• Hey Guest!
    British Car Forum has been supporting enthusiasts for over 25 years by providing a great place to share our love for British cars. You can support our efforts by upgrading your membership for less than the dues of most car clubs. There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Upgraded members don't see this banner, nor will you see the Google ads that appear on the site.)
Tips
Tips

Spark plus Gurs, Please??

Share this page

T

Tinster

Guest
Guest
Offline
I need some carb mixture advice

I am trying to set the mixture on my Stromberg 175
CD2 carbs.

I made a high speed run down the expressway for 40 minutes
at mostly between 60 and 70 mph.To experiment on mixture settings.

Before the drive :
1. I purchased my 10th set of plus this morning, installed 2.
2. I cleaned up two sooty plugs and reinstalled
3. I left two sooty plugs in place.

Did a complete tune up on carbs and ignition plus --
Leaned out rear carb by 8 flats of a hex adjustment tool.
Leaned out front carb by six flats[/color]

Here's my plugs before and after about 40 minutes of high
speed driving, only two toll both stops and exit ramp on/off to Bikers Bar,

To the non-mechanic guy, my new plugs look a bit lean.
I am totally stunned the black plugs turned white????

blackPlugs-1.jpg


plugs1.jpg


plugs2-1.jpg
 
Well, you're not rich anymore. In more ways than one, I suppose.

First question, why are #1 & #5 different on the tips than the others? Are you mixing brands?

Second, but a suggestion. I'd go two flats back rich and call it a day.

Just curious, did your engine run any hotter than before during these 40 mile runs AFTER the leaning process?
 
Tinster said:
Did a complete tune up on carbs and ignition plus --
Leaned out rear carb by 8 flats of a hex adjustment tool.
Leaned out front carb by six flats[/color]
Click to expand...
Does that translate to 1 1/3 turns and 1 turn respectivly?
If the plugs were the conventional copper electrode type, I'd feel confident enough with your excellent photography to render an opinion. But I have no experience reading those kind of plugs. It will be interesting to see how they are interpreted.
 
Unless you find other indications the engine is running lean, I'd leave the mixture alone and read again after 1000 miles or so. That nice tan color you see in the plug charts comes from running leaded fuel; modern fuel takes a lot longer to leave permanent deposits.

The cleanup of the sooty plugs is exactly the way it's supposed to work; the insulator is supposed to get hot enough to burn off the soot.
 
Brosky said:
Well, you're not rich anymore. In more ways than one, I suppose.

First question, why are #1 & #5 different on the tips than the others? Are you mixing brands?

Second, but a suggestion. I'd go two flats back rich and call it a day.

Just curious, did your engine run any hotter than before during these 40 mile runs AFTER the leaning process?
Click to expand...

<span style="color: #006600">Hi Paul !!

Nope, #1 and #5 are the plugs Western Auto Puerto Rico now sells
for 1969 TR6.

I will install the remaining 4 so I have a matching set.

No! And Frank A was kind enough to tell me to watch
the temp gauge. A constant 160* the entire run.
Two flats back into rich it is.

thanks all.

d</span>
 
Dale,

If you haven't done it yet, I'd leave it alone for two reasons.

One, no over heating, so you don't appear to be TOO lean.

Second, I agree with Randall's advice about the color and check it in a 1,000 miles.

Close hood, put in lock pins and drive................
 
OK Dale, it's been nearly 12 hours, so what's the car status as of this evening?
 
What model and make plugs are you running?

I hope NGK BP6ES
 
Hey Dale,

Being an "Ex" Reg. Sls. Mgr. for "NGK Spark Plugs"; You should be running one "MATCHED" set of whatever plug! This is the most "In-Expensive" thing you could do & here you are playing around with some "Off-Brand" and mix-matching them.

Not the best way to tweek your performance!

I agree with Ron, (Not being Prejudice), use the "NGK BP6ES" (.025 Gap) in "ALL" cyl. & or at least a comparable brand like "Bosch" or something. Autolite & Champion have lost their quality control over the years.

I had purchased some Autolites & found the Ceramic Element to have hair line cracks in some of them. This won`t help your cars performance & you won`t even be able to see it without a scope or magnifying glass.

Moral to this story: Run whatever plugs you can get but run the same plug; In the same condition in ea. cyl.

Not Rocket Science,

Russ
 
Dale, have you tried Iridium plugs yet? I put a set of Autolites in my truck and have noticed an improvement in performance, plus 1.5 mpg increase in gas mileage. When it's plug time for the "B", I'm going to try a set in it.
 
RonMacPherson said:
What model and make plugs are you running?

I hope NGK BP6ES
Click to expand...

<span style="color: #990000">Ron-Remember where I live! I have very
few choices between brands of anything.

I've swapped out my plugs into NGK BPR6EGP .

Western Auto no longer carries the BP6ES plugs
but they list the BPR6EGP are direct substitutes
for a 1969 Triumph TR6.

Russ- I know to run a single brand across the board.
I was experimenting on getting my carb mixture correct.
Therefore I tried:

2 old Bosch - badly sooted from pre-mixture adjustment
2 old Bosch cleaned back to white
2 brand new NGK BPR6EGP

After the test drive it appears I am very close on
the carb mixture. So I'll drive awhile with all six
NGK BPR6EGP and see how it goes.

BTW: The new NGK plugs are pre-gapped with a big
warning NOT to attempt to regap them.

later gator,

d</span>
 
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]still in major creep mode for me here in PR[/QUOTE]

Dale,

I must be missing something. What do you mean by that? Is it going slow or car trouble again?
 
Here is a photo of one of my new plugs.
I installed a complete set of pre-gapped,
NGK BPR6EGP plugs.

This plug has about ten hours drive time on it.
I pulled this plug after a 90 mile night ride
on the expressway at 65 -70 mph fairly constant
speed, except toll booths.

This plus is AFTER I leaned my carbs out.

What can anyone tell me about my carb mixture
based upon having 6 plugs like this one.

thanks,

d

Lean-plug.jpg
 
I think that i would leave it alone and drive the 1,000 miles suggested earlier. Pulling plugs daily is not a good plan.
 
I agree with Paul, reading plugs is ok once in a while, but each time you remove and reinstall you are compressing the sealing washer, eventually you'll just have a flat washer.
For frequent checking of a carbs mixture, it's recommended, and not just by me, to raise the air valve about 1/8 of an inch and observe the engine speed response.
 
Dale, I vote with Paul, don't pull one of my "over engineering" things.

Tinkerman
 
Back
Top