1969Mk3Spitfire

I really don’t understand my sooty No 2 plug issue. The car seemed to run very well, albeit low mileage, for my first couple of years ownership, post resto. It could be that I simply never looked for the issue, though. At the end of last season I noticed the sole, sooty plug. I’ve changed most all of the usual ignition suspects. There is virtually no play in the dizzie shaft. Cylinder CRs are within 5% of each other. Tappet clearances are ok. I’m currently of the view that it’s valve seat and/or guide but removing the head has to wait. Perhaps I check it now too often but the plug fouling seems to happen very quickly. The first misfire was fairly recent and (I thought) was solved by cleaning the plug. This last misfire episode was different and I’m not as yet sure that I either understand it or have fixed it. Sorry to read about sciatica, not pleasant. Hope it resolves.

Thanks for raising it and glad I checked because the polarity was reversed, the loom white +ve was connected to coil -ve. It looks like a brand new (now 3 years old), unmarked coil. I’ve previously measured its resistance but not noticed polarity. In what was does reverse polarity manifest itself? There’s a car on the drive blocking the garage door so a test drive will have to wait until she moves it tomorrow morning 😁

Many thanks Pete and Pete, The tank is new, fitted in 2020. Not sure of the grade of fuel hose but tank outlet to pump inlet was replaced in 2019 as part of full resto. I doubt that it's air but it would explain the symptoms. I use E5, high octane fuel. A weak fuel pump would explain it, too, but I have a very light right foot and all seems fine again now. If I go to Tatton tomorrow I'll probably reach Vmax (60 mph) so a good test. No reason to doubt coil polarity (3 ohm version) but I'll check. The revvy and willing engine has performed very well in the 3 years that I've had the car until late last year when No2 plug sooted-up quickly and readily. I've tried beating the car with the branch of a tree but this didn't improve matters.

A few weeks ago I had a misfire. Symptoms were “instant” mis and “instant” recovery. Frequency was about once per mile. I posted to seek input before I raised a spanner to the car. Consensus from the wise was spark plug and indeed number 2 (only) was sooty. I drove the car yesterday for the first time since that event. I did about a 10 mile circuit, mixture of south Manchester congested traffic and open countryside. About a mile from home the car started to misfire again, this time with quite different symptoms. It felt more like fuel starvation. I had a kangaroo in the tank and the engine would not pull. It would clear after a few seconds but return another few seconds later. I feared the indignity of having to call my wife for a tow but managed to limp home. No 2 plug was again very sooty, No 1 looked good. I removed the fuel pump cover and the mesh filter was clean. I cleaned the plug and leaned the front carb by one flat. I drove again, but not as far, probably 4 miles, and all was well. Not sure if heat from a longer journey plays a part. I’m planning to go to Tatton Park show on Saturday but I’m a bit nervous due to this issue. Number 2 sooting is probably a valve issue, pretty much all ignition components have been measured, checked and/or changed. Removing the cylinder head is a winter project. Any ideas? Many thanks.

I had the rear screen fitted to my hardtop about two weeks ago. I called at a couple of “old school” body shops to ask for a recommendation. I contacted one such and he was delighted to help. Two guys arrived within 2 hours of my making the call. Took them a couple of attempts but they had it in within 30 minutes. Their cord was blue 6mm polypropylene (aka BT line or, in the boating community, rope of shame). They charged me £40.

The glass for my Spitfire hardtop didn’t seem to match the metalwork to the point that all of my mates had said “that will not fit, it’s the wrong glass”. I contacted the guy who sold me the hardtop and he apologised and invited me to swop. He had brought along two, for me to choose one. My original was badly scratched but otherwise all were exactly the same profile. I asked an old-school Body Shop if they could recommend a mobile screen fitter with equal, old-school credentials. I phoned and within two hours, two guys in a white van appeared on my drive. It took them a couple of attempts and a lot of banging with palms but after about 30 mins it was in. They charged £40.

Searching the interweb for thread sizes and types provides only contradiction and confusion. I bought a small plastic box full of imperial and metric, straight, 45 and 90 degree. It cost around £15 and has yet to let me down.

That’s a fabulous looking interior, Josef, very impressive. What plans do you have for handbrake rubber gaiter? It’s my nemesis as I haven’t been able to anchor the base.

32 psi front tyre pressure for a standard load is way too high and risks negatively impacting ride, handling, braking distances and wear. Look for a solution from the advice already given or increase breakfast intake to 3 Wheatabix.

I’ve pretty much convinced myself that my single plug sooting issue is related to worn valve guides. I’m in no particular rush to act but just musing. It will probably become a winter project. Based upon forum wisdom, what’s a sensible approach? (1) DIY job, are guides readily available? (2) have the guides replaced by a specialist, (3) get the valve seats done (for unleaded) at the same time, (4) service exchange head Appreciate pros, cons and costs. Many thanks.

As a friend of mine always says, “don’t knock it ‘till you’ve tried it” Two blokes, kneeling on the garage floor, wearing marigolds, wresting a long piece of rubber into a small aperture using copious quantities of KY Jelly, how could you possibly misconstrue such a picture of innocence? Here’s work-in-progress. When complete, I’ll take it to nearby country lanes for some better shots.

I feel your pain! Two of us wrestled with the hardtop, on the garage floor, inverted but supported by a lot of old bedding, and after about 3 hours we had successfully fitted the side window seals. Much KY Jelly was consumed and a lot of huffing and panting by two old blokes. Wearing yellow Marigolds helped, too. The bottom skirt seal is currently held in place by strips of masking tape. I bought a tube of Puraflex but haven’t as yet used it. The hardtop doesn’t seem to fit the body profile very well, there’s a gap near the sides. As to be expected, the poor fit is just where I can’t get my fingers in to re-sit the seal so I’m still pondering a solution. We also struggled for hours trying to get the windscreen/top mount screws in place. All 4 of the 5/16 UNF captive nuts have been renewed so I should not have had a problem. In the end we gave up and I ordered screwed rod and made studs. After more hours, this time single handed, I finally managed to bolt it down. I haven’t yet addressed the side mounts. The OE tie bars are unobtainium so I’m making a pair of simple brackets and will use screwed rod with two dome nuts. I don’t have a rear screen fitted, either. I’m hoping that once I have a screen in place and have made brackets for the side mounts, that the fit to the body will improve. Then, I’ll try to figure out how to retain the skirt seal. Despite the grief, the black top on a white car looks absolutely fabulous.

I replied earlier and for the second time within thread it has vanished into the ether. I've looked again and I don't think it will rotate. Clockwise, likely the vacuum advance will foul the dynamo. Counter clockwise, likely it will obscure access to No 3 plug lead. With your help, much appreciated, I think we've exhausted all of the easy checks. I don't think it's ignition, I'm leaning towards valve guides as it's the only scenario that makes reasonable sense. I have no (current) intention to remove and work on the head so I'll live with it and adopt a regime of regular plug cleaning. More use of the car and at higher engine loads sounds like a good plan, too. A pal (owned his Elan Sprint for more than 50 years) is visiting tomorrow and we hope to fit pesky seals and mount my newly refurbished hardtop. I still don't have a rear glass but that's another thread entirely. As I'm sure is true for all Triumphs, there's always plenty of tinkering jobs to do without looking for more.

Thanks again to you all, appreciate your help in trying to solve the sooty plug issue. Rocker case breather is clear I’ve injected just 10ml of Redex into the No2 cylinder. With plug removed and using a torch, the top of the piston is nice and clean, not soot blackened, which is heartening. That said, the cylinder held pressure during CR test (which I did more than 6 months ago). I’m interested in the idea of rotating the distributor. This resonates also in that access to No3 plug is difficult. Picture attached. What is the factory orientation? How is this accomplished? Presumably, set crank position using light bulb on points, rotate distributor 90 degrees and move all HT leads? I’ve fitted the Sparkrite plug testers (only 3 because no access to No 3 cylinder) and, subjectively, all cylinders have healthy sparks

I believe that’s true but I can’t keep the seal in place once gravity takes hold. I’ve fitted it with the roof inverted, pretty much as soon as I turn it, it falls off. I was thinking about applying a slither of PU to help hold the seal to the hardtop skirt. I’m not planning to apply anything to the U channel which rests upon the body.

I believe the original spec is 3.1 to 3.5 ohm with 12v so it’s ok, n’est ce pas? Sweeper is in contact with the cap fixed brush. Yes, Chris, I’ve been through all of the swaps and I’m 100% sure that the issue is specific to No2 cylinder only. I was turning the front crank nut earlier today to measure points gap on each lobe. At one point, I managed to get my sleeve stuck between fan belt and dynamo pulley. I was not very cool at that moment. Normally, I’m quite chilled and enjoy tinkering with the 50 year old technology. Nonetheless, I’d really like to have all 4 cylinders working in unison. All offers of help or advice on this is gratefully received.

Thanks, Pete, No external oil feed. Choke returning fully (why only 1 sooty plug). Points were clean, only rotor arm and dizzy lugs were blackened. Dizzy is Delco. Coil measures 3.5 ohm across primary winding No measurable difference between points gap on any lobe (previously measured shaft rotation with DTI).

I need the help of a sparingly applied adhesive to keep a rubber seal in place along the bottom skirt of my newly refurbished hardtop. I believe that Tiger Seal is commonly used for this type of application. I can’t find this locally but have read that Puraflex 40 is a similar PU product. This is available at my local Toolstation. Anyone have experience, is it an acceptable alternative?

Thanks @Pete Lewisand @WaggerI appreciate your patience. Taken the car for a drive this morning and the revvy little engine performed flawlessly. The two actions of note were (1) clean sooty plug No2 and (2) clean blackened contacts on distributor cap. I can live with having to clean dizzie cap fairly regularly but I’m still a bit perplexed by the sooty plug issue. CR between all 4 pots is good. Tappet clearances are good and there’s no appreciable play in distributor shaft. I’m tempted by the idea of trying a hotter plug. I don’t drive the card hard, quite the opposite. Other things to check?

Appreciate your comments, Pete. 4 plug testers cost £9 so not a major outlay. I hope to find it interesting to compare spark across the 4 cylinders. Nothing ventured, nothing gained. Every day is a school day within Triumph ownership. There are two issues. The misfire is new. Having now cleaned plugs, points, dizzie cap and rotor arm I’m hoping to take the car for a ride tomorrow. No2 cylinder sooting has been a problem for at least a year, maybe more. I opened a thread on the subject last year. I fitted new ignition components but shortly thereafter out the car into hibernation. There may or may not be a link with the misfire. I wholeheartedly agree with your philosophy of avoiding tangents but sometimes helpful people make interesting comments which resonant with my experience hence warrant further investigation. Ideally, I’d like to buy a magic wand, wave it at the engine and have the issues go away……..but where’s the fun in that. I’ll also remove the rocker cover, start the engine and see if there is anything obvious. Any telltales for seized rocker? The misfire was instant with instant recovery. Pretty random. Sometimes at light load, rolling at 30-40 mph, sometimes under acceleration, albeit I don’t drive it hard.

Blimey, if that mixture doesn’t lubricate the top end, nothing will. Reminds me of the early 1970s when I ran Lambrettas on 90% Redex and 10% 4-star. Happy days. I’ll report back…..thanks

Another helpful post, thank you. Do you have a recommended brand upper cylinder lubricant? My garage is a pretty dry. I kept an Escort in it, untouched for more than 25 years and there were no signs of rust when I finally moved the car.

Another valid comment. I’m planning to add fresh fuel tomorrow. I’ve ordered a set of Sparkrite plug testers such that I can observe each spark. I think that the points pivot is ok but I’ll recheck. How to diagnose a sticking valve? A CR test shows very little pressure difference between the 4 cylinders. Help and advice is much appreciated, thank you.

Thanks, Chris, that’s all good information, much appreciated. Bizarrely, the last two posts of this thread appear to have vanished into the ether. My last post said that I’ve found the bag of nails issue. My plug spanner has a rubber grommet/o-ring to support the ceramic top of the plug and it remained on the plug when I removed the spanner, hence the HT cap wasn’t seated correctly. Operator incompetence. I’ve substituted all of the ignition components. The new ones, Club Shop, were fitted in the autumn and the car has run little since then. In the garage, this didn’t seem to make much difference so I’ve put the new one back on. It’s disappointing that everyone thinks a near-new NGK plug may be the culprit. I appreciate your recommendation re hotter plugs. The car does not have a radio and I’d prefer non-R plugs so I’ll search for BP5ES or N12Y replacements. I haven’t driven the car since my original post, hope to tomorrow (when my wife goes back to work so the drive is clear). It’s a bit of a faff because it currently has a hardtop resting on the body as I’ve yet to bolt it down.

Such extreme views would also be unwelcome on a certain sailing forum that I use 😃