The newest edition, 1987 CRX HF

[orange4boy]

It's functioning! Cap, rotor, plugs, and adjusting the valves and now the little guy runs great.

Don't you love an easy fix? So your return on investment will take, what, a week?

[texanidiot25]

Don't you love an easy fix? So your return on investment will take, what, a week?

About 3 weeks max. Insurance for me is only $30 more per month, which will be no issue. Classes end soon, so I'll be banking at work with this little car working more hours.

You should also change your tranny fluid, 0w30 or 5W30 motor oil every other year.

You mean gear oil right? I've never heard of using motor oil in the trans. And it's possible to rip all that vacuum equipment out and let the motor just be carb'd. They say it runs a hair richer, but none have seen an decrease in fuel mileage.

Originally Posted by ex-x-fire

You did really well on a swap for a honda deal, glad to hear it's running good. If you are planning on driving it alot you may want to change that timing belt, you don't want to bend up your valves.

The timing belt is in excellent shape, not stretched, cracked, or worn. And my dad is a 20+ year ASE master tech, and wasn't even worried about it.

[orange4boy]

The timing belt is in excellent shape, not stretched, cracked, or worn. And my dad is a 20+ year ASE master tech, and wasn't even worried about it.

I know some engines have clearance for the valves so if the timing belt breaks the valves won't hit the pistons. Your dad could probably tell you if the CRX had this feature, then you really don't have to worry about it. My old Volvo 240 2.4 was built like that.

[orange4boy]

And it's possible to rip all that vacuum equipment out and let the motor just be carb'd. They say it runs a hair richer, but none have seen an increase in fuel mileage.

Nooooooooooo! Don't doooo eeeeet!

Isn't all that vacuum stuff for emissions reduction and fuel economy?

Did the carbed version come with lean burn? You wouldn't want to mess with that. We are all excited to see what you can pull off with your mileage.

[texanidiot25]

Also I NEEED to rephrase that, I meant a drop in fuel economy. RedPepperRacing guys haven't seen it effect FE after "devac-ing"

It's Japan's way of avoiding EFI, to put it simply. In stead of an ECU and wired sensors, you have a mess of vacuum lines controlling, measuring, actuating, etc.

The engine is a lean burn design regardless of what the emissions controls tell it to do. When removed, the motor only runs a fraction richer. And if the emissions controls were in bad shape, it would severely hurt the performance of the motor in all aspects, and for the most part it may become easier to remove all of it rather than track down parts that don't exist and fix a complex system. In my case, I don't have to worry about any of this, everything appears to be working right and the only vacuum leak is at the carb (a common failure). I'm a "If it ain't broke, don't fix" person. But if it causes problems I won't hesitate to go old-school-simplicity, and just throw a wide-band 02 sensor to keep an eye on the motor's a/f ratios.

The lean burn aspect comes from the cylinder head design with CVCC, from what I read. Not the emissions controls. This is some interesting engineering:


CVCC refers to Honda's Compound Vortex Controlled Combustion. It was a dual chambered cylinder head that allowed Honda to run with out a cat-converter for many years, as well as develop a very efficient lean burn head that didn't risk many of the typical issues that you'd run into with this design.

Each head was basically a 3 valve/cylinder head. You had a typical intake/exhaust valve, but you also had a CVCC valve that was much smaller. This valve was actuated by the cam shaft, just like the intake/exhaust valve with it's own cam lobes.


The third valve let in a rich-mixed air charge that filled in a small combustion chamber that was placed around the spark plug. This air mixture was fed by a tiny dime-sized barrel in the carburettor, and actuated with the throttle. You can see the throat of this barrel under my finger in the picture of the carb.



While the mini-chamber was being filled with a rich-mixture, the main combustion chamber was filled with a lean-mixture, and provided the actual power stroke. The reason for this? From what I've read, lean-mixtures were difficult to ignite. The rich mixture around the sparkplug ignited easily, and the flame traveled out to the main combustion chamber where the lean mixture ignited. Combine that with 10:1 compression ratio, and the result was a very clean, efficient burning carb motor.

http://www.youtube.com/watch?v=IuVsUgCO_sI

[texanidiot25]

Originally Posted by orange4boy

I know some engines have clearance for the valves so if the timing belt breaks the valves won't hit the pistons. Your dad could probably tell you if the CRX had this feature, then you really don't have to worry about it. My old Volvo 240 2.4 was built like that.

Hondas are interference motors, in other words, when the belt goes it takes the valves with it. You'd think the "king" of small cars would design them otherwise. I'm not sure about the design difficulties with making a motor non-interference. The two things older Hondas are notorious for; Over heating and ripping head gaskets, and smashing valves after a timing belt. We'll keep an eye on this one, but it's fine for now.

[orange4boy]

Thanks for all that info. I love learning new stuff. Ingenious way of igniting the mixture.

The 240 engine has cut outs in the pistons to give the valves that extra few mm. But I bet that's only possible on certain lift/stroke/compression ratio/valve angle engines.

[Ryland]

Originally Posted by texanidiot25

You mean gear oil right? I've never heard of using motor oil in the trans.

No! gear oil will destroy the bushings in the tranny, to much sulpher in it, the Honda owners manual calls for straigh 10W30 motor oil, you can now get Honda brand manual tranny fluid but up until I think it was 1996 or so the dealer told you to, along with the owners manual and the shop manual, to us common motor oil.

I've read the shop manuals cover to cover, they are a good read.

[texanidiot25]

Originally Posted by Ryland

No! gear oil will destroy the bushings in the tranny, to much sulpher in it, the Honda owners manual calls for straigh 10W30 motor oil, you can now get Honda brand manual tranny fluid but up until I think it was 1996 or so the dealer told you to, along with the owners manual and the shop manual, to us common motor oil.

I've read the shop manuals cover to cover, they are a good read.

I don't have the car with me, but the owners manual called for 75w-something manu-trans gear oil. I'll look into this further though.

Edit: Also another reason why I will never. Ever. Attempt to fix the emissions system in this car.


I'm glad for fuel injection these days, and feel sorry for any Honda technicians that ever had to work on these things. Thank god for Honda quality though, the car appears to run great. We'll see once it's back on the road, though.

[Ryland]

Honda never used gear oil in their transmissions, maybe in the rear ends on the Wagovan? but it's always been motor oil up to the point that they switched to their own MTF, even Amsoil MTF is no longer even recommended as it can be to thin and not provide the needed protection, their site even recommends their motor oil, I've put it in all 5 of the Civics that I've owned including my CRX tranny, my Civic FE tranny and both my Civic vx transmissions, of course I used 0W30 in mine as we get rather cold winters here, changing the tranny oil makes shifting much much smoother as the oil that came out of all 5 of the Honda's I've owned looked like it had been in there a long time.
The site that hosts the 800 page or so PDF file of the dealer shop manual for the early Civic and CRX's is currently down, as soon as it's up I'll get the exact link for that manual.