Fordmods Logo

Compression Ratios in EB2/ED - EF/EL Heads. 

 

Page 2 of 2 [ 26 posts ] Go to page Previous  1, 2

 
Posted: Sat Feb 05, 2005 8:25 am 
Getting Side Ways
Offline
User avatar

Age: 54

Posts: 4102

Joined: 18th Nov 2004

Gallery: 10 images

Ride: PX2 Ranger 4x4 XLT Dual CAB

Location: Carrum Downs
VIC, Australia

Lukieman wrote:
Defective wrote:

...Secondly you do not want to take an EA head, especially an EA 3.2 litre head! Why would you even want to do this? First of all I’m not even sure if the water jackets would align with an EA 3.2 litre, secondly they flow like crap in comparison to stock EBII or EF/EL heads, thirdly the intake runners are smaller, and by fitting one you are actually making your engine a 3.2 litre as the difference between these engines was primarily in the head. Oh, and that’s if you can fit it with valve clearances as well?



Hang on, its to my understanding that engine volume is taken from the total stroke of the piston, from TDC to the lowest movement point... that is where you get your cc/litres, any volume in the head above TDC is disregarded (although you need to know the volume to figure out compression ratio)... anyway, fitting a different head wouldn't effect your engine volume. I think I remember reading somewhere that the engine volume of the 3.9 engines was made by increasing the stroke, hence why 3.2 piston heads can be used in the 3.9's...

But I have no idea about water jacket matching, but a head gasket would confirm it... even then I dont think there is any difference between a 3.2lt to a 3.9lt CFI or MPFI head gasket.

The only one I'd be a bit iffy on would be valve clearances... I'm sure there is data somewhere on all of this...

But from looking at the data in a Gregorys manual... there is no difference between an 3.2-3.9 litre engine apart from the stroke, and injection method.


I agree to get that much increase in capacity, it could only be done by stroking the motor. changing the head would not change capacity, but could change performance due to improvements made to the overall design of the head.

 

_________________

Image
She's meanness put to music and the b**ch is born to run!
Like the sign says, "speed's just a question of money. How fast can you go?"

Top
 Profile  
 
 
Posted: Sun Feb 06, 2005 1:05 pm 
Fordmods Newbie
Offline

Age: 33

Posts: 13

Joined: 27th Nov 2004

Ride: EB II i6

Location: Melbourne
VIC, Australia

We are talking about a 4.0L EB II engine here, not the 3.9L. The difference between the 3.9L and 4.0L was in the head, not the block. Yes you are right; the difference between the 3.2L and 3.9L is in the block. When I posted that I was thinking of the 3.9L head, my mistake. I was exhausted from work and was not thinking about it correctly. But none the less you do not want to fit a 3.2 or a 3.9L head to an EB II block, and my reasons above still stand. And if it’s the 3.9L head you are fitting to the EB II yes, essentially you are making it a 3.9L engine. Again sorry about the miss post.
Top
 Profile  
 
 
Posted: Sun Feb 06, 2005 1:29 pm 
Getting Side Ways
Offline
User avatar

Age: 54

Posts: 4102

Joined: 18th Nov 2004

Gallery: 10 images

Ride: PX2 Ranger 4x4 XLT Dual CAB

Location: Carrum Downs
VIC, Australia

Defective wrote:
We are talking about a 4.0L EB II engine here, not the 3.9L. The difference between the 3.9L and 4.0L was in the head, not the block. Yes you are right; the difference between the 3.2L and 3.9L is in the block. When I posted that I was thinking of the 3.9L head, my mistake. I was exhausted from work and was not thinking about it correctly. But none the less you do not want to fit a 3.2 or a 3.9L head to an EB II block, and my reasons above still stand. And if it’s the 3.9L head you are fitting to the EB II yes, essentially you are making it a 3.9L engine. Again sorry about the miss post.


Fair enough, we were referring to where the differance in capacity comes from, not where the improvements in engine performance was mostly gained.

However fitting a 3.9L head to a EBII would technically still make it a 4.0L because EBII block is 4.0L, although an engine like that would not benefit from the improvements to head design etc. As the differance between a 3.9 and a 4.0 is only about 35mill there would be no noticable advantage.

 

_________________

Image
She's meanness put to music and the b**ch is born to run!
Like the sign says, "speed's just a question of money. How fast can you go?"

Top
 Profile  
 
 
Posted: Sun Feb 06, 2005 1:40 pm 
Getting Side Ways
Offline

Age: 42

Posts: 433

Joined: 7th Nov 2004

Gallery: 3 images

Ride: ED Falcon

Location: Brisbane
QLD, Australia

speaking of some head play, would a BA twun cam head bolt on to an ED motor
Top
 Profile  
 
 
Posted: Sun Feb 06, 2005 6:46 pm 
Smokin em up
Offline
User avatar

Age: 36

Posts: 258

Joined: 7th Nov 2004

Gallery: 6 images

Ride: '98 EL XR8

Location: Katherine
NT, Australia

Are the engine blocks for the 3.9 and 4 litres the same!?!??! If so, then the head on a 4 litre is bigger (the extra 100cc) then wouldn't that decrease the compression ratio...

Once agian, it is to my understanding that the engine volume is taken by the displacement in the block and not the head.

 

_________________

"...we can rebuild him, we have the technology... we just dont want to spend a lot of money."
SIX MILLION PESO FALCON

Top
 Profile  
 
 
Posted: Sun Feb 06, 2005 7:16 pm 
Getting Side Ways
Offline
User avatar

Age: 54

Posts: 4102

Joined: 18th Nov 2004

Gallery: 10 images

Ride: PX2 Ranger 4x4 XLT Dual CAB

Location: Carrum Downs
VIC, Australia

Lukieman wrote:
Are the engine blocks for the 3.9 and 4 litres the same!?!??! If so, then the head on a 4 litre is bigger (the extra 100cc) then wouldn't that decrease the compression ratio...

Once agian, it is to my understanding that the engine volume is taken by the displacement in the block and not the head.


As said capacity is measured in the block bore x stroke, the head has nothing to do with capacity, as you pointed out it does have everything to do with compression. By the way it not 100cc more like 35cc. The 3.9 is about 3.930(rounded down to 3.9) the 4.0 is about 3.965 rounded up to 4.0. These figures may not be exact but they are close. (personally I think this is Ford playing with maketing figures).

Hope this clears it up for you

 

_________________

Image
She's meanness put to music and the b**ch is born to run!
Like the sign says, "speed's just a question of money. How fast can you go?"

Top
 Profile  
 
 
Posted: Sun Feb 06, 2005 7:37 pm 
Smokin em up
Offline

Age: 45

Posts: 206

Joined: 5th Nov 2004

Gallery: 3 images

Ride: 2004 BA Falcon MkII

Location: Manjimup
WA, Australia

Lukieman wrote:
Are the engine blocks for the 3.9 and 4 litres the same!?!??! If so, then the head on a 4 litre is bigger (the extra 100cc) then wouldn't that decrease the compression ratio...

Once agian, it is to my understanding that the engine volume is taken by the displacement in the block and not the head.


Yes. the displacement is from the bore and stroke. The head chamber volume is not a factor in that calculation. It is a factor when calculating comp ratio, though.

The 4.0 has 35cc more than the 3.9 (3984cc compared to 3949cc), but this is nothing to do with the head. The bore is a "hair" larger.

 

_________________

Kel.
BHR
A/MD 1272
240 inch Dragster
466 Big Block Ford
650hp
8.40 @ 156mph (251kph)

Top
 Profile  
 
 
Posted: Sun Feb 06, 2005 7:41 pm 
Getting Side Ways
Offline
User avatar

Age: 54

Posts: 4102

Joined: 18th Nov 2004

Gallery: 10 images

Ride: PX2 Ranger 4x4 XLT Dual CAB

Location: Carrum Downs
VIC, Australia

Epitome wrote:
The 4.0 has 35cc more than the 3.9 (3984cc compared to 3949cc), but this is nothing to do with the head. The bore is a "hair" larger.


Thanks for clearing up the capacities, I knew it was only 35cc, just couldn't remember the exact sizes for each. (I was close)

 

_________________

Image
She's meanness put to music and the b**ch is born to run!
Like the sign says, "speed's just a question of money. How fast can you go?"

Top
 Profile  
 
 
Posted: Sun Feb 06, 2005 7:42 pm 
Getting Side Ways
Offline
User avatar

Age: 54

Posts: 4102

Joined: 18th Nov 2004

Gallery: 10 images

Ride: PX2 Ranger 4x4 XLT Dual CAB

Location: Carrum Downs
VIC, Australia

Quote:
3984cc compared to 3949cc


I was close!

 

_________________

Image
She's meanness put to music and the b**ch is born to run!
Like the sign says, "speed's just a question of money. How fast can you go?"

Top
 Profile  
 
 
Posted: Mon Feb 07, 2005 1:33 am 
Fordmods Newbie
Offline

Age: 33

Posts: 13

Joined: 27th Nov 2004

Ride: EB II i6

Location: Melbourne
VIC, Australia

Go have a talk to a head specialist, because the ones I’ve talked too all seem to think the extra 84cc comes from the head. As far as I know the blocks are similar but there is a difference in pistons and in water jacket. I’ve also been told that you can not put a 4L head onto a 3.9L block due to the difference in pistons and compression as it ends up being too high, but so far only one mechanic (not head specialist) has told me that so I'm not too sure, never looked into it as I have a 4L block. Right now I’m only as good as the information I’ve been told, and if I’m wrong I’m wrong.

Now we are getting off subject here anyways, the original post was about fitting a 4L EF/EL head to a 4L EB II block and what would the compression be like. As far as I know the difference in compression came from the head between those models. I have fitted an EF head to my EB II block and ill tell you what it was worth the cost. I did have a little extra done to the head and if you’re not planing on going all out wild with head work then the EF head is a great base head to start with.
Top
 Profile  
 
 
Posted: Mon Feb 07, 2005 10:07 am 
Getting Side Ways
Offline
User avatar

Age: 54

Posts: 4102

Joined: 18th Nov 2004

Gallery: 10 images

Ride: PX2 Ranger 4x4 XLT Dual CAB

Location: Carrum Downs
VIC, Australia

Defective wrote:
Go have a talk to a head specialist, because the ones I’ve talked too all seem to think the extra 84cc comes from the head. As far as I know the blocks are similar but there is a difference in pistons and in water jacket. I’ve also been told that you can not put a 4L head onto a 3.9L block due to the difference in pistons and compression as it ends up being too high, but so far only one mechanic (not head specialist) has told me that so I'm not too sure, never looked into it as I have a 4L block. Right now I’m only as good as the information I’ve been told, and if I’m wrong I’m wrong.

Now we are getting off subject here anyways, the original post was about fitting a 4L EF/EL head to a 4L EB II block and what would the compression be like. As far as I know the difference in compression came from the head between those models. I have fitted an EF head to my EB II block and ill tell you what it was worth the cost. I did have a little extra done to the head and if you’re not planing on going all out wild with head work then the EF head is a great base head to start with.


Capacity always comes from the block, bore and stroke.
The head specialist may have been refering to where the extra power gains came from, as most of the improvements where in the head and induction area. The 4.0lt engine was slightly bored out, but only by 35cc not 84

As for putting a 3.9 head on a 4.0 block, you may be right, you may end up with too higher compression. The only way to tell is to cc the head ie measure the capacity of the combustion chamber and work out the compression ratio from there.

 

_________________

Image
She's meanness put to music and the b**ch is born to run!
Like the sign says, "speed's just a question of money. How fast can you go?"

Top
 Profile  
 
Display posts from previous:
Sort by  
 Page 2 of 2  [ 26 posts ]  Go to page Previous  1, 2

Who is online

Users browsing this forum: Google Adsense [Bot] and 20 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

 

 

It is currently Tue Dec 12, 2017 8:32 am All times are UTC + 11 hours

 

 

(c)2014 Total Web Solutions Australia - Australian Web Hosting and Domain Names