| Author |
Message |
Robert Fischer (192.76.80.74)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 08, 2004 - 6:40 am: | |
I sure hope that when this is processed, that the form, (length of line, indents and paragraphs) are not destroyed. In the event this comes across as garbage, send your email and I'll xmt the proper form. I hate "windows"....Hey, didn't loose too much so I'll leave it.
In October, in preparation for a trip east, I changed the oil and
both the full flow and bypass filters in my Detroit 8V92TA which
resides in my 1978 4108A.
Upon the next cold start, everything is normal and continues
normal until the 8V92 approaches a coolant temperature of 130
degrees (this takes approximately 15 miles). At this point in
time, when at idle (500 RPM), I am getting dashboard
indications that there is no oil pressure and the OEM hardware
will shutdown the 8V92 within ten seconds if not resolved.
The usual scheme is to hit the highway and travel for two
to three hours and thus some distance away before this
problem is actually perceived.
As this problem becomes better defined, it is found that
increasing the idle RPM satisfies the oil pressure sensor and
whatever has happened, has not yet destroyed the engine.
At a coolant temperature of 130 degrees, it has become
necessary to idle at 600 RPM to maintain enough pressure
to prevent shutdown. At 180 degrees, it requires upwards
of 900 RPM to prevent shutdown.
The shutdown oil sensor has been tested (recently) and is
known to be working and is set at 3 PSI. This sensor is
obtaining its pressure from a TEE located on the
alternator and is supplied from an oil galley at the rear
of the engine.
The short version is as follows:
It turns out that the CarQuest full flow filter (part no. 85970XE)
(manufactured by WIX) is listed as a direct replacement for the
85970. The previous filter which was removed back in October was
the 85970 and these problems were not an issue prior to this oil
change.
The WIX technical people state that the only difference in the two
filters is that the XE suffix indicates a sightly better filtration
medium. The actual numbers are not yet available at this time. (in
pursuit of).
In the mean time,
The oil pump (with a NAPA 1970 filter) for the 8V92 has been
checked out with the following results:
Oil < 130 degrees, 500 RPM
PSI at the filter........85
PSI at the alternator....25
Oil 180 degrees 1200 RPM
PSI at the filter........45
PSI at the alternator....15
Oil 180 degrees, 500 RPM
PSI at the filter........35
PSI at the alternator.....5
I am unable to ascertain any analysis which could explain the above
circumstances.
It stands to reason that upon a cold start, the bypass (in the
full flow filter) would initially open, circumventing the
filtration medium. The suspect filter did not cause any oil
alarms at this point.
As the 40 wt oil warms up, (an unknown and indirect
relationship to the coolant temperature) at some point, the
bypass should begin to close down and the oil should then be
forced through the filtration medium. As the oil increases in
temperature, resistance through the filter medium should
decrease thus increasing flow to the oil galleys. Something
in the suspect filter goes haywire in this paragraph.
If the filtration medium was the problem, oil pressure
would drop off as the bypass valve closes (presumably
around 130 degrees) and at idle, oil pressure alarms
would indicate this (which they did). However, as oil
temperature increases, resistance through the filter
medium would decrease and thus more oil flowing. What
happens with the suspect filter is even less oil and
hence more RPMs required to maintain pressure to the
shutdown sensor. Requiring more RPMs as the oil increases
in temperature is the opposite of what one would expect
as the resistance across the filtration medium should
decrease as the temperature of the oil increases.
The manufacturer (WIX) has asked that the filter be returned.
Do I dare let go of this filter? I think that I'd rather do the
investigation.
Is there anyone knowing the mechanics of the lubrication system
that can concoct an explanation of what transpired within the
suspect filter that will explain what I experienced? |
jim mci-9 (209.240.205.60)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 08, 2004 - 6:57 am: | |
i'd put another filter on...wix is a good quality filter...there may be something wrong with the 1 you have....but a "bypass" filter. just keeps the oil from being filtered in that particular filter, it shouldn't interfere with pressure....i'd start looking at the oil pressure relief spring.... it might be broken....and check the oil-cooler by-pass spring also.... |
Geoff (Geoff) (66.238.120.38)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 08, 2004 - 7:34 am: | |
It's not the filter. You have an 8V92TA in a 4108? Do you also have a V730? If so, your idle speed is supposed to be set at 625 rpm. The pressure readings sound okay to me-- you can't compare the pressure at the full flow filter to the one off the side of the block that is suppling oil to the generator-- the pressure at the full flow filter is what the pump is putting out, at the side of the block the feed line to the generator is losing pressure by suppling the generator (and that main bearing) so reading at the tee is going to be lower than normal. I have a 6V92TA with the oil pressure sensor off the same spot and suffer the same low reading in pressure, but since I have my idle set at 625 it is not a problem. Also, while I should be getting 60 psi oil pressure running down the road I am only reading 55 psi because of the pressure loss.
--Geoff
'82 RTS CA |
Bob Gallo (64.216.140.133)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 08, 2004 - 8:19 am: | |
I have been using the same Wix filter with the same sort of results, but the warning goes at 180deg. Are you saying that changing to the NAPA filter solved the problem? |
Geoff (Geoff) (66.238.120.38)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 08, 2004 - 8:37 am: | |
I re-read the original post and perhaps I was hasty in my thoughts, but in any case I have a real problem believing that there is an oil filter problem. Oil thins out as the temperature increases so the pressure goes down as the oil gets hot. If you have to idle your 180 degree engine at 900 rpms to keep the safety shutdown from activating I would test the sensor and take oil pressure reading from a different location on the side of the block that is not shared with anything else. I hope it is not something more serious.
--Geoff
'82 RTS CA |
BrianMCI96A3 (198.81.26.45)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 08, 2004 - 2:53 pm: | |
The oil pressure for a given engine at a given RPM is the MAXIMUM oil pressure the pump is putting out.
The numbers you have given for measurements at the filter look fine to me.
If you have a filter that you have used in the past that has given you increased pressure at the alternator, then I would be concerned as to just WHAT was happening.
I would hesitate to blame the filter, I would first contact Detroit Diesel and ask them if the pressure readings you've taken at the alternator are typical, AND I'd ask them if the location of the sensor at the alternator is appropriate for your engine.
Brian |
ralph7 (208.148.72.122)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 08, 2004 - 5:46 pm: | |
Last summer oil filters failed [collapsed] internaly. Spinon type on s-60 Detroit, the manfg. recalled all with a spefic build code. I worked for the international carrier. All units were put on hoist and checked and if the code was it the filter was changed an unit put back in service. All filters were checked and those that were collapsed were held for rep. then ?? But it was a real zoo. I would take an oil sample! ralph7 |
Guy Bouchard (161.184.194.111)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 08, 2004 - 8:22 pm: | |
I'll take a bit of a guess here, but i've seen it happen before. You didn't indicate if you used a different oil for your oil change, but not too important. However you do mention that the replacement filter was a finer filtration unit which would increase resistance to oil flow; this would cause the presure regulator valve (in the oil pan) to move out an increased distance on cold start-up. If there is wear in the bore of the valve or scoring on the plunger or varnish build up, the spool will stick in this open position and continue to dump oil pressure into the oil pan. These valves are about $80.00 and we always replace them after a re-bearing. When you have this condition happen a few times, you don't take chances again;cheap insurance.
Guy 4905 |
john w. roan (Chessie4905) (69.162.16.88)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 08, 2004 - 9:01 pm: | |
If you check the oil pressure at the wrong location; it could read on the low side. The tap at the alternator could be at the end of the system. Oil pressure at hot idle on 8-71's isn't very high either. Did you put in the 8v-92 yourself? What transmission are you running? I'm sure a few on this board would be interested in the particulars, including myself. |
Robert Fischer (4.5.46.153)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 09, 2004 - 6:46 am: | |
I am sure that I am not the only one who values this board and the
participants who contribute to it. My sincere appreciation to you
all.
Jim MCI-9:
In pursuit of resolving this problem, I dumped the oil and replaced
it. I replaced the Bypass filter. Finally I replaced the Full Flow
filter. The problem (low oil pressure sensor going into alarm and
subsequent engine shutdown) was resolved when the Full Flow filter
was replaced. Now the engine behaves as it did prior to the oil
change back in October. There are no longer any oil pressure
alarms at nominal operating temperatures.
Insofar as the Full Flow filter goes, prior to October, the filter
was a CarQuest 89570. In October, I changed the oil and filters and
at this time I was given a CarQuest filter part number of 89570XE.
It is subsequent to this point in time that the oil pressure alarm
begins shutdown operations. According to the WIX people, these two
filters are interchangeable. You could put quotes around that.
We need to make a distinction here. UnFortunately I had to include
a comment about the Bypass Filter. Because it is a separate but
distinct part of the oil system I felt that it was necessary to
include in the discussion. However the Full Flow filter also has an
internal component called a bypass valve and this has nothing to do
with the Bypass Filter. I don't know about others but this can be
confusing to me.
I don't have any external crankcase oil cooler on this 8V92. There
may be a cooler internal in the oil pump assembly but if there is,
I'm unaware of it. I will investigate this later. It is too cold
for me to go outside now. There is an external transmission oil
cooler but this has nothing to do with the crankcase oil.
I did pay a mechanic to drop the oil pan and inspect the spring.
This did not get done. I can't discuss this without disparaging
the mechanic. The pressure values provided above were provided by
this mechanic and I have no reason to think there is anything
suspect about them. I have made my own measurements of some of
those values and they match up with his work.
Geoff:
I want to argue with you about whether or not its the filter. But
first I need to point out that I've seen many inexplicable things
of a highly technical nature, with that in mind, I'm very cautious
to state that I know the absolute source of this problem. However,
When I remove the suspect filter and the oil sensor shutdown
problem goes away, I am of the opinion that (and this hasn't been
done yet) if I were to reinstall the suspect oil filter, the oil
sensor shutdown problem would be back. I have about 500 more miles
on the coach and as stated above, with regard to oil pressure, it
is operating as it was prior to October.
I agree that a direct comparison of the pump pressure to the TEE at
the generator cannot be directly compared. One would expect a
nominal drop of pressure along the way. I have never liked the low
oil pressure that is at the TEE and reported electrically to the
driver. But, tens if not hundreds of mechanics tell me it is
normal. Typically, at 1700 RPM and at operating temperature of 150
to 180 degrees, I will have 20 PSI at the TEE.
With regard to the coach, it is a 4108A, with a 8V92TA retrofit attached to a V730.
Bob Gallo:
When I installed the 85970XE filter is when the symptoms first
occurred. Prior to this oil change the CarQuest filter was the
85970. Prior to the October oil change there were no oil related
problems. As the investigation proceeded, I finally replaced the
85970XE with a NAPA 1970. Within the first ten miles I was
confident that the problem was resolved.
It is my opinion that whatever the problem (if it is a problem) is
with the XE suffix. I believe that I could install the carquest
85970 and would not have oil pressure problems.
As of this point in time, I would not hesitate to continue to use
CarQuest filters which are manufactured by WIX. However, I want an
explanation of why when the oil temperature increases I loose oil
pressure and the hotter the engine gets, the less pressure I have.
I want to know what is going on.
BrianMCI96:
As I've mentioned throughout this diatribe, I have talked with many
GMC/DD mechanics. Their answers are as if they've all gotten
together and discussed this amongst themselves.
I'm going to have to break away. I've been working on this for six
hours and there has been so many interruptions that I'm just not
getting anything done.
when I get back I'll continue this discussion with brian. |
Geoff (Geoff) (66.238.120.39)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 09, 2004 - 7:44 am: | |
If you only have 20 psi at the tee at 1700 rpms you have an oil pressure problem. A common cause of low oil pressure is having the oil pressure relief valves installed incorrectly (reversed). This is what the mechanic that dropped the oil pan should have looked for-- they are clearly marked which side of the engine they are supposed to go on. If they get reversed you will never have over 40-45 lbs. of oil pressure @2100 rpm when you should be reading 55-60 off the tee. Let me add that if the pressure relief valves ARE installed correctly then you may have a bad oil pump, or someone forgot to plug the oil passage for the oil cooler.
What is the maximum oil pressure reading you get driving down the road, cold and hot?
You do have an oil cooler, it is on the side of the block towards the firewall. The oil filter housing has it's own oil pressure relief valve. If one filter has more restriction than the other one because of finer filtration materials, I can buy that. But I think if you fix your internal oil pressure problem either filter will work fine for you.
Finally, have you ever broken an imput shaft on the V730 taking off from a stop? That 8V92TA is a lot of engine for a V730. Also, do you have engine overheating problems or did you find a big enough radiator for the bus?
--Geoff
'82 RTS CA |
Robert Fischer (4.5.46.153)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 09, 2004 - 7:47 am: | |
Brian,
I'm going to have to bring the mechanic into this story.
I paid a DD mechanic to drop the pan and examine the lower end.
What happened was he made several checks of the oil pressure,
concluded that everything was fine, and then removed the oil sensor
from the TEE at the generator and then ran it to the front of the
engine which is tantamount to connecting it to the oil pump. What
this accomplished was that when hot and at idle, the reading was a
good thirty PSI. The mechanic was addressing my concerns about low
oil pressure when at idle. Of course on a cold start, the
electrical gauge was pegged at 80 PSI for thirty minutes while the
engine would warm up.
In considering what the oil shutdown sensor should be doing
(protecting the engine) attaching it to the front of the engine
block would not provide any protection to the rear mounted
components should something cause a low oil condition at the rear.
I have since reversed this and the low oil sensor is now reattached
to the TEE on top of the alternator. NOTE: heretofore I've been
improperly calling it a generator.
RALPH!
Who was the manufacturer of those filters??? Can I tell a
collapsed filter without cutting it apart??
Guy:
This engine was rebuilt about 30K ago. The power steering gear
bolts backed out and the pump dropped away from the flywheel
housing. This allowed the driven gear to drop into......you get
the picture. Very ugly.
John:
I have retrofitted engines before and thus know better than to do
another. I have an appointment to see a doctor next week as to why
I own this one.
I did not do this one nor did I rebuild it after the power
steering gear disaster. |
BrianMCI96A3 (69.34.170.181)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 09, 2004 - 2:25 pm: | |
Robert, while it is true that you have a greater degree of safety in protecting engine accessories with the oil sensor at the remote location, the intent of having an oil pressure sensor is to monitor the oil pump output and the intent of the that sensor in the engine protection system is to stop the engine BEFORE engine oil pressure goes away completely.
If you are afraid of a "low oil condition" or loss of oil pressure on some component at the rear of the engine then my reccomendation would be to install an oil pressure sensor at BOTH locations.
The original sensor installed in the tee near the alternator, and a second sensor at the location the DD mechanic chose.
I'd either add a second oil pressure gauge for the new sensor, or I'd utilize the sensor at the alternator strictly as part of the engine shut-down system.
I personally would much rather have a sensor where it can accurately monitor oil pressure...
I can not tell you the amount of time I have spent over the years while driving, glancing worriedly at an oil gauge that seems LOW!
Brian |
BrianMCI96A3 (69.34.170.181)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 09, 2004 - 3:20 pm: | |
Another thought: although it probably has nothing at all to do with Robert's problem: I did have an low oil pressure shutdown occur just before leaving to take my coach home for the first time.
We then restarted the engine and both gauges read adequate oil pressure, still, after air pressure built the engine shut down again.
We were on a tight schedule (Sunday night 6pm with work Monday at 6am), and already way way behind on time (it was supposed to be ready Saturday morning), we knew it was trouble with the engine protection system and we even swapped sensors with another coach that was known to be in working order, to no avail.
With time running out we plugged the air line to the shut off cyl. and away we went.
That was not EVEN the finish to that story, but suffice it to say, once I got her home and had a chance, when the weather was warm, I traced out all the wiring and everything seemed to be in order.
Still, for safety sake, I decided to run new wiring for the shutdown sensors.
Then I connected everything back up, started the coach, aired her up and YIPEE everything worked as it should... and has continued to work since.
I now get to shut the coach down from the drivers seat!
What I believe had happened was either a broken wire in the harness or a bad crimp on one of the connectors, with the warmer weather temporarily
restoring connection.
The moral of the story is if you have a gremlin in an electrical system that defies diagnosis, if possible, change out the wiring, worse case: You'll have new wiring, but still have a problem, though you will have narrowed the possibilities.
Brian |
ralph7 (208.148.72.106)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 09, 2004 - 5:39 pm: | |
The Wix filters collapsed inward the round hole down the center would crush inward, when you dump the oil out look down inside if it is not perfect circle to bottom. We use 15w40 and DO NOT change oil, just filters at 25,000 mi. on regular filter an 50,000mi on special Wix filter. This is on s-60 only, Mack gets oil an filters at 50,000 mi. But 25,000 mi. is about 6-8 weeks for most units,execpt sleepers, less time yet. ralph7 |
Robert Fischer (4.5.37.141)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 09, 2004 - 7:02 pm: | |
Geoff:
I have never broken an axle. However, I'm not afraid to go slow and my experience has been that there isn't any such thing as "too slow".
The mechanics tell me that the radiator is "plenty big enough", and this may be. BUT (here we go again).....If the mountain is long enough and the ambient temperature is hot enough, I get extremely uncomfortable as the temperature needle moves the width of the needle past the 180 degree marker. I have a infrared heat gauge (black box radiation theory) that verifies the electrical gauge.
Of course this brings me to the engine warming up in the first place. (Oh gezzzzzzzz....here we go....) On a cold day (35 to 40), if I leave the radiator unblocked, the engine will never exceed 130 degrees (unless I can find a very long hill where I can maintain full throttle for a considerable time). During the power steering rebuild (see above) I whinned considerable about this and both thermostats were taken out and tested. Both worked just fine. Go figure. Any ambient temperature below 40, I have between half and three quarters of the radiator blocked off. I modulate engine temperature with the OEM interior heating system. I can get over most hills without having to stop and open up the radiator.
I'm working on a remote controlled shutter system but I work reallll y slow, I'm not very smart and I have only three neurons to work with and one of those controls breathing. I'm sorry, I didn't mean to whine.
With regard to the cold/hot oil pressure at the TEE:
MAX, cold start, 1700 (hwy speed)....40PSI.
MAX, 180 degrees, 1700 RPM...........15PSI.
Basied on your latest comments, I do believe I have an issue to investigate. I am going to contemplate this for a while and then probably go to Carlton OR and discuss your comments with them. |
john w. roan (Chessie4905) (69.162.16.88)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 09, 2004 - 7:33 pm: | |
If the oil cooler pressure relief by pass valve is stuck or missing,or the cooler plugged, the oil temp could be too high, causing low oil pressure. Restricter orfice missing on the return line from the bypass filter could cause low pressure. The restriction should not be any larger than .105 There is also a pressure regulator valve located at the end of a vertical oil gallery connected to the main oil gallery. This vertical gallery is located at the front of the cylinder block on the side opposite of the oil cooler.Valve is supposed to be set for 50psi., returning excess to sump.There is also a pressure relief valve right by the oil pump which is set at 105 psi. This valve is the first one in the system. Probably the one the mechanic checked. This info comes from the 92 series service manual. |
Geoff (Geoff) (66.238.120.99)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 09, 2004 - 9:49 pm: | |
Robert--
You have a serious oil pressure problem if you only have 15 psi at 1700 rpms, but I wish you could tell me what the oil pressure is at 2100 rpms under load (driving). After you told us the story of the power steering/gear train failure I suspect that your problem is that you got a lot of metal in the oil pan from the gear train that wiped out your oil pump and it was never changed.
--Geoff |
john w. roan (Chessie4905) (69.162.16.88)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 09, 2004 - 10:20 pm: | |
I guess we better ask this basic question. What weight oil did you put back in your engine? |
John Rigby (24.174.233.46)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 10, 2004 - 7:47 pm: | |
Robert
My 671 in the 4104 oil pressure runs at
65psi @ 170deg but at 185deg it drops to 38psi. this has been this way for the 17 years I have owned the bus.
Although one time my oil pressure dropped and kept dropping slowley on a 400 mile trip. at home I droped the pan and it was a cracked pipe, taking oil from the oil pump to the block.Had I not dropped the oil pump I would not have seen the crack in the pipe. $25 fix.
John |
Robert Fischer (192.76.80.74)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 12, 2004 - 5:53 am: | |
Geoff,
The power steering rebuild was a complete rebuild for the 8v92. one cracked head replaced, both cams replaced. Time & labor came to about 13k. While this may not have been a "complete" rebuild in the true sense of the word, the engine was removed and completely disassembled. Susequent work has found some metal in the sump, it was felt that this was from the steering incident. The valve train and the crank were gone over and it all looked fine.
Incidentally, The general symptoms of the oil pressure have been this way since day one.
I think that I've mentioned that as I have travelled, I have discussed this oil pressure with many mechanics and almost always (if not always) I am told that this is a common charactistic of the 8V92.
With regard to metal damage to the pump:
I cannot believe that the mechanic would break this engine down to the extent that he did and not check the pump. However, I'll check.
With regard to the discussion of oil pressure:
I would like to know where the reading is being taken from. Every junction in the main gally to feed a bearing will cause a pressure drop and of course this will be effected by oil temperature, length of the oil galley, bearing clearance and of course whatever is plugged into the end of the oil galley itself. In my case, on a cold start, the full flow filter sees 85 PSI. The TEE on the alturnator sees 25 PSI. Is a 60 PSI drop reasonable pressure drop? In the case of hot oil, the pump only achives 45 PSI and the TEE sees 30 PSI.....But this is only a 30 PSI drop. The question is .....is this reasonable??
But, as Geoff has suggested, maybe the pump is suspect. In a cold start, the oil pump is developing 85 PSI at the full flow filter. This suggests to me that the pressure regulator is probably functioning and thus limiting pressure as it should. But, as the oil warms up, the maxium pressure seen is 45 at the filter. The internal slip/loss in the oil pump isn't even developing enough flow to engage the pressure regulator. Conversely the pressure regulator may be so sloppy that once the oil heats up the regulator looses its ability to function??? Nah.
This is getting too flippin complicated.
Keep in mind the low oil pressure and what I observed as the engine heated up. The warmer the engine, the greater the loss of oil....ie: had to spin the engine faster and faster to maintain pressure. oil pressure problems aside, how can you explain that one filter causes problems and the other doesn't.
I have sent the suspect filter back to WIX. I'll post my note to them on the board at the next opportunity.
I'll warm the cosmo cruser up today and get a hot reading at 2100. |
Robert Fischer (192.76.80.74)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 12, 2004 - 7:08 am: | |
This is the communication attached to the filter that has been shipped to WIX.
01/12/04 WIX1 RGF/hms
Application:
Detroit Diesel, 8V92TA. Remotely mounted oil filter.
Vehicle: 1978 4108 GMC coach.
PROBLEM: Severe loss of oil pressure at idle as engine temperature approaches
and exceeds 130 degrees fahrenheit.
Nominal idle is 500 RPM. As engine temperature exceeds 130 degrees,
RPM must exceed 600 RPM to maintain oil pressure. As engine
temperature approaches 180 degrees, RPM must exceed 900 to prevent
shutdown from lack of oil pressure.
This vehicle has a full flow filter and a bypass filter, both from
CarQuest.
Additional information:
Prior to the October oil change, the application filter was
the CarQuest 89570. Prior to the October oil change, there
has not been any oil related problems.
All oil changes associated with this specific problem are
rated at CF2 at 40wt. There is two different suppliers
involved but the oil does not appear to be the problem.
In the October oil change, the equivalent oil filter Carquest
89570XE was provided. According to the WIX database, the
89570XE is a direct replacement for the 89570
The oil shutdown sensor is set at 3 PSI and its source
is obtained from a 1/8" pipe TEE located at the 250 AMP
alternator. In pursuit of this problem, the oil shutdown
sensor has been tested and is known to be working
properly and properly responding to a lack of oil.
In December, in pursuit of the of oil pressure alarms at idle,
the final component (the full flow filter) is replaced.
Within ten miles it is obvious that the problem has been
resolved.
There is something drastically different between these two
filters (89570.....89570XE). According to WIX technical
support, the only difference is the better filtration medium
in the 89570XE. This explanation cannot possibly explain the
higher and higher RPMs necessary to maintain oil pressure.
The oil alarm at idle problem has been resolved by replacing the CarQuest
89570XE. There are no longer oil alarms at idle. At this time, it stands to
reason that there is something catastrophically different about this CarQuest
89570XE.
I am specifically requesting an explanation of what the CarQuest 89570XE filter
is doing with the oil as opposed the Carquest 89570 which does not seem to have
any problem. What are the conditions in the 89570XE, and where is the oil going
as the engine reaches nominal operating temperatures that in order to maintain
sufficient pressure at the sensor, that idle must exceed 900 RPM to prevent
shutdown. |
BrianMCI96A3 (69.34.170.181)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 12, 2004 - 12:09 pm: | |
A better filration medium?
If by that they mean a finer filtation medium, that may be your problem from the start.
The finer the filter the higher the restriction and the greater the pressure drop.
As a mechanic working on a customer's vehicle, if I had the engine torn down looking for damage related to metal in the engine, I would surely look in the oil pump to determine if any damage occured there.
HOWEVER, if the engine had more than a few miles on it, I would strongly recomend that the oil pump be replaced, unless it was in as new condition.
Even though the oil pump is a critical piece of the engine (yet relatively inexpensive) they are almost never changed before an overhaul.
When the opportunity presents itself, which it rarely does, a new oil pump is always a good thing.
Brian |
Robert Fischer (4.12.153.172)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 12, 2004 - 5:12 pm: | |
UPDATE:
The mechanic (who has my trust) did not disassemble the oil pump
during the power steering event. While the owner of the business
considers the work done a rebuild, the crank was not dissembled.
The camshafts were installed with new bearing and thus were mic'ed.
He did agree in principal concerning Geoff's analysis about the
springs between the pressure regulator and the relief valve being
backwards.
We also discussed the orifice that should be in the top of the
alternator immediately beneath the 1/8" pipe nipple that feeds the
oil into the alternator. This orifice should be about 0.080. He
suggests that the orifice might have worn out. How could oil wear
out an orifice? ....Since I have a maintenance gauge attached there
and there is a minor leak there I'll check the orifice out when I
clean up the leak.
The discussion also covered my feelings on the lack of oil
pressure. He reiterates his feelings that the 8V92 is famous for
this discussion but when the 180 degree, 1700 RPM, 15 PSI readings
at the alternator are the topic, he is uncomfortably quiet.
Discussion:
During a cold start and the observed oil PSI at the filter being 85
PSI, would this not be a strong indicator that the springs between
the relief valve and the pressure regulator are in the proper
location?? |
Ken Turner (205.188.209.8)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 12, 2004 - 7:53 pm: | |
I am not an expert on engines but I spent most of my life around them, up in the wheelhouse.
I have been following this with a lot of thought, and what keeps coming up is:
something in the oil pressure distribution channels/plumbing system has a very fine crack or loose fitting which is basicly closed when COLD but with the heat and thinning of the oil when Hot,opens up and lets the pressure/flow go somewhere it shouldn't go ( but still goes back into the sump ) maybe same symptoms on the suction side as well.
Also could it be just one bad bearing/bushing loose letting the pressure escape more than normal when the oil thins out?
Or is this just another Sea Story?
www.pipesusmc.net |
robert Fischer (4.12.153.172)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 12, 2004 - 9:29 pm: | |
Ken:
Until I can hold something in my hands that is known to resolve the problem, and knowing what it is and that all the symptoms of the problem can be properly explained,I will consider anything and everything. |
Geoff (Geoff) (66.238.121.54)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 12, 2004 - 9:46 pm: | |
I would:
1. Drop the pan, see if the regulators are positioned correctly. If not, correct them and recheck oil pressure. If oil pressure is still not up to 55-60 psi go to #2 anyway.
2. If regulators are right, remove oil pump and check gears and housing for damage. If the oil pump is damaged, plan on changing the oil cooler also.
--Geoff |
BrianMCI96A3 (198.81.26.45)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 13, 2004 - 11:42 am: | |
If there was no scoring in the engine when the mechanic disassembled it, then I can forgive him for not inspecting the oil pump.
HOWEVER, I think if there was a serious concern of metal damage in the engine, the FIRST thing I'd look at is the oil pump, as it is the FIRST place where damage from metal is going to appear.
If there is no damage there, most likely you will not have damage elsewhere.
And, if I found any metal in the oil pan on MY engine, I would not hesitate to change the pump.
Brian |
john w. roan (Chessie4905) (69.162.16.88)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 13, 2004 - 9:06 pm: | |
Since you didn't say, I'm assuming you have 40weight oil in your engine? If metal was found in engine when ps pump went, I find it hard to believe it didn't score the oil pump gears any. You could chech the MCI or PREVOST sites and ask where their oil pressure tap is on their 92's and what the pressure is at hot idle. |
Robert fischer (4.12.153.172)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 17, 2004 - 3:03 am: | |
Update:
The default setting on the pressure regulator
should be 100 PSI. (obtained from a Chiltons manual)
The cold start readings taken at the filter were 85 PSI at 500 RPM. This is 15% below where the pressure regulator should begin to operate.
15% is a pretty good sized number. Further more, as the engine warms up, we loose more and more until it can only develop 45 PSI.
It is beginning to look like I'm going to have to tear down the pump.
Anybody have the specifications for the pump gears? |
Robert Fischer (4.12.153.172)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 17, 2004 - 3:05 am: | |
Geoff:
Nominal operating temperature, 2000 RPM, about 25 PSI at the TEE. |
BrianMCI96A3 (69.34.199.110)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 17, 2004 - 10:26 am: | |
Robert, tear the oil pump down out of curiousity...
BUT replace it, an older oil pump will lose oil pressure by wear on the pump shafts, wear in the bores AND wear on the pump gears even IF it hasn't injested any metal.
Brian |
Robert Fischer (4.5.37.141)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 17, 2004 - 8:43 pm: | |
Brian:
I am going to tear the oil pump down. This will be scheduled sometime into the future. I am confident that (through all the work & discussion herein) the analysis is correct and my pump is leaving something to be desired (like oil pressure) |
Dwight (65.138.102.253)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 18, 2004 - 1:00 am: | |
Robert let me say want happened to me, my hydrualic fan drive broke the gears, it resides just in front of the oil pump, the mechanic said that we did not have to remove the oil pan just drain it, it was just not needed, I removed the pan any way and found all the gears there, the oil pump had some damage, the full flow filter trapped all of the metal, I removed the rod bearings and had no metal there. I replaced the pump with a used one so I can not say how much oil pressure was lost because damage, sorry.
just some ifo. for you...
Dwight |
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