Chevy 350 Blown HG at oil galley?

[Chuck Leeper]

The leak during a leakdown test, can sometimes be eliminated, by rapping the end of the valve w/ a plastic hammer. Do this while the cyl is under pressure. This will snap the valve against the seat, and you will likely see the seal improve.

 

[tony moore]

i have been thinking about this today and i realized that you might have a broken oil control ring,it would smoke bad with no loss of compression.and if it was a leaking intake seal it would have a vacum leak and run bad. i don't think it is a valve seal, but i'm just a parts changer. :wink: hth

 

[acoen]

i have been thinking about this today and i realized that you might have a broken oil control ring,it would smoke bad with no loss of compression.and if it was a leaking intake seal it would have a vacum leak and run bad. i don't think it is a valve seal, but i'm just a parts changer. :wink: hth

I thought that as well at first, but wouldn't a broken oil show blowby coming out of the valve covers. I broke a control ring and piston skirt years ago on a 327 and I lost compression and blowby was really bad.

 

[Junior Samples]

So to wrap this up heres what we had,

Shade tree mechanic did work to the head, prolly shody, and im still willing to bet he hogged out that valve guide too much. but with bad torque job and oil on the gaskets so far the prize goes to Chuck L.
He also installed the Alum intake back on and did custom torque with 50 ft #s, 30 ft #s and a few other hand tightning at 5 ft#s

Arron before you reinstall, run a straight edge along the intake runners, lets make sure he didnt hobble it

And replace with seals That O ring seal fits into that extra groove cut into the valve stem. Unlike the umbrella type, it seals the gap between the retainer and the valve stem, not the guide and stem.

and now for a little good luck hocus pocus on 1st drop of distributor, just check where your oil rod tang is facing and turn your distrib a little before so it hits the grove and slides on down, unless you marked with a sharpie where the rotor sat before pull and after pull

 

[acoen]

So to wrap this up heres what we had,

Shade tree mechanic did work to the head, prolly shody, and im still willing to bet he hogged out that valve guide too much. but with bad torque job and oil on the gaskets so far the prize goes to Chuck L.
He also installed the Alum intake back on and did custom torque with 50 ft #s, 30 ft #s and a few other hand tightning at 5 ft#s

Arron before you reinstall, run a straight edge along the intake runners, lets make sure he didnt hobble it

And replace with seals That O ring seal fits into that extra groove cut into the valve stem. Unlike the umbrella type, it seals the gap between the retainer and the valve stem, not the guide and stem.

and now for a little good luck hocus pocus on 1st drop of distributor, just check where your oil rod tang is facing and turn your distrib a little before so it hits the grove and slides on down, unless you marked with a sharpie where the rotor sat before pull and after pull

I took my time today. everything was marked, I clean brackets and parts as I went along. I got it back together around 4pm and changed the oil (again), I went slow today. I pulled the plugs and turned it over several times getting rid of any coolant left in the cylinders. Put my plugs and wires back in and she fired right up......Smoked like Chech and Chong! But I remembered that there was still oil residue in the one cylinder, and 7/8 runner along with the cat with that some coolant residue in the head. I was also low on fuel and added a bottle of Lucas injector cleaner (two days ago, not helping the problem). The smoking decreased although I smoked the place up a bit. But after about 30-60 minutes of messing with it driving slowly around the neighborhood. the smoking is nearly completely gone. I drove it to the gas station and put some 91 in it and drove it home. I opened it up a couple of times and just a couple of tiny puffs of gray smoke. The burned oil smell is gone the only thing I smell in the exhaust is Hydro Carbons (no doubt from the burned oil and carbon burning away). Once I take it on a trip along the freeway I think I'm good to go....I had my doubts for the first few minutes.

Hope I didn;t ruin the cat with the oil, we will see. I will feel better once I drive it a little more in daylight to make sure everything is good.

Once everything drys out, I will do another comp and vac test.

 

[acoen]

The leak during a leakdown test, can sometimes be eliminated, by rapping the end of the valve w/ a plastic hammer. Do this while the cyl is under pressure. This will snap the valve against the seat, and you will likely see the seal improve.

Chuck, thank you...You were right on from the start. Truck runs good with no smoke now...WoooooHoooo!

 

[Chuck Leeper]

U R most welcome. When 1 gets as old as I am, they usually have "been there, done that", when it comes to hotrods, at least!

 

[meanchicken]

I took an interest in this string cuz I'm about to change the intake gaskets on my ZZ502 due to oil consumption issues. The ZZ502 has low tension oil rings, so it is notorious for burning oil. Mine will go through a quart in leass than 500 miles...sometimes faster depending on my behaviour....so this is excessive.

The reason why I suspect my intake gaskets is because a few weeks back I noticed coolant leaking from the front and back corners of the intake. When I checked the bolts, they were all very loose. The front passenger side bolt was so loose that I probably could have backed it out by finger. I had torqued them all correctly when I assembled the engine, but I obviously was delinquent in going back and making sure they were still tight.

Aluminum intake with aluminum heads. Stainless ARP 12 points. (see pic)

The torque sequence in the GMPP assy manual that came with the engine starts on the driver side middle bolt (4th from front) and then spirals out from there...sort of. It spirals through 1, 2, 3 and 4 (center bolts on both sides) and then skips over the next 4 locations to the second hole from the end on drivers side and then spirals out from there through 5, 6, 7, 8, 9, 10, 11, 12 (12 is the back bolt on driver side) then it moves back inward to the remaining 13, 14, 15, 16 which are the third bolts from each corner. It says to TQ all bolts to 25ft-lb.

Any reason why all this would be different on a BB from a SB?

Tim

 

[Junior Samples]

Crap Tim alum to alum should only be 11 to 15#s max, i'll re-check for BB though 25#s to aluminum heads sounds kinda steep, thats more along the lines for cast heads

 

[Junior Samples]

Tim, you runnin an airgap? 5, 10, 11 and #16 bolt holes have no gasket provision and should only be snugged, they are calling for 25ft #s


Ok just looked it up and its saying to torque at 25 ft #s

Degrease the bolts thoroughly and use Teflon paste on the threads. This prevents oil from working it's way up the threads and puddling up in the intake manifold. Use silicone on the end rails of the block instead of the gaskets that came with your kit. Use brakeleen or some other cleaner that doesn't leave residue, and use a lint free cloth to wipe off the heads and intake. Use a hi-quality silicone around the water ports on the gasket. This will help prevent the recurrence of leaks.

 

[meanchicken]

Thanks, Mike.
Yup...it's an Airgap RPM and I didn't fully torque those bolts you're referencing.

I also didn't put anything other than antisieze on the bolt threads since it was stainless going into aluminum, but this time I might try a small dab of teflon paste.

Yup...I always lay a bead of silicone sealer on the end rails and don't use the ones in the gasket kits.

Around my water ports, I used the wrong kind of sealer when I assembled this engine. I tried this guey blue stuff that never really cured...it stayed guey.

I've got the right kind of silicone stuff now and will use it when I replace the gaskets.

Tim

 

[gofstbuick]

Around my water ports, I used the wrong kind of sealer when I assembled this engine. I tried this guey blue stuff that never really cured...it stayed guey.
Tim

Sounds like you used Hylomar. Wrong stuff for intake gaskets. I've been using ultra black on my intake gaskets around the water ports and I used a thin coat on the bottom of each intake runner.

 

[Chuck Leeper]

Huh??
Hylomar is one of the best gasket dressing out there.
Here's a bit of info on it.
Hylomar is impervious to oil, gasoline, glycol and other engine fluids. Hylomar is oxygen-sensor safe, seals gaps .01" or less, and performs at constant temperatures up to 600°F. With Hylomar, components are assembled, reused and reassembled with ease. Use Hylomar for thin gaps without a gasket or as a gasket dressing. It holds the gasket in place during assembly as well as giving a great seal. Use Valco’s All-In-One Silicone™ for wider gaps in place of a gasket. They are great companion products. Hylomar should be removed using Valco’s Solvent 184™.

We've been using it since it first came available. NEVER a problem.

 

[chevyII]

sometimes I just have to laugh a how some thing a made harder that it really is. How do you put a tourque wench on an intake bolt with out a dogbone adapter? glue the gaskets to the heads with 3m gorilla snoe let dry. Use a good thick gasket sealer very thin around the water passages. Install intake start center work out in a circle. Use either a wrench and a 1/4 drive ratchet. Us the torque spec as a guide 15-25 lbs isn't alot. Also never used the end seals either RTV.