engine and drivetrain diagnose this plug?

[Happy Face]

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I pulled my spark plugs out of my car today and found this. The plugs have about 4000 miles on them.

Each was gapped at about 0.022. How would you diagnose the condition of these plugs?

I replaced them with new NGK plugs gapped at 0.035

the car has a Crane XR700 optical ignition system, Bosch red coil.

Engine is a rebuilt tii motor with 9.5 CR pistons, 32/36 carb, vacuum advance dizzy

feedback appreciated

thanks

dave

[Harv]

The mixture looks good and it looks like you drive the car correctly However there may be some oil contamination.

Could a long blast on the highway clean things up a bit?

John

[Beaner7102]

Try openeing the gap to 0.040" with a Crane you can go a bigger gap. Is that after lots of stop start city driving or long haul highways? What temp plugs? I would go 1 stop hotter (to help burn off the crud). Beaner7102

[bingbong]

they look pretty good, not to much else to diagnose

[Guest Anonymous]

..I pulled my spark plugs out of my car today and found this. The plugs have about 4000 miles on them.Each was gapped at about 0.022. How would you diagnose the condition of these plugs? I replaced them with new NGK plugs gapped at 0.035

The deposits suggest oil is being burned or fuel used may not be the best - OR you have a wide variation of fuel mixtures through the course of typical operation. Guessing you have a very rich idle or mid range and that at cruising not all remaining deposits are burned off.

Yours is a platinum plug and not recommended for M10 engines except with the newer 318 electronic ignitions.

Running a plug with such a small gap seems unnecessary (except with high compression/turbo application). OPt for as big as you can without misfiring or interference with valve .045" ?

hth

[alp]

I was told because of no leaded fuels you cannot read plugs accurately any more. True or false?

[Guest Anonymous]

I was told because of no leaded fuels you cannot read plugs accurately any more. True or false?

Is this a trick question?

By removing tetraethyl lead from our fuels, it only eliminated the possibility of lead fouling to consider when examining plugs. A plug that is too white can still indicate overheating or too much timing. Removing lead as a choice would not affect one's ability to read a fouled plug due to an over-rich mixture or poor oil control.

All plugs have a story to tell with or without fuel additives. Maybe things are different in Australia, where one self-appointed expert apparently believes everything is normal without defining the term: "they look pretty good, not to much else to diagnose."

[Arizona02]

White stuff is ash formation from oil, common when using Valvoline, platinum plugs normally use minimum of .040 gap & with a coil design to put out voltage to fire a 040 gap. I dont know what the red coil out put specs are, do you.

[Happy Face]

thanks for the feedback.

I pulled the new NGK plugs out and regapped them to 0.040.

there is oil though on the new plugs.

this is a new (rebuilt) carbed (32/36) tii motor,

also did a compression test on the motor tonight

first was on a cold engine with the following:

1: 142

2: 142

3 - not tested

4: 142

Then reinstalled the plugs and ran the motor (and retimed it)

with a 'hot' motor and throttle fully engaged I got the following:

1: 152

2: 157

3: 154

4: 157

all numbers are close and consistent, but I expected higher numbers, especially since the motor has 9.5 CR pistons (E12 head).

[Arizona02]

The 1st 500 miles are the key.

[Happy Face]

the first 500 miles were a combination of city (LA), then extended highway driving. (CA IH-10). The car was then driven to Texas over a three-day period.