455 Buick Engine -Burning Oil Question

[Takis]

As in another post I had an oil issue, but it turned out being the rocker levers needing to be changed.  

 

Well, I changed all of them - 30-32...  Things are running perfectly, at least with using my ear.

 

Because of the burning oil issue initially, that was more apparent with the rocker lever arms, I thought I fixed the burning oil issue. 

 

I then added a new PCV valve... very easy install...    What I noticed now is that I still have a burning oil issue, but I need to add a quart every 500-600 miles, as opposed to every 100-200 miles with the rocker levers...   

 

A little more history..  I recently bought the car over the winter - started driving during this summer.  I only drove about 1000 miles on it.  The 455 is a rebuilt 1972 engine placed in my 1968 GS.  According to the dealer I bought it from, the previous owner who rebuilt the engine stated that the engine has only 5000 miles when I bought it..So, it seems the engine was broken in when I bought it...  

 

Most importantly, I do not have any oil stains in  my very pristine nature stone floor garage.   Also, when I punch it, I do not get smoke out of the exhaust.. also, when I use my finger at the end of the exhaust pipe test, I do not get carbon/oil  residue.

 

So, is this normal burning of oil for a large block and not worry about it.. just place a quart every 600 miles?  Or should I be concerned?

Thanks,

 

Takis

 

 

 

[avgwarhawk]

The tailpipe black carbon is a rich running condition and probably the smoke you are seeing when punching it.     One qt of oil every 600 miles is not normal at all.    If the engine is  a true rebuild the rings need to seat.  However, dealer said the engine had 5000 miles on the rebuild.   If so, the rings should be seated...if the rebuild was done correctly.    

[old-tank]

Check the ignition including timing.  Compression check.  Bore scope if available to see if there are hone marks in the cylinders or a ridge indicating a 'rattle can rebuild'.

Try to seat the rings:  full throttle in the highest gear from 20mph or lower to 70mph; coast back and do 10 repetitions.

A new GM car I bought in 1976 used one quart per 400 miles...the factory service rep said that less than one quart per fuel fill-up was acceptable.  Independent mechanic found that the timing was way off and oil consumption dropped to one qt per 4000 miles.

[60FlatTop]

1 hour ago, old-tank said:

Compression check.

 

Step one. Dandy Dave had 80 PSIG on all six Olds cylinders in a post a couple days ago, not commonly referenced in the symptoms.

 

So many things to fix, and so few tools to diagnose them with.

Bernie

[NTX5467]

According to the OLD GM service bulletins, 600 miles/qt IS acceptable for BACK THEN.  It would take MORE oil consumption to warrant a warranty repair, back then.

 

At 5000 miles since the rebuild, I suspect that any ring seating that's going to happen has happened.  On a rebuilt motor, the "break-in time is much shorter as the block has seen many hot/cold cycled and is "seasoned", unlike a new "green" block.  During the "break-in period", the new block's moving components wear into each other, over time.  The machined clearances can "move" a bit, too, unlike the "seasoned" block.  Be that as it may.

 

You don't know what was used in the rebuild, quality-wise, but even a cheap rebuild should do decently well for 30K miles before anything "wear related" would start to appear.

 

Some might claim that all of GM's 450+cid engines used oil.  My uncle bought a new Caprice 454 in '74.  After it got some miles on it, it took one quart every tank of gas, which many considered "normal" for that motor back then.  BUT a new set of later 454 OEM silicone valve seals dried it right up!  Drove from DFW top Las Vegas needing only 1 quart of additional oil!

 

In using a borescope, IF the oil is coming up past the rings, you'll see "washed clean" areas around the outer edge of the piston top, rather than a consistent carbon layer.  Otherwise, it's coming in via the valve guides.  From what I've learned from my machine shop operative and some reading, if the stem-to-guide clearance is toward the tight end of the spec, a valve seal really isn't needed  for oil control, but as that clearance increases with wear, the seal becomes more important.  Some Buicks back then didn't use seals on the exhaust side as the exhaust meant "pressure" rather than "vacuum", as the intake side would see.  The fallacy to that orientation is that the exhaust has positive and negative pressure pulses rather than an appearing smooth flow.

 

A side issue is the bearing clearances on the mains and rods.  Oil is thrown-off from their sides as the engine runs.  If the clearance is too much, that additional oil can end up on the cylinder walls, from the bottom upward.  That puts an extra load on the oil scrapper rings to remove it, so when that happens, it might appear that the rings are not working as they should, letting too much oil get past them.

 

A compression check can be good to do, BUT with respect to oil consumption, the ONLY conclusion might be that the TOP (compression) ring is in good shape.  The rings which are more operative are the OIL RINGS below the compression ring!  Depending upon the style of oil scraper rings used, if they are installed upside down, they'll not scrape very much oil off the cylinder wall at all!

 

The ONLY thing is that it'd take a tear-down to see what might be going on.  With the heads, to check the valve stems and valve guides for sizing/clearance, plus the type and condition of the valve seals.

 

DO make sure the pcv valve has a baffle under it in the valve cover!  This can keep it from sucking oil mist/drops into it as it works!  Factory valve covers should have them already, but some aftermarket models have a very simple/basic set-up, by observation.

 

Look at the simple things first!  Make sure the base ignition timing is correct for the engine, PLUS that the vacuum advance is working.  When an engine is "run hard", it can use more oil than when it's "loafing".  Making sure the timing is right can ensure the engine is not laboring too much just to drive down the road, which might reduce oil consumption at the same time, possibly.

 

When the lead was removed from gasoline, the deposits on the end of the exhaust pipes turned "black", from their prior "light gray".  This is normal and is NOT an indication of an overly-rich carb mixture.  IF lead was still there, an overly-rich mixture would definitely lead to a "black" tail pipe insides, BUT without lead in the gas, only way to tell about an overly-rich carb mixture is visible light black smoke out of the pipe with the engine running.

 

What oil viscosity is in the car now?  To do an accurate oil consumption test on a '70s-era motor, do an oil change with "30" straight-weight motor oil rather than a multi-viscosity motor oil.  The single-weight oil can be more stable and give a better idea of the engines true oil consumption.  Do NOT use any viscosity improvers/thickeners in your oil, period!  With the much-improved oil base stocks and additive packages, if you really need them for oil consumption issues, you need a rebuild, by my orientations.

 

I found an article on oil consumption years ago.  It mentioned that if the engine used 1 drop of oil each revolution, oil consumption would be about 400 miles/quart.  With modern piston ring technologies, especially in the style of the oil ring scraper design, I've seen a new engine run 15K miles on the same oil change, and the oil level still be at the "Full" mark.   For a '70s engine, I'd consider 4000+miles/quart to be very good!  On my then-new '77 Camaro 305, after the "build oil" was changed at 3000 miles, I put Castrol GTX 20W-50 in it and at 4000 miles, it was 1/2 quart down when we changed it.  In more modern times, I'd be using 10W-40 rather than 20W-50 due to the observed power drain of the heavier oil.

 

Do the easier things first!  Don't open any assembly up unless you really have to!  Keep us posted on your progress.

 

NTX5467

[Rztrike]

My oil consumption on all my cars dropped just by using 15W40 oil for diesel engines. It has more zinc in the oil which is comparable with the older oils we are used too. The debate on whether zinc in the oil or not and how it effects are older engines can only be decided by personal results 

I would start there. Like NTX5467 said, "do the easier things first"

Edited August 28, 2018 by Rztrike (see edit history)

[old-tank]

4 hours ago, Rztrike said:

My will consumption on all my cars dropped just by using 15W40 oil for diesel engines. It more zinc in the oil which is comparable with the older oils we are used too.

I would start there. Like NTX5467 said, "do the easier things first"

Zinc had nothing to do with it.  The increased viscosity probably did.  Increased zinc is not needed unless you have a race engine with high lift cam and heavier valve springs.

[avgwarhawk]

I owned a 73 Estate wagon with  455/4.  100k on the ticker.  Oil consumption was never an issue.   The timing chain was so slack that every time the timing light flashed the balancer appeared to be going in clockwise then counter clockwise.   However, one day as I was getting down the highway I heard tapping under the hood.  Pulled into a gas station.  No oil registered on the stick.  Dumped in a qt.  No reading.  Dumped another qt.  No reading.  After the 4th qt I had a full reading. To this day...no idea where the oil went.

 

Another experience concerned a brand new Ford pick up.   Arrived to my shop with 1000 miles or so on the new engine  in the new F150.    Owner stopping because she heard tapping.   The crank case was bone dry of oil.  No idea were the oil went. 

 

Mystery to me....      

 

Change oil brand.  Go a bit thicker.  See how she like the thicker brew.            

Edited August 28, 2018 by avgwarhawk (see edit history)

[Takis]

Thanks to all for their respective info, especially to NTX5467.

 

A little more info..

 

I use 10W40 oil - no synthetic.

 

To baseline everything, I had a tune up and timing check as mentioned done when I first started driving the car in late May of this year. So, I will assume timing is OK, since a probe was used by a mechanic friend of mine and told me everything was correct during the tuneup.  Thus, Checked the ignition including timing.

 

Also, I have a breather on each aluminum header... no oil is leaking from any breather at all...

 

I changed the PCV valve, but not the baffle...  If the baffle is the rubber input portion...   from what I recall, the fit was snug and the rubber looked good.  btw, for the buick 455, the PCV valve goes right into the rear of the intake manifold (which is aluminum btw).  How do I check baffle the correct way?

 

I also recently opened up the headers to replace all rocker levers.. while things were opened, I did not see anything out of the ordinary.. I did tighten the rocker arms up to spec while opened with the same mechanic friend of mine.

 

So, next steps is to do a Compression check.

 

So, at this time, I am going to enjoy the rest of the summer/fall season and drive things around as is....  Live in CLE,OH area... and I contacted another friend of mind that rebuilds cars for years and offered to house my car in his garage through the winter (for short time, I hope) and open up the engine and do our debug.  

 

Of course, I will update with pictures, if taken, when I do anything for this topic.

 

Again, thanks for everyone's comments and advice.

 

Takis

 

 

 

 

[Takis]

I hope everyone is having a nice Fall.   Good news is I think I figured out the issue...  

 

Well, I did the compression test.  It took me about 1.5 hours.  only did the dry one, not the wet, by putting oil in before taking measurements.

 

here are the measurements:

 

Piston 1 - 152

Piston 3  - 152

Piston 5  - 152

Piston 7  - 152

Piston 2  - 150

Piston 4  - 149

Piston 6  - 150

Piston 8  - 155

 

Everything looks great...  So we placed it on the lift to see if we see anything underneath.  And we did.  We saw small oil splashings/drops all around the oil temperature senser/switch that is the normal switch for the engine oil light.  The blue part had oil leaking out of it...  thus when the car is running, it splashes some oil around ion that area.  So, I think we found the issue...

 

Unfortunately, it is winter time, and I will not be able to drive the car for 800-1000 miles to see if I go a quart done.  But we will see for sure next spring/summer.  But almost 100% sure that this was the issue.

 

The main lesson here when dealing with burningoil is place car on lift first to see if you find any oil anywhere on the engine before opening up engine.  of course, i did not open to piston, but I was thinking about it.

 

Below are pictures:

 

 

 

 

 

 

 

 

 

 

 

 

 

Edited November 9, 2018 by Takis (see edit history)

[Takis]

OK everyone...  I did not give up on this oil burning issue...  I could not see any stains on my garage floor from oil... I was still burning a quart of oil every 200-400 mikes of driving... I understand it's a big block and all of them burn oil - which I agree with my answer in a few....

 

So, I saw some oil leaking around the manifold, but not a quart or so to burn for 200 miles...  I also wanted to tweak the stok rochester 4 barrel carb... well. over the winter from reading and stuff.. I was going to replace the gasket of the intake manifold and replace the carb...  while investigating, I also went o a couple of engine restore places...   make a long story short, I am in the process in getting the entire engine rebuilt....

 

After they defraged, cleaned, bored out the engine block, we found out the main issue of the oil burning (where I suspected too) - of course it was rings, seals, ect. the pistons were carbon black as you can get from burning oil.  Even though this project is costing me money - could never do a rebuild on my own - I am glad I did it.. the professional engineer mechanic told me how the pistons were not all weighted appropriately, and more work was done on correctly balancing things and making sure all tolerances make sense due to larger cam and boring of piston holes...  

 

btw I am not a mechanic, still learning, so please forgive my terminology if not correct.

 

I have attached a picture of the block and the new carbon treated pistons along with the new head that I will be putting on.. the carb is a pro racing 4barell carb 880 CFM with new alum intak manifold.  new lifters.. rods.. ect.   new electrical system.. new converter (3000-3200 RPM I believe).. upgrading exhaust to 3" .. heavy duty timing chain..

 

the good news is that the tranny TH400 3 speed 3:23 is all working fine and tight - posi with a  shift kit in the TH400

 

We estimate from the previous ~410 stick HP 455 we will now have anywhere from 650-700HP..

 

And the reason why I am doing this is because I have a 68 GS where this rebuilt 455 is going in to...  but I still have the original matching numbers 400 motor, if I ever sell.

 

 I realize To much information - but this forum has 'helped' (I appreciate the advice, but it led me to spend more money - but having a muscle car always leads you that way) me, out and I wanted to contribute and close out with this issue.

 

Thanks,

 

Takis

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[carbking]

650~700 horsepower?????

 

Jon

[Takis]

sorry..  575-600HP.. the other range was for another engine I was speaking with the tech...  I will know exactly after the dyno is done on it next week...