The 'E' Type Forum

Other than on a barn find and complete engine restoration, has anyone ever seen plugs like these? PO insisted that he had regularly maintained the car and had had it serviced shortly before I purchased.... I think not! That will teach me to take things at face value; I had been meaning to look at the plugs as part of general maintenance but kept putting it off. Silly me. Old plugs are NGK BP5E and i have replaced with NGK BPR6ES. Any comments on condition of terminals welcomed - to my eye they actually look reasonable; perhaps a bit lean? Car in fact running ok other than it seems to take quite a while before can come off choke plus doesn't like it when it gets hot (misfire and some backfiring).

Erratum! Some of them look reasonable, some do not (if you can see through all the crap that's on the electrodes)....

Not wishing to state the obvious, but looks like there has been a coolant leak in that area!

Or would you say water getting through bonnet vents and settling in spark plug cavities? The car has no rain covers installed on top of the engine. Nevertheless, would coolant produce this reddish residue? ATM certainly it is green antifreeze not orange.

Redman wrote: ↑

Mon Oct 02, 2023 10:49 pm

Or would you say water getting through bonnet vents and settling in spark plug cavities?

It's rust from those plugs being in water in the divots in the head.

PO probably washed the car then put it away.

If it is coolant, I'd be surprised - engine gives no sign of head gasket issues (and I had a similar LR V8 that overheated multiple times and I had to replace the head gasket twice which included helicoiling the block to get some new studs in). But I must admit @71V12 it does not look like rust, more like chemical residue. Fingers crossed it is just water getting in and sitting there. Having replaced the plugs (and cleaned out each plug well to the best of my abilities) I'll pull them after a while and see what results. Finally, anyone any comments on the NGK BPR6ES (gapped at 0.6mm).

I once owned a CZ motorcycle that ate its spark plug. There was only one and when the central electrode had worn so far it would no longer spark the engine died. So I carried a spare two plugs with me at all times. This was not a unique phenomenon. Early Kawasaki triples also had an appetite for plugs. They even had threaded holes in the frame under the seat to carry spare plugs.

All of the orange stuff looks pretty external, so I'd also be relatively relaxed about that. If you are on choke for a long time, it implies some of the carburettors are too lean at low load. If the plugs are sooty and it isn't after a nice long run, then that may also be from your choke enrichment.

kind regards
Marek

Thanks for that reassuring comment, Marek. I took the car gir its first run with new plugs yesterday: immeasurably better. Came off choke so much quicker, plus running noticeably more smoothly (why am I not surprised). I had been planning to pull the plugs after 500km or so and see condition. I take your point about needing to think about excess choke disguising real carb settings (lean/rich). I will try to stick to longer runs to help avoid this - but I never take the car out for less than 30 min runs avoiding traffic and make sure well up to temperature. Thanks all.

200 km later......on a good fast trip, plus took the advice of others on this forum and added some good quality 2 Stroke oil to the tank. Result is a clean clean plug (this one is 6B; I'll try 6A next time I check). Engine is running very well indeed. No comparison with what was going on before. Thanks all.

Redman wrote: ↑

Fri Oct 13, 2023 2:28 pm

took the advice of others on this forum and added some good quality 2 Stroke oil to the tank.

Interesting!! I'm a big fan of 2SO in old engines as well! Pity you did not measure compression before and after adding 2SO. That might have been interesting too!

Coking up an engine by burning a 2SO mix could certainly raise compression, but why would you want to do that?

bitsobrits wrote: ↑

Thu Nov 02, 2023 11:58 am

Coking up an engine by burning a 2SO mix could certainly raise compression, but why would you want to do that?

2SO DE-COKES a non-cat, non O2-sensored engine.... among many other advantages.

jagwit wrote: ↑

Thu Nov 02, 2023 12:03 pm

2SO DE-COKES a non-cat, non O2-sensored engine.... among many other advantages.

I'll elaborate:

Using two-stroke oil (2SO) as an additive (approx 200:1) on a non-cat, non-o2-sensored petrol and diesel engines does many good things, the main ones being:

• softening and eventual removal of the carbon deposits that build up on the inlet and exhaust valves

• softening and removal of carbon deposits on the piston crown

• softening and eventual removal of the carbon build-up between and behind pistons and rings which could cause the rings to jam in the piston and thus not seal properly resulting in optimal compression over time

• lubricating carburetor moving parts

• showing fuel leaks - petrol evaporates but leaves blueish 2SO oil

• preventing rust in steel fuel tanks and fuel lines (fuel evaporates but 2SO remains)

Have a look at this YT video: https://www.youtube.com/watch?v=QLW5KEslF3A. He runs a 40:1 and a 4: 1 ratio. Compression also happen to go up by 5% .... Note the oil deposits which remain. This is what softens the carbon.

I just chuck 500ml in with a tank fill every now and then - when I remember.

Two stroke oil in a four stroke?

Nah! Not a good idea.

Of those "benefits" listed above, most are imagined.

If you have carbon on the valves or pistons using today's petrol, the engine is running rich. Adding oil to the petrol will not improve that. If you have carbon behind the rings you have a worn cylinder.

Lubricating a cylinder will usually increase the compression ratio, compared to a dry test.

Feel free to watch any number of videos on the interweb, but please forgive me if I say I think this one is a load of old tosh.

jagwit wrote: ↑

Thu Nov 02, 2023 12:43 pm

I just chuck 500ml in with a tank fill every now and then - when I remember.

Perhaps if the companies who designed, built, and warrantied these and similar 4 cycle engines over the last 60 years recommended adding 2SO to the fuel, then I might do so. But as they didn't, I'm not.

And if your are looking for interesting YT videos, you might want to check out the magnetic fuel savers:
https://tinyurl.com/Fuel-saver-video

modern day snake oil!

Well will have to see. As long as it does no harm, I'm willing to give it a try.

Those things come from the 60's, were tested by the AA & other institutions and were never proved to be of any benefit.

Redman wrote: ↑

Mon Oct 02, 2023 10:49 pm

Or would you say water getting through bonnet vents and settling in spark plug cavities? The car has no rain covers installed on top of the engine. Nevertheless, would coolant produce this reddish residue? ATM certainly it is green antifreeze not orange.

This was my first impression of the situation. That the rain shields were not in place. I removed mine several years ago, because it covers so much of the engine when I am at a car show. I don’t every wash off the motor for fear of getting standing water in the plug wells.