Never mind

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Well, they are designed to fit a 318, and you have a 318 so....... BUT, like any non-stock performance part, it's up to the builder or machinist to check and verify all clearances. UEM also says they have a .200 solid dome, so it would be very easy to cut them if needed.
 
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No experiece with 318s or those pistons, just general engine building. I would probably cut that solid dome down some. Do you really want 10+ to 1 compression ratio?
Other than that, your 360 heads should clear that dome easily, even if you don't cut it down.
 
If the pistons are hypereutectic, you WILL need to increase the ring gap....
 
According to the manufacturer piston is .010" above a 9.578" deck.
According to your shop the measured deck height is 9.59
So initially you think it'll fit.... But... That is the flat area of the piston...
The quench dome is another .140 and is intended to be machined down for optimum quench clearance... To properly use those pistons requires the combustion chambers to be machined to equalize chamber depth... Then the domes are machined to equalize quench..

Just to add to this, open area of Mopar open chamber heads are usually around .100 deep...Normal head gaskets range from .021 to around .056, block deck heights can vary quite a bit... So KB provides a quench dome tall enough to handle all the variables...

If you have the skills to do the job properly you can achieve ideal quench... However when your done you'll still have hypereutectic pistons with all their issues... Honestly if your not gonna use the engine hard they are okay... But if your not gonna use the engine hard why chase ideal quench?
 
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Wiki says that Loveland is about 4800 ft elevation, that's gonna be a downer.
Doing the math;
If your 318 is an LA with a true deck height of 9.600, those piston-tops are still gonna be .012 in the holes.
This, at 020 over, is 2.4cc, add
the dome/ eyebrows, -6
the for the heads 72 and
for 039 FelPros 8.6
this totals 77cc, and so your 318 comes in at about
(658.9+77)/77=9.56 Scr. The quench is gonna be too tight

So the bad news is that even with the stock 318 cam (Ica of 48*) at 9.56 Scr, she's only predicted to put out ~150psi.
By the time you get to two sizes bigger, a 262/266/110 cam, (Ica of 60*) the pressure is down to ~134psi, so, at 4800ft, about as powerful as the stock 318 is, at sealevel, until the rpm gets up to around 3500. aaaand yur still buying a convertor and probably gears.

IMO with that 318, at 4800ft, to run a 262 cam, the Scr is gonna need to get up to around 10.7, and that would be a total chamber volume of 67.9. And that's gonna take closed chamber heads, and pistons with no quench pads!

So, IMO, yur stuck doing one of three things
1) with your plan, a really small cam, milled pistons, and a convertor, or
2) as above but in addition; slightly bigger cam and gears
3) buying closed chamber heads and other flat-top 318 pistons, and maybe a convertor
4) buying a 360 short with Q-pads to slide under your open chamber heads, and running whatever convertor and gears you already have.

As to #4; Hint:
KB makes some nice KB-191 series Quench-pad pistons to work with the open chambers, to make a longblock with enough Scr to run just about any street cam you could think of.

4800ft is a bit of a downer.
 
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AJ/FormS said:
Wiki says that Loveland is about 4800 ft elevation, that's gonna be a downer.
Doing the math;
If your 318 is an LA with a true deck height of 9.600, those piston-tops are still gonna be .012 in the holes.
This, at 020 over, is 2.4cc, add
the dome/ eyebrows, -6
the for the heads 72 and
for 039 FelPros 8.6
this totals 77cc, and so your 318 comes in at about
(658.9+77)/77=9.56 Scr. The quench is gonna be too tight

So the bad news is that even with the stock 318 cam (Ica of 48*) at 9.56 Scr, she's only predicted to put out ~150psi.
By the time you get to two sizes bigger, a 262/266/110 cam, (Ica of 60*) the pressure is down to ~134psi, so, at 4800ft, about as powerful as the stock 318 is, at sealevel, until the rpm gets up to around 3500. aaaand yur still buying a convertor and probably gears.

IMO with that 318, at 4800ft, to run a 262 cam, the Scr is gonna need to get up to around 10.7, and that would be a total chamber volume of 67.9. And that's gonna take closed chamber heads, and pistons with no quench pads!

So, IMO, yur stuck doing one of three things
1) with your plan, a really small cam, milled pistons, and a convertor, or
2) as above but in addition; slightly bigger cam and gears
3) buying closed chamber heads and other flat-top 318 pistons, and maybe a convertor
4) buying a 360 short with Q-pads to slide under your open chamber heads, and running whatever convertor and gears you already have.

As to #4; Hint:
KB makes some nice KB-191 series Quench-pad pistons to work with the open chambers, to make a longblock with enough Scr to run just about any street cam you could think of.

4800ft is a bit of a downer.
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@thecatsfan

KB-191 is a 3.58 crank stroke slug not usable with a 319 & a 3.31 stroke crank.

The OP should use the slugs he has and let the machinist do his work fitting them in the new bored out cylinders of equal height and use the appropriate gasket thickness to achieve what he needs as best as possible. The compression ratio should fall between (rough guess here) 9.3-1 to 9.5-1 with the big chambered 360 heads.

There should be (key word - should) zero clearance issues. The machinist should easily pick this up IF he has the cylinder heads on hand to test fit.

DCR can remain reasonable if the cam is t to large in duration.
A better bet on heads would be aluminum Edelbrocks. The 63cc chamber will be much better if the dome fits. Though that is not really an issue since he (the OP) is not machining anything. Let the machinist handle it.

If you want a larger cam that makes power higher in the rpm band, your going to need a converter to get past the low rpm area which is down on the power due to your reported elevation and low cylinder pressure. This is really not a big deal. Just a normal challenge of high altitude and small engine compression challenges.

The port and valve size is excellent for a well built 318 and can use a 110 LSA to its advantage with this size valve.
 
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or...... if the crank's not ground yet then consider a 4" stroker kit to put under the 360 heads. 390 cu in sounds better while you're doing it than 318 and it's all new too.
neil.
 
mygasser said:
or...... if the crank's not ground yet then consider a 4" stroker kit to put under the 360 heads. 390 cu in sounds better while you're doing it than 318 and it's all new too.
neil.
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Already have a machined crank and rods, as well as the heads. Had an entire rebuilt engine but the block was bad. Long story. Starting with a new block and this opportunity is sitting on the shelf at a reasonable price.
 
thecatsfan said:
Already have a machined crank and rods, as well as the heads. Had an entire rebuilt engine but the block was bad. Long story. Starting with a new block and this opportunity is sitting on the shelf at a reasonable price.
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If your machinist isn't capable/willing to do the needed calculations and mock up, then skip these pistons and get something else.
 
Every engine is different, no body can look in a crystal ball and predict what's gonna work in YOUR particular combo. Either pay to have it mocked up and verified, reuse what ever cheap rebuilder pistons you allready have, or buy some other flat top without a dome.
 
This whole thread is why there is a difference between an engine builder and an engine assembler. Do not take advice of someone on the internet telling you a piston will or will not fit your engine build. Take some measurements, do the math, if you’re lucky and have the parts available to you do the mock up, and then only then will you have the answer to the question “will these pistons work in my engine?”
 
Do not take advice of someone on the internet telling you a piston will or will not fit your engine build.
Click to expand...

If I’m getting the drift of what you’re saying……… it’s like you’re implying some stuff on the “internets” may not be true and reliable info?
 
thecatsfan said:
Nobody asked for predictions. I literally asked for the opposite - actual experience from people who have these pistons.

Nobody can predict anything for certain, and I am not asking anyone to. In fact, I would prefer people don't try. But hearing other people's experiences is still valuable in determining whether the mock up is a worthy investment, or if I am better off going with a piston with a high probability of a good fit.

I don't have usable pistons right now. I have a block, crank, rods, heads, lifters, intake, etc. If I even want to mock up these pistons, I have to pay to bore the engine to get them in the hole for mock up. I am simply at a decision point - and actual experience of others could be helpful in deciding which way to go.
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I understand your dilemma, but unfortunately there is just no easy yes/no answer to your question. Your EASY way out is just buy a cheap set of stock replacement pistons.
 
PRH said:
If I’m getting the drift of what you’re saying……… it’s like you’re implying some stuff on the “internets” may not be true and reliable info?
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Everything on “the internets” is true.
 
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thecatsfan said:
I have not once asked anyone for advice on running these pistons. I am asking if anyone has run them and how it went. It is a simple question out of curiosity. And I absolutely am not looking for anyone here to tell me they will work. If the piston manufacturer cannot even answer that question, trust me, I know nobody here can. But knowing what other people encountered with the same parts would still be good information as I wait for the block to get bored.

I have taken measurements. I have done the math. We will mock it up if the .020 bore works with this block.
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So you've called United Engine and Machine. Did you talk to Marco? He's the one you want to talk to.
 
thecatsfan said:
I have taken measurements. I have done the math. We will mock it up if the .020 bore works with this block.
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That ^^^^ is great news. It’s the only way to know for sure. And when someone comes in here in a year and asks the same question you did, you’ll tell them exactly what all of us have told you. Mock it up and measure, then modify to fit. There are a lot of competent guys here, some have commented on this thread and given you good responses, and those responses were predicated by all the junk we’ve screwed together that didn’t work like the manufacturer said, or the book said, or someone else said, would work.
 
thecatsfan said:
No, if someone comes in here and asks, "has anyone used KB399 pistons", my answer would be yes. If someone asks, have you used some other piston, I would not answer at all.
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You need to understand that guys who do this for a living don’t necessarily need to use something to know something about it.

Just because you are getting responses you don’t like doesn’t mean they are wrong.

There is lots of junk **** I won’t use or have never used. And I can speak with absolute certainty about them.
 
thecatsfan said:
With all due respect, I don't need to be told what to understand. I understand perfectly that I asked a specific question and people who had no answer to the actual question chose to offer unsolicited advice I already know. I am not saying they are not intelligent and experienced in the subject at hand. I am saying everyone chose to tell me a bunch of information I never asked for.

If I could delete this thread I would. It has been a massive waste of time.
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i just checked and you've been a member here since 2019. i'd have thought you'd be nicely 'thick skinned' by now, lol. it's needed sometimes :lol:
neil.
 
thecatsfan said:
With all due respect, I don't need to be told what to understand. I understand perfectly that I asked a specific question and people who had no answer to the actual question chose to offer unsolicited advice I already know. I am not saying they are not intelligent and experienced in the subject at hand. I am saying everyone chose to tell me a bunch of information I never asked for.

If I could delete this thread I would. It has been a massive waste of time.
Click to expand...


Well then I guess I will say too bad for you.

This is a public forum and you asked a public question.

Speaking for myself now, I don’t care if you don’t like my unsolicited opinions. I don’t care what you think at all.

Some very experienced people gave you good information and you **** all over it.

That’s a YOU problem.

So the next time you ask a question and you put it in a tiny box that you think will only get responses YOU want and then get pissy like you are now I will tell you the same thing.

Put on your big boy pants and don’t act like you know everything.
 
thecatsfan said:
No, if someone comes in here and asks, "has anyone used KB399 pistons", my answer would be yes. If someone asks, have you used some other piston, I would not answer at all.
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Tried being nice, now I’m done. Piss off.
 
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