the harley is good, 51 Panhead original survivor, raked and stretched, got her all running and during the winter also finished the one next to it a 68 Panshovel. To be honest there isn't much slack or woble on the valves, at least on these 2 I've checked, there's hardly anything at all. ok thanks. was a bit worried it might damage it. i'm doing it not putting much force on it, and I'm thinking maybe use the stick for the fine compound. But i'm seriously struggling with that stick.. comes off.. just spins on the valve and doesn't actually turn the valve...
[QUOTE="[JP]But i'm seriously struggling with that stick.. comes off.. just spins on the valve and doesn't actually turn the valve...[/QUOTE] [QUOTE="[JP] ok thanks. was a bit worried it might damage it. i'm doing it not putting much force on it, and I'm thinking maybe use the stick for the fine compound.[/QUOTE] That's why I suggested the drill, chucked on the valve stem method......
Do I see a crack in between the intake and exhaust seats? - head closest to the camera, second cylinder in...zoom in...
Nothing wrong with the drill method. I usually stand the head up longways and just run the drill. Don't really want it at max speed so you don't fling the grinding paste everywhere, but it's gotta be goin at a decent speed to grind. The two pack of grinding paste has the fine and course grit, I do a few minutes on each valve with the course grit until I get a good lookin seat, then finish it with the fine. Kinda smooths out the rough spots. I also used some brake cleaner and a red scuff pad (or like... 300+ grit sand paper) to get rid of the surface rust that were on my seats. Yours look fine though. I usually turn the heads over (chambers up) over a paper towel and put the valves and an old spark plug in and fill the chamber with either rubbing alcohol or brake cleaner and watch for leaks. The valve should seal well enough just by gravity holding it down without needing the spring. Also, I suggest a few drops of oil in the valve guide so you aren't spinning the thing in there dry. WD40, or any other penetrating lubricant will work well. Even a thin film of bearing grease or something similar. Just make sure you get it out of there. That'd be one smokey bitch upon startup. However, if you're already done, disregard the previous 5 sentences.
If you want a well defined pretty line without regards to accuracy, then blob a bunch on and run a drill at high speed. It will then grind a nice clear line. At that point, nothing is truing up and even if looking good it might not seal. Otherwise, barely put any on and run the drill very slowly with very light pressure a few times F & Rev. A cordless variable speed works fine, right on the stem. You can feel when the weight of it tilts off axis from stem clearance. You'll feel it grab when it's seated. The paste is more often used to prove a contact pattern, usually differing due to slight angle mismatch. Don't try to use paste to correct an out-of-concentric seat, a high spot will just drag around in a circle. More paste will indeed clean up a circle, but not correct it (without taking all day, in which case you'd be better off with a different method).
No, can't see any cracks. here's a new photo of that one you pointed at. yes, been putting oil on the stem before doing anything on it. I asked the same question on another thread, apparently crower grinds the cams to TA spec, so they are not actually ground by TA from what I understood. I'm still struggling with all this valve grinding.... So I've tried to stay away from the drill and use the standard methods... even went over to a friend and borrowed all this: But I just can't get it to work... I might be doing something wrong though.. I put a film of past on it, then wack it in, it spins ok, but after a little bit, like 4 or 5 spins, its like the actual paste acts like glue... the valve almost doesn't turn and of course the rubber sucker comes off. I have tried to put the paste, grind till it sticks, then wipe and do it again, but I'm doing this quite often.... surely it's not right? then just now, in one of the first I have done, which looked quite nice, I even done this one by hand on the fine grit, i put the valves in place and the spark plug, put some petrol on it and it just disappeared quite quickly.... so that kind of made me put my tools away and call it a day, too cold in the garage anyway.
That's what happens when the lapped angles are seating. Hard to spin valve. Keep going, your 1st one looked ok.
So... just do the spins till it sticks, wipe off, then do it again? and keep going till its nice and clean? then use the fine and do the same, put it all together and pour some petrol? am I doing it right then? just not being very patient with my results?
You may not need to repeat 2 or 3 times if there are no pitted areas. Try shining a flashlight into ports, in pitch black room with valve in place. You will visually see if there is any light leaking thru. Or Prussian bluing, (maybe magic marker) smeared on valve seat, then rotate valve slightly with some downward pressure to see how contact patch is. You'll get it the best you can using your garage tactics. Remember, you are trying to get valves to seat/seal that should have been actually ground. (Valve job)
yes that is quite true Mart, anything I do will be a million times better than what it was, because the amount of carbon deposits, they were probably not sealing that much in the first place.
Remember, nothing that you are doing makes the valve/ heads seats PERFECTLY concentric! You will have spring pressure to help hold valve down to seal. Guides are not tight, head seats, valve seats are not perfectly ground true. Put pressure on valve head when doing your petrol test.... it will help some.
JP, Those rubber suction cups, will not hold well to a pitted, marred valve head surface. If the valve heads were new and clean (no oil traces) and the rubber suction cups rather soft and new, maybe..... Don't get frustrated.
Haha, you nailed it! I was getting frustrated today, that's why I left it alone. plus is damn freezing in the garage. we are going through a snow storm here in the UK.... it's probably even on the news over there how we here can't cope when snows starts to fall and the country grinds to a halt. I'll stay in this evening (it's about 6.30pm here now) and tackle it again tomorrow during the day as have the day off work. Now that I have more information I can go in with a clear and new head and be more patient when the paste starts to stick and have to clean up, paste up and grind again...
There you go! Just keep adding some compound on seat area to avoid wash out and sticking like f85 mentioned.
If you clean everything solvent clean, a fresh wet permanent marker (Sharpie type) will imprint if you don't have or run out of Hi-spot. Dykem is about $6.50 US. Don't try to break open an ink pen, doesn't work real good. Wipe a marker thickly around the valve face immediately prior to checking and give it a few firm raps down to seat... with one finger on the stem, one on the face. Try not to smear it with rotation, minimal OK (a degree or so with marker, zero with ink). Immediately remove to see the imprint and remember it's orientation. Do it with the stems vertical or it will tilt. Ink works the same way as the lapping paste, if you put a ton on it will certainly leave a nice transfer print and fool you into believing it will seal. You want to barely dab enough around to leave a lightly brushed shadow. Forget the solvent method. As stated already... with spring pressure, guide clearance and valve flex, it will seal better installed anyways. If you think the solvent method is fool proof, bolt up some kind of torque plate to the assembled head and see how good your valve job is. In a factory setting in which 100+ heads a day are shipped out, they don't bother with solvent or even expensive indicator gauge checks (learning tool, lol). A hand vacuum pump attached to some plexi over the chamber and a few pumps checks a head in 20 seconds. Make sure to plug the spark plug hole and a single dab of heavy oil on the valve seat spun around in a circle. An O ring around the plexi is best but a glued sheet of rubber with oil smeared will work in a pinch. Make sure it covers the combustion chamber. Any chambers not holding near 30" vacuum steady for a few seconds is no good and needs more work. The maybe 2-5 leakers a week are simply pushed back into the assembly line to be lightly re-cut and double-checked at the machine. When you do 1200 seats a week you can tell by feel how it will turn out. Since you have a lathe there's little reason not to make a piloted grinding stone holder for pennies on the dollar. Stones are a few dollars each, a carbide dressing stick will keep the stone true in a pinch. A close valve seat will clean up with a stone turned by hand on a pilot or for a few seconds or with a tool, slowly and using the weight of the cutter only for pressure. Drill rod, (11/32 with a light taper) to insert into the guide. Same size hole (+.001 -0.000) reamed into the holder, or use a valve guide pushed into the stock. No bearings needed if you are not grinding 1000's of seats. A Sioux stone has a weird 11/16-16 thread, but the lathe makes it easy. Other brands have common thread sizes. A SHCS threaded into the holder driven by a cut off hex wrench from your drill will work in a pinch. I don't know why they make the valve grinding driver spin so fast anyways when they don't cut at that high of a speed, more like skip across the surface. They begin to cut when the stone almost halts from grabbing and 'they' train the workers to simply bump the switch a few times. Pretty much any type of driving motor will do the job. Make something up and barter the VJ's for your buddies. (I said VJ, get your mind out of the gutter!)
Lathe will do the job for you. Use 3/8" valve stem, installed from spring side to use as pilot. Fab up something like this....
