the head difference

[joat]

i got a 98 explorer with heads off a 92 explorer th combustion chamber is different, what is horse power gain or loss ,any help will help ,they are both 4.0 vin x ohv

 

[99explfreak]

hello well you have to understand more air +more fuel= more power so with the combustion chambers being different if i remember correctly the 92 combustion chamber is small so it is definetly taking away some power there definetly. just not really sure how much exactly. just put 2 brand new heads on my 99 4.0 ohv had to cracked heads got aftermarket heads which are alot thicker and stronger got good deals on them through j&c cylinder head in west virginia they have them for sale on ebay i paid roughly 200 pc for them and they are awesome alot better! might want to give that a thought maybe changing back to the 98 version of the head.

 

[Maniak]

'92 heads on a 98 (aka lean burn IIRC) will lower the compression ratio, which should also lower the power.

'92 X has large relief heads while the '95+ heads have a smaller chamber.

Here is a post that shows the different head reliefs..

http://www.explorerforum.com/forums/showpost.php?p=2244505&postcount=9

~Mark

 

[Carguy3J]

'92 heads on a 98 (aka lean burn IIRC) will lower the compression ratio, which should also lower the power.

'92 X has large relief heads while the '95+ heads have a smaller chamber.
~Mark

Hmmm. Interesting. I did not know that there were diferent OHV heads. Of course, I have a SOHC, so that doesn't help me. But, I wonder if the guys who are putting blowers or turbos on 95+ OHV's know about this? Do you know how much of a difference in CR it makes. Is it otherwise fully interchangeable?

Do you know if there are any differences in the SOHC heads over the years, or intakes?


EDIT: I just looked at those pics. WOW! That is a huge difference in chamber shape and size. It's a shame the valves are so close together. Except for that, there is plenty of room in all other directions for much larger valves. Maybe if somebody really wanted to get crazy and do a custom valvetrain with offset valves????

 

[Cobraguy]

I believe there is also a piston change that goes with the combustion chamber design change. You need to match piston/head combinations IIRC

 

[Maniak]

There is a good article by Doug Anderson on the 'net that talks about the 4.0 ohv motors. I don't think he gets into the SOHC though..

just search for Doug Anderson and 4.0 and I'm sure it will popup. I don't think we have a copy of it on EF though.

~Mark

 

[joat]

the castings are 98t 92t

 

[joat]

want 2 trade?

1995 dodge neon running cold a/c heat good paint faded but otherwise a good car. selling because im not used to working on nothing but explorers