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Discussion Starter #1
I realize valve relief info is top secret but I need some help

I have 89mm wiseco 13.7cr pistons - that I would like to have the tops & skirts coated. this obviously can't be done until after the valve reliefs are deepened.

but I cannot clay the motor to find out clearances unless the sleeves are bored. (currently a k24 with 88mm sleeves)

so is the best option to estimate the thickness of the coatings & assemble the bottom end with the uncoated pistons to check v-to-p clearances & then machine the pistons & then assemble the block hoping the bore is not too much?

OR would it be possible to send the pistons to Ron & have the reliefs machined? I doubt this is likely but though about throwing this out there

fyi - I would like to run IPS kxv

any advice about how to go about this would be great
 

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up for a good ? .... However good luck you may be on your own in finding your answer .. Either way I'd like to know also when u figure it out... Pm me with your findings
Thanks
 

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Pepsi Soprano
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I realize valve relief info is top secret but I need some help

I have 89mm wiseco 13.7cr pistons - that I would like to have the tops & skirts coated. this obviously can't be done until after the valve reliefs are deepened.

but I cannot clay the motor to find out clearances unless the sleeves are bored. (currently a k24 with 88mm sleeves)

so is the best option to estimate the thickness of the coatings & assemble the bottom end with the uncoated pistons to check v-to-p clearances & then machine the pistons & then assemble the block hoping the bore is not too much?

OR would it be possible to send the pistons to Ron & have the reliefs machined? I doubt this is likely but though about throwing this out there

fyi - I would like to run IPS kxv

any advice about how to go about this would be great
you can have them machined but only to the limit the forging allows which may not be enough for kxv them r some big sumamabiches.
i suggest getting in contact with ips and making sure you get the right stuff..
if it were me i would go a diffrent route.
i just finished a motor yesterday with skunk2 cams and bullcrap manifold that made 325 whp and 231 trq ... with skunk cams...
but if you want the best of the best contact ips..... not me
 

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Pepsi Soprano
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again it can be done with them wiseco pistons but why run everything so close and not @the best t can be for street car vtc can be a great thing and
the piston should complement the cam for p2v purposes at least which means everything .if you can figure out what im saying..
bottom line is you will not be using the kxv cam to its full potetial with them pistons and if you machine them it may not be enough..
 

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we did try wiseco 13.7 with IPS kxv just for reference. Your vtc will be very limited. Not worth it.

IPS would not modify these pistons, that would be like asking ERL to work on AEBS sleeves...not possible.

For reference kxv has around 0.5mm bigger lift than K10.

I understand that you want to run the biggest cam with the cheapest possible piston but you need to take other things in consideration.

When modifying parts to meet your own specs, the ball is on your court. Just make the reliefs deeper and account for the coatings.

coating both the top and the side might not the best way to go either... Maybe don;t coat at all.

Here;s where I coming from... You are using a piston that will weigh around 335 grams.. around there... Do you know that a stock accord piston weighs around 289 grams?

Why did you decide to use coatings? How do you think they are going to benefit your motor as far as reliability or performance? What rods are you using?

Is the head going to be ported? If so approx how many CFM?
 

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sorry to thread jack but i have 87.5mm wiseco 13.7 pistons that im going to run with kxv cams. im going to have the same problem? so i wasted my money on the pistons?
 

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Discussion Starter #7
nikos - if you want to knock me for using the "cheapest pistons" thats fine. I made it obvious I was not asking about using the pistons of the shelf - but one with deeper machined reliefs

for the record from the shelf they are 357.0, 357.3, 357.5 & 357.7g, heavier than you stated.

it seems that the answer is or maybe - the wiseco's cannot be machined enough for proper clearances to maximize or warrant using the kvx. if thats the answer, then that's what I was looking for.

BTW - these pistons will be used w/crower maxi-lite & I dont have any cfm info (yet) on the head. coatings are being used to try to limit significant wear & decrease chances of detonation.

anyways I appreciate all the input from which I am able to make an informed decision. I guess I will just try to get what I have (& have access to) to work :up:
 

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I am not knocking you for using cheaper pistons. I would love to run a budget k24a with KXV that makes crazy power and it is possible but I am just saying that these cams are big and need big valve relief.

Maybe the wisecos can be modified to work great with the KXV. I don't know the dimensions of a cut wiseco piston.

Again, I am not sure why you thought I was knocking you for the pistons. Wiseco and supertech are the cheapest aftermarket pistons. CP and JE are more expensive.
 

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I am not knocking you for using cheaper pistons. I would love to run a budget k24a with KXV that makes crazy power and it is possible but I am just saying that these cams are big and need big valve relief.

Maybe the wisecos can be modified to work great with the KXV. I don't know the dimensions of a cut wiseco piston.

Again, I am not sure why you thought I was knocking you for the pistons. Wiseco and supertech are the cheapest aftermarket pistons. CP and JE are more expensive.
when custom pistons are used for KXV's, whats the average limit on them, i know VTC will also depend on the supporting mods, but what do KXV's usually like?
 

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Discussion Starter #11
nikos - sorry I took offense

so the real answer is "maybe" they can be used... nobody knows

I guess I need to contact wiseco to see how much material is there & how much can be removed - & even if compression decreases, at least one of the heads I will try will bump it back up.

I understand the best answer (for now) is get pistons that are known to work... I guess I will keep my eye open for a set... or look for some k10's :dance:
 

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There's got to be somebody that has measured the depth of the VR's on a piston that is known to work with the cams you want to run... I would think that IPS would provide that info so that they could sell you a set of cams. Not sure how to get ahold of IPS, but there's got to be a way!
 

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There's got to be somebody that has measured the depth of the VR's on a piston that is known to work with the cams you want to run... I would think that IPS would provide that info so that they could sell you a set of cams. Not sure how to get ahold of IPS, but there's got to be a way!
the convenient way would be XXX Brand Name Cams having a VTC limit on all shelf pistons from the big manufacturers. Different compression and bores. But that would cost $$$ and time.
 

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IMAKEBOOSTATIDLE
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Again, I am not sure why you thought I was knocking you for the pistons. Wiseco and supertech are the cheapest aftermarket pistons. CP and JE are more expensive.


I thought JE and Wiseco were owned by the Same person....
 

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IMAKEBOOSTATIDLE
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Im just wondering how one could be more Expensive then the other if they come out of the same place
 

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I say you get the motor clearanced and then machine the pistons. I did the kxv+wiseco 13.7 thing. Motor did not make what I wanted it to, which is when Nikos came to the rescue with some IPS pistons :p
 

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If you know how many degrees each cam needs to be advanced or retarded by the variable cam timing, you could degree in the cams with the exhaust retarded to the max you would see, and the intake retarded to the max you would see. That would allow you to see what you need to do with the VR's in the pistons. It is possible that there isn't enough material in the crown of the piston for a deep enough relief, but that is relatively easy to check.

The smartest way I can think of at this point, is to bore and rough hone the block, leaving it about .001" undersize on the bore. Mock up the piston and rod combo, and degree in the cams as stated above. If the pistons and valves interfere when you are trying to degree them in, open the LC up in two degree increments untill it will rotate over. Pull the head and clay the pistons. Re-install the head and re-time the cams to the max settings that they will still clear the pistons, and check the thickness of clay. Now is also a good time to check the piston to deck clearance so it can be adjusted when the block goes back to the machineshop for final hone. It is also a good time to check and reset a TDC mark.

If you can't find out how deep the reliefs need to be, the above method will work. You will however need to know how much each 5 VCT units is equal to in crank degrees...
 
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