KN_TL

iTrader: (3)

This thread should be closed. The information here is totally bogus.

I just took my time tonight and found that I am protruding .001" above the deck.

Have to believe that the information about the pin offset is valid and screws up the flipped side of the engine.

This project may officially die for the summer......

thisaznboi88

iTrader: (7)

wow.... Guess no K piston for use J guys..

UTAH TSX

The head gasket is .025, it should clear, or double up on the gaskets, or try to find a thicker hear gasket, .002 compression difference is nothing but I know you can't do it, this sucks so bad for you KN sorry man

KN_TL

iTrader: (3)

Yeah, thanks, I would never be comfortable driving it if it isn't done right.

I was ready to push the car to the side of the house and cover it up for the winter, but I've got a great wife who is encouraging me to continue. So I am going to see what Wiseco says and see if I can get some info from alternate sources.

yungone501

iTrader: (4)

Thicker Cometic head gasket?

gerzand

iTrader: (3)

Cometic didn't make a j32a3 style headgasket back in October of 2011:

Andy,



I would not be able to manufacture this gasket in MLS due to the one area (oil drain) that I have circled on the attached CAD picture. Adding the larger area from the new J35 would require an embossment which my current tool does not have. If there are any other questions, feel free to let me know.



Thanks




Chris Workman

Technical Sales

Cometic Gasket

8090 Auburn Road
Concord, OH 44077
Phone: 440-354-0777 Ext. 133
Fax: 440-354-0350

KN_TL

iTrader: (3)

I originally purchased these and the vendor made a mistake and only sent me one, so I sent it back.

I didn't have my engine apart yet to compare but I took a picture of it and Andy confirmed it wasn't going to work on a J32a3.

Aside from that, I don't want to half ass this by having the offsets on the wrong side. I said I was done but I have too much into this already and not doing it right would just be stupid.

KN_TL

iTrader: (3)

I mentioned this in another thread but I will update this as well.

The wristpin offset is as stated in a previous post as .060" to the exhaust side.

It was also suggested that I check the actual deck clearance for each cylinder and to rock them to get the worst case measurement.

Every single piston protruded ranging from .0101-.0065". Worse on the pistons with the offset on the correct side.

For N/A builds, these will probably work fine so my statement to close this thread was hasty. But for high hp builds, I am finding there's a lot to consider. It's been an expensive learning process but it's been worthwhile.

14j35y2

I'm still wondering... is TonyTigers 700+whp engine still running around with these backwards offsets? If it is, I'd like to think it doesn't affect things as much as wiseco and your measuring tools say, but I think like you do and I don't want something "not right" in a 500+whp build regardless if a reputable builder did it or not.

I'm still stuck with my shop not wanting to take back to k24 pistons and wiseco not wanting to take them back and give me even partial credit towards the custom ones. I might just buy the custom ones for full price ($202 each with upgraded wristpins) and try and sell the k24's privately, just not sure what 4 cylinder owner would want to buy 6 or 2 pistons

Definitely a learning experience.

KN_TL

iTrader: (3)

Also, is that motor still alive?

thisaznboi88

iTrader: (7)

Try to sell the 3 for the correct side on j32a or on here and let people know they will need to go custom for the other 3.

UTAH TSX

I think that motor went south and he is running a j32 now

flexer

Another guy was from Canada and knew the build and said it went south and they went to a J32. I would like to really know what went south on the motor, but unless we can get Tony the Tiger to come back we may never know. I will try reach out.

14j35y2

Well 700+ hp 12.5:1 compression daily driver... Unsleeved block... The possibilities are endless lol.

Euro-R_Spec_TSX

Just wanted to correct some of the misinformation in this thread.

I have more accurate piston weights for the OEM pistons. I recently purchased a more accurate scale and found that my previous corrected measurements were off. See post #24: https://acurazine.com/forums/perform.../#post15140039

Here are the accurate piston weights (in grams):

J32 RDA: 372
J35 RJA: 353
J35 RK1: 353
J35 R9P: 370
J37 RKG: 362

14j35y2

Just to add more data, the R72 from my J35Y2 (2014 Accord MT engine)

yungone501

iTrader: (4)

Anyone have any Wiseco K568m89's they would be willing to part with? Hoping someone that purchased these pistons to use in their j-series still has them so I can move forward with a much needed forged build to run higher boost levels. My stock J35Z3 bottom end is a ticking time bomb here at 12lbs.

If you do, please PM with details. Thanks!

KN_TL

iTrader: (3)

I brought them in the house from the garage just the other day.....PM sent

booostin21psi

Great information but one issue that I didn't see addressed on the k series aftermarket pistons is the stroke. Stock stroke is 93mm almost all aftermarket manufactures offer the pistons is 86mm or 99mm. That's def an issue.

screaminz28

iTrader: (1)

How is that an issue? Stroke is set by the crankshaft, not the pistons.

booostin21psi

Yes and no. Stroke is set by the crank shaft but if you notice on almost all aftermarket pistons spec sheets they have a number for stroke. In this case wiseco offers two number on that piston and the factory number is in between both of them. That number is the position of the wrist pin which will change the stroke and combustion chamber either raising or lowering the piston in the cylinder

screaminz28

iTrader: (1)

Not yes and no. The stroke will never be changed by the piston. That is impossible. What can change is the compression ratio, but if you are debating which piston to use based on what stroke, you also need to consider rod length.

But in every single scenario, the piston won't have any effect on stroke, at all. Ever.

If you're referring to a piston that could be used in a K20 or K24, then they are basically different pistons because there would be small differences in compression height, or pin placement.

yungone501

iTrader: (4)

Actually, both of you are technically correct. In the matter of the k-series piston for use in a j-series block, there are differences but no any that will affect its use in a build. I'm already in the midst of a build using the k-series Wisecos that I've posted at the start of this thread. Prior to moving forward, I have blueprinted the pistons by mocking them up and taking measurements. The piston is not an issue.

I will be using them in a build that consists of using a short stroke j25 crankshaft in a "big" bore 89mm cylinder making a 2.7 liter and uses a 8.0:1 CR.

UTAH TSX

THOSE PISTON DO NOT WORK PERIOD YEAH YOU CAN PUT THEM IN BUT THE OFFSET PIN AND VALVE RELIEFS ARE WRONG.
JUST ASK KNTL THIS IS WHAT HE FOUND AND THE JE PISTONS WE GOT WOULD NOT WORK ETHER PERIOD AGAIN PERIOD PEOPLE DON'T WASTE YOUR MONEY TRYING TO USE THESE PISTON THEY ARE WRONG PERIOD

I mentioned this in another thread but I will update this as well.

The wristpin offset is as stated in a previous post as .060" to the exhaust side.

It was also suggested that I check the actual deck clearance for each cylinder and to rock them to get the worst case measurement.

Every single piston protruded ranging from .0101-.0065". Worse on the pistons with the offset on the correct side.

thisaznboi88

iTrader: (7)

Is this why the rear cylinder bank were all jacked up?

KN_TL

iTrader: (3)

Utah's had 3 custom made to flip the offset if that's what you're referring to.

I'm not sure what Robert is up to. He appears to be using the pistons with the offsets reversed....unless he is going to get the valve relief milled or something.

BTW Robert, I assume the slugs arrived ok and met your approval.

thisaznboi88

iTrader: (7)

ooo nvm then. Anyone try the odyssey piston? They are lower comp and cheaper to get

UTAH TSX

I don't mean to offend you Robert I just don't want people to buy off the shelf pistons thinking they will work as is like we did it cost us some $$$ to buy 3 reversed pistons and we have a spare rear bank piston from the k24 set we bought we spent enough to have gotten fully custom pistons because of this thread

booostin21psi

Utah thanks for an intelligent answer. I saw this thread and as I started digging into the number it just didn't make sense. That's why i reached out here before digging into a pile of crap.

Oh and to the know it all above that responded to me. When you look at a piston spec and it gives you a stroke size, that number is changing the position of the pin height which changes the stroke.

screaminz28

iTrader: (1)

I'm sure that was directed at me. I wasn't trying to be a know it all - but make sure we all understand things properly. Please correct me if I'm wrong, as I don't claim to know it all.

If you were to change ONLY the piston pin height - would the stroke of the engine change? My understanding is that it would not, but the compression would.

If you were to change ONLY the stroke of the crankshaft - would the stroke change? Yes, because you changed exactly that - the stroke. Ideally, you would then need to run a shorter rod, or a piston with the pin moved to compensate for the additional stroke, or the piston would stick that much further out and potentially crash into the cylinder head.

When you order pistons and it gives you a stroke number, my understanding is because with the Civic, you have the 2.0 and 2.4 which have the same bore, but different stroke, so you have to move the pin to use the same rod length.

Hope that clarifies what I was referring to. Again, if that is not correct, and if simply changing the pin placement can change the stroke, please let me know, as I'd like to understand 'the how'. I can't just accept a "this does that'" and don't ask how or why.

booostin21psi

It was directed at you cause to context of the response came off condescending. My apologies. The only thing that changes compression is the piston deck and the cylinder head chamber. Nothing else. Stroke is controlled mainly by the crank but can be change by pin position and rod length. Stroke essentially is how much or how little the piston travels in the cylinder bore. So if you use a stoke rod but the piston position is changed in the piston it's going to change how much it travels in that cylinder bore. Compression is only happening at the top of the stroke at ignition. Make sense?

KN_TL

iTrader: (3)

My understanding is that the stroke is the distance that the piston travels which is determined by the rod length and crank offset from it's centerline.

The compression height is the measurement from the piston crown to the centerline of the wristpin.

A change the compression height WILL change the compression. If the compression height is shorter, then the crown at TDC will be lower and therefore lower the C/R.

I can't see how the piston can have any influence on stroke.

gerzand

iTrader: (3)

Actually, stroke does DIRECTLY impact compression. An engine with a longer stroke, given the same chamber CC's at TDC as an otherwise identical engine with a shorter stroke, will result in higher compression. Why? - Because the longer stroke is compressing a larger volume of air into the same space on the compression stroke. Though the difference between a 3.2L and a 3.5L may be small (perhaps one half of a compression point or less without doing any math for an 89mm bore jseries), its still a difference and does matter when building an engine.

screaminz28

iTrader: (1)

That's not what he said - he said that a PISTON alone will change the stroke, which to my knowledge, it will not.

Using the same piston with a longer stroke will increase compression, yes, I agree, because of the swept volume increase. That would be why piston makers sell different pistons with the same compression when using different stroke cranks, right?

Once again to clarify - to my knowledge, changing ONLY the PISTON PIN POSITION will NOT affect the STROKE of an engine.

gerzand

iTrader: (3)

correct

f1racrnz

Hi guys,

Long time lurker, first time poster. Apologies for digging this thread up from the dead as it were.

I know there's a whole load of info in this thread, but just wanted to get confirmation from those involved in the thread, or those in the know. Based on what's been said here, we can realistically use the JE K20 pistons as long as we flip the 3 pistons and just machine the valve reliefs right ? If we did that then we're pretty much golden ? I know that technically that would make the reliefs on one side slightly too large, but I doubt that'll make a massive difference in the grand scheme.

It's just that I have 4 x J32A2's that we're building for use, and we have access to a CNC machine so if I can use K20 pistons and save some cash and just machine the valve reliefs on 12 pistons then that'll be a great result.

I get why people here have said not to use them as for your average guy doing this stuff themselves without access to machine the pistons then it's a no go, but if that is all that's needed then I think for us, the money saved is worth it...…………

Have I got all my ducks in a row ?

Thanks in advance all.
Fraser

Euro-R_Spec_TSX

In my experience, being thrifty never results in a desirable outcome. I would use stock Honda pistons or have custom pistons made that are exactly what's needed.
If you don't like the price of custom JE pistons, then look into other manufacturers, such as Wiseco. Perhaps buying in quantity will reduce the price?

14j35y2

If you do decide you want to do it, I STILL have my set of 6 K568M89 pistons I bought 3 years ago if you want them cheapish.

f1racrnz

PM me the details and we'll talk turkey

f1racrnz

Also, sorry but I meant Wiseco, not JE...… was looking at Wiseco, it was just 3am here when I wrote that !