Speedmaster spark plug holes improvement??

Did I help them ?

  • for sure it helped !!

    Votes: 6 21.4%

  • not sure, but didn't hurt....

    Votes: 18 64.3%

  • no, you wasted your time....

    Votes: 4 14.3%
  • Total voters
    28
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TrailBeast said:
Hey, at least you got rid of a bunch of detonation causing hot edges.
That said, I'd be a little pissed off about my plugs being shrouded that deep.
But then again, if you end up loosing a race to Jason you have an excuse.:D
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LOL... agree with everything except...… I'm racing who??? LOL
 
Smokey Yunick was keen on indexing all the plugs for optimum spark saturation.
 
TrailBeast said:
Hey, at least you got rid of a bunch of detonation causing hot edges.
That said, I'd be a little pissed off about my plugs being shrouded that deep.
But then again, if you end up loosing a race to Jason you have an excuse.:D
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Get those 3: 55 gears in there and you can be in the race to! Is it still hard! LOL..
Wait a minute I don't want to know!...
 
It would be a shame to bolt them on and not take the time to clean up the plug threads and end up with a hot spot that causes pre ignition.
 
MoparMike1974 said:
It would be better to machine the plug seat so the plug sits down further.
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I mentioned that earlier in another thread. I think I'll ask Radar how necessary it is and how big of a pain and $$$'s it would take to do. A Bridgeport and a the correct end mill or carbide insert tool would be the ticket.
 
toolmanmike said:
I mentioned that earlier in another thread. I think I'll ask Radar how necessary it is and how big of a pain and $$$'s it would take to do. A Bridgeport and a the correct end mill or carbide insert tool would be the ticket.
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Keep in mind, PHR got 589 hp out of them with nothing done with the plug hole..
 
There’s always better everything. Where does it end? Me? I’m talking about a guy in his shop doing **** himself, as much as he can. Hit em with a sanding roll and on to the next thing.
 
318willrun said:
Keep in mind, PHR got 589 hp out of them with nothing done with the plug hole..
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And what if someone actually took the time for a back to back comparison and saw a (name a minuscule number) increase. Then would you incorporate it in a chamber cleanup for instance? I do it anyway!
 
12many said:
There’s always better everything. Where does it end? Me? Hit em with a sanding roll and on to the next thing.
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Couldn't agree more... and I like agreeing with a guru :) If I'm going to pay a machinist to machine on the plug area, port them, 5 angle valve job..... I'll just take my money and buy ProMaxx Shockers or TF. The catch 22 is the price... I gave 703 fully loaded to my door (I said for J par... LOL).
 
318willrun said:
Couldn't agree more... and I like agreeing with a guru :) If I'm going to pay a machinist to machine on the plug area, port them, 5 angle valve job..... I'll just take my money and buy ProMaxx Shockers or TF. The catch 22 is the price... I gave 703 fully loaded to my door (I said for J par... LOL).
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When I was on the tool truck for 28 years I always kept my eyes open for a valve/seat grinder. Never found one that anyone wanted to part with. I can see a good assortment of grind stones to get the job done. Way back when, a 3 angle was hot stuff. I've done quite a few.
 
318willrun said:
Couldn't agree more... and I like agreeing with a guru :) If I'm going to pay a machinist to machine on the plug area, port them, 5 angle valve job..... I'll just take my money and buy ProMaxx Shockers or TF. The catch 22 is the price... I gave 703 fully loaded to my door (I said for J par... LOL).
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With my quickly changing plans for those heads I went from bolt em on as is on that pickup, to really going all out on them as much as I could, aside from a valve job, for my van to realizing all the work I’d be doing at this time, to ultimately going with the TF’s. There were a few areas I saw that were huh?moments. The plug holes especially and I just wanted to point that out to others more as a “take a look and think about it if you haven’t” especially after seeing how the TF’s address that area. I didn't care for the unfinished look, that there are a gazillion Edelbrocks and SM’s out there the same don’t make it acceptable to me. No sir, I don’t like it.
 
12many said:
With my quickly changing plans for those heads I went from bolt em on as is on that pickup, to really going all out on them as much as I could, aside from a valve job, for my van to realizing all the work I’d be doing at this time, to ultimately going with the TF’s. There were a few areas I saw that were huh?moments. The plug holes especially and I just wanted to point that out to others more as a “take a look and think about it if you haven’t” especially after seeing how the TF’s address that area. I didn't care for the unfinished look, that there are a gazillion Edelbrocks and SM’s out there the same don’t make it accepts to me. No sir, I don’t like it.
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well, you put me to work today... LOL.
 
How much would you need to sink the plug to make it come out the amount you want? Two or three threads at the most? Very doable in aluminum with piloted hand tools. Do it all the time for correcting the muzzle crown on rifle barrels. Not like the engine would explode if the plug was tilted half of an RCH. Just need a pilot that threads in the plug hole and a cutter that fit the pilot. Drive it by hand or with a drill motor or drill press. A milling machine would be better still. Not much different than the tooling used to cut valve seats. The end result doesn't need to be as precisely aligned though. I'll see if I can find an extra plug and see what my ProMaxx look like. Probably the same. I think that removing the excess threads in the chamber and smoothing everything out will only help things, or do no harm other than the volume added to the chambers. Unshroud the valves while you are at it.
 
gzig5 said:
How much would you need to sink the plug to make it come out the amount you want? Two or three threads at the most? Very doable in aluminum with piloted hand tools. Do it all the time for correcting the muzzle crown on rifle barrels. Not like the engine would explode if the plug was tilted half of an RCH. Just need a pilot that threads in the plug hole and a cutter that fit the pilot. Drive it by hand or with a drill motor or drill press. A milling machine would be better still. Not much different than the tooling used to cut valve seats. The end result doesn't need to be as precisely aligned though. I'll see if I can find an extra plug and see what my ProMaxx look like. Probably the same. I think that removing the excess threads in the chamber and smoothing everything out will only help things, or do no harm other than the volume added to the chambers. Unshroud the valves while you are at it.
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Good idea! Finding the end mill or the carbide tooling would be the trick.
 
toolmanmike said:
Good idea! Finding the end mill or the carbide tooling would be the trick.
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It exists already, most likely. I've got a bunch of replaceable pilot counter bores that would get it done, though a multi-flute dedicated cutter would be best. Might want to cut a smaller diameter first and then finish at full diameter. If you are clever, an adjustable stop could be incorporated to get them to same depth on all holes. A custom tool would be a couple hundred bucks professionally done. I could do a one off in my basement. Because it is cutting aluminum, the tool doen't need to be extremely hard to work. I've made a couple dozen custom taps and dies over the years for unusual threads. In aluminum for a couple holes I don't even harden them anymore. O-1 or W-1 tool steel will outlast the aluminum and is easy to hone.
 
A long 14-1.25 MM bolt with the head removed may make a good pilot. Or run a 14-1.25 die down on some 1018 steel round stock. You could use DOM over that with a homemade broach cutter fitted to the end and internally thread the other end for a fine thread bolt and a jam nut and so you could set the length. A drill (or preferably a drill press) with a hex to 1/2 drive adapter and socket to fit the bolt head would work nicely to run it. Like you had said, O-1 tool steel would only need minimal hardening (it would continually work harden with the heat involved in cutting aluminum) and would outlast most of us.
 
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Garrett Ellison said:
Not up to "guru" status yet except for maybe a few in my small circle, but I'll comment nonetheless. I would like to see the plug deeper into the chamber myself, but I definitely don't like seeing sharp thin threads waiting to break off. I would be looking for longer reach plugs or look into getting the plug seat cut deeper (probably both!), and maybe some chamber cuts around the valves... Thank again you for sharing, these are the types of posts that make this thread!
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Agree here ^^^ , getting rid of sharp edges should b SOP tho-
 
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