Changed Plugs, Sooty

[ekamm]

I changed my plugs in my TR3a yesterday first time since getting car in July.They were all 4 pretty sooty, a sign of carbs being too rich? Is that necessarily true? Also the plugs remove were champion L92yc gap .035 and I replaced with L87YC gap .025 as recommended. Haven't driven it yet. Hopefully I can drive today. If I decide to dive into carb adjustment ( I'm scared to death of it) Is there a staight forward explanation of how to get them tunned correctly. Su's for Dummies or something like that.

 

[Andrew Mace]

Yes, "sooty" usually is a sign of rich running. Interesting that you had hotter than normal plugs but with a wider gap. I don't know if that wider gap might contribute to the "sootiness" or not....

 

[PeterC]

Sooty plugs can also be caused by older fuel. Locally here in WI, anything older than 4 weeks doesn't burn completely and the plugs look sooty. Try fresh fuel first. Cheap and easy.

Peter C

 

[poolboy]

If it were me, Eric, I'd be wanting to do a complete tune up. Valve clearance, ignition timing (points, plugs, condensor, rotor and dizzy cap). Then it would be time to check and possibly adjust or recondition the carbs.
Change the oil and filter, especially if the engine has been runnung rich.
The SU's are pretty easy to adjust and not bad to recondition. Worn throtle shafts might require skill or a professional to correct, but the rest is more or less "cook book".
https://www.jcna.com/library/tech/tech0006.htm
https://www.zparts.com/zptech/articles/mal_land/ml_sucarb2/images4/SUcarb_111601d.htm

 

[M_Pied_Lourd]

https://www.jcna.com/library/tech/tech0006.html

Hope you don't mind PB

Cheers,
M. Pied Lourd

 

[ekamm]

Wow an encyclopedia of info, not looking that easy. I have new; points,condenser timing set. I need to set valve clearances. Oil change has less than 100 miles on it. I did all of that to get the car running, in addition to replacing most of the fuel supply up to the carbs.

 

[TR4]

Wow an encyclopedia of info, not looking that easy.

This VTR SITE might help you tune those carbs.

I had no experience tuning my Strombergs so I bought a book similar to this one on EBAY and ended up completely taking the carbs apart and rebuilding them. It was not all that hard and like I said, I had no prior experience and I am no mechanic. My carbs work great now.

 

[sail]

not looking that easy

Don't be intimidated by them. I have not done SU's but I rebuilt my Strombergs mainly using the one page instructions that came with the kit. Pretty simple. And they work.

 

[achtungeveryone]

eric, I would bet that your plugs were sooty due to the wide (.035) plug gap. Unless you are sure you are running a hotter than stock coil your plugs won't sure fire and will occasionally miss trying to make that gap and consequently build up carbon...You might try sticking with the .025 gap, I think you'll be happier.

Achtung

 

[DrEntropy]

SU's are dead simple once you grasp what's happening in there. About as complex as a bathroom faucet. :wink:

Mixture is controlled by raising and lowering the jet orifice via a large hex head device on the bottom of the carbs. One flat at a time on each (they're right-hand threaded) to the "tight" direction will lean it out... using plug "color" to check the adjustment after a bit of a run each time.

I'd have a look at the new plugs before ya start tweakin' 'em. The wider gapped ones wouldn't give good info. You should be looking for a Cadbury/Sudbury chocolate color. :wink:

 

[ekamm]

The PO(my dad) had the old wider gap hotter plug in. I replaced with recommended plugs with.025 gap Now am waiting for new float delivery. So when I get it and can run her again I'll take my turn at watching the new plugs and carb adjust.