SABB valve job

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SABB valve job

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krv3000:
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krv3000:
HI sos for not geting back sooner but me intrnet went off right as regards to threding for a valve seat replasment with this low reving engine anything will do i have even cut into water jacets to reper them 1 set up in the mill by yousing the valve gide to set it up on center with the ade of a boring hed tack out just the amawnt need to form a new valve seat + thred i youse fine mm thred mace up new valve seat the way i scruw the new seat in depens on the overall od but the way i normaley do it is by leving a large ring at the top in to wich i drill in too for c spaner lick the type you youse to remove your grinding discks from your angelgrinder i have scruwd them in with nothing on the threds and i have scruwd them in with locktite plumers tape red jonting compawnd all with no problems i can if you wish lend you my set of valve seat cuting tool if you is preperd to pay for the postige to you and back to me regards bob

AdeV:
I've decided to mock the job up on the mill, to see how difficult it is to line up the cutter with the valve guide.

1st job, find 4 level risers to raise the head off the mill bed. As luck would have it, my recent lathe tool gloat contained 4-off clamps, which when sat on end, happen to be dead level. Chuffed? I was... So, using the 4 head bolt lands as a reference the head is mounted & clamped.

Next up, I turned down a piece of scrap brass tube to 0.351" dia - exactly the same as the valve stems. This was then mounted in a collet & checked for runout in the spindle (about 0.001"). Finally, the head was manoevered under the spindle until the brass rod cleanly passed through the valve guide.

Here it is in the "up" position:

...and down...

The bottom of the brass tube can be seen poking out of the top of the valve guide:

After that, I blued it up & passed it through again, to ensure that the blue was removed uniformly; thus ensuring an absolutely dead centre (within 0.001" anyway) on the valve guide. The valves themselves wobble about by at least 0.010" anyway, so IMHO this is plenty close enough for the job in hand.

Next up will be to actually get a round to visiting another friendly MadModder who has some valve seats going begging.

Hat-tip to Bogs for a) spotting & pointing out the 4 datum points on the head, and b) suggesting the valve-guide-in-quill to get it centered up.

:nrocks:

Divided he ad:
Looks very nicely mounted :thumbup: Good enough for a skim too?

Paper shims, nice sharp flycutter and a really slow feed? Or if you know someone with a surface grinder big enough you could get a hell of a good finish on cast iron :dremel:

Couldn't clamp it like that though?! Maybe a clamp or two in the holes in the sides of the head? Anywho, that's a bit further down the line.

Valve seats.... I'm sure I had some somewhere? ::)

Ralph.

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