tappets and rocker cover gasket

[jms700]

hello,

just changed my rocker cover gasket and adjusted my tappets ( roughly ) and when i got back in the car my idle had dropped from 1000 , where it normally is, to around 600. also my oil pressure has droped from 50 to around 40 at idle, ( but im guessing thats because of the idle ?

does any one know what would cause this and if its an issue? ( first time doing tappets)

thanks

[sparky_spit]

It could be linked to either of the 2 things you have done...

Setting the valve clearances incorrectly will alter valve timing, and will change the idle speed to a lesser or greater degree depending upon how far out the clearances are. As you probably know, they all should be set at 10 thou cold.

Less likely, but still something to check, is that your new rocker cover gasket is leaking air, or the filler cap is not on properly. As the engine breather system (depending upon which car it is) breathes into the inlet manifold or carbs, any air leak will weaken the fuel mixture and  upset the idle speed and general performance. A very badly fitting rocker cover gasket could possibly give a big enough air leak to do this, although I would expect you to see oil leaking out as well.

[Hogie]

Have you left any breather pipes into the carb undone.

Roger

[jms700]

i didnt undo any pipes on purpose but i will check that. wee confesion here, the cars not a triumoh, its an mgb sorry. the spitfires next though , thought id practise on the mg first.

im not sure if the idle speed is too low or not. it doesnt stutter or cut out. is it possible that 1000 revs was because the tappets were out of position and its back to how it should be ?

i checked for leaks, and all i could feel was a small jet of air out of the side of oil filler cap, but i thought that was normal ?

thanks

ps, the performance does seem slightly better actualy, but that might just be me