Slalom4me

A Canton Road Race pan has been on my '89 L98A4 since
Sept/06 last year. I experienced (or noticed for the
first time) a Low Oil Pressure light a week ago while
braking from well over 60 MPH into an AutoX stop box.
I noticed this again this past weekend while braking hard
from 60 MPH (but not to a stop) during testing at a
different track.

The stock L98 had been reving at perhaps <= 4,500 prior
to braking. The oil level was at the mark determined to
indicate 7 qts when the pan was installed. The car
has C5 calipers w/ GM Durastop rotors, stock pads and
aged GY GS-C tires. Logs of G traces show values in a range
of -0.94 to -0.98 (with dips below -1.0) for 3 seconds.
The oil is 5W-30 typically operating at about 210ºF.

• Is the Canton pan considered good for oil control under braking?
  
• Is there any history of the baffle doors sticking open (up)?

To finish the session, I reduced braking effort until
I did not trigger the oil light. During discussion in
the pits, I proposed adding 1/2 qt but met resistance
from people who warned if the existing level was optimum,
the additional oil would wind up as windage around the crank.

After weighing this advice, I added the oil and still kept braking
effort down for the rest of the day. No further oil lights were
observed.

• Does overfilling result in maximising the fluid level
  around the pickup with the extra oil being left up in windage?
  
• Or does overfilling result in a counter-intuitive outcome with
  the fluid level falling lower around the pickup because of siphoning
  where the windage whips additional fluid from the pan up around
  the crank?

I have and use an Accusump on another vehicle. I know that C4 people
here are using an Accusump together with the Canton RR pan but
I believe their vehicles are dedicated track cars with suspension
and tires that place their performance a good deal above that of
my stock dual-purpose car.

• Is an Accusump necessary for braking at -1 G with a Canton
  pan, or is it just a band-aid for something else I should be looking at?
• What engine areas suffer most from brief low oil pressure at low RPM?

Thanks,
Ken R.

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WNDOPDLR

Ken-

Be careful!!! My new engine is in the machine shop now for exactly the same reason. I used the Canton RR pan with an Accusump and still experienced a low preassure light. My C4 is strictly track with Hoosier R compound tires, Z51 handling package and Wilwood H brakes on ZO6 calipers. My 383 stroker was built with a Melling oil pump with +10% volume. Hard braking and a sharp turn at the end of the straight would trip the OP light and cause OP to drop to the 10-15# range.

Last event at VIR my OP had dropped to 20-25# at an idle down from 60# hot. I cancelled the second day and brought it home. Found metallic looking oil when I dropped the filter. I pulled the engine and took it to my engine builder for an autopsy. We found the main bearings were shot because of starvation. Thankfully we caught it early and it will just need a set of mains, but still a PITA.

I talked to Canton several times and they were no help. Suggested I try different oil levels which didn't help. Alternately said the oil was too low then said maybe it was too high and foaming.

My solution is to go with a dry sump set up, and, while expensive, it should put an end to the problem altogether and be cheaper than rebuilds every 6-7 events. I am sick and tired of losing track time and that alone is worth the expense.

Sidney004

I know we are not comparing apples to apples, but my 94 LT1, stock oiling system, 1/2 quart overfill does not experiance the oil light coming on with 1 g braking and heavy cornering g's in a track application. Are the GM engineers smarter than Canton? Are there people that experiance this oil starvation with a stock setup?

96GS#007

Canton Pan
Hoosier R compound tires

Threshold braking....


No low pressure or oil light

63Corvette

Is an Accusump necessary for braking at -1 G with a Canton
pan,

YES!!!

MarkBychowski

Sorry, I'm no help here -- even with R compounds and the new 6-pot brakes (and PFC 01 pads) I have no oil pressure issues under braking. (Mods in sig) Only time I ever see it dip is towards the end of a long sweeper.

Ever since seeing WNDOPDLR's post a little while ago, though, I'm nervous. I'm building a new engine next year and waiting to see how his dry sump project turns out.

Vetracr

Unfortunately extreme manuvers, hard braking, autoX corners, etc. send oil flying around the oil pan. On my 90 L-98 ITE race C-4 I had the Canton pan and TWO accusumps, a one quart in the stock battery location and a 3 quart on the passenger floor. On severe drop offs such as the corkscrew at Laguna Seca or the mini mountain at Thundehill (Turn 6?) my 20psi low pressure oil light would come on. The reality is you cannot control the oil flinging around a wet sump pan. Thats why dry sumps were invented. No wet sump can control the oil like a dry sump.

One other note regarding Accusumps. They can overfill your oil pan!!!! The amount of oil in the pan or in the accusump depends on the temperature and pressure of the oil. When the engine is cold and the oil pressure high, the pressure will keep the oil in the accusump. After the oil heats up and the oil pressure drops less oil is retained in the accusump. The rest is in the pan. I ran an Oberg filter that I could open and inspect and I never saw any bearing damage from the momentary drops in pressure. They always occured in an off throttle situation. If your bearings went south in a such a short time, I would not overlook another source of oiling problems or you might repeat your problem again.

BrianCunningham

I've been calling http://www.drysump.com/ trying to figure out the best way to get a dry sump system into a C4. It's definitely easier on an L98 since you don't have the opti down there.

Here's their SBC setup.


Since you're buying a road race pan an accusump and all the fitting, the cost isn't really that much more. It's getting it to FIT that's the PITA!

Slalom4me

Thank you all for your replies.

The troubling part for me is that I am seeing a problem with
equipment that should limit my loads to well below what all of
you are capable of generating.

After considering this, I wonder whether differences in the
nature of our events and driving styles/abilities are part of
the explanation: a smooth driver on a road course may be less
likely to generate the kind of decelleration numbers/durations
that an AutoX hack who stands the car on its nose from well above
60 to a complete stop at the end of every 1.7 mi.

The delay in my reply is due to researching this and other sites
for dissatisfaction with the Canton pan. Didn't find much - with
the exception of CorvetteForum, many seem to regard the Canton as
a panecea by itself.

One tidbit I came across in searching is some info from
Corner-Carvers about the FORD version of the Road Race pan,
While that info is about the FORD pan, it seems in character with a
post made here. I went back to a C4 Tech thread
from last year that had an image of oil in a Canton, but the image has been
removed from CF member ericcer's site - I PM'd him to ask whether
he might be able to restore the pictures.

Sidney004, it is noteworthy that you and and MarkBychowski do
not observe oil pressure drops with your LTx OEM pans. I do not know
if the L98 and LTx pans are different but I notice two features
about the OEM L98 pan that might influence results.

First, the OEM pan has a horseshoe-shaped sheetmetal baffle around the
sides and forward edge of the sump, the Canton has the side kickouts
but hardly anything at the front to prevent surge. Second, the OEM
pickup is positioned in the forward section of the sump - the Canton
pickup is situated in the rearward section. Does the stock design trap
fluid under braking more effectively and keep the pickup forward where
there is more fluid for heavy braking? I don't know.

.

A third difference is the design of the OEM pickup. I've read
time and again that this pancake shape spoils the vortex and helps
prevent air & cavitation in the pump that can occur using the 'box'
style pickup like the Canton unit. When we get down to the dregs
at the bottom, is the OEM pickup better at vacuuming the last bits
and separating air from oil? I don't know.

WNDOPDLR, past experience and instinct told me that Canton might
not be much help. I followed your earlier posts about trouble with
the new engine - glad you caught it. Be sure to look at the oil
pump and the cam bearings. CLEAN the bypass and all passages
thoroughly, including the oil cooler adapter, cooler lines and cooler.
(If it had been a major meltdown, I'd say a new cooler would be in order.)
The dry sump will change the game for you but it is not an option
for me. Here is a link about dry sump tech - you might find the
remarks near the end about tuning GPM flow and the effects of
over-scavenging useful.

Vetracr, you are the first I've known to use two Accusumps.
Your remarks about overfilling are in part why I am not keen on
the Accusump. Not only can it happen during operation, inattentiveness
or lack of knowledge will lead to the Accusump discharging while
the engine is stopped. Then one eithers drains the surplus or risks
blowing seals if he trys to start the engine and recharge the Accusump.
It is comforting that Vetracr did not observe damage after off-throttle
pressure drops.

BrianCunningham and WNDOPDLR, the dry sump is
a deal breaker for me but I'll be interested to follow along on
any reports you care to make about your progress.

For now, I seem to have dodged the bullet. My operating pressure at
idle and higher RPM seems to be normal, the only change (real or
imagined) since is a momentary low OP light upon starting.

I had to drive the car a few hundred miles after the event but I will
have the oil tested and cut open the filter this week. I am also going
to insert a boroscope through the oil level sensor bung to look at the
baffle doors and the pan/pickup clearance.

.

Slalom4me

Another observation is that when the oil pressure goes away under
hard braking, it takes a while to be restored. Even with the car at rest.

I didn't have the OP sensor for my data logger installed so I can only
offer the opinion that the oil light displayed for a minimum of 3 - 5 sec.
Long enough that the second time it happened, I shut the engine down
- a very unsafe practice in the stop box with another car on course, so
this was only momentary.

Because my car is an automatic, I looked back at logs to see whether
the RPMs were dragged down low enough to trigger the OP light by the
rear wheels while braking. But the logs show the RPM did not fall below
625 until I shut down. They also show that there was 4.5 sec from
coming to a complete stop to when I cut the engine.

.

MarkBychowski

Just for clarification, I have a canton pan and no oiling problems.

Now that I've said that, I'll probably spin a few mains this summer due to something stupid like a faulty oil pressure sensor

larryfs

I run my LT4 all stock, and over filled by 1qt. 6000 track miles, and still fine...

Slalom4me

Thanks, MarkBychowski and larryfs.

Does anyone happen to know whether the LTx and L98 pans are
the same?

BTW - my thanks go out to ericcer who restored the image of the
oil fill level in his Canton. He said it might not be on his site forever
and gave permission to copy it. I resized the image a bit for the
dial-up members and added his copyright.



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