> I've bumped the timing on my 93 5.0 I set it by ear to the max I could
>>>run on 87 octane gas.
>>> Normally, the temps up here in Alberta don't get too hot, and 87 octane
>>>works nice at about 70F or 20C. Lately, it got up to the high 20s low
>>>30s (mid to high 80s) and it was knocking under WOT at about 3 grand. So
>>>I put 89 octane in it and it now pings under WOT at about 4 grand.
>>>Apparently, temp makes a lot of difference, I assume cause the air is
>>>thinner, but what does the higher octane have to do with that? I guess
>>>when it gets this hot, I have to run 91 octane, but I'm not sure why.
>>>Anyone?
>>> Thanks all.
>>> BRad
>>>
>
>
>

On Tue, 02 Aug 2005 03:04:26 GMT, "BradandBrooks"
> wrote:

>
>"RSCamaro" > wrote in message
...
>> On Mon, 01 Aug 2005 07:26:47 GMT, "BradandBrooks"
>> > wrote:
>>
>> <snip>
>>>I've bumped the timing on my 93 5.0 I set it by ear to the max I could =
>>>run on 87 octane gas.
>>>
>>>Normally, the temps up here in Alberta don't get too hot, and 87 octane =
>>>works nice at about 70F or 20C. Lately, it got up to the high 20s low =
>>>30s (mid to high 80s) and it was knocking under WOT at about 3 grand. So =
>>>I put 89 octane in it and it now pings under WOT at about 4 grand. =20
>>>
>>>Apparently, temp makes a lot of difference, I assume cause the air is =
>>>thinner, but what does the higher octane have to do with that? I guess =
>>>when it gets this hot, I have to run 91 octane, but I'm not sure why. =
>>>Anyone?
>>>
>>>Thanks all.
>>>
>>>BRad
>>
>> The reason that you need higher octane fuels when you advance the
>> timing to the max is....
>>
>> The lower octane fuel burns faster than the higher octane fuels thus

It does not burn faster, it ignites earlier. The compression stroke
compresses the air/fuel mixture in the cobustion chamber. Lower octane
fuel combusts at lower pressure. The trick is to get the compression
up as high as possible (power) but not too high before the mixture
ignites by itself before the spark plugs ignites it. Higher octane
basically delays the ignition longer (by itself).

>> when a lower octane fuel is ignited at an earlier time, the fuel being
>> lower octane burns too quick causing an explosion before the piston
>> can even get to the top of the stroke. The explosion you hear is that
>> darned ping and if it continues to do this, eventually you will wear
>> into the wrist pin or the rod bearing or it can just as well put a
>> hole in through the top of the piston.
>>
>> ...Ron
>> --
>> 68' Camaro RS
>> 88' Firebird Formula
>> 00' Mustang GT Vert
>
>That would royally suck. Royally. And how does air temperature affect this?
>When it's cold, it never pings, when it's hot, it does.
>
>Thanks.
>
>Brad
>

On Sat, 06 Aug 2005 13:56:49 -0700, RT > wrote:


>It does not burn faster, it ignites earlier. The compression stroke
>compresses the air/fuel mixture in the cobustion chamber. Lower octane
>fuel combusts at lower pressure. The trick is to get the compression
>up as high as possible (power) but not too high before the mixture
>ignites by itself before the spark plugs ignites it. Higher octane
>basically delays the ignition longer (by itself).

>>Brad

Higher octane slows down the combustion process giving you a slower,
more controlled burn. The advantage is that it helps to prevent
pre-ignition, preventing detonation from hot spots in the combustion
chamber. (taken from the link below)

http://www.imagestation.com/picture/...e/fbb758d6.jpg

Here's one that describes the combustion process even better. A long
read though.

http://www.sdsefi.com/techcomb.htm

...Ron

--
68' Camaro RS
88' Firebird Formula
00' Mustang GT Vert