Hitchcocks Forum

Need to remove valve guide,what gas mark to get right temp for removal, thanks having a senior moment.

I put my heads in oven at gas mark 3 to warm them gradually for 20mins then turn up to gas mark 7 for 15 mins. They should fall out then.ed

I build up the heat over about 20 minutes to maximum which is 250 deg C in my workshop electric oven. You won't melt or damage alloy at this temp and as far as I'm concerned, the hotter the better. The valves might fall out as Barnes says but often don't, (especially on heads which haven't been played about with much before,) so have a suitable mandrel to hand as well as a heavy hammer. One swift blow is better than a lot of tapping while it cools! REgards, Mark

Melting point of (pure) aluminium is 660C - no chance of getting near that in a domestic oven.
Annealing is 300/400C depending on the alloy. Gas mark 9 is only 240C.

I put them in the oven at 200 deg until the smoke alarm goes off, I find that is plenty warm enough.

..20 to 25 mins at gas mark 5 OR until a nice crispy brown all-over......Carefully add the sliced potatoes along with 1/4 pint of prepared stock....onions and carrots add a distinct "English" flavour.....then another 10 mins with the radiant grill on at position 7...........Remove and allow to cool for 20 mins....Serve with a fresh, crisp green salad and a bottle of chilled Qiante'......(Eh??..wot abaht the guides then mate??....as per Mark M).....Delicious...ENJOY !!

Thanks chaps did this years ago,on C15T in aga oven untill they fell out! better to be safe than sorry, thanks again.