Im currently still in the process of tuning my engine and decided to pull the spark plugs out to have a look at how they are running. This is what I found. Seems like the outer cylinders and running lean.
Any ideas?
| ausmini https://www.ausmini.com/forums/ |
|
| Reading spark plugs. https://www.ausmini.com/forums/viewtopic.php?f=2&t=82743 |
Page 1 of 1 |
| Author: | 1380 K [ Sun Sep 15, 2013 8:30 am ] |
| Post subject: | Reading spark plugs. |
Im currently still in the process of tuning my engine and decided to pull the spark plugs out to have a look at how they are running. This is what I found. Seems like the outer cylinders and running lean. Any ideas?
|
|
| Author: | drmini in aust [ Sun Sep 15, 2013 11:25 am ] |
| Post subject: | Re: Reading spark plugs. |
It is hard to read plugs properly now the tetraethyl lead has gone out of the fuel. I'd say the inners are rich rather than the outers being lean, unless those electrodes are blistered too. BTW, this week all 4 of mine look exactly the same with a Dellorto 45 carby on, they are light grey. |
|
| Author: | Morri68 [ Sun Sep 15, 2013 11:45 am ] |
| Post subject: | Re: Reading spark plugs. |
Yes I agree with the Doc number 2-3 cylinder look rich rather than 1-4 being lean not unless you want it running really rich. |
|
| Author: | TheMiniMan [ Sun Sep 15, 2013 2:10 pm ] |
| Post subject: | Re: Reading spark plugs. |
its pretty typical for a single SU car/manifold system to run like that |
|
| Author: | Irish Yobbo [ Sun Sep 15, 2013 3:54 pm ] |
| Post subject: | Re: Reading spark plugs. |
You can expect the two inner cylinders to be a bit richer than the outer, simply due to the siamese inlets. The fuel needs to travel further to the outer cylinders. If they were my spark plugs, I'd say that's a good result for tuning. I'd rather have my inner cylinders a little rich than the outers lean. |
|
| Author: | 1380 K [ Sun Sep 15, 2013 5:05 pm ] |
| Post subject: | Re: Reading spark plugs. |
Right. So I'm best of not leaning it off too much then? |
|
| Author: | drmini in aust [ Sun Sep 15, 2013 7:00 pm ] |
| Post subject: | Re: Reading spark plugs. |
According to Vizard? (I'm pretty sure it was him) when running a single SU you can reduce this mixture variation by grinding a radius into the outer faces of the intake manifold just before the gasket face, biasing flow more towards cylinders 2 & 3..... |
|
| Author: | 36 [ Sun Sep 15, 2013 8:30 pm ] |
| Post subject: | Re: Reading spark plugs. |
I note you're running BP7ES - thats a colder than normal plug. Engine has had a bit of work done to it? |
|
| Page 1 of 1 | All times are UTC + 10 hours |
| Powered by phpBB® Forum Software © phpBB Group http://www.phpbb.com/ |
|