Valve Adjustment

[Croc]

Hi I have had to adjust my tappet clearance, as the exhaust clearance has tightened right up on 1 and 4.

No1 took 3/4 of a turn of the screw and no4 took 1/2 a turn. all others were fine as it was all checked 3 weeks ago.

The car has run fine up until this week when it really started to become undriveable.

Do i have a problem with my valves stretching or is it another cause.

 

Can anyone shed any light on the subject?

My next course of action will be to take the head in to have the valves changed if needed.

By the way all the nuts were tight.

The engine is a 12r in a 67Corona. These are a pushrod with solid lifters.

[Taz_Rx]

Was the headgasket recently replaced? Sometimes they'll need re-adjustment after say 500km.

 

As were they set to the right clearance while the engine was hot or cold? If you say set them to the hot clearnace while the engine was cold then they'll be all up the shit.

[Croc]

Well it's all over for this engine. :y:

Pulled the head off to find no 1 exhaust seat missing all together and no 4 just about to fall out.

Top of the piston has a nice mark from the valve hitting it and lots of other marks as well.

Plus the engine has been pinging and has destroyed the sides of all 4 pistons.

I guess it pays to have the head looked at when you freshen up an unknown engine.

Oh well guess i'll bolt the old motor back in. I only changed it because i could.

On the plus side the engine was still running fine today after i adjusted the valves. looking at the pistons it wasn't long before she went bang. :)