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Does it Iook like the seat is smaller than where it transitions to the bowl?
I haven't taken mine apart yet but if they look anything like the pictures of those that have, a little valve grind and bowl blend wouldn't be a bad idea.
I didnt think you were near 190. Your thinking in the 2.05 getting more angles is correct. Maybe why the return of floor/ssr work was less than 8-10cfm . The thread should be edited down to what you do, locked and then a link thread for the discussion thread.
I’m no we’re near the smart engine or head porting group and being self taught has been a journey but that just doesn’t look right to me. We can rebuild it, we can make it better than before. Lol. If a snow sled rider was trying to navigate that, he would crash for sure.
I meant using an 82 off the bottom of your 75 if you can get it in there. Sometimes there isn't room for all that unless you go to the bigger valve. And I agree 15 degrees is the maximum I would use. If you can keep it down to 10 degrees all the better. If I use a back cut I try and use a 7 or 8 degree back cut if at all possible.
I doubt they could keep the TIR to under .050 if they just used the guide as a pilot if I'm getting your drift. I have never liked a live pilot cutting system. I prefer a dead pilot with a ball drive tool head. The ball drive takes up any misalignment you might have, up to a point.
? Are you referring to .050 TIR on a seat that was precut and THEN installed in the head, .050 TIR is a Football field of runout.
I'm thinking TMM was suggesting that rather than use a pilot in the valve guide to machine the seats, they were somehow piloting off the OD of the guide. That's the was I understood his question but I could be wrong about that. I have seen several valve jobs with .050 TIR. They were all BBC's with 2.400 valves and .311 stems. Just junk crap.
We don't know how sophisticated their machining centers are. If they are all cnc stuff they could machine the pockets for the seats and the bores for the guides in the same machine with a change of tooling. Just thinking out loud.
Actually, this very topic was being discussed over on speedtalk.com and I'd say most likely if SM or whoever is doing the finish work is using some form of CNC machining, I'd suspect they are using a Newen Epoch or similar machine. I doubt they are tooling up a CNC machine just to cut seats. Most likely they are using a regular seat and guide machine. If you are setting up to cut say 2.02/1.60 valves, you can do a 4 cylinder head in about 10 minutes max once you have the tooling set up. So I'd say floor to floor in 12 minutes per head. That's 4 heads an hour, 32 heads a day from just one machine. Doesn't sound like a lot, but it really is for just one machine. And if you have your crap together you could cut some time off of that.
Not me. I live less than 1.5 miles from a coal mine. Have to constantly level the machine. You would not believe how much it moves after a blast! A real pain in the rear.
IMO a valve job with a 65° bottom cut narrowing the 45° seat to a width of .035-.040 would probably widen out the bottom cut to a more acceptable width with the 2.02 valve. The real answer as PBR has alluded to is moving to the 2.055-2.08 valve.
I agree. Or....................you know I'm going to say it...................a 50 degree valve job.
This is probably what the seat machining looks like at SM. wham bam
No wonder why you get some chatter. Thanks for the video.
High capacity production line machining isn't pretty. I'd never cut seats so fast as to make that kind of heat/smoke.
Me neither. I was surprised to see that. The spindle speed needs to match the feed rate. He was leaning into it pretty hard.
He ain't the one paying for the tooling.
I highly doubt if you buy the non-cnc ported SM heads....... that there is any machining of any kind done in the states.
Not a fan of the live pilot. Not sure how he is correcting the guide centering from the last head. I can promise no two heads are the same, and unless he is getting the guide level in both directions I have no idea how the tool head is doing it. Especially with the live pilot. Are the guides all sized exactly the same? I doubt it. Way too much tool speed. Unreal. I call that junk. Now you know why most of us do a valve job when we do heads. Getting them to seal is the easy part. Just garbage.
The man has a pallet of heads to get through. And more pallets after that. Speed is money. Production is a whole different animal than blueprinting for maximum results.
^^^ unfortunate truth
Actually, it looks to me as though the spindle is aligned with the guide twice per seat. And there’s two stages of the cutting operation..... roughing and finishing.....with a realignment between the two. Also, it’s automatically varying the spindle speed during the cut to minimize chatter. Pretty nice piece of equipment imo.
Well guys I’m done for now. I had a stone shatter trying to put a 75 degree bottom cut on this head. I ended up taking a sanding roll and slightly rounding the edge off at the bottom of my 60 degree cut. My valve job looks like she-ite and a swear a kindy gardner could do better with Play-doe. Would it make horsepower yes. The pinch speed is 350-300 across the entrance and it carries it well throughout the port. Even down the pushrod wall. The shortside speed is high (380-pegged 401) but is hugging the shortside curve nicely. I got to get my butt moving on my 408 build for next year so it would be a waste of needed money going any further here till I can get my local shop to do a professional 75-60-45-30-15 degree seat for my 2.05 or 2.08 valves I have sitting here. It’s times like this where I would have bought my buddies mill.
Final numbers for now with suck-azz valve job .100————71 .200———-142 .300———-202 .400———-245 .500———-265 .600———-274 .700———-282