I have smoking fumes coming from a silver vent thing, on the rocker cover, why is it smoking?, what is this sliver vent thing?
here's a pic, vent on righthandside of rocker cover


cheers

dave

 

im no mechanic but the last vet i had 20 years ago had same problem . i beleive it was called blowby that came from the breather on valve cover, anyway i ended up rebuilbing engine. im sure someone with more knowledge will know for sure.

 

On the driver's side is a PCV valve in the valve cover, attached to a vacuum line attached to the tree on the manifold.

Pull that PCV valve out, and see if it rattles when you shake it. If not, spray it with some brake parts cleaner to help free it up.

Buy some Sea Foam next time you are at an Autozone or Oreilly and when you have that PCV vacuum line disconnected, slowly suck up some Sea foam through it.

It should suck it up quick and the engine idle will speed up so go slow with it. It'll clean everything out. If you can, suck a little bit of Sea Foam through all the vacuum tubes leading into the carb.

After you do that see if that smoke goes away. You may have bad valve guides.

 

My god thats a nasty looking engine compartment. The headers and new fuel lever return spring sure brightens things up. Check the pvc valve...it might be plugged in that shrine to cleanliness. Otherwise. yea , the rings are going south.
Oh, that silver thing is an "oil beather cap". good luck

 

Thanks! lol, Ive only had the car for 2 months, give me a chance to sort out all the more important probs, then I will clean up the engine bay, lol

does it need a vent there?, and pcv is on the other rocker cover, does that make any difference?

cheers

dave

 

I was thinking, give were talking about worn rings, etc, then there would be smoke coming out of zorst?, at the present time there is no smoke coming out of zorst, even when you rev it hard, it still clean??

thoughts?

dave

 

DB: Daves's from the uk,
I'm not sure but i dont think we have Autozone or Oreilly in the Uk yet.

 

Ha yeah I see it now from his writing style but I had no way of knowing that, his profile is not filled out.

 

My apoligies Dave. When I saw the engine picture,and the modifications ,I thought you were pulling our leg in humor.
The silver oil cap is a vent. It should allow the engine to breath..the PVC valve sucks vapors out of the crankcase and runs them back thru the base of the carb. If you look at the engine from the front of the car, just in back of the carb is a line running off to the right,makes an
90*elbow,into the valve cover. Simply pull it out. Shake it. It should have a rattle. If it doesnt,replace it,their cheap. Vapors should not be comming out of the oil cap over on the left side valve cover. If the PVC is good, then that might very well be a sign of a tired engine. Dont worry,its not about to blow up or break, its just getting loose. Perhaps this winter you might think about a rebuild. Before I did that tho, I would run a compression test on each cylinder to find out more info. Heck, it might just need a valve job or less.Keep an eye out for the helicopter in my avatar..its near Blackpool/Whisem. I was over there in Jan/feb flying on it with BBC filming the event,then showing it on "Inside Out" NW edition. best of luck.

 

Simplest way of seeing whether your engine is knackered is to start-it up and remove the oil filler cap. If the rings have severe blow-past you will get significant pressure and possibly oil smoke pumping out of filler opening.

 

You'll also get some smoke if the PCV system isn't working correctly.

 

If there is smoke coming out of the breather and your PCV is hooked up (I can see that it is), it means your rings are shot (smoke is from excessive ring blowby, pressurizing the crankcase with oil fumes and blowing them out the breather faster than the PCV can inhale them). Time to yank that engine out and give it a rebuild.: Sounds like I need to send you an engine rebuild kit rather than a carb...

 

Yes, you need the vent. PCV on the opposite side should pull a suction on the crankcase and pull clean air into the crankcase through the vent. The fact that you're blowing crankcase vapor out the vent indicates that ring blowby is so severe that the PCV suction can't keep up. You need an engine rebuild.

 

You can have bad rings and ring blowby without excessive smoke out the exhaust: Since the cylinders are pressurized, they don't "suck in" that much oil off the cylinder walls. Bad valve guides will easily pull oil into the cylinders and cause visible smoke - typical of the "worn engine syndrome." But bad rings will pressurize the crankcase and blow oil fumes out the breathers as you've described.

 

Blipping the throttle to see oil smoke is the territory of worn valve guides or seals, rather than rings, as Lars said. If you let it sit at idle, hot, for a bit, and then blip the throttle, if it puffs blue smoke then, you'd be looking at worn quides or seals.
The important thing here is "idle", as that is when you have the deepest manifold vacuum because the throttle's shut. And that vacuum likes to suck oil down past worn guides and into the cylinder! Another sign is a puff of smoke on startup, after you switch it off hot and leave it for a few hours. This comes about because the oil seeps down past the guides onto the backs of the valves or into the cylinder, then burns off when you start her up. Pretty typical of SBCs with some miles, I understand. Mine certainly does it! (Quite embarrasing in the pub carpark!) but valve guide wear isn't really the end of the world. Ring wear's a bit more serious though.

What state's your oil in? If it needs changing that might exacerbate the problem with the smoky breather, but having said that even changing it is only really a band-aid on the deeper problem. A bit of smoke's not the end of the world on an old engine - just exactly how much are we talking? Is it enough to show in a picture that you could post?

Someone may have said it before but the best way really know what state your motor's in is to do a compression test (HOT, throttle wide open). One of the most fundamental measures of engine health. If you ain't got no compression you ain't got no engine.

 

cheers for info guys

I noticed there is not a baffle underneath silver vent, would that make a difference?

Lars - best thing you could do is send me over a new big block engine, and come install for me, I'm buying the beers!

cheers

dave

 

First off, if you have a functioning PCV you shouldn't need a breather.

Some great information in this thread and to sum it up going from easy to hard or cheap to expensive as the case may be.

check

1) PCV for correct operation
2) Valve stem seals for wear
3) do a cylinder leak down test
4) Pull the heads and check the valves and upper cylinders and also the cylinder head gaskets.

The 3rd option will give you a very good idea what shape the engine is in over all.

Lars really has some awesome info in his post.

Andrew

 

That's not correct. The PCV system requires an air inlet in order for the PCV to work. Every PCV-equipped engine has a breather. The factory systems used a tube running up to the air cleaner to pull clean air into the crankcase through a filter located inside the air cleaner. If you remove the factory system, you have to install a breather with a filter element in it in the valve cover. When engine vacuum is high, the PCV pulls clean air through the breather, through the crankcase, and up through the PCV valve to the carb. At WOT, when there is no engine vacuum, the engine crankcase vents crankcase pressure the opposite direction out the breather. The breather is an essential component in the PCV operating system.

 

Yeah without a breather or air bleed of some sort the engine would, um.. suck on itself "too hard" when the manifold vacuum was high. The PCV isn't intended to put the crankcase at a really deep vacuum, just fractional psi negative pressure, enough to keep the blowby gases re-cicrulating. Hence the fairly low restriction pipe running from the stock air box down to the p/s rocker cover, to bleed some air in.



Dave, grab a compression gauge from Halfords mate, (or somewhere else that does tools and isn't as pricey!) and "follow the instructions on the box". You can tell a lot about the health of the engine with it. A leak down test, as VetteThunder1 mentioned, is also a good test but requires a bit more faffing about and other equipment (air line and gauges etc), so for the moment a compression test would be a good start.

By the look of that engine bay I think you've got all sorts of fun ahead of you

 

cheers for info, im on the case!

dave