I have a set of JE pistons and the box says that the Dome height is 0.05. I'm using the C-speedracing compression calculator to determine my compression. So my question is what's the dome height? Is it the same as the "piston to deck height? Also the box says that the compression distance is 1.181, where do I punch these numbers into the C-speedracing calculator? Piston displacement is -1.7 cc.

http://www.c-speedracing.com/howto/c...c/compcalc.php

Please help my out. It's a B20 block with B16 head and 85mm pistons. Can someone help me figure this out? Thanks.




[Modified by GapxGuy, 4:41 PM 12/21/2002]

 

no piston to deck height is the distance from inside the cylinder at top dead center, to the top of the block. usually in most hondas the deck height is 0.00 - 0.02 or close to it.. therefore the motors are designated "zero clearance" motors. otherwords, if you snap a timing belt, your probably gonna bend a few valves.

dome height is more for use on compression values, and such. if there is a high dome height, make sure the piston has the notches for the valves to go into.


[Modified by 2k1_itr_0736, 1:53 AM 12/22/2002]

 

So on the bottom of the page for C-Speedracing, I just use the stock number for B18/B20 piston to deck height? Or does that varible depend on the spec. of the piston?

I was trying to follow this chart.




[Modified by GapxGuy, 7:43 PM 12/21/2002]

 

Do you have a chart for bseries motors? JE calculated their compression on motors strangely. they use a "0.00" piston to deck height.
but what i don't understand is..Does piston to deck height change with certain pistons. or will it always be a specific P to D height?
if you have that other chart post it please.
thanks

 

Well, I'm now complete confused about "piston-to-deck-height" refers to. At first I thought it was depending on the block you use. Then I thought it was determine by what piston you use. So now I have no idea what to do lol. But I really need to figure out this varible to have a proper setup.

All I could find was this...
http://tech.hybridgarage.com/tech/bseries.html


[Modified by GapxGuy, 12:20 AM 12/22/2002]

 

ttt

 

go to the c-speed forums, then go to b-series questions.. i posted a question "je compresssion quetion..or something" check it out, explains a little more.

 

Hold up...I thought I got this figured out, but now this. I've heard JE pistons use 0.0 piston to deck height a couple of times. I see you're somewhat in the same delima, if you figure this out let me know.

For others that may have the same question, here's the link to C-Speed forum...

http://www.c-speedracing.com/ubbthre...b=5&o=0&fpart=

 

So the guys at the C-Speed forum are saying to set the "piston to deck height" at zero (0.0)? I'll be much happier if this is true, but I need to know for sure.

 

yep, i sure am in the same dilemma. Piston to deck height IS the distance from the top of the piston to the top of the block. The top of the piston is not the top of the dome but from the flat top part of the piston like .......^....... this. understand, cool. Now the question is...Are JE pistons measured at stock piston to deck height or at ZERO..(0.000) I know that stock pistons have a Piston to deck height of 0.030 but JE's pistons might rise higher up in the cylinder so it would be measured at 0.000 or less if the top of the piston passes the deck of the block thus making your PTDH a negative number (meaning higher compression ). JE's are not stock pistons with higher domes. they are totally redesigned race pistons. This is my understanding and my theory anyway.
The c-speed forum didn't give us an absolute for sure answer eithier huh. we will figure it out don't worry. Importbuilders recomended these pistons to me so...i'm hoping i get the compression i want.
laters

 

I totally agree with you. Let's hope JE pistons measure at 0.000 PTDH, but if it's not that's okay too. I just wanna know for sure what compression I'm getting from these pistons and same for you. Feel free to PM me if you find out what settings JE pistons should be set at.

Here are my pistons...






[Modified by GapxGuy, 12:25 AM 12/23/2002]

 

anymore info guys. anything else would be greatly appreciated

 

I found out some a H-T member (Sonny) that the piston to deck height is 0.30. I also asked my mechanic, which also have JE B20 Pistons in his motor, that the piston to deck height is NOT flushed with the deck, the piston rest a bit lower than the deck. So in that case, for the C-Speed calculator, just use the B18/B20 PTDH. And in my case, I have a total of 10.5:1 CR...which will be 11:1 CR after I surface the head. Hope this helps, goodluck.

 

so is it squared away? Sorry to bring it up from the dead.

wiseco said that the h22's piston to deck is .015