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what to do when it's raining...

exdeath

exdeath

Lifer
Take advantage of the down time for maintenance of course.

Uh oh something's missing...

engine.jpg


intake.jpg


Yuck... going to have to build a oil separator and catch can for the PCV system again. Clearly the check valve function of a PCV valve is no match for 17 psi boost.

ic.jpg


Intercooler core.

Ah there it is:

kb.jpg


Misc parts:

inj.jpg


What started this whole mess? Ever since the blower swap, I've not been able to get more than 15" vacuum. Strange thing car idled and drove fine, just a faint miss at idle and the worst part, every now and then it would stumble and hesitate for a second when going WOT, lifting, shifting, and getting back in it. Started getting really annoying as it got colder out.

Checked PCM parameters, fuel trims were fine, O2s fine, no codes, etc. Wideband looked perfectly fine. Fuel pressure solid.

A while ago I redid the entire vacuum line system: PCV, EGR modulator, eliminated the entire factory boost bypass system (2 modules and about 10 feet of vacuum line removed) no change. Checked EGR, it was perfectly fine. Checked for exhaust leaks, nothing.

Damn EFI, makes things easier most of the time, but sometimes it's so good at accommodating and hiding basic problems. Maybe it's just a tuning issue. Hmm Vacuum gauge still says 15"... took it out where I could boost it hard in 4th gear. It's normally hard to hold boost long enough to look down at the gauge due to either tire spin, rear ending someone, or staying in it long enough to do triple digits in the city in the blink of an eye. But I'm going to get to the bottom of this. Drove out of the way to a long desolate stretch and did a pull from 2k to 7k in 4th gear. AFR holding at 11.8, pulling hard.... oh wait, what's this?! Boost gauge fluttering between 15 and 17 psi. Definately a vacuum leak... BUT WHERE?!

WTF? Ok it's gotta be a intake manifold gasket or something, there is nothing else left!! Started listening around with a hose again, this time around the perimeter of the blower and intake instead of hoses... AH HA! Bad hissing coming from the front edge of the blower... but it's NOT the blower to lower intake manifold gasket, it's higher up than that. Hit the spot with a shot of carb cleaner and killed the engine. Gotcha bitch!

It was the interface between the blower and the base plate... which comes together that way, eg: nothing I did or messed with when I got the blower. #(@#*$)@(#*$@)(#$*


Close up of the flange:

rotors.jpg


And the base plate:

base.jpg


Leak was in between those two. When you get a new blower, this plate is already attached... Kenne Bell says no gasket, use silicone. There was hardly any on it when I took it apart 😡:twisted:

$70 for new gaskets for something I didn't do...

gaskets.jpg


Oh well, it's raining all weekend, can't drive the car with that much power and drag radials in the rain anyway, and I'm just about able to do blower swaps on these cars blindfolded by now.

PS: having to bend and reach to wrestle a 100+ lb blower, intercooler, and intake assembly up and out of an engine valley by yourself sucks balls.
 
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I am not familiar with blowers. So you apparently have vacuum and not boost at idle so the carb cleaner trick found it.
I would have figured the blower was downstream from the throttle plate and there would be little to no vacuum.
When does it switch over from vacuum to boost? What RPM?
 
skyking said:
I am not familiar with blowers. So you apparently have vacuum and not boost at idle so the carb cleaner trick found it.
I would have figured the blower was downstream from the throttle plate and there would be little to no vacuum.
When does it switch over from vacuum to boost? What RPM?
Click to expand...

Boost is just 0+ vacuum. It switches between vacuum and boost based on engine load, except instead of just going to 0 vacuum like a normal engine it goes beyond that to be called boost. With a twin screw you can pretty much step on it at any RPM in any gear and see boost immediately. If you spin the tires or are rolling too fast in too low a gear, you will have no load and probably won't see much boost but for an instant.

Everything up to the blower inlet is always vacuum (between the throttle blade and blower inlet). Everything between the blower outlet and intake ports can be under vacuum when there is no load, and boost when there is load.

If you need a constant vacuum supply, you would tap into the upper inlet before the blower, this is always vacuum regardless of load. If you need to hook up a boost gauge or fuel pressure regulator that sees total manifold pressure no matter vacuum or boost, you would tap into the the lower maniold after the blower.

My leak was right at the discharge port in the blower, so it was both a vacuum leak at idle/cruise, and a boost leak at WOT.
 
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Howard said:
Probably would've wanted the name Exodus instead. (semi-obscure reference)

😉
Click to expand...

The serious name he means is Kenne Bell.

To be fair I bought the blower used, no telling if the base plate was ever disturbed after it left Kenne Bell or if it left the factory that way.

There was practically no sealer/silicone between the base plate and blower.

Didn't manifest until after I drove home after tuning 😡

Oh well, the weather will allow me to let it sit a day or two before being driven to allow time for it to set well.
 
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that was the part that had me; it was after the outlet.
Glad you found it and fixed it readily.
One day we were working on our trucks and I had the intercooler outlet pipe off. Apparently I did not get it back on securely🙂
We were adjusting the pre-boost fuel and having some issues with lag. There was a ginourmous hole at low boost. At that point is was a smallish leak and had not noticed it yet. we started home on the 200 mile trek and continued to monkey with the pre-boost screw. WHOOSH! the hump hose popped off and it sounded like a leaf blower under the hood. We laughed our asses off and got it bolted back on. Funny how 32 PSI will find a way out 🙂
 
Bah, in my haste to pull the blower last night by myself, I broke the barb off the plastic vacuum diaphram that controls the idle/cruise boost bypass valve at the back of the blower (this bypasses the blower when it's not being used to keep charge temps and heatsoak down). Somewhere when I was propping up the front of the blower to remove the intercooler hose adapter, I probably slammed the back of it into the firewall or something.

Getting one overnighted from Kenne Bell, about $100 including shipping, should have it tomorrow. No hacks or JB weld here, just going to do it right and make sure that once it's back together, it will never be a problem again.

😡
 
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exdeath said:
Bah, in my haste to pull the blower last night by myself, I broke the barb off the plastic vacuum diaphram that controls the idle/cruise boost bypass valve at the back of the blower (this bypasses the blower when it's not being used to keep charge temps and heatsoak down). Somewhere when I was propping up the front of the blower to remove the intercooler hose adapter, I probably slammed the back of it into the firewall or something.

Getting one overnighted from Kenne Bell, about $100 including shipping, should have it tomorrow. No hacks or JB weld here, just going to do it right and make sure that once it's back together, it will never be a problem again.

😡
Click to expand...
Machine a fitting out of aluminum and create a flange for it?
 
I HATE those intake gaskets. They are made with a small plastic "tab" or "pole" on them, meant to line up to the intake. As you said, the blower is a bitch to install: even on the engine assembly line. That plastic tab is the main thing that lines up the blower to the head, and it used to break off ALL the time. We went through dozens of those head gaskets until the teams got good at installing the blower so they didn't break them off.

Of course we didn't have the hood in the way, so I give you mad props for managing it.
 
So the part I ordered (boost bypass valve vacuum actuator) was supposed to be overnight and Saturday delivery, it got lost in Phoenix and I didn't get it until Monday 🙁

bypass.jpg


I'm rather amused that the new part has a full metal insert for the vacuum hose barb, glad to know I'm not the only one breaking these 🙂

Made 100% sure it's not going to leak this time, made sure there was a full bead of continuous silicone seeping out on both inner and outer edges. Again, this isn't part of the normal install process with one of these blowers, the blower ships with that base plate installed and it shouldn't need to be messed with normally, and this is where I found my vacuum/boost leak. The place you DO need to look out for when you install these are the two sunken front bolts that hold the base plate to the blower. Notice how the manifold gasket passes right over the middle of them? Pack these suckers full of silicone, don't be stingy.

seal.jpg


Intercooler hosed out with a can of carb cleaner until clear then bolted up (dry of course):

ic2.jpg


The excessive oil in the lower manifold and intercooler fins prompted me to build a catch can. Normally I'm pulling a Eaton and installing a KB, this is the first time I've pulled a KB. It usually a little oily but nothing crazy, I guess the added boost from the KB does a number on the PCV system. Picked up everything for around $10 at Harbor Freight when I was picking up a set of long metric swivel tip allen sockets for $5. The main part is actually a air-water separator for air compressor hoses, with the particulate filter removed (would restrict vacuum and collapse hoses). Catch cans work like those old cloud jars with the rubber lid you've seen in science projects: in addition to the mass separation caused by the sharp change of direction, the small hose under pressure/vacuum suddenly opening up to a large chamber causes a drop in pressure, which causes the suspended oil vapor to condense and fall out of the air into the catch can, instead of your intake manifold and cold intercooler:

catch.jpg


Picked up some deeper M8x50 6mm socket head cap screws instead of using the M8x35 ones that came with the blower. The threaded holes in the cast aluminum manifold are nearly two inches deep and the short screws that came with it barely bite into maybe half an inch of thread? Didn't trust torquing them down with that little thread. Threw in some smooth chrome washers as well, not included before, to keep the screw heads from biting into the billet plate, and make them torque down smoother. Yes I'm paranoid, I've stripped the threads out of one of these lower manifolds before, before the torque wrench ever clicked at 18 ft-lbs. I don't intend on doing it again. I no longer use a torque wrench on cast aluminum manifolds: I just do it by hand until it's snug and the allen bit starts to flex. Or you can watch the silicone: torque down and watch it ooze out, when it stops oozing out, you're done. I've busted way to many bolts and stripped way too many threads waiting for a torque wrench to click at that low a setting. 18 ft/lbs is difficult as it's too low on a 3/8" wrench to be reliable, but beyond the range of a 1/4" in/lb wrench.

All assembled and ready to install, just awaiting another set of hands and allowing time for all the silicone to cure. Wrestling it out is one thing, but I don't want to be that rough sliding and rocking 100+ lbs on top of a brand new set of gaskets... so I'll just be patient and wait for some help to gently lower it into place.

assembled.jpg
 
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I hear ya on the waiting. I'm building some custom sides for my truck bed, and they get heavier and heavier. The other day I manned up and picked one off the floor to a bench, and I have paid the price for a few days now. It is not just the parts that can suffer 😉
 
Much better.

vac.jpg


Yeah all that work for a lousy 3.5" of vacuum. D: But that's all it takes for MAF based EFI to act wonky.
 
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Pulsar said:
I HATE those intake gaskets. They are made with a small plastic "tab" or "pole" on them, meant to line up to the intake. As you said, the blower is a bitch to install: even on the engine assembly line. That plastic tab is the main thing that lines up the blower to the head, and it used to break off ALL the time. We went through dozens of those head gaskets until the teams got good at installing the blower so they didn't break them off.

Of course we didn't have the hood in the way, so I give you mad props for managing it.
Click to expand...

We got it in with the lower manifold and everything attached (except for the EGR to leave some room in the back).

Didn't break the pegs, just sat it on gently, had a gap in the back, slide it to the side, and *thuump* slipped right onto both pegs simultaneously.

First time I've tried with the whole manifold. Didn't realize the ribs on the manifold slide between the head ports... made things rough being that it had to go back all the way before going down, but you can't because the firewall pinch seam is in the way, etc. Definately easier bolting the lower in first, but I didn't feel like playing slip and slide with the metal lower gasket and wet silicone 😀

Figured I'd try it this way only having to mess with two dry gaskets and everything else completely assembled. Of course however hard it was getting them on at the factory, the KB is 50% larger than the M112 in every dimension :awe:
 
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