Johnny_Cracker

iTrader: (1)

So I removed the air pump to make accessing the OMP easier for removal (been premixing since I got car 2 yrs ago).

I decided to clean up the air pump while it was off and was careless while washing it, allowing some water to get inside . I got as much out as I could, but the remaining water either loosened crud already there, or initiated new rust formation as it sat for the next few days until I could get back to it. In any event it became much harder to turn and noisier (scraping sounds).

I thought it would be fairly straight-fwd to disassemble, grease, clean and reassemble. Disassembly wasn't an issue, but the innards weren't quite what I expected as I've never seen an eccentric vane pump before.

I was unable to remove the rotor which houses the vanes (needs to be pressed out I believe). This sucked as THAT is the bearing I need to repack... I resorted to squeezing grease into it (the rough front bearing) using the pulley screw holes for the "outside" face of the bearing, and a small (2-3mm?) hole adjacent to the pulley mount to squeeze grease on the "inner" face, which without pressing the rotor shaft out is nearly impossible to get at properly. This seemed to work as it now rotates at least as freely as it had initially.

My problem is that after reassembling it, it clicks and get's hung-up as I try to rotate it. I've looked everywhere for a diagram to ensure I reassembled it properly. It definitely seems to be an issue with the vanes. In fact one of the black plastic "sleeves" which guide the vanes is loose and falls out without the vane to hold it in place, so I'm considering this could be the culprit.

I'd like to find a diagram so I can retry it with guidance, as I'd prefer to keep the pump functional but have struck out with the FSM and net searches. I am however considering just deleting it (and the ACV). The only issue for me would be the cat clogging since I'm stock exhaust. Or at least that's what is claimed with stock cat and pump/ACV delete. Not my daily driver and only sees perfect weather FWIW.

In the end it comes down to this question:
...Would you guys just remove the air pump, ACV, install yoohoo belt/dual sheave pulley and block it all off??? OR INSTEAD make every attempt to get the pump fixed? I'll be upgrading the exhaust in the future as well, so I'm leaning towards the delete at the moment. I figure keeping the RPMs up before putting her to bed will help burn off the deposits not being burned due to the pump/ACV delete.


For anyone who HASN'T seen the inside of one of these it looks more like a friction inducing device than an air pump ... Three vanes (each with 2 bearings), 2 main bearings (front pulley and rear), dry surfaces the vanes slide against as they rotate. Not saying I believe the guys claiming 10hp gains from removal, but if you have one in bad repair then I can see where removal could free up a few hp.

EDIT: I'm not subject to emissions testing.

PK_12A

iTrader: (3)

Seeing as your aux ports are exhaust actuated and your not subject to emissions use it as an excuse to delete the emissions altogether. Heck look into headers and exhaust too and gain some actual hp and make your engine happier.

Johnny_Cracker

iTrader: (1)

That's kind of how I'm leaning on this.... I was gonna wait until I plunked down for the exhaust but my hand is more or less forced now. I don't really relish spending several nights troubleshooting the pump anyway, so safely tucked in the parts bin it goes.

On to fabbing ACV and OMP plates so I can continue putting her back together. Damn now I gotta remove a bunch of nice new vacuum lines and the polished ACV.

Oh well, more weight and more clutter out of the bay, and it'll show off the cleaned LIM and restored actuators better too.

If anyone has direct experience with having removed the pump and it's effect on the cat and backfiring I'd love to hear about it. Especially from 13B owners.

t_g_farrell

iTrader: (1)

The cat needs the extra air to keep it cool otherwise it will get too hot, glow and fail. I'd hollow
out the cat or replace it with a pipe.

Johnny_Cracker

iTrader: (1)

If I hollow out the cat I won't lose enough back pressure to affect the 6 ports opening right?

Would back pressure change AT ALL just from hollowing a cat?

DerrickS

Talking out of my **** here, but I think you will not lose that much back pressure from a gutted cat.

Doesn't the 6 port tube come off the exhaust AFTER the main cat? I'm trying to remember but it's a little fuzzy right now. If so, the back pressure the tube see's should be due to the rest of the exhaust from the cat back, right? Or am I full of bovine excrement...

Johnny_Cracker

iTrader: (1)

...FSM shows it coming right off the side of the main cat. Yeah, it looks to be closer to the rear-end of the cat, so you're likely right in that the cat would appear to play minimally in the back-pressure needed for port activation. Just the muffler and piping after the cat seem to be responsible for proper back-pressure. Good call!



I confirmed that my county has no emissions checking, but there is the visual inspection to worry about. I have an independent mechanic inspect the car normally so I could pass visual w/a straight pipe likely. I could then tap the exhaust mani like Ive seen done for the 6port line in other threads.

What are the pros/cons of a straight pipe vs the hollowed cat???

PK_12A

iTrader: (3)

If I remeber right the test pipe has aux port provisions as does a version of the rb headers. As for pros and cons, you will help open the exhaust up a bit and lose a few pounds cons you won't pass a visual.

Cookboy

iTrader: (10)

The test pipe is, relatively, cheap, quick, and easy. But if you're going to a header anyway go there now.

rx7lives

I thought the 5 & 6 air came from the smog pump? I'm looking at the circuit in my 2nd gen manual and it clearly comes from the smog pump with an electric valve in between in one view and the CAT in another.

The one coming from the cat looks most like the SE system. For some reason I can't find my 1st gen manual.

OK, I just looked at my SE and while it's not too clear, there's a small pipe coming of the CAT pipe before the one way valve and it looks like it's going to the actuators.

Johnny_Cracker

iTrader: (1)

Yeah on the SE the actuators get psi from exhaust backpressure, not the ACV/smog pump. There's a nipple on the split-air pipe that is connected via vacuum hose to the pipe that runs along the bottom of the LIM that activates the actuators.

Johnny_Cracker

iTrader: (1)

Re: test pipe vs hollow cat...

Any difference in response or low end torque?
Loudness/tone differences?
Any power gains with a straight pipe?

...Or no significant difference between the two?

DerrickS

A test pipe is always going to be better than a gutted cat. Think of blowing pulses of pressured air down a pipe, then it hits this fat area that causes an expansion, changing the speed and to a lesser degree, the temperature of the air. The ideal is to have a tube which is tuned to the pulses at the right frequency by it's length and diameter. Harder to do with exhaust than with the intake unless it's just a race car.

That's the science of it, but real world? With everything else in place and just the cat being changed out, you might not notice much between gutted cat and test pipe. Maybe others have a better idea about this. Personally, my first two cats have been gutted, but I didn't do it, so I can't tell you about the differences there.

Johnny_Cracker

iTrader: (1)

Great, thanks for the help!

I'll likely just gut the cat until I can get the RB setup. Shouldn't be too long for that. (makes offering to rotary gods)


The car is so close to being ready it's making me NUTS!