Oil smoke at idle

[AJ/FormS]

I think I see your problem
It appears to me that your intake gasket is sitting too low. Any angularity issue. and the intake will suck oil from the valley.

The gasket has been pulled down during the torquing procedure. the torque spec on 5/16 bolts is around 16, not the factory spec of 35 which is for 3/8 bolts.
What I would do;
Firstly, the valvecovers have to come off, both sides. Next I would smooth the flanges on the intake to let it slide better. Then , I would get a small-port thick gasket, and open it up to fit your ports. Next I would glue the gasket to the head so it can't move . And finally, I would maybe smear some thin-film grease on the intake flanges, around the bolts so it can slide without tearing the gasket

And one more thing; Those valve covers usually require a notch over the runners, else they will not seat properly on the heads. Check yours out carefully after the intake is back on. And remember; 5/16 bolts are ~16 ftlbs!

BTW
you can find a valley leak by flipping the PCV out,sealing the valve covers, and
putting a vacuum gauge on the dipstick tube. Then start the engine and let it idle. There should not be any vacuum in the engine when set up like this. In fact, it should begin to build pressure almost right away. Shut it off before it hits 2 or 3 psi, so you don't blow your cam-plug out.

 

[charlesvolare]

I think I see your problem
It appears to me that your intake gasket is sitting too low. Any angularity issue. and the intake will suck oil from the valley.

The gasket has been pulled down during the torquing procedure. the torque spec on 5/16 bolts is around 16, not the factory spec of 35 which is for 3/8 bolts.
What I would do;
Firstly, the valvecovers have to come off, both sides. Next I would smooth the flanges on the intake to let it slide better. Then , I would get a small-port thick gasket, and open it up to fit your ports. Next I would glue the gasket to the head so it can't move . And finally, I would maybe smear some thin-film grease on the intake flanges, around the bolts so it can slide without tearing the gasket

And one more thing; Those valve covers usually require a notch over the runners, else they will not seat properly on the heads. Check yours out carefully after the intake is back on. And remember; 5/16 bolts are ~16 ftlbs!

BTW
you can find a valley leak by flipping the PCV out,sealing the valve covers, and
putting a vacuum gauge on the dipstick tube. Then start the engine and let it idle. There should not be any vacuum in the engine when set up like this. In fact, it should begin to build pressure almost right away. Shut it off before it hits 2 or 3 psi, so you don't blow your cam-plug out.

Post #4 in thread:

Unplugging the pcv didn't change it. Capping everything and vacuum gauge on dipstick showed crankcase was building pressure, so I'd start to rule out intake gasket from that.

When it's not 30 degrees and rainy I'll pull the valve covers and see if the valve seals are all looking okay, seals were fresh on the heads less than 20,000 miles ago.

It's not burning a crazy amount, and when it is it's after the engine has sat at operating temp for a few seconds. I did the vacuum gauge without it fully warmed up so it may be incorrect.

 

[volare 1977]

From memory mine only seemed to be smoking slightly at idle too. Not when I ran it hard or on decel .

 

[AJ/FormS]

@charlesvolare

Ouch; busted.
IDK how I missed that.
I mean it was only the 4th post,lol.

But you know, at idle, a stock engine will read a very high intake vacuum. As the cams get bigger, the highest vacuum moves up the rpm scale. With the bigger street cams, peak vacuum may not arrive until 2000 rpm or a little higher.
Since you have eliminated the valley as the oil source, then there are only two other ways into multiple chambers.

 

[AJ/FormS]

What's going on , on the top of this piston?
Sorta looks like evidence of detonation.......

 

[charlesvolare]

What's going on , on the top of this piston?
Sorta looks like evidence of detonation.......


View attachment 39405

Just a crappy inspection camera. I hope. Looking through the sparkplug hole the pistons look fine.

 

[charlesvolare]

Chinese intake seemed to have 85* flange angle, got a deal on a new Edelbrock 7577 and it was 87* using the same method. Installed the new intake, STILL burning oil. Still only after it's up to temp at idle, nothing on initial startup so I don't think it's valve seals. It's worse with the pcv unplugged, and with the pcv and breather plugged, it's slowly building crankcase pressure, so no vacuum leak. No excessive blow-by so I don't think it's headgaskets.

Oil is still visible on top of multiple pistons. Did a dry/wet compression test. Three cylinders were low dry- 170, 180, 190. The rest were 205-210. Adding oil brought everything to 210. So rings seen to be the last choice.

The engine ran great up until the day it started smoking.... Kb107's, fresh hone, new moly rings. Top compression rings were gapped to .032", second were 0.020" oil control rings were checked and within recommended spec.

Any ideas on what could cause ring damage so suddenly? Detonation, pinching the top ring and scoring cylinder? I haven't verified this yet, but it seems to me to be a ring problem, there's not much left to check other than pulling it apart.

 

[charlesvolare]

Here's a video of it at it's worst, no pcv, idle at temp

 

[charlesvolare]

Something like this:

Does that make sense as to how rings would possible damage and cause smoking so suddenly?

 

[Duke5A]

Damn man, this sucks. I know those KYB pistons have their own ring gap specs and it looks like you've got that per their spec. Moly rings require a special type of honing process or they won't seat properly. Other than, check the carb? Is it washing the rings out with fuel?

 

[charlesvolare]

Damn man, this sucks. I know those KYB pistons have their own ring gap specs and it looks like you've got that per their spec. Moly rings require a special type of honing process or they won't seat properly. Other than, check the carb? Is it washing the rings out with fuel?

It ran good for 500 miles, I assumed they had seated fine. It was a Saturday fun day "autocrossing" with my buddies that started it.

I haven't thought about it getting fuel washed, it seemed fine. I messed with the carb the weekend before the autocross, took the carb apart a few times getting things tuned up. Wideband showed ~13:1 idle at the time, 14:1 cruise, 12.5:1ish hard acceleration. It wasn't too much off. The oil has fouled the sensors I think so it's not reading correctly now so I'm not sure how it's doing exactly. I did notice it looked like it was leaking slightly around the accelerator pump area. What would be some things to check for fuel wash?

 

[volare 1977]

Damn, at least you know it wasn`t the intake. Sorry to see that on such a new engine. Detonation maybe?

 

[Duke5A]

What kind of carb are you running? I have to admit carbs are a little out of my wheelhouse. You know what the fuel pressure PSI is?

Sorry, I haven't gone back through the thread, but have you attempted a leak down test?

 

[charlesvolare]

What kind of carb are you running? I have to admit carbs are a little out of my wheelhouse. You know what the fuel pressure PSI is?

Sorry, I haven't gone back through the thread, but have you attempted a leak down test?

Holley 750, electric fuel pump w/ regulator and pressure should be around 6 psi. I did adjust the secondary float level a bit the weekend before it started happening, but it's not flooding as far as I can tell. I was wanting to go through it all with new gaskets but wanted to figure this out first.

I attempted a leak down test, most were pretty similar cylinder to cylinder besides one or two if I remember, but I really need to redo it.

I feel like if it were rings it would be more constant. This weekend I'll hopefully strap a GoPro under the car and see what exactly it's doing while I'm driving. The more I think about it the more I'm suspecting a guide/seals issue but I don''t see how that could occur suddenly out of nowhere.

 

[charlesvolare]

So the smoking ended up stopping on its own. No problems for about a month and a half, and I've driven it long and hard without any problems. Then it started back today....

Rings were seated during initial break-in, oil changed and GP-1 oil added. Great for the first 500 mile break-in

Did the first oil change, drove hard, started smoking. Smoked slightly for a few weeks. I did all kinds of things, replaced intake gaskets, intake, added trans fluid to oil to swell the seals. It eventually just stopped on its own. Drove many miles, was hard on it, no problems. Even had a 700 mile road trip day, 3000rpm at 65mph for 700 miles in a single day. Cruised like a dream.

Did the second oil change at around 2,000 miles since rebuild (odometer stopped working). About 30 miles of light driving, starts burning oil again.

That's were I'm at. Still need to stick a go-pro under the car to see if maybe it's seals/guides.

It never burned enough to need to add any oil, only happens when sitting at idle for a bit on a hot engine. Doesn't do it when the engines cold.

I have another thread about this in fabo and I think the conclusion there is that the bottom end is trash and I need new rings. But also say rings don't seat and unseat and seat back again. I'm at a loss for what it could be.