mbeeman350

Well I only have about 900 miles on my new 383.The only thing orignal is the block. Engine has smoked since 50 miles. Thought it was the Pro Comp heads...no, valve seal...no, or the intake leaking from the lifter valley..not likely after all the changed parts.

What are the chances of 2 new sets of heads, 2 new intakes sucking oil from the lifter valley. The last time I took the intake off (3rd time) had it machined .010 on the top to be sure it clamped down good. The gaskets were crimped all the way around when I took it off. Still had oil in the intake and puddled on top of the vales Still smoking....

I think it's the rings. I have Speed Pro Hypo pistons .030 over with Perfect Circle moly faced top rings.
Talked to the tech dept at Perfect Circle/Clevite and they says the rings have not seated, and most likely won't now OR the 2nd ring is installed wrong side up on some or all the pistons. Short block was professionally machined, blue printed and assembled

So can bad rings along along with reversion put oil in the intake, the runners and the valves. I have a steady stream of blow by coming out the passenger side tube (that goes to the air cleaner base Compression was 202-212 at 450 miles.....
This whole deal makes we want to

Bob3700

Here's a couple of thoughts.

First - what kind of valve covers do you have? I had a set once that did not have a shield on the inside where the PCV valve was installed. This allowed the rocker to throw oil right at the PCV and oil consumption was an issue.

Second - have you spoken with the engine shop what put the engine together? Perhaps they can run some diagnostics (like a leak down check) and see where the problem is.

hope you get to the bottom and find your problem. Nothing worse than having your pride and joy having a problem.

Bob

mbeeman350

Thanks Bob for the input. I can't run a PCV valve because I have no baffles on the covers. I had to remove them due to clearance issues with the roller rockers. Talked to the engine builder, he wil make it good. But I have to take engine out and deliver the short block to him.
If the rings are installed wrong a leak down test will not show anything... Either way I have spent a ton of money on gaskets, fluids etc....who pays for that if the builder screwed up?

Said it before and I will say it again....crate motors are the ony way to go...Thought it would be cheaper to redo my matching numbers block...big..big mistake.

Greg

Hey Mark,
Who did your machine work and what do they think? It sounds like you've covered (and recovered) all the bases that could be the problem outside of rings.
I'll share this with you....back in the late 70's I had a '66 GTO, pulled the engine and had it rebuilt with more high perf. parts including chrome molley rings. The machinist told me at the time that they could be a bitch to seat but once seated they were terrific. Well, after about 4 or 500 miles I still had a smoking issue and did all the same stuff you did to no avail. I was working in a garage at the time with a really good old school mechanic who I was apprenticing under. He followed my problem and I finally begged him to shed some light on things.

Here's where it gets weird.

He said he had seen this a few times over his 40 plus years as a mechanic and knew a way to seat the rings but highly recommended I did not try it myself as it was a real feel/experience type of thing. He said the trick was to run the engine at about 2,000 rpm and sprinkle the slightest amount of Comet Cleanser (no kidding) down the carb and this abrasive would cut the glaze between the ring edge and the cylinder wall and immediately seat the rings.

I trusted him and I had nothing to lose at that point so I asked him to go ahead. Long story short, he did it, I watched, it worked.
I realize it sounds completely insane and, in my 26 plus years as an ASE certified tech/GM heavy line tech/etc., etc. I have never used this technique or seen it used again, but I did witness it and the results.

Now I am certainly NOT RECOMMENDING you try this but it sounds as though your problem was similar to mine and you have a glazing issue that is preventing your rings from seating. I'd talk to your machinist and see what he recommends. If the engine has to come apart for a re-hone to clear up the problem, he should step up to the plate and do it for you.
Good luck with this...I know how frustrating it can be.

Best,
Greg

happiedazs

Mark:

Keep us informed as to what the problem is and how it gets solved. I have a 75 L-82 convertible that could use an engine rebuild and I've been flopping back and forth between a rebuild (becuse the numbers match) and a quick swap crate engine. Sincce is seems that virtually everybody on this forum that does a rebuild has to do it two and three times to get it right ---- and often it's never right --- I think reading your story had mide up my mind. Forget the matching numbers and go for the crate engine. If I had the time and skills and tools to do it myself, then I would because I am a perfectionist and I would get it right ---- But since I don't have the time, the tools and the skills to do it myself, then it's the 350ci
330HP Goodwrench crate for me.

Let us know your ultimate solution.

Good Luck

Rudy

mbeeman350

Thanks Greg...that is a new ...Comet...hmmmmm

Here's another one that will make you say hmmm. Some "old school" guys told me to drain the water from ther block, could just disable the water pump, and run the motor and get it hot to help seat the rings...again a little scarry too.

Greg

Rudy,
YOU should definitely find a reputable machine shop and go for the rebuild and MAKE ABSLOLUTELY SURE THEY DO NOT DECK YOUR BLOCK.
I don't know if you are aware of this or not but, your '75 L-82 convert. is one of the rarest Corvettes to come down the pike.

Most people don't know that, unlike later years, the L-82 was not certified for use in the first few months of production due to emission issues so the L-82 only had a 7 month run in '75. Couple that with the convertible and, if I remember correctly, your car is one of only about 600 made. It's a Vette.....don't forget: Very rare = $$$.

Best,
Greg

mbeeman350

Rudy what's amazing when I was 15 in 1967 I rebuild a 283 with 70,000 miles, with original pistons, rods, crank timing chain on a gravel driveway, no cover. Honed the cylinders with an electruic drill hone with stones. Got a valve job from the local machine shop, who also knurled the guides and added PC seals. Plasti-gauged the rods and mains...never checked ring gap. Added a Duntove 30/30 cam, 2-4's, CarterAFBs..car ran great....no smoke. Never even thought about intake gaskets sucking oil, even after milling the heads to up the compression!!!!
Was it luck? I don't think so because I did a few more small blocks with buddy's.... and never had a problem. Even built one with with mis- matched pistons and rods....with no viibration. Not a 7,000 rpm engine but it ran and didn't smoke. These were not built for 100,000 miles but they ran
So I built this one right, no short cuts,and and now I have a POS engine that smokes. Smokes worse than the original 109,000 mile set up!! Go figure!

jackson

My money's split:
Upside down rings ... or ...
those heads' notoriously goofy ports still aren't a good match to gasket/intake ... or it ain't venting because you have no pcv.

Anyone ... including a pro ... can & do make that mistake on rings.

Almost anyone ... including a cheap asian knockoff shop ... can make a head that don't fit right.

Motor has to have some sort of vent/evacuation ... or it will smoke/burn oil.

If it ain't got a vent or pcv ... first thing I'd do is fix that.

SEVNT6

A GOOD machine shop that has rebuilt alot of motors & knows what they are doing will be just as good as any crate motor. And a good new motor thats broke in right should last for years.

If a new engine gets flooded it will flush the cylinder walls of oil and that will stop the rings from ever seating. I've seen that more than once during the initial start-up............

63mako

If you don't have PCV and a breather the crankcase will pressurize causing oil to be pushed past the rings and valve seals. It will use oil, smoke and have oil puddling in the intake. I have a set of nice aluminum valve covers that will clear your roller rockers, Brand new in the box with a hole and baffles in each one. They are the Edelbrock elite tall covers with no logo. These have never been installed.http://forums.corvetteforum.com/show....php?t=1675309

bashcraft

I watched my Grandfather do the exact same thing, but he used a different cleanser, I think it was Bon-Ami. Worked great. Like you said, at this point, there's nothing to lose.

mbeeman350

Jackson after the Pro Comps, I installed a new pair of Trick Flow KD 23 degree, 195's and another intake. Now the intakes were both Professional Products. The first was a Performer Knock off, second was a square bore Performer RPN knock off.

As far as venting on the engine I have a breather on the pass side and the vent tube from the valve cover to the air clener base. That should be enough. I see a steady stream of blow by coming of of the tube.

When the engine is cold, no blow by or smoke, after it warms up, different story. My guess is the oil heats up and thins out...

mbeeman350

Mako I bought and sent back a pair of tall covers

http://store.summitracing.com/partde...5&autoview=sku

But these would not clear the Scorpion 1.6 aluminum roller rockers. These covers hit the edge of the rockers and were not as wide as the regular steel covers. The height was an issue with the AC compressor.

Thinking about going to a stamped steel roller tipped rockers. They are not as long, then I could use my LT1 covers with baffles.
Mark

Oklahoma Academy

5 years ago I bought an AMC 360 "core" engine form a guy whjo took it out of his Cherokee because it smoked so badly. Funny thing was, this motor had just been rebuilt. When I tore it down to rebuild it for my AMC Hornet, I found that it looked great inside...except for one thing. The gaps on the rings were lined up! I rehoned the block, got a new set of rings and put the motor back together. I ended up with a screamer 360 AMC for about $400 ($150 for the engine,$80 for the Summit cam and lifters, $70 for the rings and gaskets and $100 for a rebuilt Holley 750).

But serioously, I would look to the breathing problem. That crankcase pressure must go somewhere....

Doug 61

I've seen the Bon-Ami trick done a couple of times, and it can work well. But I've also seen the results of using too much. Involved removing the pistons from the block with a very large hammer. If you do end up going this way, be very, very careful.
From what you've described, I don't think this is the problem. As a couple of people have said, you must have some means of crankcase ventillation. Instead of removeing the engine and stripping it again, get another set of rocker covers that have breathers, and then give the car a good run. It may take a little while to clear the oil from the intake, and you will probably have to clean the plugs a couple of times, but I would definately try this before pulling the engine.
Always go the simple way first.

Cheers, Doug

mbeeman350

Thanks to everyone for your help...seems to be alot of concern over crankcase venting. I do have a breather on the drivers side and the tube from the valve cover to the air cleaner base on the pass side
THIS SHOULD BE ENOUGH VENTING??? OR NOT??? There is a lot of blowby...

Greg

That should be adequate Mark. As long as the crank case can breath you won't build up too much pressure down there.

Big2Bird

As I stated on the last thread you posted. You have eliminated everything else. Take the engine back to the builder, and shove it up his .....!

Greg

This might be the answer....