noisy engine

daveball

Hi I have a 67 spitfire, only got it, giving me some grief


when I started it today and drove off it sounded very rough like a beetle engine it sounded raw and with little power.
I checked oil which was ok, there is a raw sound coming from air filter.
also checked the HT leads and on the 3rd lead when I took it off while the engine running it made no differance to the revs, not sure what to do with it , any ideas , appreciate it , and thanks:eek:

Spit62500

Hi,

Check the colour of the spark plug base. They should be a tan/grey colour. If number 3 is significantly different then there may be a problem. How's your oil pressure? Does the oil pressure light flicker come on when the engine is warm and idling? Have you an oil pressure guage fitted and if so what are the readings? Might be a good idea to check your valve clearances as broken rockers are relatively common on Triumphs if the oil supply to the rockers is interrupted.

You probably need to do a systematic diagnostic of the ignition system before doing much more. That'll eliminate faulty ignition leads, distributor cap, rotor etc.

If its happened suddenly it might well be something simple - maybe a blocked carb jet after running low on petrol....

Hope some of this helps...

daveball

Thanks for ur reply, Well now that u say the oil pressur is down to about 20 it was up to 60/70 but when u rev it it moves with the rev,
would taht make it easier to diagnose.
will i be damaging it if I drive it. thanks for replying so soon

Spit62500

Hi,

The oil pressure should read somewhere over 10 at idle and anywhere between 40 to 60 at 3000 rpm.

I can't say if you'll damage it or not by driving it but if it was me I'd find the problem before doing too much mileage as there's a risk that it'll let you down somewhere as well as the risk of damage to the engine.

Check the plugs and see what number 3 is like. Try swapping the leads around and see if that makes any difference - if the misfire transfers to a different cylinder then you've a dodgy lead. Check the inside of the distributor cap for cracks and scratches. Check the rotor to make sure that it looks ok. If you've got new points and a capacitor then it'd be a good time to swap them around.

Take off the air filters and make sure that the dashpot (visible through the air intake) can rise and fall freely. You can do this by revving the engine while watching then or else you can raise them with a small screwdriver and let them drop. See if the noise is any more specific or localised with the filters off.

Check the water in the radiator for drops of oil and the oil on the dipstick for drops of water. Have a look at the underside of the oil filler cap for white creamy deposits.

Take off the rocker cover (you may need a new gasket afterwards) and check the rocker arms for cracks. It might be a good idea to turn the engine over by hand while watching them move, just to see if there's anything wrong there.

Did you change anything recently? Are there any new leaks or smells that weren't there before? Have you adjusted the timing or done anything else like that?

Eric318

This reminds me when the head gasket went on my MGB... The leak was between two cylinders.