|
The PCV system draws air from the rear of each valve cov=
er
(for '99-up; from the center of the passenger side valve cover for '97-=
'98)
to the intake manifold. Fresh air is provided from a tube connecting the
front of the passenger side valve cover to the throttle body. The facto=
ry
arrangement results in oil being drawn from the valve covers into the
intake manifold. You can see for yourself by removing the PCV valve and=
by
looking behind the blade of the throttle body. You'll notice oil in both
areas. This oil is being drawn into the combusion<=
/span>
mixture, resulting in carbon deposits, plug fouling, and pinging.
Some LS1 owners have eliminated their oil consumption
through the PCV system simply by reworking the PCV valve to be in a
vertical position. We did this on our Trans Am, but oil was still getti=
ng
into the intake manifold. This modification prevents this, while retain=
ing
the forced evacuation of the valve covers, and has a fairly stock
appearance. It does not require any permanent modification to existing =
factory
components or tubing, and can be reverted back to the stock arrangement=
in
a matter of minutes.
Detailed instructions for this modification can be found
below. Scroll down past the instructions for Discussion and FAQ section=
s.
NOTE: Installation photos below are taken on a 2001 Tran=
s Am
unless otherwise noted. <=
/o:p>
Parts list:
2 Deutsch fuel filter, PN FF314, $1.99 each
1 Deutsch PCV valve, PN PCV183, $1.59
2 Vacu-Tite 1/4" x 3/8&=
quot;
connector, PN 47306, $1.79 each
1 Vacu-Tite universal connec=
tor,
PN 47309, $1.49 (not needed for '97-'98)
1 Vacu-Tite universal tee, PN
47349, $1.49
1 Vacu-Tite 5/16" rubbe=
r cap,
PN 47394, $1.49
1 ft 1/4" fuel/emissions tubing, $0.99
2 ft (for '99-up; 3 ft for '97-'98) 3/8" fuel/emiss=
ions
tubing, $1.98 ($2.97 for '97-'98)
Flat black paint (optional)
Total cost: Approximately $20 with tax
The Deutsch fuel filters and PCV valves can be found at
AutoZone. The Vacu-Tite parts and tubing ca=
n be
found at any auto parts store. It has been our experience that Advance =
Auto
carries the 1/4" x 3/8" connectors and AutoZone does not. It =
has
also been our experience that Advance Auto is consistently more expensi=
ve
for an identical item, so when possible, we get everything but the 1/4&=
quot;
x 3/8" connectors at AutoZone. We do not have =
a Pep
Boys in the area to compare parts availability and pricing.
Illu=
strations
1 and 2 are from the '01 F-Body Service Manual, to give you an idea of =
how
the factory system is arranged on the '99-up LS1's. Illustrations 3 and=
4
show the PCV arrangement before and after the modification on '99-up LS=
1's.
Illustrations 5 and 6 are from the '98 F-Body Service Manual, and show =
the
factory arrangement on the '97-'98 LS1's.
![](3D"SMHPCVModificationforLS1_files/image001.jpg")
Illustration 1
![](3D"SMHPCVModificationforLS1_files/image002.jpg")
Illustration 2
![](3D"SMHPCVModificationforLS1_files/image003.jpg")
Illustration 3
![](3D"SMHPCVModificationforLS1_files/image004.jpg")
Illustration 4
Addendum: "3/8" tee" should read
"universal tee"; fuel filter catch can and drip leg has been
deleted. Bottom of tee is capped using 5/16" rubber cap.
![](3D"SMHPCVModificationforLS1_files/image006.jpg") Illu=
stration
5
![](3D"SMHPCVModificationforLS1_files/image008.jpg") Illu=
stration
6
Most of the new arrangement can be pre-assembled. If you=
want,
you can start by painting the Vacu-Tite uni=
versal
connector and tee with flat black spray paint. You only need to paint t=
he
center portion that will be exposed when the tubing is installed. The
1/4" x 3/8" connectors are already black.
Next, cut the tubing to the required lengths. Take the
1/4" tubing and cut 3 pieces, each 1-5/8" long. Cut the 3/8&q=
uot;
tubing into 3 pieces, in the following lengths: 1-3/4" long, 2&quo=
t;
long, and 15" long.<=
/o:p>
NOTE: for '97-'98's, replace the 1-3/4"-long piece =
with
a 13"-long piece.
Take the universal tee and trim the smallest section
(approx. 1/8" diameter) from the top and side branches. Trim the
bottom branch to the widest section.
Now pre-assemble the portion that will be upstream of the
PCV valve. Refer to Illustration 4. Take the tee and orient it as shown.
Slide the 1-3/4" piece (or 13" piece) of 3/8" tubing onto
the side branch. Put the 5/16" rubber cap on the bottom branch.
![](3D"SMHPCVModificationforLS1_files/image009.jpg")
Addendun=
: Ca=
tch
can and drip leg have been deleted. Rubber c=
ap is
used to cap bottom of tee.
Now pre-assemble the portion that will be downstream of =
the
PCV valve. Refer to Illustration 4. Connect the two small fuel filters
together with one piece of the 1/4" tubing. Pay attention to the f=
low
direction on the filters. Then connect the other two pieces of 1/4"
tubing to the other end of each filter. Take the two 1/4" x 3/8&qu=
ot;
connectors and connect the 1/4" end to the ends of the 1/4"
tubing lengths. Now connect the 2" length of 3/8" tubing to t=
he
upstream side of the filters. Connect the 15" length of 3/8"
tubing to the downstream side of the filters. Put the universal connect=
or
on the other end of the 15" length of tubing. Don't cut the small =
ends
off the connector, just install it "as-is" out of the packagi=
ng.
To complete the pre-assembled portion, install the plast=
ic
elbow on top of the PCV valve. You can use a rubber mallet to pound it =
on.
To get it to go on more easily, you can soak the elbow in hot water for
about 30 seconds. Connect the other end of the elbow to the 2"-long
3/8" tubing on the upstream side of the filter arrangement you just
put together.
![](3D"SMHPCVModificationforLS1_files/image010.jpg")
This is as much as you can do at your workbench. Take the
pre-assembled upstream and downstream pieces and head out to the car. T=
he
only tools you'll need will be a wrench with a 10mm socket and extension
and a flat head screwdriver.
The installation will be easier if you remove the airlid and silencers, MAF sensor, and throttle bo=
dy
tubing as one piece. Disconnect the IAT and MAF electrical connectors, =
pop
the air lid clips, loosen the metal band around the tubing at the throt=
tle
body, and just rotate the assembly over to the driver side of the engine
compartment. It isn't necessary to do this, but it will give you more r=
oom
to work, and allow you to clean the throttle body while you're at it.
(NOTE: on the C5, it will be necessary to remove the passenger side fuel
rail cover.)
![](3D"SMHPCVModificationforLS1_files/image011.jpg")
NOTE: the following instructions and photos are for asse=
mbly
on '99-up LS1's. After reading these instructions, see below for '97-'98
LS1's.
Remove the wire clip that is connected to the narrow end=
of
the PCV valve boot. Just pop the metal band off the boot. Next take a 1=
0mm
socket and remove the nut which secures the heat sink wire. =
![](3D"SMHPCVModificationforLS1_files/image012.jpg")
Pull the PCV valve from the tubing connecting to the int=
ake
manifold. Now slide back the foam where the PCV valve boot connects to =
the
hard rubber tubing going back to the valve covers. Pull the boot off the
tubing. You should now be holding the PCV valve boot with the valve ins=
ide,
and the heat sink wire hanging off. You can slide the heat sink out of =
the
boot, but remember its orientation. Now pull the PCV valve out of the b=
oot.
It's easiest if you pry the edge of the boot back from the ridge on the
valve. Start at one point and just work your way around the circumferen=
ce
of the valve. Once this is done, just pull and twist on the valve until=
it
works its way out of the boot.
![](3D"SMHPCVModificationforLS1_files/image013.jpg")
![](3D"SMHPCVModificationforLS1_files/image014.jpg")
![](3D"SMHPCVModificationforLS1_files/image015.jpg")
Now take the heat sink wire and re-attach it to the boot.
However, you need to slide the band back in the opposite orientation fr=
om
how it was originally installed. This will allow you to reinstall the w=
ire
and nut even though the valve will be in a different position.
![](3D"SMHPCVModificationforLS1_files/image016.jpg")
Now take the pre-assembled section with the tee and conn=
ect
the 1-3/4" length of tubing to the hard plastic tubing from the va=
lve
covers.
![](3D"SMHPCVModificationforLS1_files/image017.jpg")
Addendum: the drip leg and catch can shown
have been deleted. The bottom of the tee is capped with the 5/16"
rubber cap.
Now take the pre-assembled section with the PCV valve and
install the boot onto the valve. Install the other end of the boot onto=
the
top of the tee. Reinstall the wire clip to the tubing and reconnect the
heat sink wire nut. The elbow on top of the valve should be facing the =
rear
of the engine bay. The 3/8" x 1/4" connector nearest the valve
will have an exposed edge in the center. Slide it into the spare groove=
on
the throttle cable bracket. (Note: this doesn't apply to the C5, which
doesn't have a throttle cable bracket. On the C5, the filters will be
hidden under the fuel rail cover.) Take the end of the 15" tubing =
with
the universal connector and route it between the middle injectors. Loop=
it
back to the intake manifold and insert the connector into the manifold
tubing. The manifold tubing has a slight angle on it...you will need to
hold it straight to get the connector to slide all the way in.
![](3D"SMHPCVModificationforLS1_files/image018.jpg")
![](3D"SMHPCVModificationforLS1_files/image019.jpg") Inst=
allation
on '99-'02 F-Body
![](3D"SMHPCVModificationforLS1_files/image020.jpg") Inst=
allation
on '99-'02 F-Body
![](3D"SMHPCVModificationforLS1_files/image022.jpg") Inst=
allation
on '99-'02 C5
NOTE: the above instructions and photos above are for
assembly on a '99-up LS1. For assembly on a '97-'98 LS1, follow the ste=
ps
that are applicable. The longer piece of upstream tubing will relocate =
the
PCV valve up to the front of the valve cover. You won't need the univer=
sal
connector at the throttle body, install the tubing onto the throttle bo=
dy
nipple.
![](3D"SMHPCVModificationforLS1_files/image024.jpg") Installation on '98 F-Body
![](3D"SMHPCVModificationforLS1_files/image026.jpg") Inst=
allation
on '98 F-Body
Finally, get some throttle body cle=
aner
and clean the oil off the throttle body. Reinstall the air lid, MAF sen=
sor,
and throttle body tubing. (Note: on the C5, reinstall the fuel rail cov=
er.)
That's it. This should prevent any oil from getting into
your intake manifold. To verify that this is the case, you can pull the
tubing at the connector at the intake manifold to make sure there's no =
oil
on it. Don't worry if you see a little oil in the filters. That's what
they're there for.
You'll want to make sure that this modification hasn't
created too much of a pressure drop through your PCV system. To do this,
start the car and let it idle. Pull the fresh air tube from the connect=
ion
at the throttle body. Stick your finger at the end of the tube... you
should feel some suction. It won't be nearly as much as before the modi=
fication,
but it should be noticeable. If not, the pressure drop is choking the f=
low
too much. To correct it, remove the universal elbow and cut off the
smallest ends like you did originally. This will present the next diame=
ter
size to the airstream and improve flow.
Doing this modification, along with swapping plugs, usin=
g GM
Top Engine Cleaner, and resetting the PCM, instantly cured the audible
pinging and up to 9 deg of knock retard we were experiencing on our fac=
tory
stock 2001 Trans Am. We verified the contribution of the factory PCV
arrangement to the pinging problem by temporarily disabling the
modification. The audible pinging and knock retard immediately returned=
. We
restored the modification without resetting the PCM, and the pinging
immediately disappeared again.=
It is our opinion that the problem with the PCV system
accounts for the majority of LS1 vehicles that experience pinging from =
the
factory. We have heard of disappointed LS1 owners pursuing lemon law bu=
ybacks
or selling their vehicles as a result of this problem. It's unfortunate
that GM chooses to lose customers over this problem when providing a
solution would be simple, especially with GM's considerable resources.
We've discussed this with =
Pontiac
Customer Assistance, and were told that GM is aware of the pinging, but=
doesn't consider it a problem. GM engineers have s=
tudied
the situation and concluded that the pre-detonation "does not affe=
ct driveability or engine durability."
The modification also appears to have significantly redu=
ced
the engine's oil consumption. The car had previously used approximately=
1
qt of oil every 3000 miles, regardless of driving style. After the
modification, there has been no drop in oil level during daily driving.=
To investigate the impact of reduced PCV airflow on oil
quality, we sent an oil analysis off for analysis. The sample was taken=
at
13451 miles, which was 3135 miles and 72 days since the last oil change.
The oil level dropped 1 quart between changes, and was not topped off
between changes. The oil was Amsoil 5W-30, =
and
the filter was Amsoil. Here's the results:<=
/span>
Physical properties:
Glycol: neg
% water: <0.05
% fuel: 1.26
Viscosity 40 deg C: NA
Viscosity 100 deg C: 12.0
% solids: TR
Oil degradation:
Soot: NA
% OXD: 14.4
% NOX: 28.6
TBN: 12.0
TAN: NA
Spectrographic Analysis (PPM):
Iron: 7
Chromium: 1
Lead: 3
Copper: 79
Tin: 1
Aluminum: 5
Nickel: 0
Silver: 0
Manganese: 1
Silicon: 9
Boron: 12
Sodium: 2
Magnesium: 376
Calcium: 3148
Barium: 0
Phosphorous: 1280
Zinc: 1567
Molybdenum: 0
Titanium: 0
Vanadium: 0
Cadmium: 0=
Results of tests performed indicate:
Fuel dilution elevated: fuel present in oil – fuel
leak, excessive idling, or incomplete combustion
Oil is suitable for continued use
Resample at next regular interval
Interpretation:=
The fuel number doesn't appear to be related to oil
degradation or a result of the PCV Mod. We ran a big bottle of Techron Fuel System Cleaner in between changes, w=
hich
may have caused it. The "oil is suitable for continued use"
conclusion indicates that the SMH PCV Mod doesn't have a negative effec=
t on
oil quality when regular change intervals are maintained.
The drip leg and catch can have been deleted from the mo=
dification.
The catch can doesn't catch much oil, and the bottom of the tee is now
capped off.<=
/p>
Thanks to Steve Levine for providing the details on using
the modification with the C5's. Thanks to Jeffrey =
Dressel
for the photo of the C5 installation.
Thanks to Shane Floyd, Galen Parker, and Mark Reynolds f=
or
providing information on using the modification with the '97-'98 LS1's.
Thanks to Mark Reynolds for the photos of the '98 installation.<=
/b>
Now that people have been running the kit for awhile, we=
've
been getting some feedback. All of it has been positive. Thanks to ever=
yone
who's posted positive experiences on LS1.com and Corvette Forum. Steve
Levine was one of the first to install this modific=
ation,
and his results were shared on Corvette Forum on May 4, 2001 (thread was
not archived):
"Thanks to all that responded to my post on the rec=
ent
pinging in my 2001. I wanted to start this new thread because one of the
respondents appears to have provided a fix that I believe is very
noteworthy....Virtually immediately, the pinging is gone.=
Check out the links below for other forum discussions on=
the
SMH PCV Mod:
(Note: these links don't work on the Geocities mirror si=
te.)
PCV =
Mod by
stevenmh installed...=
SMH
Filtered Vertical PCV Mod Update
New =
PCV
Mod
PCV
vertical mod with filters
Stev=
e Hovis PCV Filter Mod
Long=
term
SMH PCV mod results
This is from an email received from someone who did the =
SMH
PCV Mod from the website instructions:
"I want to thank you for the valuable information on
your web site. I own a
2000 Camaro SS. As soon as the PCV modification was
done, the pinging went
away. I verified this using ATAP. Your atten=
tion
to detail made it very
easy. Thanks for making this information available."=
;
|
Frequently Asked Questions
|
Q. How long does it take to build the kit? How long does=
it
take to install it?
A. Once you have the parts in front of you, it should ta=
ke
approximately 30 minutes to pre-assemble the kit. It should take anothe=
r 15
- 30 minutes to install the kit, depending on how familiar you are with
your car.<=
br>
Q. How often do the filters need changed?<=
span
style=3D'font-size:13.5pt;color:#3366FF'>
A. Based on our observations, the filters should be repl=
aced
with each oil change.
Q. Is there any danger of restricting the PCV system too
much?
A. Yes. The LS1 crankcase is designed to operate under
negative pressure, which the PCV system provides. This is why it's not a
good idea to simply cap off the PCV ports to solve the problem. If the =
PCV
line were to be restricted too much, the blowby
gas could enter the crankcase faster than the line could relieve it,
causing crankcase pressure to rise. That's why it's important to check =
the
suction at the fresh air tube after doing the modification. Also, check=
the
fresh air connection at the throttle body after running the modification
for awhile. In the event that the PCV line is restricted enough to allow
crankcase pressure to rise, the pressure will relieve by backflowing through the fresh air tube once it ri=
ses
above the pressure at the throttle body. If this were to happen, the
throttle body connection would become coated with oil. This would also
happen if the PCV valve were to stick shut, either on the stock or modi=
fied
arrangement, so it's not a bad idea to check the throttle body connecti=
on
as part of your regular maintenance routine.
Q. Will this modification completely eliminate my oil
consumption?
A. Not necessarily. It depends on how and where your oil=
is
being consumed. Our car no longer uses oil during daily driving, but can
still consumes some oil under very aggressive driving. This is due to a
common problem of oil getting past the rings at high RPM's.
If your car is burning an excessive amount of oil, say more than 1 qt p=
er
1500 miles, or to the point where you can see blue smoke from your exha=
ust,
then the majority of your oil consumption is due to the rings. Doing th=
is
modification will not make a noticeable difference in your consumption =
with
so much being consumed elsewhere. If your car's oil consumption is with=
in
GM's "acceptable" limits, though, this modification should ma=
ke a
noticeable difference.
Q. Will this modification completely eliminate my pinging
and knock retard?
A. It might, but not necessarily. This modification can =
only
eliminate the pinging COMPLETELY if getting oil through the PCV system =
is
the EXCLUSIVE cause of the pinging. There are many things which can cau=
se
detonation, such as damaged, fouled, or misgapped<=
/span>
spark plugs, high coolant temperature, carbon build-up, lean fuel mixtu=
re,
and excessively advanced timing. If any of these are contributing, then=
you
may continue to experience pinging after the modification. Several peop=
le
have reported the same results that we experienced....the pinging stopp=
ed
immediately after doing the modification. There have also been reports =
that
the pinging was reduced, but not eliminated. The modification is more
likely to eliminate pinging completely on factory stock vehicles, which
detonated from the factory, where it's more likely that oil through the=
PCV
system is the only contributing factor. However, even if the modificati=
on
doesn't eliminate the pinging completely, it does eliminate the PCV sys=
tem
from the list of corrective actions, allowing you to concentrate on fin=
ding
the other source(s) of detonation. Oil in your combustion mixture doesn=
't
do good things for your octane rating, so getting rid of it should be y=
our
first step in diagnosing a pinging problem.
Q. If there really is a problem with the LS1 PCV system, wouldn't GM have corrected it by now?
A. Not necessarily. It was more cost effective to claim =
that
consuming 1 qt of oil every 2000 miles is normal than to devote resourc=
es
to correct a problem on a platform which is being discontinued. The LS6
does have a different PCV system, which would indicate that GM is aware=
of
the problem. Here's a quote from Bill Halverson, from the article Ru=
thless
Pursuit of Power: GM Brings us to the Next GEN III: LS6, from the
Official C5 Registry website:
"Closing out the LS6 story
The last major change made during the development was in=
the
positive crankcase ventilation (PCV) system. In the fall of 1998, LS6
in-vehicle testing was underway at road race facilities in the
north-central U.=
S.
Once Z06 prototypes neared production intent with expected suspension a=
nd
tire improvements, on tracks with long, sweeping turns, engineers notic=
ed
excessive oil consumption at high-rpm and high, lateral acceleration. <=
/span>
Further testing during the winter of ’98/’99
proved oil was being trapped in the valve covers then sucked into the
engine through the PCV system. The solution, which took the first half =
of
’99 to perfect, was new PCV hardware. Taking a page out of the
13-year-old, LT5 book, LS6 uses a valley-mounted oil separator assembly
rather than the rocker-cover units of the LS1. This significantly reduc=
es
oil aeration and oil consumption and simplifies the system."
From the following website:
http://www.c5registry.com/Documents/ls6/INDEX.H=
TM
GM now offers a revised PCV valve, which essentially does
the same thing that this modification does: it chokes off the PCV flow.
However, the revised valve does not filter any oil that does get throug=
h,
and the last time we checked, the valve is not off=
ically
recommended for F-Bodies, but only for LS1 trucks.
We do not guarantee the accuracy of the information prov=
ided
in this article. Perform this modification at your own risk. We are not=
responsibile for damage to you or your vehicle
resulting from the installation of this modification. This modification=
has
not been tested for compliance with emissions requirements, and should =
be
considered for off-road use only. Installation of this modification or =
any
of its components could cause GM service centers to attempt to void the
manufacturer's warranty on your vehicle.
Design, write-up, photographs, and hand sketches by Stev=
e Hovis. You may copy, distribute, and use this doc=
ument
freely, provided you are not taking credit for the content. You may NOT
sell this document or the information contained within.
|