Can you guys help me figure out my Compression ratio

[Aspen79]

I have a stock stroke 360 with icon Pistons, 10-12 be low deck.
Pistons

 

[Aspen79]

I came up with 11.5;1

 

[Aspen79]

63 cc edelbrock 60779

 

[nm9stheham]

Using the Pat Kelley calculator with the following parameters:
4.03" bore (.030" oversize)
63 cc chambers
.011" below deck in LA block
.051" thick standard Felpro head gasket
4.17" head gasket bore size
5 cc eyebrows

Result is 10.15:1.

I suspect you are leaving out the head gasket.

 

[Aspen79]

Using the Pat Kelley calculator with the following parameters:
4.03" bore (.030" oversize)
63 cc chambers
.011" below deck in LA block
.051" thick standard Felpro head gasket
4.17" head gasket bore size
5 cc eyebrows

Result is 10.15:1.

I suspect you are leaving out the head gasket.

.040

 

[barnett468]

View attachment 1714948155

View attachment 1714948155
.040

i would run a .027" thick head gasket t reduce the quench/squish clearance

 

[70aarcuda]

with the piston down .011 I would also run the .027 gasket also...

 

[nm9stheham]

Run the thinner .027" gasket if you can tolerate the higher CR.
With .040" thick head gasket, the CR is 10.44
With .027" thick head gasket, the CR is 10.80

OP, you are only halfway there. Have you thought about your cam, its installed angle, and the resulting DCR (Dynamic compression ratio)? How are you going to use this engine?

 

[AJ/FormS]

With aluminum heads, you can get away with just about any cam, on that Scr..
I have run 11.1 with a 249*, and 10.7 with a 223*, and a 230*. All of these I ran on 87E10.I have recently discovered that these 360 Eddies might actually be 63cc chambers, and not 65 which is what i used for calcs.. I never measured mine. If that's true, then my actual current Scr is 10.9, and not 10.7 as previously believed.It also means I was running 11.4 with the 292.The Dcrs with all of these was 8.5 to 8.75, adjusted to 900ft elevation.

 

[Aspen79]

Very small cam for now.
The car is a weekend fun car street racing and 200 hp shot is the plan

 

[AJ/FormS]

That is not a very small cam
308/318/114/.488/510 lift
and 050 of 234/244

You are gonna need more compression
And more lotsa things.
I get a 82*ICA for a DCR of 7.2@ Scr of 10.7. Your target Dcr should be much closer to 9 or a bit better, to pick up the lower end.I ran 8.75Dcr on 87E10.
Unless you are racing, you will need to rethink that choice. That is a terrible street cam. This cam will be a ripper after 5000. But the getting there will need all kinds of help; from a big TC, and big gears; to, some special tuning skilz, and don't forget all the oiling mods to keep that beast alive at over 7000. If you short shift it, guys with smaller combos could/will be driving around you..With 3.55s and a 2.45 low ,5000 is 46 mph.I'd like to say the cam has lazy ramps, but that would be an understatement. If it sounds like I'm ragging on that cam, it's cuz I am. That is not for street. That cam is for idling around the parking lot and trying to scare guys with higher intensity cams. If that's what you are after, and you are a whiz at tuning, then this will be perfect; just know your limitations.....I ran a 292/508/108 @ 8.54Dcr, and that thing was very lazy with a stick and a starter gear of 9.44. That cam needed a starter gear of 12/1 or better, just to get out of it's own way, off-the-line.I cannot imagine it at 7.2. I got rid of it in a hurry.
With a 10.7Scr you need a high-intensity/ fast rate cam of about 268 advertised.This will pick up your Dcr to 8.7( on a 112LDA for the automatic).This might be a 223 to 226 cam, depending on who you buy it from.It will be 7 million times better a street cam. Well maybe not 7 million, but you get the Idea. Properly combo'ed that thing will be a beast to 65 mph and really strong to 85/95
I know what you're thinking ;223 is a wiener cam.
Well, I had a 223 cam, and I can assure you there was nothing wiener about it.That cam had the strongest bottom end of the three I have installed.It was also the most funnest
Whatever you decide, enjoy the ride!

 

[barnett468]

View attachment 1714948355
Very small cam for now.
The car is a weekend fun car street racing and 200 hp shot is the plan

ok, well thats a different story.

is your engine together?

if it is together, how do you like the way it runs now?

if you tune it properly for the nitrous, you are ok with that compression and that much quench/squish although i would still run less quench squish.

you can also buy a deto sensor called a safeguard that controls the timing and retards it if it senses deto.

J&S Electronics SafeGuard Indivdual Cylinder Knock Control

you "should" not quite be in the area where you need water or water meth injection.


r

 

[nm9stheham]

That is not a very small cam
308/318/114/.488/510 lift
and 050 of 234/244

You are gonna need more compression
And more lotsa things.

What I cannot say is how/what the 200 N20 charge will be doing to the engine's peak combustion pressures. It may be fairly well on target with that.

Without N20, the engine with that cam will have a DCR of around 7.2, even with the .027" thick head gaskets. With 5 degrees of cam advance, it is still in the 7.6 to 7.7 range. 7.2 is like a stock 318 DCR.....

That is a pretty lazy cam and it not meant for low RPM torque when normally aspirated. Better be ready to do some revving!

 

[Aspen79]

I basically have package five-B

 

[Aspen79]

ok, well thats a different story.

is your engine together?

if it is together, how do you like the way it runs now?

if you tune it properly for the nitrous, you are ok with that compression and that much quench/squish although i would still run less quench squish.

you can also buy a deto sensor called a safeguard that controls the timing and retards it if it senses deto.

J&S Electronics SafeGuard Indivdual Cylinder Knock Control

you "should" not quite be in the area where you need water or water meth injection.


r

It's all together it runs fairly well

 

[barnett468]

It's all together it runs fairly well

ok, then you seem to be set . tune the engine for nitrous then let er rip until she blows...or doesnt blow.

 

[Aspen79]

ok, then you seem to be set . tune the engine for nitrous then let er rip until she blows...or doesnt blow.

It should be a fun little street car about 550ish hp

 

[barnett468]

It should be a fun little street car about 550ish hp

sounds like it.

 

[Aspen79]

With aluminum heads, you can get away with just about any cam, on that Scr..
I have run 11.1 with a 249*, and 10.7 with a 223*, and a 230*. All of these I ran on 87E10.I have recently discovered that these 360 Eddies might actually be 63cc chambers, and not 65 which is what i used for calcs.. I never measured mine. If that's true, then my actual current Scr is 10.9, and not 10.7 as previously believed.It also means I was running 11.4 with the 292.The Dcrs with all of these was 8.5 to 8.75, adjusted to 900ft elevation.

What's normal operating temp?

 

[barnett468]

What's normal operating temp?

"normal" operating temp is never more than around 10 degrees over the t stat rating.

 

[Aspen79]

"normal" operating temp is never more than around 10 degrees over the t stat rating.

I don't have one in my car.

 

[barnett468]

I don't have one in my car.

then there will be no "normal" operating temp, however, you should run any street engine at 180 minimum.

 

[brasil]

found out ..that 195 °F is perfect My 340 runs much better with the 195 °f over the 180°f Thermostat, I had installed before...

Greetings Juergen

 

[Aspen79]

then there will be no "normal" operating temp, however, you should run any street engine at 180 minimum.

So is 200 too hot?

 

[barnett468]

So is 200 too hot?

not in my opinion as long as the engine is properly tuned for that temp and you use high quality oil.