Engine Builders-KB356 Piston Milling

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I appreciate all the replies! Not the news I was wanting to hear but would rather know exactly what I am dealing with. Looks like a conservative tune, 160* thermostat, some 93 and some octane boost each fill up will be what my formula is. Will try and find a thicker head gasket but at the same time I am opening up my quench area in doing so. I think short of ordering a custom cometic, or opening up the chambers on my cylinder heads I dont have many options.


The 160 degree thermostat is a BIG deal. You don’t have near enough cylinder head to warrant a 114 LSA. I’d leave the compression where it and use a different cam. Don’t know what you have for gear or converter but both of those affect the CR you can use.
 
That’s what I have been getting too.

I am curious how my iron heads with pump gas will be with that ratio. Was hoping to keep it lower 9s but I think without having a custom cometic gasket that may be tough.
That's not right.
Back the train up duders...

I get 9.06 if you assume .040 down...and round the 23.5 dish volume to 25cc to account for the quench pad that is milled off.
Pardon me but I don't know where the **** anyone got 9cc for a dish volume from when the ******* pistons dish volume grew when the taller quench head with pad was milled down past the pad and into the quench head itself to make it flush with the dish.

That piston untouched was designed to yield about 9.7 compression max...bringing it to 10.1 takes 59-60cc heads and still has a quench head with pad milled to .040 for the gasket... so think about it folks...if you relieve a piston you lower the compression...you're in effect increasing dish volume!
Been here n done this.. twice now!
Have the piston in front of me now...
 
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The 160 degree thermostat is a BIG deal. You don’t have near enough cylinder head to warrant a 114 LSA. I’d leave the compression where it and use a different cam. Don’t know what you have for gear or converter but both of those affect the CR you can use.

He doesnt know his compression yet.
It's more like 9.1
Their math is inaccurate.
 
I appreciate all the replies! Not the news I was wanting to hear but would rather know exactly what I am dealing with. Looks like a conservative tune, 160* thermostat, some 93 and some octane boost each fill up will be what my formula is. Will try and find a thicker head gasket but at the same time I am opening up my quench area in doing so. I think short of ordering a custom cometic, or opening up the chambers on my cylinder heads I dont have many options.

Leave the thermostat alone. It should be a 180 or 195. A 160 will do nothing to make it run cooler.
 
scan0001-jpg.jpg


these numbers are spot on, if presented,a lil goofy.
At .040 in the hole the deck clearance plus the dish volume totals 8.36+9.0(measured)= 17.36cc for a total chamber volume, not including any crevice volume of;
17.36 + 8.8gasket + 62 head =88.16,
and Scr is
(836.1 +88.16)/88.16 =10.484

As for the Ica; I don't see any advertised numbers , but the numbers are close enough to be a 268/276/114
Which could be installed at 112, making the Ica, best guess, to be 66*... and so;
At 20ft elevation; Jacksonvill FL
Static compression ratio of 10.49:1.

Effective stroke is 3.09 inches.
Your dynamic cranking pressure is.................. 172.41 PSI.
Your dynamic compression ratio is................... 8.33:1 .
V/P (Volume to Pressure Index) is 163

Hope that helps
 
Right on the UEM site they list that piston UNMODIFIED having a static compression of 9.9 with a 62cc head. So how can the same piston be 10.4 with the step dome milled off? PLUS he's .040 in the hole. I'm leanin more toward what @MOPAROFFICIAL is saying here.
 
2c2a5597-d24e-48ca-a84e-a5e79613586a-jpeg.jpg

I assumed the piston top;
is flat above the dish, as can be seen in the measuring set-up pic and
none of the crown was removed,and
that the flat part is the reference surface, that yielded the .040 down number. and
a 4.030 bore x 4.00 stroke.

With a 23.5cc net dish factor and .040 down to the top of the piston proper, the total chamber volume would be 14.5cc more for a total of 102.66 and a Scr of;
(836.1 + 102.66)/102.66 =9.14
If you mill the Q-pad off and get 9cc, then the crown was milled a lot further than just enough to remove it..
And to get the piston back up to .040, the current decks must also have been cut.
With the Q-pad gone, and the dish known, I see no reason to do a .500 down measurement. I mean, at 4.03 bore we can easily do the math to find the cylinder volume as 8.36cc per .040 inch down. Add that to the measured dish and badaBoom!
I mean, with the Q-pad gone, it's just like every other build.
The .500 down is only necessary with an irregularly shaped crown, like one with a dome or q-pad..
 
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Leave the thermostat alone. It should be a 180 or 195. A 160 will do nothing to make it run cooler.


If the cooling system is correct, he can run a 160 and keep it there. He can run more compression, and make more power doing it. He just needs to make his cooling system right.

He will only know his compression ratio IF he does an actual .500 down fill. If he doesn’t, he is guessing.
 
View attachment 1715719177
I assumed the piston top;
is flat above the dish, as can be seen in the measuring set-up pic and
none of the crown was removed,and
that the flat part is the reference surface, that yielded the .040 down number. and
a 4.030 bore x 4.00 stroke.

With a 23.5cc net dish factor and .040 down to the top of the piston proper, the total chamber volume would be 14.5cc more for a total of 102.66 and a Scr of;
(836.1 + 102.66)/102.66 =9.14
If you mill the Q-pad off and get 9cc, then the crown was milled a lot further than just enough to remove it..
And to get the piston back up to .040, the current decks must also have been cut.
With the Q-pad gone, and the dish known, I see no reason to do a .500 down measurement. I mean, at 4.03 bore we can easily do the math to find the cylinder volume as 8.36cc per .040 inch down. Add that to the measured dish and badaBoom!
I mean, with the Q-pad gone, it's just like every other build.
The .500 down is only necessary with an irregularly shaped crown, like one with a dome or q-pad..


Now you see.
 
View attachment 1715719177
I assumed the piston top;
is flat above the dish, as can be seen in the measuring set-up pic and
none of the crown was removed,and
that the flat part is the reference surface, that yielded the .040 down number. and
a 4.030 bore x 4.00 stroke.

With a 23.5cc net dish factor and .040 down to the top of the piston proper, the total chamber volume would be 14.5cc more for a total of 102.66 and a Scr of;
(836.1 + 102.66)/102.66 =9.14
If you mill the Q-pad off and get 9cc, then the crown was milled a lot further than just enough to remove it..
And to get the piston back up to .040, the current decks must also have been cut.
With the Q-pad gone, and the dish known, I see no reason to do a .500 down measurement. I mean, at 4.03 bore we can easily do the math to find the cylinder volume as 8.36cc per .040 inch down. Add that to the measured dish and badaBoom!
I mean, with the Q-pad gone, it's just like every other build.
The .500 down is only necessary with an irregularly shaped crown, like one with a dome or q-pad..

This is blowing my mind trying to wrap my head around it. I am sure if it was explained to me in person I could better grasp it but it does stand to reason that if an unaltered piston with 62cc head would be 9.9:1, then removing any part of the piston would naturally lower the compression. I would better understand I suppose if I had an unaltered piston next to one of mine and could see the two.

Feeling like I should have enrolled in a automotive shop night class! :BangHead:

I just want to know what head gasket size to run to have a pump gas friendly motor.

FYI, I was told second hand that this was a 9.5:1 motor as built.
 
With a 72cc head and FelPro 1008 gasket it would be 9.5:1 compression. Measure compression height of the piston and compare to manufacture spec. of 1.465
 
The 4 inch stroke adds almost one point of compression over 3.58 stock stroke. Are you sure it's only 9cc valve pocket and dish volume
 
Yea I am sure, I have been thinking about this all wrong. Realizing today when I got home, I measured and am way down in the hole, much further than I anticipated. Essentially the 9cc I was able to fill is what's left of the original 23.5cc dish. So a considerable amount has been milled off and is now represented by empty cylinder volume with my piston to deck measurement. I am piddling on it some today and should have more accurate measurements when I get a depth micrometer this evening but I am thinking I will be around 9.2:1 with a .040 gasket, but my quench is going to be huge.
 
With the piston .040 (or more) in the hole, and a .040 gasket, you dont have any quench to speak of already.
As oldstyle has said, post #37, compare your compression height to the factory spec, to find out how much has been milled off.
 
Common sense tells me no way this is over 9.5:1 with a 62cc head

View attachment 1715719243

That's because your common sense has kicked in.

The unaltered piston has a compression spec of 9.9 at 62cc of chamber volume. Your pistons have had the step dome REMOVED, so you are a good bit lower than 9.9.

Put this stupidness to rest. CALL United Engine And Machine. Tell them what you have and they can probably tell you almost to the n'th degree what your compression is. My guess is it will be around 9:1, possibly under 9. CALL THEM!
 
Chamber volume can be measured. Head gasket thickness and diameter can be measured. Dish volume can be measured. Deck height can be measured. Bore can be measured. Stroke can be measured.
Until you have ACTUAL MEASUREMENTS, you're guessing.
 
Yea I am sure, I have been thinking about this all wrong. Realizing today when I got home, I measured and am way down in the hole, much further than I anticipated. Essentially the 9cc I was able to fill is what's left of the original 23.5cc dish. So a considerable amount has been milled off and is now represented by empty cylinder volume with my piston to deck measurement. I am piddling on it some today and should have more accurate measurements when I get a depth micrometer this evening but I am thinking I will be around 9.2:1 with a .040 gasket, but my quench is going to be huge.

There'll be zero need for quench. Call UEM. Let us know what they say.
 
Yea I am sure, I have been thinking about this all wrong. Realizing today when I got home, I measured and am way down in the hole, much further than I anticipated. Essentially the 9cc I was able to fill is what's left of the original 23.5cc dish. So a considerable amount has been milled off and is now represented by empty cylinder volume with my piston to deck measurement. I am piddling on it some today and should have more accurate measurements when I get a depth micrometer this evening but I am thinking I will be around 9.2:1 with a .040 gasket, but my quench is going to be huge.
You'll have no quench.

Tried telling you.
Love when people listen, as if I have the time to waste to give bad advice. Lol

Did anyone even go check out the two threads I mentioned I have plenty of info on these pistons.

There's another part number he could have got that would have been flush with the deck on the quench side instead of above and then milled too far.
 
You'll have no quench.

Tried telling you.
Love when people listen, as if I have the time to waste to give bad advice. Lol

Did anyone even go check out the two threads I mentioned I have plenty of info on these pistons.

There's another part number he could have got that would have been flush with the deck on the quench side instead of above and then milled too far.

I definitely appreciate you taking the time to respond and the knowledge you provide. Thats why I reach out because this is all new to me and I have read that "wise men seek wise counsel". I know when I am entering areas unfamiliar and I would rather learn the mistake now rather than be able to provide a catastrophic anecdotal failure.

The biggest problem was the information I gave at the beginning was not accurate or complete. Thats my fault and I understand that now more today that yesterday which is my main goal.......learning as much as possible. This lent itself to a lot of conflicting information being posted from members that were just going by what bad information I provided. Bad information renders bad advice.

This is the first motor I have assembled and I purchased it as a used assembled long block with very little knowledge on what components it was comprised of so a lot of investigative work has went into just trying to figure out what I have. Mistakes have been made and I am sure will continue as I learn.

I listen, but I equally listen to everyone and because you had correct information that I omitted and misrepresented you were ahead of everyone on this one for sure. I appreciate you taking the time to explain for hard learners like me.

And I think the piston you're referencing is the KB416. Its this same piston without the quench pad I think. I thought that's what these were at first til I cleaned them and was able to find a part number.

Thanks everyone for their input!
 
I definitely appreciate you taking the time to respond and the knowledge you provide. Thats why I reach out because this is all new to me and I have read that "wise men seek wise counsel". I know when I am entering areas unfamiliar and I would rather learn the mistake now rather than be able to provide a catastrophic anecdotal failure.

The biggest problem was the information I gave at the beginning was not accurate or complete. Thats my fault and I understand that now more today that yesterday which is my main goal.......learning as much as possible. This lent itself to a lot of conflicting information being posted from members that were just going by what bad information I provided. Bad information renders bad advice.

This is the first motor I have assembled and I purchased it as a used assembled long block with very little knowledge on what components it was comprised of so a lot of investigative work has went into just trying to figure out what I have. Mistakes have been made and I am sure will continue as I learn.

I listen, but I equally listen to everyone and because you had correct information that I omitted and misrepresented you were ahead of everyone on this one for sure. I appreciate you taking the time to explain for hard learners like me.

And I think the piston you're referencing is the KB416. Its this same piston without the quench pad I think. I thought that's what these were at first til I cleaned them and was able to find a part number.

Thanks everyone for their input!
Take it lightly. I'm just busting balls.
Yes... I know these pistons well and knew more than you thought you had figured...which is why i butt in so hard.
I don't fault you for anything, well... maybe for listening to all the other wrong stuff and going along with it at 1st. Lol.
For a min it was all paved in and tamped with some already onto debating how the compression will or wont work on pump gas.
Get the #416 pistons or just just run those and dont worry about the octane with them the way they are. Good luck and have fun.
 
Take it lightly. I'm just busting balls.
Yes... I know these pistons well and knew more than you thought you had figured...which is why i butt in so hard.
I don't fault you for anything, well... maybe for listening to all the other wrong stuff and going along with it at 1st. Lol.
For a min it was all paved in and tamped with some already onto debating how the compression will or wont work on pump gas.
Get the #416 pistons or just just run those and dont worry about the octane with them the way they are. Good luck and have fun.

I have a Kenne Bell and Powerdyne sitting on the shelf that was hoping the compression was going to be on the lower end.

Also, it was mentioned that a 114 LSA was too much for my cylinder head. What exactly does that mean? I went with that based on the fact I am retaining EFI and I had originally planned on putting 5-6lbs boost to it. Any information pertaining to that would be great!

Thanks!
 
I have a Kenne Bell and Powerdyne sitting on the shelf that was hoping the compression was going to be on the lower end.

Also, it was mentioned that a 114 LSA was too much for my cylinder head. What exactly does that mean? I went with that based on the fact I am retaining EFI and I had originally planned on putting 5-6lbs boost to it. Any information pertaining to that would be great!

Thanks!

Cc it in the cylinder, do the math, and let us know.
Its not over yet.
 
Cc it in the cylinder, do the math, and let us know.
Its not over yet.

I am (on average) .085 in the hole. Low .081 high .089 averages after checking 4 spots on each piston then averaging those.

Will CC the cylinder hopefully tomorrow. I suspect 62-63cc. Should put me 9.2-9.5 if so with dynamic compression of 7.7-7.9
 
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