head buttons

[Chris Wood]

I would like to hear from specially marty and andy on this.. since andy touched on it on the other thread.

what is more important.. squish angle or bowl shape and size.

we have TONS of heads we made with different angles and bowl size and shape.. bowl & hemi ... taper squish and flat.

is there a general rule of thumb or is it all over the place.

chris

 

[ek kustomz]

Man, this is really getting good!!! I think these should be archived!!!

 

[Marty Davis]

I would like to hear from specially marty and andy on this.. since andy touched on it on the other thread.
what is more important.. squish angle or bowl shape and size.

we have TONS of heads we made with different angles and bowl size and shape.. bowl & hemi ... taper squish and flat.

is there a general rule of thumb or is it all over the place.

chris

Chris:

I doubt that anyone has specific test data to provide you. Maybe someone has....

I am about to have test data. I designed 6 heads in AutoCAD that have EXACTLY the same volume and each is different in configuration. I had them produced on a CNC machine so that they are super accurate. I have some with flat squish bands, some with angled squish bands, some with 60%, 70%, etc of the total area in squish band. One head was designed by Brian Callahan using some high end simulation software, so it will probably be best - who knows though. I have noticed that the newest .21 CMB's have a very small squish band area and I believe that may be one reason that they don't run as well as some with wider squish bands.

All will fit my test engine. Just as soon as we get finished with some projects, I will be testing them on the Dyno to see which is best, worst, etc. I believe that the best configuration SHOULD transfer to all sized engines (I might be wrong, but I believe that the configuration should transfer to other engines).

As for design, I have built HUNDREDS of buttons of almost any shape that you can imagine. Some ran well, some terrible. The tests were probably skewed because volume was so difficult to maintain and the comparisons were not really "apples to apples". I was able to find some that I could duplicate that ran well, but I have no real idea why. This should help quantify some things.

FINALLY, we have the basis to run a test that should have validity. I am very anxious to see the outcome.

I would bet that Jack O'Donnell, Rod Geraghty, John Ackerman and Andy have built as many or more head buttons than I have and will have a lot to say about this topic.

There was someone on the Forum that indicated that he has a source to produce head buttons. Maybe he will use some of the finding....

Once I find out the results, I might incorporate the findings into the new EAP Revision in some way.

Marty Davis

 

[moparbarn]

that someone was jerry wyss. had a person that was going to be making head buttons. all my experience is with .21 k&b ob's. head buttons make a big difference. of the 4 i have tried, the stock thick button (large 'double bubble' shaped chamber, angled squish band) is slowest. stock thin button (much smaller, shallower single bubble chamber, very slight angled squish band) is good, one that was cut out of a air cooled gold ss, to work with a water jacket (turbo cuts, almost flat squish band, chamber very similar to thin button) is better/faster. one more, a stock thin one (custom turbo cuts, and thinned to give more adjustability in squish clearance) is fastest, but hardest to get set up right, i.e.-mixture, prop, boat set up.the one cut out of a air cooled gold head is the best compromise between speeed and ease of set up, imo. seems to be smoother on the power, doesn't explode when it stages, nice and progressive. very easy to drive. couldn't really say why, kida a 'shade tree' kinda guy. as long as it works, i'm happy.that, and i ENJOY going to the pond with a few head buttons, pipes and props for the day. burning nitro and having fun trying to learn . don't get much better, imo. all of these things we are discussing are good, but each one (head button, ex. timing, intake timing, prop and HULL SET UP) have to work together, or it's a waste of potentially good parts. if 1 single thing doesn't work well, it doesn't mean that it's not a good idea, might just need other things to work WITH it. not the parts, but the sum of the parts.

 

[Jerry Wyss]

That would be Jim Walker @ "King Headz", I contacted him about making "low volume head buttons" and

he thought that meant "just make a few". He was willing to do even That, before I told him it was the

volume of the "head bubble" in "cc's", (low volume)

He instructed me to send him the button/plug I was using that worked well. I had tested and raced another

manufacturer's stock button with slight lathe adjustments to make it fit into the engines sleeve I am using.

I wanted to have this same bubble configuration that could be used in a long stroke and SS engines I am

running.

The issue of Marty's cad drawings were addressed to Jim as to wether he needed them or not. His reply

was he would rather have the original button, measure it with his devices, get it on the screen and adjust

it from there and make it the volume and shape you want. I would imagine that Martys CAD drawings

would help in the adjustments,, sure would save on phone calls, but I haven't talked to Jim since I got

back from Hawaii.

FYI, he said that he was willing to invest some time in making what we need "if it could be beneficial to

his buisiness down the road". This is why I was wanting to workout the XM aircooled buttonhead, there's

allot of XM's out there,, also alot of CMB's, the CMB's alone could net him some real profit.

I just wanted to have some buttons (like above) on hand to help out some TT users and mine as well.

Jim's involved with a car/buggy parts project probabaly still, so we have time to gather our eggs together,,

most of mine are already gathered. Jim also said that he could pop out a few for testing and get back to

him with any needed changes,, I don't know how you can beat that arrangement.

Jerry

 

[Marty Davis]

that someone was jerry wyss. had a person that was going to be making head buttons. all my experience is with .21 k&b ob's. head buttons make a big difference. of the 4 i have tried, the stock thick button (large 'double bubble' shaped chamber, angled squish band) is slowest. stock thin button (much smaller, shallower single bubble chamber, very slight angled squish band) is good, one that was cut out of a air cooled gold ss, to work with a water jacket (turbo cuts, almost flat squish band, chamber very similar to thin button) is better/faster. one more, a stock thin one (custom turbo cuts, and thinned to give more adjustability in squish clearance) is fastest, but hardest to get set up right, i.e.-mixture, prop, boat set up.the one cut out of a air cooled gold head is the best compromise between speeed and ease of set up, imo. seems to be smoother on the power, doesn't explode when it stages, nice and progressive. very easy to drive. couldn't really say why, kida a 'shade tree' kinda guy. as long as it works, i'm happy.that, and i ENJOY going to the pond with a few head buttons, pipes and props for the day. burning nitro and having fun trying to learn . don't get much better, imo. all of these things we are discussing are good, but each one (head button, ex. timing, intake timing, prop and HULL SET UP) have to work together, or it's a waste of potentially good parts. if 1 single thing doesn't work well, it doesn't mean that it's not a good idea, might just need other things to work WITH it. not the parts, but the sum of the parts.

What are the specs of the buttons that you are describing. Difficult to do much unless you tell us the volume, the squish band width, the squish angle.

Marty Davis

 

[moparbarn]

marty, to be perfectly honest, i haven't measured any of them. 3 of the buttons are stock k&b 3.5 ob (poss. ib also?) head buttons. the "thin" button is stock for a 12 mm (8906) k&b ob.don't have the part # handy, listed as head for short plug in parts. the "thick" one is on a lot of 13 mm's. listed as head for standard plug. the last is a gold "ss" air cooled head with the fins machined off, and the outer surface milled to accept the stock water jacket. the bowl/chamber, squish, and turbo cuts are as it came stock. all of these measurements should be readily available-all these heads have been around for ages. the one head that james at O.E.R. cut for me, was just turbo cuts, and machining to the sleeve contact area, to give more squish clearance adjustment. no mods to the squish band or bubble, just jame's 'flow cuts'. they did increase the volume, but i haven't checked it. he started with a stock "thin" k&b head. k&b stuff is fairly cheap, and i'm addicted as badly as anyone here . i tend to test and tune and modify on a comparative basis. i grew up when you adjusted a carb on a car with your eyes closed and one hand one the motor. since all i do is .21 tunnel with k&b's, it's easy to have 20 blocks, some already modded. a gallon baggie full of pistons & sleeves, some modded. and 11 pipes, and 12 boats. you try stuff, see what others have done, find combos that work, and then compare to stock and try to duplicate/improve. but pretty much "seat of the pants".i have bought a etrex gps. i am an auto tech (ase cert. master for 22 years). and i can use degree wheels and dial indicaters, i choose not to. this is fun to me, my relaxation. i love to go to the pond for the day, and burn lots of nitro. take a box of parts, and have a fun relaxing day. these motors can be pretty much rebuilt, short of bearings in 45 min. my son and i can go run 3 or 4 boats with 3 or 4 different motors on them in a day. and have a ball doing it. if i were to keep notes and measure every little thing, it wouldn't be fun anymore. that's what i have to do at work. document everything for the warranty dept. every car i fix has to have a fair amount of paperwork and computer time online to get info. sorry, i ain't going home to do more :lol: . i'm old school in a lot of ways, but my '73 dodge charger does have fuel injection and 6 speed auto (gear vendors). i want to learn and understand why what we all do works and doesn't work, and add input when i can. but what i add is going to be fairly subjective. and besides, k&b's are outdated junk, sell them all to me :lol: :lol: . sorry, i kinda got lost there. all of this, and the timing threads have helped my understand a lot. thanx to everyone who has shared their knowledge with us. i'll probably nevers set a saw record, hell, may not ever win a dist. or club race, but i bet i'll have just as much fun as anybody else! that and this community of boaters is why i'm her-and to try to learn a little in my old age. please continue, pardon my getting way off topic.

 

[L Akre]

Hello Chris

Have you experimented with Plug height as well?

Getting this dimension spot on for the fuel and plug you're using can give some pretty large increases in power, especially if it was far off to begin with. Many manufactureers err on the side of caution and leave this dimension excessive. This dimension also varies depending on the size of the engine.

Myself, I never use more than 3 degrees taper on the squish band.

Regards, Les

I would like to hear from specially marty and andy on this.. since andy touched on it on the other thread.
what is more important.. squish angle or bowl shape and size.

we have TONS of heads we made with different angles and bowl size and shape.. bowl & hemi ... taper squish and flat.

is there a general rule of thumb or is it all over the place.

chris

 

[Jerry Wyss]

Good question Les concerning "plug depth" from the "squishband face". I have gotten some my

hand made buttons with the plug pretty deep while going for .17cc (.21 O/B) volume and trying

to get to the 50/50 ratio between the squishband and bubble opening.

Plug face was in the .165" depth area and was a real bear to get the engine to take off from

its 4 laps in the mill. Since then I have found better results between .118 to .136" with a lesser

radical ratio than the 50/50 stated above. Also have found that my engines like a little more

radius or shoulder (as I call it) in the "roof" of the bubble next to the outside of the plug.

A great way to clean-up the area next to the plug is make it for the "turbo" plugs,, have to be

seriousley precise when doing this by hand but would be a snap for CNC equipment,,, another

consideration.

I was just getting into with the angled squish this last year,, mostly with the Mac O/B. The angled

squish had a desirable effect with the Mac but theres no real concensus on that yet.

My mod TT engines have no problem with the flat squish,, probably due to they're "not so snug"

P/S fit. I know the TT BX-R buggy engine had a much better fit than the TT21PRO-R engine and

the sleeve design of that engine should be they're standard,, it's great!

Jerry

 

[FlyinFinn]

That would be Jim Walker @ "King Headz", I contacted him about making "low volume head buttons" andhe thought that meant "just make a few". He was willing to do even That, before I told him it was the

volume of the "head bubble" in "cc's", (low volume).....

FYI, he said that he was willing to invest some time in making what we need "if it could be beneficial to

his buisiness down the road". This is why I was wanting to workout the XM aircooled buttonhead, there's

allot of XM's out there,, also alot of CMB's, the CMB's alone could net him some real profit.

I just wanted to have some buttons (like above) on hand to help out some TT users and mine as well.

Jim's involved with a car/buggy parts project probabaly still, so we have time to gather our eggs together,,

most of mine are already gathered. Jim also said that he could pop out a few for testing and get back to

him with any needed changes,, I don't know how you can beat that arrangement.

Jerry

Jerry,

I'd be interested in testing head buttons with you for both the XM and the CMB 21's, since I am running both engines, XM on a TSII and the CMB on the L Y N X. I have my MAC carb from the CMB out to Geraghty for "re-working". I am very interested in what could be done with the XM, since it is such a solid and reliable running engine, IMO. Anyway I could "shoe-horn" my way in on this one? Jeff.

 

[Jerry Wyss]

Finn, it's in the works, I'll get sumthin to test here soon, hang on.

JW

 

[jydracing]

Hi All. Marty the heads that Robin was talking about on the k&b 3.5 older engine is a single bubble head with a .30cc volume I personally found that this head works even better with a flat squash band. Now that is for a K&B 3.5. On my nova rossi 3.5 mod engine the numbers are diffrent. Single bubble with a .19 cc volume remove the cooling. Now here is what is funny on the os stock I have made a lot of heads cooling and non cooling and the factory head works the best. .30cc and half of the squash band with a 3 deg taper.

Now on the larger engines I use almost the same numbers on all of them .30cc bubble, flat squash band that is 65% of bore except for the nelson the factory head is perfect for the engine. Now before the popshots start there are a few things to consider here. First what works for me might not work for you. It all depends on hull setup, engine timing, prop, and pipe and even driving style. I have foung out over the years a good place to start with a head is with a .30cc bubble a flat squash band that is 65% of the bore. These numbers set at .010 head clearance will usealy have a compression ratio of 10 to 1 to 11 to 1. This seams to work on most engines except for a few.

Also when making the combustion chamber to get the cc's you need to know the cc's of the glow plugs that you are using and if the top of the piston is dished. Also i never let the glowplug hang into the combustion chamber I set it up to be flush with the top of the chamber. There is something else that works for me I polish the head button to a high gloss and take the sharp corner to a small radious while ploishing the head.

Well thats all for now see ya later Jimmy

 

[Marty Davis]

Hi All. Marty the heads that Robin was talking about on the k&b 3.5 older engine is a single bubble head with a .30cc volume I personally found that this head works even better with a flat squash band. Now that is for a K&B 3.5. On my nova rossi 3.5 mod engine the numbers are diffrent. Single bubble with a .19 cc volume remove the cooling. Now here is what is funny on the os stock I have made a lot of heads cooling and non cooling and the factory head works the best. .30cc and half of the squash band with a 3 deg taper.
Now on the larger engines I use almost the same numbers on all of them .30cc bubble, flat squash band that is 65% of bore except for the nelson the factory head is perfect for the engine. Now before the popshots start there are a few things to consider here. First what works for me might not work for you. It all depends on hull setup, engine timing, prop, and pipe and even driving style. I have foung out over the years a good place to start with a head is with a .30cc bubble a flat squash band that is 65% of the bore. These numbers set at .010 head clearance will usealy have a compression ratio of 10 to 1 to 11 to 1. This seams to work on most engines except for a few.

Also when making the combustion chamber to get the cc's you need to know the cc's of the glow plugs that you are using and if the top of the piston is dished. Also i never let the glowplug hang into the combustion chamber I set it up to be flush with the top of the chamber. There is something else that works for me I polish the head button to a high gloss and take the sharp corner to a small radious while ploishing the head.

Well thats all for now see ya later Jimmy

Jimmy:

Something must be wrong with the cc measurement. I don't have any .21 heads with over .20cc.

How are you measuring the volume of the head?

Marty Davis

 

[topfuel443]

Yeah, the head that Robin has and likes that I cut (if memory serves me right) has a volume of .19cc. No way any of the K&B 3.5 heads are .30cc.

I have always had great success with a .18-.19cc and 0 (flat) - 3 degree taper on 33% of the squish. K&B's in the past have like the flat squish, OS, Rossi and NR have been good with a 2 or 3 degree taper. Burn pattern seems to be the biggest advantage of the taper to me, much more centralized and tight. Just my observances.

~James

 

[jydracing]

My Mistake i looked at tne wrong line on the computer. .19 is what i have see ya jimmy

 

[Chris Wood]

i used to us a flat squish band.. had TONS of detitnation.. i have since switched to a tapered with better results.. what i cannot figure out is some mfg switch back and forth between bowl shapes... and at what point is the squishband essentially none effective.

chris

 

[Marty Davis]

i used to us a flat squish band.. had TONS of detitnation.. i have since switched to a tapered with better results.. what i cannot figure out is some mfg switch back and forth between bowl shapes... and at what point is the squishband essentially none effective.
chris

Chris:

I don't understand what you are asking : "and at what point is the squishband essentially none effective."

Are you talking about the angle, the width, ????

What kind of angle are you using on the squish band? Has that eliminated the detonation for you?

Why do you think there was so much detonation on the flat squish band? Could it be that the squish band is REALLY working and making power? If the angled squish band is not detonating, is it not making as much power?

Marty Davis

 

[Chris Wood]

i used to us a flat squish band.. had TONS of detitnation.. i have since switched to a tapered with better results.. what i cannot figure out is some mfg switch back and forth between bowl shapes... and at what point is the squishband essentially none effective.
chris

Chris:

I don't understand what you are asking : "and at what point is the squishband essentially none effective."

Are you talking about the angle, the width, ????

What kind of angle are you using on the squish band? Has that eliminated the detonation for you?

Why do you think there was so much detonation on the flat squish band? Could it be that the squish band is REALLY working and making power? If the angled squish band is not detonating, is it not making as much power?

Marty Davis

hey marty,

what i meant by that is that the squish area is most effective in the center.. on the outter edge it isn't..

lets say you have a deck height of .007

so you have effective .007 at the closest part to the center of the bowl.. the further out you go.. your clearence changes due to angled squish.. so you may have .009 or .010 on the outter edge. that fuel out on the edge of the head cannot burn as well as it would closer to the plug. ( does that make sence? )

as for the angle.. my motors work better with it than with out.. used to use flat.. and honestly angle pulls the same props as before with more rpm and MUCH MUCH MUCH better throttle.

i would never use flat again.. that is just personal preference.

chris

p.s. this could be a very very good topic

 

[topfuel443]

Chris, am I reading you post right? It seems like you are saying on the outer edge of an angled squish the clearance would be larger?

If you are running....say.... a 3 degree taper on 1/2 of the squish band, then that would mean the outer edge (closest to the cylinder wall) would have tighter clearance, and the closer it got to the center of the bowl, the looser the clearance would become. If you had a head clearance of .007", that number would be in reference to the outer portion of the squish, in this case the flat portion. The angled portion of the squish would increase in clearance, at a linear rate, depeneding on how close toward the center of the head that you measure.

Basically, I view the angle as a way of packing the fuel charge a little more smoothly into the bowl.

If I am reading what you wrote in the wrong way, its because I just woke up, and its too early for me to decipher... LOL

~James

 

[Chris Wood]

hey james no i just messed up when i was trying to type this.. i have a hard time explaining things on the puter lol..

chris