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-   -   DIY - Head Swap (Project KDA complete!) (

SVOboy 01-01-2008 07:48 PM

DIY - Head Swap (Project KDA complete!)
5 Attachment(s)
For those of you who remember project KDA, which was sidelined because the engine I had sourced had a chipped intake valve, it is now complete! I replaced the valve about a year and a half ago but I pretty much just never got around to actually doing the swap.

First thing to note: Can anyone tell me how to use my damn timing gun so I can check the timing on the engine? It's not intuitive for me, :p

Okay, like the title suggests, I just completed a cylinder head swap on my 91 crx dx. I removed the stock head (~92 hp) and slapped on the head from a civic cx (~70 hp). There's really no good comparison of EPA values because of the different transmissions in the different cars, but it's safe to say that my car is pretty much a slightly bloated CRX HF at this point.

1. My speedo is broken, so I have no idea what kind of mileage I'm getting now. I can only roughly ballpark, but my best chance to ballpark will be the trip from home to school, which is 350 highway miles. I will use google maps and fill ups to see how I do.
2. The car is hella slow. It can get around of course, but there's no question that it's slower.

Okee, now on the the work...this will be an awful write up since I was preoccupied with the work and didn't take many good pictures, but it's not really that hard of a job.

1. Pick up a good shop manual, it will tell you pretty much everything you need to know to do it properly, including torque specs.
2. Take off your bling so you don't scratch up the car.
3. Examine the head you'll be swapping on. Mine was covered with cobwebs, cat hair, and dust. So clean it a bit. I used intake cleaner and an oil rag, then reoiled everything to keep it slick.
4. Check out the old gasket junk and then clean it off. I was very careful with a razorblade. Do not nick the surface!
5. Take a look at the before

More in the next post!

AndrewJ 01-01-2008 11:49 PM

chipped valves must be a common problem with the HF heads. My 91 HF had a chipped valve, and by "chipped" I mean that about 1/4 of the valve was gone. But I never hear of chipped valves in 92-95 CX's even though it's the same engine. They must have addressed the problem in '92.

Oh, and I've always scraped the head with a putty knife, less chance of nicking the head that way.

SVOboy 01-02-2008 12:49 AM

I didn't have a proper gasket scraper, :p

The chip was rather small on this valve, I could dig up a picture at some point...but the cx and hf engines were actually really different, but had the same results, or so I am told.

I'll finish this up tomorrow when I'm at the library!

MetroMPG 01-02-2008 01:14 PM

OK, spell it out for me please: Why is the 2 valve head going to be more efficient than the old 4-valver?

I'm assuming it's probably got a different cam profile - perhaps tuned more for lower end torque, where the 4-valver cam profile is mostly about high RPM hp?

SVOboy 01-02-2008 01:17 PM

Indeed, good sir, indeed. I'm also make the assumption that, based on other characteristics (eg. 190cc injectors, presence in FE models, etc) that this head will give better economy.

MetroMPG 01-02-2008 03:00 PM

Is there something about 2 valves vs. 4 that would make them inherently more efficient, all else being equal (eg. cam profile)?

SVOboy 01-02-2008 04:28 PM

Well, the cam profile certainly is different, but I'm not technical enough to give you a real answer on that one. I do know the the part of the VTEC-E business is that along with the 1 intake port the dished pistons create a swirling, which improves combustion efficiency a tiny amount, but Iono.

SVOboy 01-02-2008 06:07 PM

5 Attachment(s)
6. Take a picture of your spark plugs so you don't forget how they go on, :p

7. This is where it gets annoying. You'll need to remove the valve cover, the distributor, some hoses and plugs below the distributor, the exhaust manifold, the intake manifold, and the timing belt before you can remove the head. A few of those things are highlight here.

8. But wait! Don't forget to drain your coolant. You'll find this plug under some plastic on the passenger side.

9. Here's some of the junk I advise you to remove to at least push the intake manifold to the side.

10. When I was taking out my spark plugs one of them came apart in the tube. Good thing I had spares.

More in a minute.

SVOboy 01-02-2008 06:15 PM

5 Attachment(s)
11. Once you've got all that junk out of the way you'll need to remove the rocker arm assembly by take out these bolts.

12. That done, remove the timing belt cover.

13. To get the timing belt off I just pushed it with my fingers.

14. With the belt and rocker arm assembly off, remove the retainer on the passenger side, yank the cam out, and take out the head bolts. You'll want to remove them a 1/4 turn at a time backwards from the order shown in the picture (to prevent warping).

15. Luckily my head surface was clean and didn't need any work. I did need to rag out some junk I spilled in the cylinders, however.

More coming up!

SVOboy 01-02-2008 06:18 PM

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16. For the new headgasket I bought one for the d16y8 since it has a nice metal HG that is a bit thinner and easier to work with. Cost a little less than 40 bucks.

17. Yay! Now put it all back together, :p. Following specs I torqued the head bolts in two steps, first in order from the previous picture to 22 ft-lbs, and then finally to 49 ft-lbs, piece of cake.

Questions, comments?


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