Saturday, April 17, 2010

Off with her head!

Molly's rattling valve gear has finally spurred me into acton - her head has been removed! I have a new (second hand) set of rockers, new tappits and pushrods. The reason for this is that the rattling noise can only get worse (they always get worse) and the only way to investigate to to get the spanners out.

this is what happens when you cross the Queen of Hearts

Once the rockers were off, I noticed a fair amount of sideways play on one of them so I am (probably) vindicated on this course of action. Anyway once the head was off, I got a chance to take a look at the head. Its a 12G295 spec casting as used on some (proper) mini coopers. And boy does it make a difference. Lots more torque and a generally smoother run. I got it from eBay a good while ago, and had it refurbished with new valve guides and hardened seats so it was in good nick. I had difficulty remenbering when I fitted it but the power of blogs is such that a little searching and it was way back in 2006. Now cylinder heads should last longer than 4 years, and she has been laid up for a lot of that time, however most of the journeys have been short ones to the shops which are't good for engines. So we have a bit of a carbon build up...

a little dark on #3 I think...

It looks as though #3 cylinder is a bit over rich for some reason too (either that or the rings are shot, but the blackening doesn't feel greasy so I'm going with rich).

decoke please

Finally I took a look at the old pushrods and found a little nipple on the end of each one. Now I'm pretty sure they are not supposed to be like that. A new set of pushrods and cam followers (thats what tappets are supposed to be called you know...) should fix this, but I just hope there is nothing else untoward which is causing this problem.

nipples - the bad kind


Anonymous said...

Yes Rupert it certainly looks like wear and tear has worn the hardened face awayon that push rod but I hate to bring this up but what condition are the cam lobes like, unless you've put a new cam in somewhere in bygone years then the cam lobes should be ok.

Rupert said...

yeah Richard, the pushrods are in the bin along with the cam followers. the bottom of the cam follows looked in pretty good nick (i.e. the face that is against the cam lobes) so I'm not too worried about the cam at the moment. I can always swap out the cam in the future when I rebuild the engine (for something hotter obviously!)