Who has do this and what type of benefits does it offer other than increased compression. Topend, Bottomend?
tomos head decking
Re: tomos head decking
You'll have better low end torque which will aid in hill climbing and a bit more acceleration. It won't help top end. You may have to adjust timing as well and start using 93 octane.
Re: tomos head decking
my head is milled 1.5 mm's, and it will beat damn near any kitted bike off of the line.
Re: tomos head decking
the two speed will help, dallas...
but yeah, better torque mostly, combined with other stuff its good for an increase across the board.. you might have to start running premium or retard your spark if you go too crazy- it will cause detonation if it gets too high. I've been milling a few heads for people lately, email me if you want it done all pro-like on a lathe and stuff.
Re: tomos head decking
Graham,
I have found I can deck heads faster in a mill than in the lathe.
Do you have a mill ?
Raz
Re: tomos head decking
I want a fucking lathe. we're decking with sand paper and a power drill.
Re: tomos head decking
I use a piece of thick glass and tape the sandpaper to the glass.. Sand back & forth for 10 strokes then turn the head 45 degrees and repeat.
Re: tomos head decking
50/50 baking soda/tooth paste works well for glass method, but it's so damn slow. we tape the sand paper to a piece of wood, chuck a shot spark plug into the drill, insert in the head, and blast metal off. kind of imprecise, but it only takes like 10 minutes, including setup time and cigarette breaks.
Re: tomos head decking
haha holy shit zack that sounds awesome. may have to try that.
You use a lathe over a mill? Im in mech. eng. major so I just got machine shop access at UNH (pumped), so im a complete rookie. But im gonna try to get the instructor to let me mill my heads down, my variator, and other various ped tasks. I know this is your side business but any tips? Why do you prefer the lathe over a mill? Ideally id persuade him into use of a CNC machine... its nicer to have robots do the work for you. mmmm CNC machining....
Re: tomos head decking
zack
thats a brilliant idea!
saves on elbow grease
Re: tomos head decking
From an older fools point of view. I will give Graham some free publicity here... The Lathe is the better of the two from my point of view. I took 3 years of Machine Shop in college before the CNC came to be, I had a taste my last year with just a plotting machine. The lathe will leave a true flat surface and more. Anyhow. Increasing the Compression is good but cutting a squish band is better still and that is best done on a lathe. I think for the price, Graham has a good thing here. He is doing my Garelli Head at the moment. This simple modification carries major combustion improvements. He charges about 30 bucks. For that price you just can not go wrong! You want good power cut the squish band
Re: tomos head decking
I thought people would be horrified... but I guess not. more info, then. shitty cordless drills seem to work best, easier to control the speed and hold the head flat. we tried it with a corded dewalt but it was just to much drill. also, the plug nipples usually break off halfway through. we're currently working on a better solution, involving a cutoff socket extension welded to a plug bottom with the ceramic smashed off.
Re: tomos head decking
Mark,
I have been a Journeyman Tool and Diemaker since 1994 and as far as decking heads , I can do them faster and indicate them in faster on a mill. Now, cutting a squish band in a head that does not have one would be faster in a lathe.
Raz
Re: tomos head decking
Anybody have a good starting point for reducing the squish on an A55 to run %30 nitromethonal? Who has the ability to do it? email me please.
Re: tomos head decking
That may be for a flat style Head. But if the Head is the type that needs to be recessed like the Garelli then the lathe is the way to go again. Back int he 80's we were taught to do everything on Southbend Lathes. We even did our milling on them too! We were taught the Vertical Mill but the versatility of the Lathe is great. I am sure that now with the CNC set-ups the Mill can do the recess just fine. Hell I am even sure the mill could be programmed to cut the Squish with the use of a rotary table! But the lathe will still be my machine of choice.
Re: tomos head decking
I'm sure someone who is a good machinist could easily make them better or faster, i'm just a college student who has spent wayyy to much time trying to figure out how to do it quickly and accurately using the 1930's era lathes in the school machine shop. I think for most tuning applications, especially using domed pistons, the proper shape for reliable running cant be achieved without re-cutting the squish band area of the head. Stock doesn't matter because there is no sealing face coming into the bore area, but when there is, on a big-bore kit, you cant get as low without hitting the piston, and if you do, the edge will be a hot spot.
I really don't have any time to do it lately anyhow.
Re: tomos head decking
How much would you take off on an a35? like .030 inches?
Re: tomos head decking
thats mine a tomos a5, basically same as an a35
Re: tomos head decking
Damnit. 
Re: tomos head decking
Why isn't it working?
Re: tomos head decking
because you're doing it wrong. link the picture, not the page it's on.
i use a piece of flat marble and some heavy paper, get it to where i want it, then switch to fine paper, done.
on magnomos, i took the head down until it started to touch the piston, then put in a head gasket. works perfect!
Re: tomos head decking
I am linking the picture, it's the image's url from photobucket. I guess ill take .030 off, that should almost make it touch the piston.
Re: tomos head decking
One more try.
Re: tomos head decking
Start with less, you can't put it back on! Why use a gasket if you don't need too. Do 20 thou to start.
Re: tomos head decking
_Why use a gasket if you don't need too_ Why shave your head if your not going to seal your head properly? You will leak more compression by not running a gasket than you would gain by shaving your head. I do agree with starting with less and work your way up. You can use playdo or modeling clay to see what kind of gap is between the head and the piston. Using the clay as a guide to how much can be cut off will help. Just be sure to remove it before running your motor lol.
Re: tomos head decking
Tomos don't use gaskets. If you can't surface the head properly then by all means use a gasket. running it around on a spark plug or using "sandpaper" is really going to get the job done. lol Shadetree Machinists. more lol
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