Head gasket questions!

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doogievlg

doogievlg

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I'm getting ready to put my motor back together and I'm sort of lost on what type and thickness of head gasket to get. I have edelbrock heads and sealed pro flat tops. I'm looking to get between 10:1 to 10.5:1. Is this going to require going with a pretty small gasket?
 
I would mock up the engine with an old gasket and some clay to check the piston to valve clearance that way if the clearance is not right you can get a little more clearance with a thicker gasket. From what I can remember most stock head gasket thickness somewhere around 39-42 thousands thick when compressed. The compression or cylinder pressure is all ready set by the compression height of the pistons and the cc's of the cylinder heads a thicker or thin gasket is not going to raise or lower the compression any great amount. I hope this helps.
 
What bore, stroke, piston number, deck height and combustion chamber cc's. If this is a 360, .040" difference in gasket thickness will change the compression 1 point.
 
doogievlg said:
I'm getting ready to put my motor back together and I'm sort of lost on what type and thickness of head gasket to get. I have edelbrock heads and sealed pro flat tops. I'm looking to get between 10:1 to 10.5:1. Is this going to require going with a pretty small gasket?
Click to expand...


Have you measured the volume of any of your parts?

Heads? volume above the piston at TDC.

You don't even say what size engine you have...


If you tell me what your volumes are, then give me the diameter and thickness of the gaskets that you plan on using, and engine size, I can calculate your compression and tell you which gasket to use.


Without that information, you are on your own.... "Guesstimates" are meaningless...



They once had a sign in a parts store that I used to go to. It said:

Wrong information will get you the wrong parts everytime...


Very true.
 
IQ52 said:
If this is a 360, .040" difference in gasket thickness will change the compression 1 point.
Click to expand...


I would challenge you on that point.

I did a compression calculation for another thread earlier this week for a 318 comparing a .026" gasket to a .040 gasket and came up with approx. .22 compression difference. A 360 would be a little bit different, but still close... Read post #4 & #5 for details.

http://www.forabodiesonly.com/mopar/showthread.php?t=268956

But you are correct about asking for the other information.
 
The motor is a 360 bored .30 over. Eddie heads with 63 cc combustion chambers, stock stroke.
 
It's the mp cam with .484 lift. The heads or block hasn't been milled at all. Haven't figured out how far in the hole to set the pistons yet.
 
For 10.0 compression, you will need a clearance volume of 83.1 cc.

Subtract your head chamber volume: 83.1 cc - 63 cc = 20.1 cc

You will need to have 20.1 cc volume with your gasket and above the piston.



For 10.5 compression, you will need a clearance volume of 78.8 cc.

Subtract your head chamber volume: 78.8 cc - 63 cc = 15.8 cc

You will need to have 15.8 cc volume with your gasket and above the piston.


So you will need your piston deck and gasket to equal 15.8 cc to 20.1 cc to get your compression where you want it between 10.0 and 10.5.
 
krazykuda said:
For 10.0 compression, you will need a clearance volume of 83.1 cc.

Subtract your head chamber volume: 83.1 cc - 63 cc = 20.1 cc

You will need to have 20.1 cc volume with your gasket and above the piston.



For 10.5 compression, you will need a clearance volume of 78.8 cc.

Subtract your head chamber volume: 78.8 cc - 63 cc = 15.8 cc

You will need to have 15.8 cc volume with your gasket and above the piston.


So you will need your piston deck and gasket to equal 15.8 cc to 20.1 cc to get your compression where you want it between 10.0 and 10.5.
Click to expand...

I don't understand a word you just said…….. :banghead:

[ame="http://www.youtube.com/watch?v=LMbXpBA45qU"]Napoleon Dynamite - YouTube[/ame]
 
I got the answer I was looking for and the link to the calculator for future reference. Thank you for the help.
 
Mad Dart said:
I don't understand a word you just said…….. :banghead:

Napoleon Dynamite - YouTube
Click to expand...


Let me put it this way:

For 10.0 compression, you will need a clearance volume of 83.1 cc.

You will need 83.1 cc of volume at TDC.


For 10.5 compression, you will need a clearance volume of 78.8 cc.

You will need 78.8 cc volume at TDC


Then subtract the volume of the head to figure how big your gasket volume and piston volume need to be.


But go ahead and use the calculator. Sorry to have confused you....
 
You give an answer but your not explaining how you got there.
Sorry.. I know others are confused as well because your speaking a different
language than most speak.

So your measurement is taken where? As if the head has no chamber?

If you can, please show your math and give the correct gasket that is required to be within the
op's specs.
 
Once you figure out your thickness needed Buy a set of the Cometic MLS (multi layer steel) head gaskets and spray both sides with cooper coating,let them tack up before installing. This will help prevent water seepage when running alum heads.
 
With the aluminum heads - you need to use a gasket that has the pre-flattened fire ring... If the .039" gasket is too thin, you might consider enlarging the chambers slightly to get the compression you want. These calculations should have been done prior to you having the block and/or heads machined.
 
Mad Dart said:
You give an answer but your not explaining how you got there.
Sorry.. I know others are confused as well because your speaking a different
language than most speak.

So your measurement is taken where? As if the head has no chamber?

If you can, please show your math and give the correct gasket that is required to be within the
op's specs.
Click to expand...

Ok, just remember... YOU ASKED FOR IT!

This assumes that you have a good understanding of high school geometry and algebra. People that are not strong in geometry and algebra may have difficulty following, but I will try to explain as best I can for all to understand.


Area = (Pi) x (r)**2

Voluime = Area x depth


Volume = (pi) x (R )**2 x depth

Volume = (Pi/4) x (D)**2 x depth

Volume = (.7854) x (D)**2 x depth --> This is the basic formula for finding the volume of a cylinder shaped object.


* note: you have to keep your units consistent. If one measurement is in inches, you have to keep the rest of them in inches. You cannot mix your calculations with both cubic inches and cubic centimeters - it won't make any sense and you will get errors. For cylinders, start out in inches, and then convert to centimeters. One inch = 2.54 centmeters, or to put in in math form;

1 in = 2.54 cm


To find the displacement of the engine for one cylinder:

Bore = 4.030 in
Stroke = 3.58 in

Formula:

V1 = (.7854) x (4.030 in)**2 x [3.58 in] = (.7854) x (16.241 in**2) x [3.58 in] = (12.756 in**2) x [3.58 in] = (45.665 in**3) or 45.665 cubic inches

Now let's check to see if it matches a 360. Take the volume of one cylinder and multiply by 8 cylinders:

(45.665 in**3) x 8 = 365.3 in**3 or 365.3 cubic inches


This sounds right for a .030 over 360. So our calculation checks out.



Now you have the volume of one cylinder in cubic inches, we need to convert it into cubic centimeters as heads are measured in cubic centimeters. You have to pay attention to your UNITS Cubic inches vs Cubic Centimeters.

Now convert cubic inches to cubic centimeters:

V1 = (45.665 in**3) x [(2.54 cm/in) x (2.54 cm/in) x (2.54 cm/in)] = (45.665 in**3) x [(16.387 {cm**3/in**3})] = 748.313 cm**3 or 748.313 cc's


So the volume of the cylinder in cubic centimeters (cc's) is: 748.313 cc

* keep in mind that this is the volume that the piston displaces during one stroke. It is equal to the "swept volume". From now on, I will refer to this as "swept volume" or sv for short.

*************************

Here are smme numbers someone in another thread gave for a Fel_pro permatorque head gasket:

For a Fel Pro permatorque head gasket:

Bore = 4.060 in
Thk = .040 in

Formula:

Volume = (Pi/4) x (D)**2 x depth

V2 = (.7854) x (4.060 in)**2 x [.040 in] = (.7854) x (16.484 in**2) x [.040 in] = (12.946 in**2) x [.040 in] = (.5178 in**3) or .518 cubic inches


Now convert cubic inches to cubic centimeters:

V2 = (.5178 in**3) x [(2.54 cm/in) x (2.54 cm/in) x (2.54 cm/in)] = (.5178 in**3) x [(16.387 {cm**3/in**3})] = 8.49 cm**3 or 8.49 cc's

So the volume of a Fel pro permatorque head gasket is = 8.49 cc's


Note: For volume of the head gasket, you use the diameter of the fire ring to calculate the volume, not the diameter of the cylinder bore. The diameter of the cylinder bore is only used to calculate the "swept volume" (volume that the piston displaces - Bore squared x stroke).


ARE YOU STILL WITH ME??? DO I HEAR A "YES"???

to be continued: [/SIZE]
 
ARE YOU STILL WITH ME??? DO I HEAR A "YES"???


Now the 'fun' part. Calculating the compression ratio:


Compression is the volume above the cylinder at BDC divided by the volume of the cylinder at TDC.

The volume above the piston at TDC is also known as "clearance volume" or I'll call it "cv" for short.

I find it easiest to break the clearance volume into 3 parts:

1. Volume of the combustion chambers in the head (measured in cc's - cubic centimters)

2. Volume of the head gasket.

3. Volume of the piston above or below the head deck surface of the block.

I do this because it is easier for us to measure on an engine in "the real world", meaning that it is something that we are capable of measuring fairly easily.


What I do is make a "cover plate' out of 1/4" plexi glass that is available at any hardware store. Cut a square piece of 1/4" plexi glass so it will cover one cylinder completely including the bolt hole pattern around the cylinder. This way, it can be used on any cylinder in the block or head. I then lay out & drill the head bolt pattern into the plexi glass, so I can use 1/2" bolts to secure it while I'm measuring. Then test fit the plexi glass on the cylinder with bolts through it to put it in place.

Then mark a spot on the top of the cylinder and drill a hole (just big enough to fit the end of a very small funnel in it) at the very top of where the cylinder edge is on the plexi glass. This hole is used to fill the part with water and measure the volume.

Then you get "slave" bolts in 1/2 coarse thread to use to bolt the cover plate to the block, and also get the bolts, nuts, and washers so you can tighten the plate to your head.

Now your plate is ready for measurement. You will also need a graduated beaker/cylinder that is marked in cc's. You should be able to find this at a school supply store that sells science equipment and a very small funnel to fill the parts through the hole that I described above.

Now for the block cylinder measurment, you put the piston at TDC. For simplicity, let's assume that your piston does not stick above the head deck. Now smear a some axle grease around the edge of the piston and cylinder bore to fill the gap above the rings to keep your water from leaking out through the piston ring gaps while you measure it. Then smear a small coat of grease around the cylinder to seal the plate to the top of the block and just snug the slave bolts so it is nice and tight. Take care to wipe off any excess grease around the bore gap and not let too much squish into the cylinder when you snug the bolts.

Now let's fill the graduated cylinder with water to a convenient level to make the calculations easy. Start at 100 cc or 200cc, then pour the water into the cylinder until it is just to the bottom of the fill hole in the cover plate without spilling any. When the cylinder is full, look at the level in the graduated cylinder and record that. Then subtract the beginning volume in the graduated cylinder from the ending volume after the engine cylinder is filled to the top. This is your volume above the piston to the head surface taking into account any cut outs for valve releifs or domes. Keep this handy.

A piston that sticks above the head deck is a little more complicated to measure this way, but can be done. I'm not going to get into that now for sake of trying to keep things simple and understandable.

Now do the same for the head. Put a spark plug in the hole and use the slave bolts. washers. and nuts to secure the plate to the head after putting some grease on the surfact to help the cover plate seal and not leak while you are measuring. Tilt the head slightly so the fill hole is at the very top, and then fill with water as above. Again fill the graduated beaker to say 100cc and then without spilling, fill the combustion chamber with water. Then record the amount of water left in the graduated cylinder when the combustion chamber is full. then subtrace the end reading from the beginning. Example. A typical 340/360 head is 72cc. If you fill the graduated cylinder with 100cc's of water, then you should have 28cc's of water left in the graduated cylinder when you have filled the combustion chamber of the head.

Then all you have left to measure for the clearance volume is the head gasket. the head gasket would be difficult to measure like we just did on the block and head, so I just measure a used gasket just like it (this way you have the proper "crushed thickness" for the gasket. Remember to use the diameter of the fire ring in the gasket for this measurement, not the bore of the cylinder of the block.


Are you still with me again? Now for the compression calculations...


Compression is the volume above the piston at BDC divided by the volume above the piston at TDC.


The volume above the piston at TDC is also known as "clearance volume" or I'll call it "cv" for short.

I find it easiest to break the clearance volume into 3 parts:

1. Volume of the combustion chambers in the head (measured in cc's - cubic centimters)

2. Volume of the head gasket.

3. Volume of the piston above or below the head deck surface of the block.

I do this because it is easier for us to measure on an engine in "the real world", meaning that it is something that we are capable of measuring fairly easily.



Ok, lets get our terminology straight:

Compression is the volume above the piston at BDC divided by the volume above the piston at TDC.

the volume above the piston at TDC is called the "clearance volume" or "cv" for short. I broke it down in the three points above.

clearance volume (cv) is the volume of the combustion chamber + the volume of the head gasket + the volume of above the piston below the head deck below TDC.

So to put it into a math equation:

cv = head cc's + gasket volume (in cc's) + volume above the piston (in cc's)

Now the volume at BDC:

The volume above the piston at BDC is simply the volume displaced by the piston (bore & stroke) + clearance volume (cv).


We calculated the swept volume (displacement of one cylinder) in the post above.

SV = [(Pi/4) x (bore)**2] x (stroke)

SV = .7854 x {(bore)**2] x (stroke)

to avoid going through this again, from the above post we found:

So the volume of the cylinder in cubic centimeters (cc's) is: 748.313 cc


Ok now to put compression into an equation:


compression = Volume at BDC / volume at TDC

the volume at TDC is the swept volume as described above with the volume of the head, head gasket, and above the piston.

Assume the piston is below the deck to make the calculations easier.

so now:

Compression = [(swept volume) + (clearance volume)]/(clearance volume)

OR:

Comp = (sv + cv) / (cv)

Or to write it another way using the distributive property:

Comp = (sv/cv + cv/cv)

Which if you reduce becomes:

Comp = (sv/cv) + (cv)/(cv)


To end up with this equation for compression:

Comp = (sv/cv) + 1


Or to rearrange to find clearance volume (cv):

Comp = (sv/cv) + 1


Comp - 1 = sv/cv


Now solve for cv:

cv (comp - 1) = sv

or:

cv = [(sv) / (comp -1)]


this is the equation to back track to find your clearance volume if you know swept volume and target compression:

cv = [(sv) / (comp -1)]


Now we have

sv = 748.313 cc

Now he wants to be between 10.0 and 10.5 compression.

for 10.0 compression:

cv = [(sv) / (comp -1)]

cv =[(748.313cc)/(10.0 - 1)] = [(748.313cc)/(9.0)] = 83.1 cc's


For 10.5 compression:

cv = [(sv) / (comp -1)]

cv =[(748.313cc)/(10.5 - 1)] = [(748.313cc)/(9.5)] = 78.8 cc's


So for 10.0 to 10.5 compression, you will need a clearance volume of 83.1 cc's to 78.8 cc's.


Now clearance volume is just:

Head volume + gasket volume + volume above piston


He stated earlier that he was going to use a head with 63 cc combustion chamber.


Then using the .040" fel pro head gasket from above:

gasket volume = GV = 8.49 cc's


Now you can calculate how much area above the piston you need to run with a permatorque head gasket and eddy 63 cc heads:

for 10.0 compression:

83.1 cc - 63 cc - 8.49 cc = 11.61 cc or 11.6 cc's


for 10.5 compression:

78.8 cc - 63 cc - 8.49 cc = 7.28 cc or 7.3 cc


In my first post, we didn't use an example for a gasket, so I gave the clearance volume for the gasket and piston needed together.

For this case with the fel pro permatorque gasket he will need a volume of 11.6 to 7.3 cc above the piston.

Now if you take that volume needed above the piston and divide by the area of the bore, you can find out how much your piston should be below the head surface. Now let's assume that it is a flat top piston without any valve reliefs cut into it:

The area of the bore for a .030" over 360 will be:


Area = [(pi/4) x (bore)**2] = .7854 x (4.03 in)**2 = .7854 x 16.24 = 12.76 in**2 or 12.76 square inches

Convert to cc's:

(12.76 in**2) x [(16.387 {cm**3/in**3})] = 12.76 x 16.387 = 209.06 cm**2 or 209.1 cm squared

for 10.0 compression, you need 11.6 cc's above the piston which can also be said you need 11.6 cc's below the head deck and above the piston

Now take the 11.6 cc's volume divided by the 209.1 cm squared:

(11.6 cm**3/209.1 cm**2) = .0554 cm

Now convert to inches:

.0554 cm (1 in/2.54 cm) = .0554/2.54 = .0218 in

For a flat top piston to get 10.0 compression, you will need the piston .0218 in below the head deck or 22 thousandth of an inch below the head deck. that is the number that you give your piston manufacturer for your pistons.


Now for 10.5 compression:

for 10.5 compression, you need 7.3 cc's above the piston which can also be said you need 7.3 cc's below the head deck and above the piston

Now take the 7.3 cc's volume divided by the 209.1 cm squared:

(7.3 cm**3/209.1 cm**2) = .0349 cm

Now convert to inches:

.0349 cm (1 in/2.54 cm) = .0349/2.54 = .0137 in

For a flat top piston to get 10.5 compression, you will need the piston .0137 in below the head deck or 13.7 thousandth of an inch below the head deck. that is the number that you give your piston manufacturer for your pistons.


However you may want to tell the piston manufacturer what cc's you need above the piston and let him make the piston with that volume including valve reliefs. This will be more meaningful to them than just telling how much below the head deck to make a flat top piston. I did the calculations to show how much the piston should be below the deck for illustration purposes.


Dis you make it here? This is the end....

I tried to make it as simple as I could.
 
krazykuda said:
I would challenge you on that point.

I did a compression calculation for another thread earlier this week for a 318 comparing a .026" gasket to a .040 gasket and came up with approx. .22 compression difference. A 360 would be a little bit different, but still close... Read post #4 & #5 for details.

http://www.forabodiesonly.com/mopar/showthread.php?t=268956

But you are correct about asking for the other information.
Click to expand...

Challenge accepted!

Please, if you would be so kind, calculate the compression ratio difference using this information.

gasket thicknesses of .040" and .080"
63cc head volume
5cc piston volume
4.100" gasket bore
4.030" cylinder bore
.015 deck clearance
3.58 stroke.

I would like to know if the website I use to ease my work load is in error.
 
IQ52 said:
Challenge accepted!

Please, if you would be so kind, calculate the compression ratio difference using this information.

gasket thicknesses of .040" and .080"
63cc head volume
5cc piston volume
4.100" gasket bore
4.030" cylinder bore
.015 deck clearance
3.58 stroke.

I would like to know if the website I use to ease my work load is in error.
Click to expand...

Ditto on that. Way too much work and information from Krazykuda than I care to digest to figure out a compression ratio.

I will stick with the calculator! You can build a complete bottom end before you will have your answer using Krazykuda's math calculations! Lol

Here is the link again for everyone!

http://www.summitracing.com/expertadviceandnews/calcsandtools/Compression-Calculator/
 
IQ52 said:
Challenge accepted!

Please, if you would be so kind, calculate the compression ratio difference using this information.

gasket thicknesses of .040" and .080"
63cc head volume
5cc piston volume
4.100" gasket bore
4.030" cylinder bore
.015 deck clearance
3.58 stroke.

I would like to know if the website I use to ease my work load is in error.
Click to expand...

Ok, You asked for it...


However, I'm not going to take "baby steps" on this one, like the other two. It took me over 2 hours to do the last one, and I can't keep doing it "the long way". If you need the explaination, refer to the other threads. Lets call this "short hand"....


Ok here's what you've given me to work with:

gasket thicknesses of .040" and .080"
4.100" gasket bore

63cc head volume

5cc piston volume
.015 deck clearance

4.030" cylinder bore
3.58 stroke.


To find the displacement of the engine for one cylinder:

Bore = 4.030 in
Stroke = 3.58 in

Formula:

V1 = (.7854) x (4.030 in)**2 x [3.58 in] = (.7854) x (16.241 in**2) x [3.58 in] = (12.756 in**2) x [3.58 in] = (45.665 in**3) or 45.665 cubic inches

Now let's check to see if it matches a 360. Take the volume of one cylinder and multiply by 8 cylinders:

(45.665 in**3) x 8 = 365.3 in**3 or 365.3 cubic inches


This sounds right for a .030 over 360. So our calculation checks out.


Now convert cubic inches to cubic centimeters:

V1 = (45.665 in**3) x [(2.54 cm/in) x (2.54 cm/in) x (2.54 cm/in)] = (45.665 in**3) x [(16.387 {cm**3/in**3})] = 748.313 cm**3 or 748.313 cc's


So the volume of the cylinder in cubic centimeters (cc's) is: 748.313 cc


Now for the gaskets, you have given me two options, .040" thick and .080" thick:

Given:

gasket thicknesses of .040" and .080"
4.100" gasket bore


*************************

The volume of head gasket 1:

Bore = 4.100 in
Thk = .040 in

Formula:

Volume = (Pi/4) x (D)**2 x depth

VG1 = (.7854) x (4.100 in)**2 x [.040 in] = (.7854) x (16.81 in**2) x [.040 in] = (13.203 in**2) x [.040 in] = (.528 in**3) or .528 cubic inches


Now convert cubic inches to cubic centimeters:

V2 = (.528 in**3) x [(2.54 cm/in) x (2.54 cm/in) x (2.54 cm/in)] = (.528 in**3) x [(16.387 {cm**3/in**3})] = 8.65 cm**3 or 8.65 cc's

So the volume of head gasket 1 is = 8.65 cc's


***********************************************

For the volume of gasket 2:

Bore = 4.100 in
Thk = .080 in

Formula:

Volume = (Pi/4) x (D)**2 x depth

VG1 = (.7854) x (4.100 in)**2 x [.080 in] = (.7854) x (16.81 in**2) x [.080 in] = (13.203 in**2) x [.080 in] = (1.06 in**3) or 1.06 cubic inches


Now convert cubic inches to cubic centimeters:

V2 = (1.06 in**3) x [(2.54 cm/in) x (2.54 cm/in) x (2.54 cm/in)] = (1.06 in**3) x [(16.387 {cm**3/in**3})] = 17.3 cm**3 or 17.3 cc's

So the volume of head gasket 2 is = 17.3 cc's


VG1 = 8.65 cc's
VG2 = 17.3 cc's

This looks right since the second gasket is twice the thickness of the first gasket, it makes sense that the volumes for the first gasket is half of the volume of gasket two.


***************************************

Ok, now since the calculation is the same for piston drop volume, we will calculate the piston drop volume now (you didn't put units for deck clearance, so I will asume inches):

Bore = 4.030 in
thk = .015 in

Formula:

Volume = (Pi/4) x (D)**2 x depth

Vdh = (.7854) x (4.030 in)**2 x [.015 in] = (.7854) x (16.24 in**2) x [.015 in] = (12.756 in**2) x [.015 in] = (.191 in**3) or .191 cubic inches


Now convert cubic inches to cubic centimeters:

Vdh = (.191 in**3) x [(2.54 cm/in) x (2.54 cm/in) x (2.54 cm/in)] = (.191 in**3) x [(16.387 {cm**3/in**3})] = 3.14 cm**3 or 3.14 cc's

So the volume for the deck height at .015" is = 3.14 cc's



Now we get to the fun part, calculate compression:

Comp = (sv/cv) + 1

Ok, the volume above the piston to the deck is simply the volume of the deck height plus the volume for the valve reliefs. You give volume of valve reliefs to be 5 cc's:

Vp = 3.14 cc + 5 cc = 8.14 cc


Now we calculate clearance volume, which is simply the volume above the piston at TDC:

All we need to do is add the three components up. Volume of the piston + volume of the gasket + volume of the head:

For the .040" gasket:

cv1 = 8.14 cc + 8.65 cc + 63 cc = 79.79 cc


For the .080" gasket:

cv2 = 8.14 cc + 17.31 cc + 63 cc = 88.45 cc


Now we have both clearance volumes, now lets see how they affect compression:


cv1 = 79.79 cc
cv2 = 88.45 cc
sv = 748.313 cc


Comp = (sv/cv) + 1

Comp1 = (sv/cv) + 1 = (748.31/79.79) + 1 = 9.38 + 1 = 10.38

Comp2 = (sv/cv) +1 = (748.31/88.45) + 1 = 8.46 + 1 = 9.46


So compression with the .040" gasket is = 10.38

So compression with the .080" gasket is = 9.46


The difference is: 10.38 - 9.46 = 0.92


Who has a .080" head gasket???

However you were right. The other engine that I calculated was much lower compression (8.0). The starting point makes a difference.
 
Mad Dart said:
Ditto on that. Way too much work and information from Krazykuda than I care to digest to figure out a compression ratio.

I will stick with the calculator! You can build a complete bottom end before you will have your answer using Krazykuda's math calculations! Lol

Here is the link again for everyone!

http://www.summitracing.com/expertadviceandnews/calcsandtools/Compression-Calculator/
Click to expand...


The calculators are nice for quick calculations. I calculate compression for how you would actually measure it on an engine if you were building it. I like to apply it to "real world" situations. I have used my method to calculate the actual compression on some of the engines that I have built.


If you actually check the specifications in the service manuals for piston drop, head volume, block deck height, piston compression height, rod length, and check an actual factory head gasket for thickness and diameter, the numbers don't match up. That's why I started measuring it myself. By measuring it on the engine as I build it, I know for sure what I have.
 
krazykuda said:
The calculators are nice for quick calculations. I calculate compression for how you would actually measure it on an engine if you were building it. I like to apply it to "real world" situations. I have used my method to calculate the actual compression on some of the engines that I have built.


If you actually check the specifications in the service manuals for piston drop, head volume, block deck height, piston compression height, rod length, and check an actual factory head gasket for thickness and diameter, the numbers don't match up. That's why I started measuring it myself. By measuring it on the engine as I build it, I know for sure what I have.
Click to expand...

I hear you. KB-Solovite had a calculator that had all of those included in the calculator. It has dis appeared from the net or at least I can't find it.

It had Rod, Stroke, Piston CC, Head Volume, Piston to Deck, Gasket thickness, Gasket Diameter, Cylinder Bore etc.
 
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