I know that the head on the HF's have only 8 vavles in them so I have all the other stuff to do the swap. CRX Si:Intake manifold, ECU, just won the distributor and know all I need is the head can anybody tell me what's the best head? I heard at one time that the best was off a D15B7. The B2's are okay but the B7's have more compression from the factory.

 

dont even waste the time.. get a complete 88-91 si longblock

 

I agree Si engines are cheap enough why mess with anything less. Heck if cash is tight a ZC swap with engine and trany isn't much more and its much lower milage and more powerfull. And still a lot cheaper than A B series swap.

 

Its not worth it. The pistons dont have valve reliefs for 16 valves.

 

i have a complete SI head with complete intake manifold. i also have ecu and distributor. i need to get rid of them from my garage real cheap. 200 for everything leave me a messege if you are interested

 

youll have valves collide if you try any other head than the HF head(8 valve)

the hf engine isnt performance friendly....ditch it

 

Okay the reason I am not able to do the ZC swap first is because I have a baby on the way. Second The HF motor I am riding is only has like 133k on it. Where it has cost me like 200 bucks total to do the head swap it'll take at least 600 to do the ZC and that's not including shipping from any shop from which I'll buy it from. I have 2 choices do this head swap or don't. It's either have like 62hp or have like 102hp. I auto-X alot so it's almost impossible to build up speed with a 62 hp motor. And what is this valve collide stuff that was said earlier? Oh and whoever posted on the parts for sale on here this freakin' sucks. Where the hell were you a couple of weeks ago? Damn I alomost have everything I need now. How much will you sell me your head for? I live in mississippi, 39759. Hit me up on this post and let me know.

 

Thanx for postin something worth while.

The HF engine is an 8 valve engine, the Si/DX engine are 16 valve. .If you want to ATTEMPT to put an Si/DX head on the HF block, you'll have to swap out the pistons/rods for those of the Si/DX. Reason being the HF pistons on have recess in the tops of the pistons for 8 valves, you drop a 16 valve head on there and you're gonna be crunching valves before you even get out of the driveway. Honestly everything on the inside of an HF engine is tiny especially the rods. I doubt swapping the head will yeild you that much power. You'll probably have to keep the HF's stock 5500 redline, to preserve the engine life. The HF's ECU is made for fuel economy not performance also. An Si ECU would work better, but it's made for a 1.6L engine, so your MPG is gonna go in the *******.

Honestly the proposed swap is NO NO. It's one of those, "Hey I've got all these spare parts laying around. Wonder if I can do this......". A nice swap for you car would be a properly tricked out Mini-me. A fresh D16A6(Si) bottom-end with a D16Y8(96+ EX) head/intake mani. You'll get about 11:1 compression and VTEC. Using a 1st gen 'teg ECU and an RPM switch it ought to be a fun car to drive. I ran something similar to that in my '91 Si for a while. I got 35mpg and it was fun to play around in. You can get the head intake mani for around $300. The block if not the whole Si engine should be that hard to come by, with as my people that do swaps. I seen people getting rim for stock D-series engine all the time for 2~300 bux.

Bottom-line. You DON'T hot rod and HF engine. It's got a whooping 62HP, 5500 RPM redline, and not to mention the longest gears in the history of a civic/crx (maybe not, but they're loooooooooooooong). Use the car for what it's designed for - 50 MPG. Else swap in an Si or ZC engine. HF's are light and good for swaps, but the stock engine is a turd if you're looking for performance. If you don't have the money to invest in a good engine i'd suggest sticking with the HF engine. Getting 400~500 miles to a tank can't be that bad, now can it?

[Modified by Speed PHreak, 1:37 AM 1/31/2003]


[Modified by Speed PHreak, 12:58 AM 2/1/2003]

 

I agree if money is so tight you can't afford a ZC swap , WAIT UNTIL YOU CAN. Anything else is going to be throwing money away. If you can afford to do that you can afford to spend a little more and do it right.

 

d16a6 w/ MPFI swap

a6 for life!

 

its down right now but hondaswap.com has an article on this exact build up of putting a DX/Si head on the HF bottom end and dyno'd at 106-109 HP with an I/H/E and PM6 ecu, so are you sure the valves will hit the pistons? according to their site it has been done. If it is possible than adding the Si tranny to this hp combo would make a decent get around car in an HF body for cheap and if you were that bored.

 

Nobody is saying that the HF block cant be used if you CHANGE THE PISTONS

To be able to get any real HP out of the HF you would need to do the following

Change Pistons
Change Rods(most likely)
DX/SI or y8/z6 head
d16a6 Intake Manifold
d16a6 throttle body
The stock HF exhaust is a Close Coupled cat so that would need replacing as well
aftermarket intake or dx/si intake arm/box

Now for all the $$$ you would spend on above parts....why bother?

 

how convient that you have to be a member to view their board and when u try and register

"The error returned was:

The board administrator is no longer accepting any new registrations at the moment.
"

 

They HF is an 8 valve engine as is the Std engine, the DX and Si are 16 valve engines. Valve reliefs on the piston crowns are different and HAVE to be there. Besides the HF has such spindly little rods they would likely break at 6,000 rpm. and you could buy a used Si engine for less than it would cost you to build on the cheap with used parts to make the same power.


[Modified by virginia_dude, 11:48 AM 1/31/2003]

 

Sorry bud, the D16A6 already is MPFI, you're thinking about the D15B2 and D15B1(DX) engines. Those are throttle-body injected. Do MPFI conversion on one of those and they do become quite "peppy". Dx engines are cheap to come by as well. VTEC head swaps also result in lots of fun on the d-series engine. 1.5L blocks give you between 10.8 and 11.2 compression depending on which head you use.


Summed it up in a nut shell. "Why bother?"



[Modified by Speed PHreak, 12:59 AM 2/1/2003]

 

to tell the truth i didnt think it could be done but rioninja and a friend of his say different and so did phatwhippin_crx they said it was done on a kids car in PA no changing of pistons or anything.....If u wanna go and try it go ahead u may loose compression if ur valves hit the pistons....or u can get a dx short block to do it and not run into any problems.....this is what i would do it will be cheaper than buying a complete si motor and maybe u can get the dx for free if u find someone wanting to get rid of it....good luck with the thing but once u do this for auto x ur gonna have problems since ur modifying ur fuel system gonna be in a higher class

 

if he has an HF the car isnt MPFI, so if he does the d16a6 swap, he is going to need a MPFI swap


stolen from hondaswap for those of you having trouble viewing.

Creating an HF All-Motor Monster


Overview:

This is dedicated to everyone driving around in an 88-91 CRX HF getting 50 miles to the gallon. Honda’s little 8-valve motor is great for fuel economy, but as you HF drivers will attest lacks the power to chirp the tires when driving spiritedly. For those wanting a very inexpensive solution, keep reading. For fewer than 500 dollars you can transform your CRX HF into an all-motor beast that’s capable of running high 14’s.



The Setup:

For starters, you’ll want to find a DX head off of any Honda motor. Newer heads are better for the obvious reasons and they can be found everywhere. Look to spend no more than 50 dollars on a clean DX head. Next, search the local junkyards for a 4th Generation Si intake manifold. This should cost around 25 dollars, although friends with Honda’s will probably have a few lying around so this could be had for even less. Ideally you’ll want a CRX Si Distributor, CRX Si Ecu and CRX Si transmission for the setup, along with a timing belt the same year as the head. For example, if it’s a 95 DX head, you’ll want a 95 DX timing belt. Other belts will probably work, but its guaranteed to work if you use this setup, although you can match parts numbers to make sure everything is to OEM specs.

What Makes the Power:

Well, if you’ll remember the HF motor has an 8-valve head, which is great for fuel economy and miserable for performance. The 16-valve head will raise compression substantially creating a surprisingly powerful hybrid. Now, what kind of numbers can you expect from this setup? A friend of mine recently used a similar setup and put down 112, 109 to the wheels. With this type of power, look to be pulling on GSR’s, Civic Si’s and even the occasional unsuspecting Type R owner.



Conclusion:

Remember, this setup should cost no more than 500, and if you have a CRX Si parts car sitting around this should cost no more than 150. Using Si parts will yield the best parts but if you’re trying to keep a budget a DX transmission/ECU will work if their readily available. And the best part, when you blow up this motor you’ll have saved enough money to buy a ZC, D16Z or even B16A.





[Modified by kyle h., 5:01 PM 1/31/2003]

 

sorry for you bud BUT the HF IS MPFI its just got tiny throttle body, tiny everything


heres my old 88 hf unmodified

 

also the HF distributer is the same as the si and will work with the si ecu.....and 500 is a lil steep unless ur changing exhaust to make real power outa the new setup

 

so why did honda bother making a TB injection on the DX?

 

why does honda do anything? they did it because their engineers made it that way

 

im going to shut up now. but that write up seems interesting.

 

i didn't argue that if it was worth it or not, just saying it can be done without changing pistons or rods. I agree that shifting over the HF's pathetic 6000's will not last in time, but the same arguement can be stated to an LS/VTEC and its poor R/S ratio but people still do that(with a lot better results however, powerwise). Plus i don't think that project would cost that much anywayz, i can get an A6 head complete for 50-100 bucks, ecu for 25bucks, and a header for cheap too since the HF header wouldn't be used anywayz. I'm not arguing just saying the head swap IS possible without doing the above things. BTW the site is having difficulties today that is why it isn't accepting new users, its not like honda-tech doesn't have it's share of problems ever once in while. But i have all love to you, CRXgurlll, so beautiful, so angry.

 

Okay here is the problem. Some are saying that it wil work others are saying that it won't? Honestly I don't know who to believe. I guess that I'm gonna try it and take pics of the whole thing. And I guess we'll see who is right and who isn't. All together I guess I'll be the one to lose. By the way if I have another D15B2 block what is a better head the D16A6 or the B2 head?

 

u could do this clay the pistons to see if there is enough valve clearance in there what ull have to do is take some clay and put it on ur pistons slap the head on and timing belt rotate the motor and few times by hand and see if ur valves hit the pistons or not safer way to do it