Ford Forums banner

Benifit of EL block over EA/ED

3K views 5 replies 4 participants last post by  ebxr8240 
#1 ·
Im going to perfrom some performance mods to my car, and with 235000km on the clock i dont wanna put my block/bottom end under a heap of stress on to have it break and have to pull the engine out.

Stage 3/DEV 4/5 equivelent camshaft for LPG performance
Head work: clean up the bowl and increase compression to 10.5 or 11:1 for straight LPG application.

Now......
If i run a compression test on my 3.9 block and it returns all good compressions, would i have any benifit using an EL block and head, rather than using my current block and a new worked EL head? If i can avoid removing block it would be excelent. :)

Seeing that the EA engine has 8.8:1 compression stock, and the EF? have arround 9/9.5:1 i can only assume that the compression was made through head work. Or was this done by the factory decking the block? Can a EF/L head be machined to achieve 10.5 + compression on an EA block, or would the block need to be decked, and thus have to remove the engine.

Any help would be appreciated.

Also, Bass_crasy, you have worked EA head on your engine, what compression did you manage, and how much did your head work cost?
 
See less See more
#3 ·
Ok some more questions.

1) can compression be braught up to 10.5:1 + by just machining the head?
2) is it possable to achive this compression ratio by using a machined EF/L head (better ports/chamber)
3) what is required in changing the rear main seal

cheers
 
#4 ·
TThe difference in compression was due to the different pistons. EA had a deeper dish (for the want of the proper term) than an EF/EL set. Also using an EL head on an EA wont give any benifit, it mnay actually lower the compression since it doesnt have the swiel port which means the ef/el head has a slightly bigger compression chamber. A good way to get a boost in power would be to fit a set of 3.2 pistons as they had a flat top. EF had a compression ratio of 9.3:1
 
#5 ·
so, does the EF/L head have any flow benifits to that of the EA head? Or if my head is in good condition would it be better to get a mild bowl+port job on my 3.9 head rather than go for a EF/L head.

Speaking of pistions. So using either EF/L/AU pistions will increase compression as their dish isnt as large. Also using flatop 3.9 pistons would also beifit compression. So, which set of pistions would result in higher compression. Im assuming the 3.2 pistions as they are flattops and the EF==>AU's are dished some what?

Also if i get the 3.2 pistions and have the head machined to higher compression and run a highlift cam there is the possablility that i will run into problems with the valves touching the pistions? Do the 3.2 pistions have enough crown to enable valve releaf machining to be done, or wont this prove to be a problem?

sorry for all of the questions but if im going to do it i want to do it right 1st time.

Cheers
 
#6 ·
Are you sure the 3.2 are the same bore and pin location ?? As the 4Ltr..Thought of a ported 3.2 head ??
Porting doesn't raise "static" compression, but unshrouding the valves will lower compression as its making the combustion chamber bigger, same with valve reliefs..Porting will make "effective" compression higher due to more air & breathing better while engine is running.
Flat top pistons seem the way to go. Quench is power/torque!! You'll have to talk to your local machinist he should have a catalogue on piston application etc..
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top