AHS 1,411 #26 Posted January 5, 2021 On 7/9/2020 at 4:12 PM, RandyLittrell said: No I didn't, but its a stock cam and head gasket. With a bigger cam or copper gasket, you may need to check clearance but its pretty common to mill .050 off for stock pulling. It takes just enough off it doesn't get into the combustion chamber, so its still legal for a stock class. I have also ran an LP head on a stock 12 and it feels like more compression than a newer milled head. I don't know the CC difference though. Randy I believe that’s what Brian Miller said... you can shave the heads .050” (I believe!) 2 Share this post Link to post Share on other sites
Greentored 3,195 #27 Posted January 6, 2021 13 hours ago, AHS said: I believe that’s what Brian Miller said... you can shave the heads .050” (I believe!) Its been awhile now and the ol girl is up and going strong. Think I ended up taking .060 off, its a K241 (10hp) head with the material between the valves, kinda a heart shaped chamber. Between the milling, zero decking the block, touching the valve reliefs in the head just a bit, and ball milling to unshroud the valve area, I ended up at 9.3:1. So far zero issues at 20 degrees timing and 93 octane 2 2 Share this post Link to post Share on other sites
ebinmaine 62,932 #28 Posted January 6, 2021 7 minutes ago, Greentored said: Its been awhile now and the ol girl is up and going strong. Think I ended up taking .060 off, its a K241 (10hp) head with the material between the valves, kinda a heart shaped chamber. Between the milling, zero decking the block, touching the valve reliefs in the head just a bit, and ball milling to unshroud the valve area, I ended up at 9.3:1. So far zero issues at 20 degrees timing and 93 octane I've got a K341 that needs your attention. 2 Share this post Link to post Share on other sites
AHS 1,411 #29 Posted January 6, 2021 Yup, I made sure! .050” stock cam and valves. I did not know they made so many different heads! Share this post Link to post Share on other sites
Greentored 3,195 #30 Posted January 6, 2021 2 hours ago, AHS said: Yup, I made sure! .050” stock cam and valves. I did not know they made so many different heads! Neither did I til getting on Brians page. Crazy! Hey @ebinmaine you should yank that head off and send it down sometime! Would be interesting to see what gains could be had just by unshrouding the valve area...and of course milling. 1 1 Share this post Link to post Share on other sites
ebinmaine 62,932 #31 Posted January 6, 2021 7 minutes ago, Greentored said: Neither did I til getting on Brians page. Crazy! Hey @ebinmaine you should yank that head off and send it down sometime! Would be interesting to see what gains could be had just by unshrouding the valve area...and of course milling. Once I get another tractor or two up and running I will ABSOLUTELY take you up on that. Cinnamon is my go-to everyday working tractor. 1 Share this post Link to post Share on other sites
oliver2-44 8,830 #32 Posted January 6, 2021 50 minutes ago, Greentored said: Would be interesting to see what gains could be had just by unshrouding the valve area...and of course milling. @Greentored Can you explain or show a picture of what "unshrouding the valve area" in the head is? 1 Share this post Link to post Share on other sites
ebinmaine 62,932 #33 Posted January 6, 2021 8 minutes ago, oliver2-44 said: unshrouding the valve area I'll let Scott answer this one too but basically every engine is an air compressor and if you add something flammable and it goes boom at the right time you can move something with it... The more boom you make and the more air you move the more power you have. Unshrouding the valves lets the air flow around the valves so the engine can breathe better. It varies with every setup but if you can imagine a cereal bowl ... and you scrape the insides of the cereal bowl out ... you now have a slightly larger cereal bowl. 2 Share this post Link to post Share on other sites
AHS 1,411 #34 Posted January 6, 2021 What’s the difference between the magnum and K series? K series has the coil where the magnum does not. I was wondering if the modifications would work on a magnum 14? That’s all. Share this post Link to post Share on other sites
Greentored 3,195 #35 Posted January 7, 2021 21 hours ago, oliver2-44 said: @Greentored Can you explain or show a picture of what "unshrouding the valve area" in the head is? Here ya go, in the 'roughed in' step. Basically taking the vertical 'wall' in the head where the valve is, and 'rounding it out' with a ball mill, so when the valve is open, the incoming/outgoing air has more room to move without the wall obstruction. 3 Share this post Link to post Share on other sites
ebinmaine 62,932 #36 Posted January 7, 2021 43 minutes ago, Greentored said: Here ya go, in the 'roughed in' step. Basically taking the vertical 'wall' in the head where the valve is, and 'rounding it out' with a ball mill, so when the valve is open, the incoming/outgoing air has more room to move without the wall obstruction. Am I correcting assuming that there's plenty of aluminum "meat" to do that there? I've heard of moving the spark plug as well. Is that something that you'd normally do only for a race engine? 1 Share this post Link to post Share on other sites
Greentored 3,195 #37 Posted January 7, 2021 1 hour ago, ebinmaine said: Am I correcting assuming that there's plenty of aluminum "meat" to do that there? I've heard of moving the spark plug as well. Is that something that you'd normally do only for a race engine? Oh yeah, plenty of material there to do this. As for the spark plug, that's something I never did much research on. According to Miller, the 4th gen head and all K341s had the plug over the exhaust valve, keeping all the heat in the same area, and that theres a benefit to it for WOT use. I have one of those heads, but used a K241 head on this one ('heart' shape around the valves vs straight across) for a little more compression, and MAYBE thinking that heart shape could help 'guide' the incoming mixture toward the piston. 1 Share this post Link to post Share on other sites
ebinmaine 62,932 #38 Posted January 7, 2021 5 minutes ago, Greentored said: thinking that heart shape could help 'guide' the incoming mixture toward the piston I can see the logic in that. 1 Share this post Link to post Share on other sites
oilwell1415 563 #39 Posted January 7, 2021 This pic does a decent job of showing what shrouding is. It is for an OHV cylinder head, but the principles are the same. The areas shown in green are where the cylinder head shrouds the valve and interferes with flow. These can be fixed with port work. The red areas are where the cylinder wall interferes and are only fixable with a larger bore. 1 2 Share this post Link to post Share on other sites
AHS 1,411 #40 Posted January 12, 2021 On 1/7/2021 at 10:11 AM, Greentored said: Oh yeah, plenty of material there to do this. As for the spark plug, that's something I never did much research on. According to Miller, the 4th gen head and all K341s had the plug over the exhaust valve, keeping all the heat in the same area, and that theres a benefit to it for WOT use. I have one of those heads, but used a K241 head on this one ('heart' shape around the valves vs straight across) for a little more compression, and MAYBE thinking that heart shape could help 'guide' the incoming mixture toward the piston. @ebinmaine I have the 4th gen, over the exhaust valve on my 414. I also see the heart shape ‘guiding’ it toward the piston. Very good points! 1 1 Share this post Link to post Share on other sites
