LenWoodruff

I have factory L82 Cast Aluminum Valve covers. The intake for the PCV valve is in front of the carb.

71VetteLover

The interior floor of the intake manifold slopes slightly down hill to the rear so any fluids dripped into it run directly into the #6 cylinder. Are you sure you're not putting too much oil into it? The reason I'm mentioning these things is sometimes it's the simple things that get overlooked. For your sake I'm hoping a simple solution can be found before tearing into it. As the 265" and early 283" didn't even use stem seals I can't see stem seals being the problem. If the #6 cylinder is scored a leak down test would likely show it.

I have seen many cases of cylinder wall scoring caused by dropped lock washers, ball bearings, nuts, bolts, snap rings, and other odds and ends that got into cylinders. Sometimes the object is just big enough to get wedged between the side of the piston top and cylinder wall (like a little spring clip of a carburetor or a tiny piece of debris that was lying in an intake manifold runner and not noticed).

LenWoodruff

I sure hope it is not what your last paragraph outlines.

I have been checking the oil after every outing so I have been meticulous about the oil level.

71VetteLover

Sealing intake manifold bolts doesn't accomplish anything other than preventing a teensy tiny bit of external oil leakage around the heads of the bolts over a long period of time. I do however use RTV on the threads of the bolts next to the water jackets because without a sealer they get pretty rusty because of water seeping in from the bolt head down. The screw-in rocker arm studs need to be sealed with RTV if the holes are tapped clear thru into the intake ports.

71VetteLover

If you're using an aftermarket dip stick it may be marked wrong for your oil pan. Is it an OEM dip stick? With the longer oil filter 5 quarts should bring it just shy of the FULL mark after the engine has been run up to operating temperature. For your sake I'm hoping it's something simple.

LenWoodruff

It is the factory dip stick. I do use the long filter.

I hope it can be resolved with changing the valve seals to a more positive seal type. We will see next week.

rklessdriver

I would suggest you keep track of oil useage after the switch to PC seals.... if the guides are just too loose the new PC seals will cut oil useage down for a short while but with the valve flopping around in the guide it wont take long for it to start sucking oil again.

It would also want to be present and have them give the valve stem the "wiggle test" while the springs are off. If you can see preceptible movement... guess what? Those guides are too loose.
Will

71VetteLover

There's no way valve stem seals alone would cause the severe fouling like your #6 spark plug got because the 265's and early 283's didn't even have valve stem seals. Do you have a TH350 transmission by any chance? If so there is a slim possibility the modulator valve has a tiny hole in its diaphragm which is allowing ATF to be sucked into the #6 intake runner BUT that usually produces a LOT of white smoke. But if it's an itsy bitsy hole it would continually allow a little bit of ATF to enter the #6 runner and foul the spark plug. If you have been losing ATF lately it might be going there; into #6 cylinder.

Do you know if the previous owner ever had any "angle milling" of the intake manifold or heads done? Was your #6 spark plug getting fouled before the recent engine work was done? Does your cylinder heads have screw-in rocker arm studs? If so there's the possibility oil is getting sucked past the threads of the #6 intake stud IF the hole was drilled and tapped clear thru the roof of the runner and the threads weren't sealed with RTV.

But I'm still betting on a scored cylinder wall OR something really wrong with the oil rings of that #6 cylinder.

LenWoodruff

I have owned the car for 36 years. I rebuilt the engine myself in the mid 80's but did not bore it. Just new rings, bearings and a second set of L82 heads that I had the bronze wall valve guides installed in with a 3 angle valve job. I used some umbrella seals that I got from a local engine rebuilder and they lasted almost 30 years.

The transmission was rebuilt last December.

Since all of the plugs are fouling I think it is more likely the valve guides than the transmission.

Vortecpro

"But I'm still betting on a scored cylinder wall OR something really wrong with the oil rings of that #6 cylinder"


Then how do you explain his oil being clean? Simply the heads are not done correct, as "rebuilt" engine cores come through my shop maybe 1 out of 50 does not have a guide/valve job problem, and when they don't have a problem its a big deal and notice is taken, its that common. Bottom line it takes many hours by a craftsman who actually cares to rebuild a head right, and lots of specialized equipment, most shops will not be bothered with the details, the only shops I've seen myself that will do what it takes were always one man shops, now shops like BES and other high end engine shops will get it right, but make no mistake there not building 2000.00 small blocks.


"

gg521

One possibility is that a ring could have been installed upside down. This will result in high oil usage.

rklessdriver

As you know, (but most if these guys don't) it cost alot of money to have even decent equipment to properly repair cyl heads.

Heck just guide reamers are $50 each.. for HSS and those don't stay sharp for very long on bronze. The guide hone I have was $400+ back in 1999.... and replacement stone sets are $40 each. Need some spot facers and seal cutters.... couple hundered before you have enough to everything common. Then theres cost of a seat and guide machine.... skys the limit today. Even an abused Serdi start at $15,000.... and Newen or Rottler $45-50K all tooled up. I guess one could get an older used Van Norman or DCM or Kwik Way or something for about $5 grand with some useable tooling.... I still hang on to my dads old VN PH2000.... it sits in the corner of the shop, takes up a bunch of space for something we rarely use today as an actual SGM - But its a great valve spring compressor for todays monster valve springs lol..... honestly its still a good machine if used within its limits. As long as the table and roll over fixture is tight and tooling good on one of those old SGMs you could at least do guides and hard seat inserts right (if you know how to use it).... but with one of those old SGMs you'd need a seat grinder stone set to valve jobs, cause none of the seat cutters for that old stuff is worth a ****. I have a few stone seat grinder sets and actually enjoy breaking one out occasionally to touch up seats, its good to keep my skill up on it, but I dont have a clue what those grinder sets would cost to replace $2 grand??? Need a Surfacer/broach too.... another $5-$25 grand.... gonna take a while to make you $$$ back on this stuff at the prices the work will stand in todays market. Glad our stuff is paid for currently but I'm always eye balling new stuff. Everytime I have to touch up a seat with the stone because a Serdi pilot is worn or blade is dull or I used too much pressure on my cut and I ended up with some chatter, I think about investing in one of those automated SGMs...... but dang its a big investment for the small amount if work we do today.

Then once one has the equipment - As you stated, one needs the skill to run the stuff and the pride to actually put out good work. Both seem lacking these days.
Will

fishslayer143

Instead of all this speculation....why don t you tear it down and find out why the rings are passing so much oil ?

LenWoodruff

I agree but since it is the engine builders responsibility I have to go with his diagnostic process to get the oil usage resolved.

Vortecpro

I understand you have to work with the builder, but I think after 170+ posts the informed are trying to tell you this: I'm not sure your builder is capable of getting the heads right, so at some point you might want to get with someone who can get it right. Personally I know way more machine shops that I wouldn't let, fix the chain on my pedal car, than I would, much less rebuild my heads, infact in my town heres the ratio-6 to 1 that's every machine shop in town except 1. It will be interesting to see what valve seals will do.

LenWoodruff

Thanks. I appreciate what you are saying and agree with your points. I should have the car back Wednesday or Thursday and then I can put some miles on it to see how much the oil usage is reduced.

71VetteLover

The Viton umbrella seals are garbage because they'll harden and break apart in less than 25,000 miles. The nylon umbrella seals will last virtually forever but they're hard to find. But even if NO valve stem seals are installed the engine will just use a little bit more oil and not foul a single spark plug. There has to be a scored cylinder or something wrong with the oil rings on that #6 piston.

See Three

Any updates?

LenWoodruff

I was going to post tomorrow after I have driven about 100 miles.

I got the car back last Thursday. They put new seals with springs that go over the valve boss on both the intake & exhaust. They did find 1 intake with no valve seal which I thought was odd.

I have driven it about 75 miles and the oil usage seems to be less.

I will drive it another 50 or so miles today and take a reading and post tomorrow.

LenWoodruff

I have driven the car about 130 miles and the oil usage seems to be still there.

Since the oil usage was 1 quart every 300 miles I want to drive it some more to get close to that mileage.

I will post again on Monday with an update.