Poorly 803

[cillacat]

HELP!!!!!!

My Lovely moggy Kitty is sick! i appear to be running just three cylinders and its not anything simple like plugs.
Have recently replaced the head gasket and Thermostat as these had gone but am pretty good with my engine so im sure the work is ok.
I am also suffering from whisps of smoke coming out of the air filter im thinking that i may have a knackered piston ring or piston...
any suggestions????
Im thinking it could be terminal and that is really upsetting me
please help if you can
thanks

[JOWETTJAVELIN]

Do you know for sure there is no spark? Plugs gapped properly? Any difference in colour from other plugs? Does anything come out of the offending cylinder with the plug removed?
Also, is there compression, ie if you stick a finger in the plug hole and turn the engine a few times can you feel pressure building up or escaping?

Take the oil filler cap off, rev it up and watch what comes out.

Welcome to the forum but don't talk about 'terminal' 803's. I would be a happy man if all I had was a bad cylinder.

[cillacat]

Thanks for that.
Beleive me even if i have to change the engine i will i love my car dearly and dont want to get rid.
Hubby has been working on it and knows what hes doing. have spoken to him and he says it sounds like its running on three and a half cylinders. So there is spark on all four but when we looked at it,(the third cylinder back) sounds lumpy ie if you unplug the front one you can tell that its dropped a cylinder if you unplug the third back then it obviosly runs on three but when plugged back in the effect is much less dramatic and still runs lumpy.
Im guesseing the next thing is to compression test when it stops raining!!!!

[cillacat]

Forgot to say when the engines hot and you rev the engine you get whisps of smoke from the rocker box but will as suggested re-check the colour on the spark plugs.
do you have any problems with whisps of smoke out of your air filter when hot???

[JOWETTJAVELIN]

Not from the air filter. Does this happen once the engine is thoroughly warm?

It might be a case of 'off with the head' although you say the head gasket was recently changed. What did things look like then, and why was the head gasket replaced?

[cillacat]

It was changed because it had blown (serious amounts of water in the oil). im thinking this could have been because the thermo was Knackered.

we have litterally just changed the head gasket put it back together and now we are having this problem.
the reason im sure about the work is because my husband is ex army Corp of transport so he knows his motors. im learning quite a bit too and like to get my hands dirty, so i stripped it down and cleaned it all up and he checked it and put it back togehter again.
on inspection the head and block were good (checked flats) all good and the valves and pistons were good a bit coked up but ok.
One thing i did notice though, was that the back of the head had a hell of a lot of heat build up on it especially around the back cylinder head stud all the spark plugs were cleaned and gapped all seemed ok but i will check again this weekend and test the compresion.
Im really hoping its something stupid poss a HT lead. for the sake of a new set of plugs ill change them anyway.
Just out of interest are there any problems that are common to the 803 that you know of?

[cillacat]

oh and yes the engine is thoroughly warm when the whisps of smoke appear!

[JOWETTJAVELIN]

Not a stupid question, but did you change the engine oil after the gasket problem? Just thinking the smoke could possibly be steam and the cylinder still misbehaving due to the water in the oil.

[JOWETTJAVELIN]

803 is v. prone to big end failure if flogged, i.e. travelling above 50-55 MPH for long periods. Apart from that and the lethargic performance they're decent little engines.

[moggiethouable]

803 is v. prone to big end failure if flogged, i.e. travelling above 50-55 MPH for long periods. Apart from that and the lethargic performance they're decent little engines.

What are the symptoms of a scored valve Jowett?

[MarkyB]

the valves and pistons were good a bit coked up but ok.

I'm guessing they weren't removed, my guess would be a leaking valve, have you done a compression test?

[JOWETTJAVELIN]

What are the symptoms of a scored valve Jowett?

Don't know what you mean by scored valve.... I've come across pitted valves but the symptoms are obvious... they're pitted.

[bmcecosse]

So -the head gasket, when opened up -WAS it blown between cylinders ? Why do you think the 'thermo' caused a problem? They always fail OPEN - so running cold is the problem - not overheating. When the head was off - did you remove the valves and grind them in? Fitting new oil seals on re-assembly?? The gasket was changed, the head torqued down correctly? And since then - have the valve gaps been re-set ?? This is the most likely problem - unless of course the plug leads have simply been refitted in the wrong order ?? 1342 anti clock around the dizzy is the correct order......

[David53]

I was going to suggest plug order too. Easy to get mixed up if not labelled. If, as you say, the head gasket had blown then it is possible the head was damaged slightly - did you check it or have it skimmed?

[chickenjohn]

Do a compression check- borrow a compression tester. Your husband's comment about 3 1/2 cylinders makes me think the likely cause of the misfiring is a broken/chipped/burnt exhaust valve. That means the head will have to come off and the damaged valve replaced, After all valves have been ground in, then the car will run much better!

[moggiethouable]

Do a compression check- borrow a compression tester. Your husband's comment about 3 1/2 cylinders makes me think the likely cause of the misfiring is a broken/chipped/burnt exhaust valve. That means the head will have to come off and the damaged valve replaced, After all valves have been ground in, then the car will run much better!

and thats what I meant by a scored valve.
I had a v8 once that lost half an exhaust valve, in that case it was barely missed as 7 other cylinders made a big effort to compensate, but the symptoms were very similar.
In an effort to fix it I think I changed the coil first (just kidding BMC)

[chickenjohn]

Yes, an A series will run quite well with a chipped valve but as the compression is down will be a little down on power. Just needs a little chunk missing off the edge of the valve to lose half the compression from that cylinder. A compression test will show which cylinder is down.

[bmcecosse]