hi all,
just wanted to get some experience from others on the following topic: my E-Type S3 needs new spark plugs every 3-4 months which I can easily change but it is a hassle. I use the right fuel (98) and I get the engine warmed up before I drive so most likely, the mix is too rich. Now, I admit that I drive mostly short drives <1 hour. My question to the forum is whether that is normal and that the V12 just needs longer drives to keep the spark plugs clean or should I get it tuned?
Thank you
Are you using the correct plugs?
I had a Daimler V8 and when I took it to a Dyno they replaced my plugs with new champion plugs of the ācorrectā grade. By the time I had driven home it was missing, I replaced the plugs with a hotter plug and it cleared up the mis fires.
I doubt that the plugs are the problem. Get someone experienced to tune your car.
My 68 6 cylinder used to run rich and sometimes foul the plug most in line with the rear Zenith carb so I switched to the adjustable mixture needles like in the carbs on the Series 3 so that I could lean things out some. A also got a Gunson Colortune tool to help me so that I did not set things too lean. No more fouling and the car runs much better too. There is a special long allen key tool sold by many of the usualās to reach down to the bottom of the carb damper oil reservoir to adjust the needle toward leaner or richer.
David
68 E-type FHC
Hi all, thank you very much for your answers/ suggestions.
Iām using the NGK BPR6ES Spark Plugs which I believe are the correct ones.
I had a closer look at the sparks and it looks like that the spark plugs that are towards the back of the car looking worse than the ones from towards the front. That may just be the way the carburetors are currently tuned. Another friend of mine suggested that it might also be because the choke may only works on the two carbies towards the back of the car and therefore, the spark plugs for the 6 cylinders towards the back of the car are more dirty. Thoughts?
Thank you
Cheers
Looks like there are only three plugs anywhere near the correct fuel mixture.
BTW idling the car till warm is very old school and may be part of your problem. Start it and drive, not too hard to start with but certainly not mollycoddling it either.
Are the black ones gooey at all ā¦oil ?
ā74 OTS here. There is really not a lot of adjustment to be had in the Strombergs as they were designed that way. That said, lower the needles to the limit (turn counterclockwise) with the adjustment tool to lean them out as much as possible and see if that makes a difference.
As for your chokes; push the knob in to get off choke and inspect to verify that the cam between each pair of carbs is not touching the adjustment screw head on the choke lever. The gap should be 1/8 inch or so.
VERY old school, and largely irrelevant, especially with virtually any given street engine of the last 80 years.
Start it, let it warm up no more than 1-2 minutes, then drive it.
Hello Frank,
Your picture tell a thousand talesā¦ Clearly you have a mixture problem on RR, LF and LR carburetors. Additionally, is the dark material just soot or is it oily also?
First, lets go down a quick list so weāre on the same page.
Do you own the Official Jaguar Repair Operations Manual (ROM). Itās a very good start point. The manual gives a pretty good account how to synchronize the carburetors. That must be done first.
Second: Do you own an air flow gauge - UniSyn or similar? The method of sticking a hose in the carb intake, listening for the hiss and matching all 4 is C R A P!! Use a Unisyn or similar tool.
Third: Do you own a fuel meter needle adjuster tool. S3 Strombers, the mixture is fine tuned via this tool. Tool runs around $10 USD.
Read up all the articles you can find on the Internet regarding tuning (mixture, etc.) of Strombergs. They arenāt as difficult as most think. They do require periodic attention and maintenance but they work well when properly functioning IMHO. If carb oil level(s) are constantly low then the o-ring(s) probably have become brittle and need replacing.
Your posted spark plug photos clearly suggest three (3) carburetors are supplying an overly rich mixture to the engine. With the proper tool and sampling meter that can be corrected easily.
Are the carbs original (factory - never been worked on) or have they, at some point in time, been rebuilt? Rebuilt and Overhauled are not the same! If youāre running Ethanol laced fuel then the floats must be the newer āEthanol Resistantā type, otherwise they will suffer the effects of this blended fuel.
Lastly, a little more car info would be helpful to the group. Update your member info will help that.
Soon More Happy Trails,
Dick
P.S. A correct mixture and properly tuned motor, the spark plugs should last 50,000 miles or more. Re-gaping the plug my be required at some point also.
Huh.
Wonder how I got by, for all those years.
You have good ears??? Certainly the newer equipment can be very helpful, but not needed.
Tom
Close but NO CIGAR!!! Egyptian measuring stick vs Laser measuring - NOT??? Lets face it, we made do with what we hadā¦ and it worked (I guess). Technology moves on - improving and so should weā¦
Happy Trails,
Dick
Except, and you might be forgetting this, early on I checked my garden hose measurements with the UniSyn (a move my Dad insisted on, to ātune my earsā), and they were always dead on.
Sometimes, as Wendell Barry insists, a lower technology works just fine.
The Strombergs are remarkably simple and easy to maintain. I had mine rebuilt with standard kits 26 years ago when I bought the car and Iāve never had a problem since except.for split diaphragms and leaky O rings. Last month I tuned them for the first time in several years and they were still in almost perfect balance according to the Unisyn gauge. I used the piston lift method to adjust the mixtures and the car has never run betterā¦ Once you get them right they pretty much stay that way.
Thatās the beauty of a constant depression carburetor like the SU or the Stromies: if in good nick, they just donāt change much.
Agreedā¦ Rubber seals (shaft seals) and other rubber components need servicing on a scheduled basis. For a multitude of reasons they age, become less effective and cause problems. Each car came with a Preventative Maintenance Schedule which, if followed, would alleviate most wear-n-tear problems and age related ones too. Most owners ignore the massive amount of work the Schedule calls for and suffer laterā¦ Jaguars were not know for their reliability. Owner maintenance didnāt help either!!! They become even less reliable when the PM isnāt done, ignored or scoffed at. Car components donāt come with a Time Before Overhaul (TBO) as do aircraft components or train wheels. The big difference is once airborne you canāt just pull over to āfixā a rough running motor, etc. Automobile motors are actually made of better materials than Aircraft motors. Aircraft motors operate in a mainly clean environment while street driving is anything but clean! When car components fails or acts up then attention is given, usually not before! An aircraft component is serviced (TBO) before it becomes a problem (usually)ā¦
Twenty Six years a quite a span to go without typical maintenance although Iām sure youāve done some. They need attention and the message is thru your spark plugs. Seems you have the tools, data and such, they just need maintenance! Good luck in setting everything back on an even keel so failure isnāt in your concern listā¦
Iād also recommend replacing the floats at a bare minimum due to changes in our fuel supply (Ethanol).
Dick
I agree entirely with the notion that Stroms are good reliable carbs, so, does anyone know where one can obtain a three-Strom manifold for the jag?
Use a 3-SU manifold off of 4.2, and the Stroms will bolt right on.
Good to know, thanks.
