Finally got GMC back - But have leak?

marcus mcgee

New member
Sep 29, 1997
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Ok folks, the dead GMC saga continues.

Went to NC to pick up the coach from Blue Ridge Machine Shop. Hersa,
the owner is a very nice, soft spoken southerner. Needless to say I
have been anxious to get the GMC back with the rebuild. He put all the
good stuff in - forged pistons, SS valves, Wolverine cam kit, High
volume Melling pump, ARP bolts & studs, copper exhaust gasket plus other
stuff I will write about later. He also installed the following parts I
furnished him - Caspro power drive, the Mondello torque converter, new
degreed harmonic balancer. Had block line bored and gone through and
did heads. Total installed cost of $2,700 to remove rebuild and
reinstall. I think a very good price.

On to the problem. Picked it up and drove it about 75 to 100 miles and
checked for leaks. It ran like a champ, lots of power and good
acceleration. No leaks found and time to hit the road to get home - a
740 mile trip. On the way home it was drinking 1/2 quart of oil every
300 miles. No smoke out tail pipe as confirmed by some friendly
truckers on the way. Opened it up today and found oil on passenger side
rear most plug. I have "Kool Sox" on the plugs and wires and this one
was soaked. In the valley where the plug goes there was a puddle of oil
and along the lower portion of the block and transmission it was covered
in oil. I have not removed the plug yet, the oil could not be coming
out of the cylinder as far as I know. The wires to the starter are
soaked and the general area is wet with oil. So there is a leak on the
rear passenger side of the block.

The only place I can determin is where the oil filter attaches to the
block. Perhaps he did not get a good seal or the oil filter has a
leak? The oil lines are dry and there is nothing in front of the oil
filter. OK Zak, Tom, Jim and others - do you think this is it or should
I look somewhere else? Pictures are available if you would like to see
them.

Hersa siad he would refund what ever it took to repair, and if it did
happen to be that it was burning oil he would do a nother engine and
swap it when I brought him the coach.

Marcus
 
Two possible places.

1. The fittings to the oil cooler lines, but not likely since the oil was
puddled in the #8 spark plug valley and it is not likely the leak would be
spraying exactly into that place.

2. The passenger side valve cover gasket. I would check for improperly
installed and torqued bolts, or a bad gasket installation. Also The 455 is
notorious for puddling oil in the rear of the valve cover, and than leaking
down on the #8 plug. Mondello chamfers the rear hole to allow for quicker
oil drain back down into the block. When blue ridge rebuilt the engine did
he install oil resticters in the crank main journals? If there is a lot of
oil in the top of the block that could also account for increased oil
consumption thru the valve seals.

>Ok folks, the dead GMC saga continues.
>
>Went to NC to pick up the coach from Blue Ridge Machine Shop. Hersa,
>the owner is a very nice, soft spoken southerner. Needless to say I
>have been anxious to get the GMC back with the rebuild. He put all the
>good stuff in - forged pistons, SS valves, Wolverine cam kit, High
>volume Melling pump, ARP bolts & studs, copper exhaust gasket plus other
>stuff I will write about later. He also installed the following parts I
>furnished him - Caspro power drive, the Mondello torque converter, new
>degreed harmonic balancer. Had block line bored and gone through and
>did heads. Total installed cost of $2,700 to remove rebuild and
>reinstall. I think a very good price.
>
>On to the problem. Picked it up and drove it about 75 to 100 miles and
>checked for leaks. It ran like a champ, lots of power and good
>acceleration. No leaks found and time to hit the road to get home - a
>740 mile trip. On the way home it was drinking 1/2 quart of oil every
>300 miles. No smoke out tail pipe as confirmed by some friendly
>truckers on the way. Opened it up today and found oil on passenger side
>rear most plug. I have "Kool Sox" on the plugs and wires and this one
>was soaked. In the valley where the plug goes there was a puddle of oil
>and along the lower portion of the block and transmission it was covered
>in oil. I have not removed the plug yet, the oil could not be coming
>out of the cylinder as far as I know. The wires to the starter are
>soaked and the general area is wet with oil. So there is a leak on the
>rear passenger side of the block.
>
>The only place I can determin is where the oil filter attaches to the
>block. Perhaps he did not get a good seal or the oil filter has a
>leak? The oil lines are dry and there is nothing in front of the oil
>filter. OK Zak, Tom, Jim and others - do you think this is it or should
>I look somewhere else? Pictures are available if you would like to see
>them.
>
>Hersa siad he would refund what ever it took to repair, and if it did
>happen to be that it was burning oil he would do a nother engine and
>swap it when I brought him the coach.
>
>Marcus
>
>
>
Tom & Marg Warner
Vernon Center NY
1976 palmbeach
 
Arch I have the original valve covers on mine. They don't leak a drop.
They only have to be installed correctly and have straight (not bent) gasket
flanges. the trick is to put sealer only on the valve cover and one side of
the gasket, not the cylinder head side. Torque the bolts to the factory
setting and absolutely do not over tighten.

>Marcus
>
>The guy who helps me with my engine problems says check the valve
>covers. They are real easy to get to leak. It seems that the 455 has a
>habit of putting lots of oil in the valve covers. If the seal on the covers
>is not perfect they leak. He wants me to put on cast aluminum covers.
>He says they seal a lot better. He should know he has had a 455 in
>his dragster for as long as I have known him. We wont talk about
>how long that has been. That's what I have been told.
>
>Take Care
>Arch
>
>> In the valley where the plug goes there was a puddle of oil
>> and along the lower portion of the block and transmission it was covered
>> in oil. I have not removed the plug yet, the oil could not be coming
>> out of the cylinder as far as I know. The wires to the starter are
>> soaked and the general area is wet with oil. So there is a leak on the
>> rear passenger side of the block.
>
>
Tom & Marg Warner
Vernon Center NY
1976 palmbeach
 
Marcus,

Sounds like your engine guy really stands behind his work. I don't know
too many that would even think of suggesting that they would redo an engine
for burning some oil. From the price you mentioned, I'd say you got a
pretty good deal.

With as much oil outside the engine as you say, it is probably a simple
leak. Finding it may not be so simple though.

I would check the valve cover gasket first since this would give the oil
the easiest path to the spark plug valley. I would check and make sure the
valve covers are tight. The gasket may have compressed a little after it
got hot.

My other idea would be the rear intake seal. This is a common leak on many
engines. It is also a difficult one to fix without reinstalling the
intake. It can be done if you really clean the area with some type of
cleaner (Brakeclean/Laquer Thinner CAREFUL WITH ANY PAINTED SURFACES!), and
then re-silicone (Ultra Blue) over the top of the old silicone where you
think it is leaking. This is not the ideal method, but it is much easier
than redoing the intake. If there was not silicone already there, this is
probably the spot of the leak. The rubber gaskets for the intake included
with most gasket sets are best thrown away. A big bead of Ultra Blue given
enough time to dry before putting oil in the engine has been given us the
best results. It is also a commonly used method for original equipment.

As far as the oil filter goes, we did have the oil cooler adapter above the
filter loosen up once which did cause a leak. This adapter uses an oil
filter gasket to mate with the engine. The gasket is not usually included
in Olds gasket sets, so the old one is often reused. We took a gasket from
a new filter and put it in. You could also just try tightening it without
replacing the gasket. IIRC the threaded part that the oil filter screws
onto also holds this adapter to the block. It has a hex portion which is
used to tighten the adapter to the block.

We have also had the oil filter gasket leak once. The filter turned out to
be pretty tight, but not tight enough. We were able to stop the leak by
getting another 3/4 turn out of the filter once the engine was hot.

That's all the possibilities I can think of right now. Good luck!

Hope this helps,

Zak
Seemann Motorsports

>truckers on the way. Opened it up today and found oil on passenger side
>rear most plug. I have "Kool Sox" on the plugs and wires and this one
>was soaked. In the valley where the plug goes there was a puddle of oil
>and along the lower portion of the block and transmission it was covered
>in oil. I have not removed the plug yet, the oil could not be coming
>out of the cylinder as far as I know. The wires to the starter are
>soaked and the general area is wet with oil. So there is a leak on the
>rear passenger side of the block.
>
>The only place I can determin is where the oil filter attaches to the
>block. Perhaps he did not get a good seal or the oil filter has a
>leak? The oil lines are dry and there is nothing in front of the oil
>filter. OK Zak, Tom, Jim and others - do you think this is it or should
>I look somewhere else? Pictures are available if you would like to see
>them.
>
>Hersa siad he would refund what ever it took to repair, and if it did
>happen to be that it was burning oil he would do a nother engine and
>swap it when I brought him the coach.
>
>Marcus
>
>
 
Marcus:

I had the oil leak problem on the valve covers. What I did was use 1/8" by
3/4" flat stock and placed this on the outboard (lower) top side of the
cover flanges. Drilled holes to match the cover bolt holes. You have to do
a little grinding or filing in a couple of places. This plate reinforces
the metal cover flange. Got the idea from my Audi's that I owned. This
standard equipment for them When tightening down the bolts pressure is
distributed evenly between the bolt holes. You may have to retorque the
bolts after running you engine to seat the gaskets. My leaks stopped.

Bob

77 PB

>Marcus
>
>The guy who helps me with my engine problems says check the valve
>covers. They are real easy to get to leak. It seems that the 455 has a
>habit of putting lots of oil in the valve covers. If the seal on the covers
>is not perfect they leak. He wants me to put on cast aluminum covers.
>He says they seal a lot better. He should know he has had a 455 in
>his dragster for as long as I have known him. We wont talk about
>how long that has been. That's what I have been told.
>
>Take Care
>Arch
>
>> In the valley where the plug goes there was a puddle of oil
>> and along the lower portion of the block and transmission it was covered
>> in oil. I have not removed the plug yet, the oil could not be coming
>> out of the cylinder as far as I know. The wires to the starter are
>> soaked and the general area is wet with oil. So there is a leak on the
>> rear passenger side of the block.
>
>
 
The stamped steel valve covers can become warped if the bolts are
tighten beyond the factory spec's. Cast Aluminum valve covers are nice
and would prevent leaks because they are not flexible. A more
inexpensive method would be to use extra wide vlave cover hold down
clamps. These have been around for 20 years or more. You can find these
at auto wrecking yards, but you can also buy them from JC Whitney for
4.95 for a set of 4 and they are chromed plated to boot. In my latest
catalog they are listed in the chrome and dress are or in where the
valve covers are listed.

J.R. Wright
77 Eleganza II

>
> Marcus:
>
> I had the oil leak problem on the valve covers. What I did was use 1/8" by
> 3/4" flat stock and placed this on the outboard (lower) top side of the
> cover flanges. Drilled holes to match the cover bolt holes. You have to do
> a little grinding or filing in a couple of places. This plate reinforces
> the metal cover flange. Got the idea from my Audi's that I owned. This
> standard equipment for them When tightening down the bolts pressure is
> distributed evenly between the bolt holes. You may have to retorque the
> bolts after running you engine to seat the gaskets. My leaks stopped.
>
> Bob
>
> 77 PB
>

> >Marcus
> >
> >The guy who helps me with my engine problems says check the valve
> >covers. They are real easy to get to leak. It seems that the 455 has a
> >habit of putting lots of oil in the valve covers. If the seal on the covers
> >is not perfect they leak. He wants me to put on cast aluminum covers.
> >He says they seal a lot better. He should know he has had a 455 in
> >his dragster for as long as I have known him. We wont talk about
> >how long that has been. That's what I have been told.
> >
> >Take Care
> >Arch
> >
> >> In the valley where the plug goes there was a puddle of oil
> >> and along the lower portion of the block and transmission it was covered
> >> in oil. I have not removed the plug yet, the oil could not be coming
> >> out of the cylinder as far as I know. The wires to the starter are
> >> soaked and the general area is wet with oil. So there is a leak on the
> >> rear passenger side of the block.
> >
> >
 
As someone said, what's the part number and what do they cost.
Where can you get cast valve covers. Mine have always leaked a little.
Straightened them, different gaskets, long washers, new PVC valves.
They always leaked enough to create a smell off the the manifolds.
Ted Schurman
73 Glacier VA

>
> Marcus
>
> The guy who helps me with my engine problems says check the valve
> covers. They are real easy to get to leak. It seems that the 455 has a
> habit of putting lots of oil in the valve covers. If the seal on the covers
> is not perfect they leak. He wants me to put on cast aluminum covers.
> He says they seal a lot better. He should know he has had a 455 in
> his dragster for as long as I have known him. We wont talk about
> how long that has been. That's what I have been told.
>
> Take Care
> Arch
>