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-   -   Disabling intake and exhaust valves (going to 8 valves in a 16-v head) (https://ecomodder.com/forum/showthread.php/disabling-intake-exhaust-valves-going-8-valves-16-a-21931.html)

Gasoline Fumes 05-15-2012 01:48 PM

Disabling intake and exhaust valves (going to 8 valves in a 16-v head)
 
My original plan was to install a CRX HF camshaft along with the roller rocker arms in my 16-valve Civic Wagon. The HF torque peak is something like 2500 RPM lower than my engine. The HF has only 8 valves, but it's pretty clear that the head is very similar to the 16v head. There are blank spaces where the valves would be.

http://img.photobucket.com/albums/09.../crxhfhead.jpg


Unfortunately (and surprisingly) the HF cam has larger lobes that hit the 16v head, so I was unable to install the HF cam. So what I ended up doing was just using the spacers that are used on the HF in place of the missing rocker arms.

http://img.photobucket.com/albums/09...6to8valves.jpg


So far I like it. It's more responsive and torquey at the very low RPM I usually drive at. I kept overshooting my 2000 RPM shift point. But it will not make it to redline in second gear anymore. It's probably not an ideal setup, since the camshaft wants to make midrange power and the valves won't let it. I'm hoping for an increase in MPG, time will tell.

Not surprisingly, the exhaust is much quieter now. :)

t vago 05-15-2012 02:30 PM

Interesting! Looking forward to seeing your results.

MetroMPG 05-15-2012 03:38 PM

Cool! You mentioned this at GGP. Nice to see it come to fruition.

More torque down low is usually a good thing for the light-footed.

Subscribed for updates.

drmiller100 05-15-2012 09:35 PM

good idea. i'll be curious how it works out!

Gasoline Fumes 05-15-2012 10:42 PM

Quote:

Originally Posted by MetroMPG (Post 307400)
Cool! You mentioned this at GGP. Nice to see it come to fruition.

More torque down low is usually a good thing for the light-footed.

Subscribed for updates.

I was really hoping to use the HF cam too. Or "diesel cam" as I had been calling it. :D

It seems to make the most difference at part throttle and at low RPM. I probably lost 20-30 HP at the top end, but I wasn't using it anyway. :)

Christ 05-15-2012 10:57 PM

Why not just swap the HF head on? It doesn't take long, and you get the proper intake manifold to deal with the required higher air velocity at lower speeds, as well as slightly larger valves than the 16V heads have, which allow better flow at low RPM.

And you can use the HF cam. You can also use your stock electronics to run that head, as long as you only use the head, and don't try to incorporate the recirc valve on the intake manifold.

I also have a complete HF swap I'm selling, if that's something you're interested in. It's currently in Johnson City at a buddy's house.

Gasoline Fumes 05-15-2012 11:12 PM

Quote:

Originally Posted by Christ (Post 307490)
Why not just swap the HF head on? It doesn't take long, and you get the proper intake manifold to deal with the required higher air velocity at lower speeds, as well as slightly larger valves than the 16V heads have, which allow better flow at low RPM.

And you can use the HF cam. You can also use your stock electronics to run that head, as long as you only use the head, and don't try to incorporate the recirc valve on the intake manifold.

I also have a complete HF swap I'm selling, if that's something you're interested in. It's currently in Johnson City at a buddy's house.

I would swap the whole head, but the one at the junkyard has been sitting for at least a year with no valve cover or hood. Might be OK, the cam was fine. But it's missing the injectors and possibly other parts. I saw your ad and I'd buy your swap if this poor Wagon wasn't so rusty. I'd look for a better shell, but like Darin, I'm suffering from TMP. :)

I'm tempted to swap in the HF trans, but I'm scared of gearing that tall in a heavier Wagon that I use like a truck. I'm often wishing for a shorter first gear.

Christ 05-15-2012 11:18 PM

The first gear is the same, the final changes it a bit. With the added low-end torque of the HF swap, you'd probably be net about the same.

One problem I had with the HF's gearing was that, even in my +100 HP sedan (~120HP at that time, IIRC), I couldn't pull anything except 3rd gear up long hills, and accelerating past 60 or so was just wishing in a bucket (on those hills). I was also running 205/40ZR16 street performance tires and hadn't done much else to the car at that point.

For the record, I'd entertain trades for the swap as well, if you know anyone that's interested in it.

Gasoline Fumes 05-15-2012 11:45 PM

Quote:

Originally Posted by Christ (Post 307498)
The first gear is the same, the final changes it a bit. With the added low-end torque of the HF swap, you'd probably be net about the same.

One problem I had with the HF's gearing was that, even in my +100 HP sedan (~120HP at that time, IIRC), I couldn't pull anything except 3rd gear up long hills, and accelerating past 60 or so was just wishing in a bucket (on those hills). I was also running 205/40ZR16 street performance tires and hadn't done much else to the car at that point.

For the record, I'd entertain trades for the swap as well, if you know anyone that's interested in it.

The HF 3rd gear is slightly taller than my current 5th gear! First gear with the HF final drive is about halfway between my 1st and 2nd gears. I can take off in 2nd gear now on flat ground, but it would kill my clutch on a hill. I might try the HF trans, I keep thinking about it.

I don't have much to offer in trade. Have any use for a Chevy 350? :)

Ang84Indy 05-16-2012 12:07 AM

I had no idea that you could run a 4-valve head with a 2-valve cam! I'm very interested!


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