Need some advice on 3 angle valve job. (Civic vx)

[vtecn8ive]

My current setup up is 91 Civic rt4wd (wagon four wheel drive) that I swapped in a d15z1 (Civic Vx engine) long block and I have converted it to obd1 to run the proper o2 5-wire and ecu (etc.)

I am in the process of finishing my spare d15z1 rebuild and just had a question about 3 angle valve job.

I am having my valves reconditioned and cylinder head valve seats recut, and then the guy doing them asked me if I wanted a 3-angle valve job that he would charge me the same amount (he is in school for this stuff and can do it at a discounted rate)

I'm just curious if it would be wise to get the 3-angle done or should I just stick to stock 45 angle seats?

I understand the 3-angle will increase the air flow (with less restriction) but wouldn't I need to to tweak the fuel to accommodate the extra air?

By the way the car is running code free, but I can tell the punk kid before me beat on the motor so I picked up this spare to rebuild.

Thanks,
Shane
(TomO I figure I should get on here a little more often )

[Frank Lee]

It's not going to make THAT big a difference. No reason not to do it if the price is the same.

[bgd73]

Originally Posted by Frank Lee

It's not going to make THAT big a difference. No reason not to do it if the price is the same.

true..
if the head matches the 3 angles, it is simply another ridge of seal. Given precision of today, one could make it so many angles it looks curved...no angles about it. The ridges aren't good, but for aluminum heads and stuff, it all takes peacefully...no matter what they do for angles jobs..

its like 8 bit pixelated to 64 bit high definition..not many car parts have evolved the same yet. I could guess 3 angles will fade away...

[vtecn8ive]

I understand what a 3-angle valve job consists of.

My concern was with the slight increase in airflow if it'll affect air/fuel ratio at all and if that can affect FE?

I may be a newb on Ecomodder, but definitely not a newb to these cars

I appreciate the immediate responses. I tried googling and checking the faqs here and didn't notice anything on it so just felt like asking.

[vtecn8ive]

haha and this post is strictly so I hit a 10 post count so now I can view sigs :P

[Frank Lee]

You're not a newb so that means you know it has efi so that means you know that efi compensates the mixture depending in part on what the O2 sensor tells the computer.

[moonmonkey]

3 angle jobs are for hi-po,, but like frank says it wont make any difference to you.

[99LeCouch]

FWIW, my car has a ported intake manifold. The computer adjusted just fine. All the porting did was make the intake runners more consistent in size. The car knocks less, which is good for fuel economy.

Reducing restriction in the intake is almost always a good thing. It makes the engine's job pumping air easier.

From what I have heard, it's a "little detail" that makes the "big statement" modifications work a whole lot better. I'd get it done if I were you. It's not going to hurt anything.

[TomO]

You should be fine with the three angle Job, Shane. The ECU should have no troubles compensating for any changes. I can't see it hurting anything, but it might not be a noticeable boost either. Let us know how it turns out though!

[vtecn8ive]

Thanks for the responses.

Yeah I knew the ecu adjusted, I guess I wasn't 100% on how much it is able to adjust.

Haha, didn't really want to be a guinea pig but I'll be sure to post up numbers (mpg :P) when all is said and done. Hopefully having it installed in the middle of March (I normally do it myself but with school+work= no free time).