1979-1993 & 94 Conv [Subscribe to Daily Digest] |
First, the spring compressor is a big c-clamp wiht a lever to close the clamp. The fixed jaw goes on the valve and the movable jaw has a fadget that slips over the valve spring retainer. Close the lever and you compress the spring. When compressed, remove the keepers and then release the lever/pressure slowly (so the SOB don't jump out atcha!)
insofar as the valves. Inspect the candidates very, very carefully. Any...any..did I say ANY?...nick or suck on or near the seating surface needs to be removed, if there's enough meat to do so. Lapping can't do that.
Lapping is a final finishing, not suitable for getting the angles correct or making the seating surfaces flat at the correct angle (you may have taken a 2 credit Mfg Processes class about 2nd year, and this sort of thing might have taken up half a page in the textbook<G>). There should also be a lip on the valve of at least about 1/16...by this I mean the edge between the angled seat and the bottom/face of the valve should not be sharp...you need a lip or step of 1/16 or more otherwise you'll burn the SOB right quick. If you can, look at a new valve for guidance.
It is also critically important to examine the valve seat(s) for any nicks or mechanical damage. Use a good light and magnifier if you can. A proper seat will have three distinct angles ut on it, 75-45-15 degrees whher the 45 degree angle is the face upon which the valve seat (0ften cut to 44 degrees) sits. The idea is to avoid sharp edges; the 75 and 15 "blend" the 45 into the "90" that is the port itself.
A knackered valve, as you describe, is likely to have caused damage to the seat or piston. If the piston has nicks, you may be able to smooth then out with fine emery paper...you do not want to leave a sharp edge in the combustion chamber. (it attracts hot spots, causing pre-ignition and otehr nasties...refer to your heat engines texts<G> (yeah, I know...I know!<G>)
There are some things that IMHO (my engineering degree is 45 years old, and mostly forgotten by now) are best handled by pros and this sort of thing is a candidate for this kind of attention.
OTOH, there is stong evidence that screwing it up once produces Significant Wisdom at a later time<G>
Bouna Fortuna!
posted by 67.127.191...
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