Valve clearance shims?

citronut · Post by **citronut** » 12 Jul 2005, 00:33

it is best to check clearances whilst head is on the bench before you refit it regards malcolm

vanny · Post by **vanny** » 12 Jul 2005, 02:00

any suggestions to make sure the vlaves dont hit the bench or the head rock around? Im handy with the ole wood and have a set of spare head bolts which might be the solution! But i wonder if there is a proper way!
Any advice on wha thtis lapping in thing is and or how it's done?

citronut · Post by **citronut** » 12 Jul 2005, 02:58

what my workshop landlord who dose cylinder haed work for a liveing uses two lengths of steel about 10/12''long by 2'' by1/4'' with a tapered matal post aprox 10'' one fixed to each bar at right angles so the post sticks up wards,put one post into a bolt hole at oposite ends of head and bongo you have pair of head stands regards malcolm

jeremy · Post by **jeremy** » 12 Jul 2005, 04:15

Lapping is the good old practice of valve grinding to get a good seal. Its done using carborundum paste and the idea is that you hold the valve head with a rubber sucker on the end of a wooden handle, put a dab of paste on the seat and rotate the vave against the seat forward and backwards. Getting a good seat is rather more difficult than it sounds as the things tend to groove and generally after about 5 minutes you discover pits that are too difficult to get out while getting a good seal. (Excessive grinding tends to produce curved seats or seats that are too wide or have rings.)
The best solution is to have the valves re-faced (if possible) on a special grinding machine and the seats cut with a dedicated cutter (which is in fact generally a hand held cutter on a suitable shaft that fits the guide) The valves should then be lightly lapped to get a perfect long lasting seat.
Manufacturers actually cut the valve seat valve face at slightly different angles so that lapping isn't required.
jeremy

Allanxantia · Post by **Allanxantia** » 12 Jul 2005, 14:00

Would be alot easier out the car, yes but the head is back on the car so it will be a lit bit more hassle. will get bottom end so all cylinders are half way and cam will turn freely, just need to remember which way to turn it back when cam is back in the right position!

citronut · Post by **citronut** » 13 Jul 2005, 00:32

with crank set with pin in flywheel through crank case behind starter motor,so you know its in right place,take pin out rotate crank a quarter of a turn anti clockwise when faceing crank pully,then once you have reset cam after you have finnished checking shims,just turn crank clockwise by quarter of a turn till pin goes into flywheel regards malcolm

Allanxantia · Post by **Allanxantia** » 13 Jul 2005, 14:04

Thanks Malcolm, this is what I reckoned, will give it a go tonight.
Cheers

Allanxantia · Post by **Allanxantia** » 14 Jul 2005, 03:44

measured all the gaps tonight, not too difficult at all. I need 5 shims 2.69,2.59,2.46, 2.84 and 2.74. Hopefully these should be easy to get hold of. Will keep you updated

Allanxantia · Post by **Allanxantia** » 18 Jul 2005, 15:26

Just a big thanks to everyone for their help. Could not have done it without you. Got the Xant going on Saturday, goes like a dream, a very very very slow dream. Delighted, cheers

citronut · Post by **citronut** » 19 Jul 2005, 02:26

well done regards malcolm