LS block with Endyn 11.3:1 Pistons.
B16A head, ported and polished.

I want to see 12:1 CR. What's the best way?
Mill the head? By how much?
1-layer, 2-layer headgasket? What kind? What's the thickness I should get?
What's the thickness on a stock LS OEM headgasket?

Thanks.

 

Head gasket, then mill.

Milling cannot be undone while you can always replace a head gasket.

 

1-layer head gasket, but I don't suggest milling the head for reliability issues, etc.

 

Thanks for the quick response. I know milling the head and thinner headgasket will increase my CR. However, I am looking for
specific response.
What's the thickness of the headgasket should I use?
Maybe tell me what the thickness of the OEM LS headgasket is so
I can have a clue of what thickness to get.
How much do I have to milled the head? .005"?
Thanks.

 

Why would milling the head create reliability issues?
Isn't using 1-layer pretty dangerous too considering OEM headgaskets are 3-layer?

 

http://www.c-speedracing.com/howto/c.../compcalc.html
That'll tell you the thickness of the gasket layers & allow you to calculate your compression with each thickness... provided that you know your piston dome displacement. Although, even if you don't know the piston dome displacement, you can use the calculator to get a good idea of where you'll be.

Hopefully someone else can help with how much to mill the head because I can't answer that one.


[Modified by 94gsr, 2:27 PM 9/10/2002]

 

you'll need to provide more specific details RE: your engine setup

How many CC's are your pistons. Larry should have specified that info to you.
Im assuming that you also have 81.5mm bore as larry's pistons are oversized.

I'll run some numbers for you but i'll need the following info:
Stroke
Bore Diameter
Head CC's per chamber - is it a stock head?
Deck Clearance - has the block been decked at all, is it stock deck height?
Piston Dome displacement - larry should have given you that info

Note, the stock head gasket can be dismantled to get 3 layers.
Use the bottom or top layers, DONT use the middle.
The thickness of either top or bottom layer is approx 0.254mm

Get me that info, and i'll do the numbers for you

 

Why cant you use the middle layer? I have heard its work GREAT.

 

The middle layer is the only one that is consistent in it's coolant hole sizes. I too would like to know why you recommend to not use it. Plus, the top & bottom layers have bigger coolant holes in different places.

 

Thanks for the reply and help.
Here's the info.

Stroke = ???
Bore Diameter = 81.5mm
Head CC's per chamber - is it a stock head? Head is stock but ported and polish.
I want to mill it to get high CR and hopefully make more power.
Deck Clearance - has the block been decked at all, is it stock deck height?
Stock deck height, just honed and balanced.
Piston Dome displacement = ??? Endyn did not tell me. I just told
Larry I want NA piston for LS/VTEC with B16A head. I requested 11.3:1
and 81.5mm bore. And That's all the info I got.

I know OEM has 3 layers. But
my concern is that OEM is made 3 layer, wouldn't I run into some reliability
issue If I take out a layer or two? Woulnd it be better to get a Spoon or Mugen
1 layer headgasket? Or should I just save myself some money and use OEM and take out 2 layers? I can use that money on milling my b16a head Thanks
for all the help.



[Modified by fwu, 7:21 AM 9/11/2002]

 

From the info you have provided me:
Stock B16 Head, Chamber CC = 42.7cc per chamber
B18 stroke = 89mm
Bore = 81.5mm
Standard Deck Clearance = .076mm
Standard Head Gasket thickness = 1mm

From my calculations, if larry provided you with pistons based on the above measurements, then your piston displacement should be approx 3.2cc's. This will give you a CR of 11.3:1 (exactly)

Based on this piston displacement, if you used a 1 layer OEM head gasket (.254mm) you would get a CR of 12.3:1

If i were you, i would take the necessary measures to guarantee that both the block surface, and head surface are square(no warpage). If this holds true, then a 1 layer OEM gasket will be reliable!

 

I'm sorry but what and how do I measure the block surface and head surface to
make sure they're square?

 

Well I used the middle layer of an OEM gasket. I have been using it for about 10k at least. I have had no problems. i used some copper gasket spray on both side to fill ni anything unknown. It works!!!

 

"Copper gasket spray"? What the hell is that?

 

I'm not a big fan of head milling, simply because it cannot be undone, and changes your timing. It by itself is not a cause of reduced reliability however, the problem comes when you use all these "tricks"(milling, thin gasket, flat faced valves) to increase compression and then choose some aggresive cams and cam gear settings. I'd rather just get higher compression pistons myself, though flat faced valves are essentially "free" compression...though very small... +.2ish.

 

You need a true straight round bar, lay it across the head (or block deck)corner to corner both ways, and basicly every possible way it will cover the surface and run a feeler gauge under it, if you find that the feeler gauge gets looser in certain areas it is probably warped. Make sure the surfaces are 100% clean and free of debris, dust , oil. I find that lint free baby wipes work well for cleaning and preping surfaces.