Oil Mystery

R

richard dobson

New member
Jul 18, 1999
59
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0
Okay, I'm home and back in the routine, hot, and getting things
fixed.(I'm the one with the unwelcome furry stowaway stalled in Texas)
Got my ign all fixed,found leveler problem to be relay on left pump,
taking out my air cond compressor today, made wife happy by putting new
door panels on fridge, BUT NOW I MUST ADDRESS THE MAIN PROBLEM.

I used approx. one quart of oil for each 100-150 miles, that was about
24 quarts from Ca. to here in Fl.

Please let me give you the details and see if anyone can come up with
some advise(other than pulling the engine out, I don't want to hear that
one) The previous owner performed the following work 600 miles before I
bought the coach, a'78 Royale with 403.
The block was cleaned and inspected by a reputable machine shop, the
ring ridge was not noticeable enough to machine off. Cylinder wear was
minimal. P.O. reassembled engine, had a shop grind valves, valves and
guide were deemed good cond.The following parts were installed, oil pump
TRW, cam original w/new lifters and bearings, Fed Mog/TRW/Sealed Power
engine kit #MKP695A, new forged TRW standard pistons #8635p, premium
rings TRW #83230M, bearings, gaskets etc.
P.O. says the cyls were "power honed "by machine shop. He reassembled
made sure staggered gaps in rings. I removed valve cover to check valve
seals, they are the "positive type" rather than umbrella type. I
installed mew PCV valve, it doesn't smoke on hard acceleration, let up,
repeat, no blow-by noticeable at valve cover breather hole, absolutely
no leaks anywhere, pulled the spark plugs, perfect tan color on cone and
clean down in the deep recess in plug. I have not checked the
compression, but it runs great, good power, and almost 10 mpg at 65-70
mph. Has 3.66 ratio. Runs about 3100-3200 rpm at 65-70 mph. It of course
has the 3000 miles since overhaul.
Talked to TRW man and he says proper cross hatching is of course
important, (I don't want to hear that), the oil rings are s/s and the
comp rings I believe he said some moly coating.
I want a miracle simple answer. Did I dream this or did someone write in
something about oil return in valve covers ???
I am starting to like my '78 Royale again (it's hard) dick dobson
 
Hi Dick
There was some talk on the list a while back about some dipsticks being too short and showing a
quart low when they were actually OK.

I think the solution was to drain the oil and replace the filter, then add 6 quarts of oil. Start
it up and let it warm up a bit then shut it down and check the oil level. If it reads a quart low
you have found a simple fix, just file a new full mark on the dipstick. You may even want to start
with only 5 quarts and get a setting for the ADD line.

Dave Mumert
dave
- ----- Original Message -----
From: "Richard J. Dobson"
To:
Sent: June 01, 2000 9:44 PM
Subject: GMC: Oil Mystery

> I used approx. one quart of oil for each 100-150 miles, that was about
> 24 quarts from Ca. to here in Fl.
>
 
>
>
>I used approx. one quart of oil for each 100-150 miles, that was about
>24 quarts from Ca. to here in Fl.
> I installed mew PCV valve, it doesn't smoke on hard acceleration, let up,
>repeat, no blow-by noticeable at valve cover breather hole, absolutely
>no leaks anywhere, pulled the spark plugs, perfect tan color on cone and
>clean down in the deep recess in plug.

That's a lot of oil. It has to be going somewhere. It is either
going out the exhaust, leaking to the exterior or going into the
coolant and out the overflow.

If it is leaking into the cylinders you would expect that much oil to
show up on the plugs. It would also have to go out the tailpipe. Did
you check your tailpipe? Is it oily in appearance?

Check your radiator, the overflow tank and the drip tube from the
overflow tank. I doubt that its going there but check to see. If
its going there it could be a bad head gasket or other leak in the
block or a leak in the oil cooler built into the radiator.

Do you know for a fact that your dip stick is calibrated properly?
If you have too much oil in the engine it will try to throw it out
fast. Drain all your oil and replace the filter. Then put in six
quarts of oil, start the engine for a short time, shut it down and
wait about an hour to let it drain down totally into the pan. Check
the dip stick. It should be at the full mark. If it shows low, then
the stick is not right and when you bring it up to the full mark it
really is overfilled. If this is the problem either put a new line
on the dip stick or else shorten the fill tube so that the oil is at
the full mark.

Let us know what you find. I'm sure that we are all curious.

Emery Stora
77 Kingsley
Santa Fe, NM
 
Dick,
Hopefully Dave has the answer about the dipstick. Did you try running it at
a lower RPM? 3200 RPM is pretty high for a break in period or sustained
running for that matter. Could be that old bugaboo about rings not seating
cause the cylinder walls were too smooth. Folk lore has a number of ways to
seat the rings. Other than that it's probably something you don't want to
hear. Considering all the horror stories heard about products from
professional rebuilders, a person really has to worry about one put together
in the back yard by someone who's only an 'occasional' mechanic. Good luck.
Bob McLaughlin
- -----Original Message-----
From: owner-gmcmotorhome
[mailto:owner-gmcmotorhome]On Behalf Of Richard J.
Dobson
Sent: Thursday, June 01, 2000 10:45 PM
To: gmcmotorhome-d
Subject: GMC: Oil Mystery
 
Richard,
Since the plugs are clean after losing 24 quarts I think the oil is being
"pushed" out of the engine as opposed to being burned in the combustion
chamber or leaking past gasket seals(intake manifold, rocker covers
etc.--you said the engine is clean). Also, 24 quarts would have caused plug
fouling; by "plugs are clean" I assume you checked all 8. I see there have
been a few posts about overfilling and pushing out the oil. Good advice,
may want to try that first. Also, try looking where the oil is under
pressure: oil pressure sender, oil cooler lines(see Patrick's latest post) ,
oil filter and rear main seal. Try looking with engine running (be
careful).

HTH
Bob Schoner
- ----- Original Message -----
From: "Richard J. Dobson"
To:
Sent: Thursday, June 01, 2000 8:44 PM
Subject: GMC: Oil Mystery

Okay, I'm home and back in the routine, hot, and getting things
fixed.(I'm the one with the unwelcome furry stowaway stalled in Texas)
Got my ign all fixed,found leveler problem to be relay on left pump,
taking out my air cond compressor today, made wife happy by putting new
door panels on fridge, BUT NOW I MUST ADDRESS THE MAIN PROBLEM.

I used approx. one quart of oil for each 100-150 miles, that was about
24 quarts from Ca. to here in Fl.

Please let me give you the details and see if anyone can come up with
some advise(other than pulling the engine out, I don't want to hear that
one) The previous owner performed the following work 600 miles before I
bought the coach, a'78 Royale with 403.
The block was cleaned and inspected by a reputable machine shop, the
ring ridge was not noticeable enough to machine off. Cylinder wear was
minimal. P.O. reassembled engine, had a shop grind valves, valves and
guide were deemed good cond.The following parts were installed, oil pump
TRW, cam original w/new lifters and bearings, Fed Mog/TRW/Sealed Power
engine kit #MKP695A, new forged TRW standard pistons #8635p, premium
rings TRW #83230M, bearings, gaskets etc.
P.O. says the cyls were "power honed "by machine shop. He reassembled
made sure staggered gaps in rings. I removed valve cover to check valve
seals, they are the "positive type" rather than umbrella type. I
installed mew PCV valve, it doesn't smoke on hard acceleration, let up,
repeat, no blow-by noticeable at valve cover breather hole, absolutely
no leaks anywhere, pulled the spark plugs, perfect tan color on cone and
clean down in the deep recess in plug. I have not checked the
compression, but it runs great, good power, and almost 10 mpg at 65-70
mph. Has 3.66 ratio. Runs about 3100-3200 rpm at 65-70 mph. It of course
has the 3000 miles since overhaul.
Talked to TRW man and he says proper cross hatching is of course
important, (I don't want to hear that), the oil rings are s/s and the
comp rings I believe he said some moly coating.
I want a miracle simple answer. Did I dream this or did someone write in
something about oil return in valve covers ???
I am starting to like my '78 Royale again (it's hard) dick dobson
 
>
> Also, try looking where the oil is under pressure:
> oil pressure sender, oil cooler lines(see Patrick's
> latest post), oil filter and rear main seal.

My worst oil leak right now is at the filter. The oil runs down the front
of the filter and drips off the bottom. Running down the road at 70mph, I
can see the possibility that this oil might not even touch the bottom of the
coach. IIRC tho', the engine in question is a 403, which has a slightly
different oil filter arrangement.

> Try looking with engine running (be careful).

I've done this a lot lately and it's not fun. Remove the wheel well liners,
use a bright light and a good extending inspection mirror. Darn near lost
my light in the air conditioning compressor belt last night :-0

Definitely be careful!
Patrick
 
Rich, this is just a wag, but my bet would be that you have a warped intake
maniflod and you are sucking oil from the lifter galley. Same thing happened to
me and the subsequent investigation revealed that there is more warped intake
maniflods out there than you can shake a stick at. The horrendous heat in our
engines causes this warping. It will be ok until the manifold is unbolted from
the block That is when it warps.
Just a wag on my part but worth a look
Pat 77 Birch

> Okay, I'm home and back in the routine, hot, and getting things
> fixed.(I'm the one with the unwelcome furry stowaway stalled in Texas)
> Got my ign all fixed,found leveler problem to be relay on left pump,
> taking out my air cond compressor today, made wife happy by putting new
> door panels on fridge, BUT NOW I MUST ADDRESS THE MAIN PROBLEM.
>
> I used approx. one quart of oil for each 100-150 miles, that was about
> 24 quarts from Ca. to here in Fl.
>
> Please let me give you the details and see if anyone can come up with
> some advise(other than pulling the engine out, I don't want to hear that
> one) The previous owner performed the following work 600 miles before I
> bought the coach, a'78 Royale with 403.
> The block was cleaned and inspected by a reputable machine shop, the
> ring ridge was not noticeable enough to machine off. Cylinder wear was
> minimal. P.O. reassembled engine, had a shop grind valves, valves and
> guide were deemed good cond.The following parts were installed, oil pump
> TRW, cam original w/new lifters and bearings, Fed Mog/TRW/Sealed Power
> engine kit #MKP695A, new forged TRW standard pistons #8635p, premium
> rings TRW #83230M, bearings, gaskets etc.
> P.O. says the cyls were "power honed "by machine shop. He reassembled
> made sure staggered gaps in rings. I removed valve cover to check valve
> seals, they are the "positive type" rather than umbrella type. I
> installed mew PCV valve, it doesn't smoke on hard acceleration, let up,
> repeat, no blow-by noticeable at valve cover breather hole, absolutely
> no leaks anywhere, pulled the spark plugs, perfect tan color on cone and
> clean down in the deep recess in plug. I have not checked the
> compression, but it runs great, good power, and almost 10 mpg at 65-70
> mph. Has 3.66 ratio. Runs about 3100-3200 rpm at 65-70 mph. It of course
> has the 3000 miles since overhaul.
> Talked to TRW man and he says proper cross hatching is of course
> important, (I don't want to hear that), the oil rings are s/s and the
> comp rings I believe he said some moly coating.
> I want a miracle simple answer. Did I dream this or did someone write in
> something about oil return in valve covers ???
> I am starting to like my '78 Royale again (it's hard) dick dobson
 
I am a bit behind on my GMCnet reading but are you sure you
are not over filling the crankcase. Try dropping the oil
and refilling to the correct capacity based on the manual
then stick the dipstick in and see what it reads. If you
are overfilling this engine will eat it up.

>Okay, I'm home and back in the routine, hot, and getting
>things fixed.(I'm the one with the unwelcome furry
>stowaway stalled in Texas) Got my ign all fixed,found
>leveler problem to be relay on left pump, taking out my
>air cond compressor today, made wife happy by putting new
>door panels on fridge, BUT NOW I MUST ADDRESS THE MAIN
>PROBLEM.

>I used approx. one quart of oil for each 100-150 miles,
>that was about 24 quarts from Ca. to here in Fl.

=====
Alan Bredbury
Clinton, Ct.
1974 GMC 26' Classic Motorhome
http://www.finesttool.com/index.html/special.htm

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On Fri, 2 Jun 2000 08:26:27 -0700 "Robert Schoner"
writes:
> Richard,
> Since the plugs are clean after losing 24 quarts I think the oil is
> being "pushed" out of the engine as opposed to being burned in the
> combustion chamber or leaking past gasket seals(intake manifold, rocker
covers
> etc.--you said the engine is clean).

Dallas Jensen ran across an owner who was using oil at the same rate and
discovered he had a hi pressure oil pump installed and the oil was
literally pushed out the engine.

David Lee Greenberg
GMC Motorhome Registry
Dedicated to the preservation of the Classic GMC
http://www.gmcss.com/registry.htm
 
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