327 Not Breathing Right?!?!
 

I need some of you breather gurus to check this out for me. The oilfiller cap popped off from the crankcase pressure. It WAS routed to the PVC on the manifold, but now I know that was incorrect. I realize that the PVC needs to be replaced with a 90 fitting to the brake booster, but where can I get enough vacuum with no holes in the valve covers???? The engine is a fresh engine that has not been broke in yet so this also adds to the equation. Longhorn Man, chime in!!!
Attachment 796953

Attachment 796954

Attachment 796955

Re: 327 Not Breathing Right?!?!
 

http://i306.photobucket.com/albums/n...1/SAM_1340.jpg

Where i drew the arrow, there is a 1.375" hole that used to have an old drain pipe connected to it, (it is now clearly capped off, and very common on old blocks). And you have valve covers with no holes for a breather or a PCV, but you do have a breather on the front of the intake.

So it looks to me like you need to either put the old drain pipe back on, or get some valve covers with holes for a breather and PCV

Re: 327 Not Breathing Right?!?!
 

either one of the "large" ports at the base of the carb should be fine.

my 327 has ALOT of crankcase pressure aka "blowby" so I have to run 2 PCV valves into my carb,
one on the front port and one on the back port.
If I don't I get oil out of the breather on the valve cover, even with baffled ports.

http://lh6.googleusercontent.com/-S3...0/DSCF0388.JPG

Re: 327 Not Breathing Right?!?!
 

I could not find any indication that there was a hole on the back of the block. My goal is to keep the valve covers clean, but not at the expense of issues with the engine running properly. If I run the hose from the breather cap to the PCV in the manifold and another Tee'd off to the carb base plate would that be an option?

Re: 327 Not Breathing Right?!?!
 

There has to be points for crankcase venting to work. Your set up there is really only one. In the original set up for an early 265/283/327 the hole back by the distributor is where the "road draft tube" would go and on the later PCV vehicles it would have an oil seperator that had a hose run to the air cleaner. The PCV valve screwed into the oil fill tube on the front with a non-vented oil cap. Look at the way the later valve cover systems work, one side is fresh air pull from the air cleaner (or filter air) and the other side is has the PCV valve placed in the valve cover and the hose attached to a full manifold vacuum source. You need a place for filter air to replace the fumes being pulled by the PCV system or your going to have oil leak problems in after awhile.

Re: 327 Not Breathing Right?!?!
 

Where you have the arrow, there should be a hole in the block for a special fitting that a hose attached to for pc valve to carb base. I have one that I'll take a photo of later this morning. There was also a canister that bolted inside the lifter gallery which kept oil from being sucked up from the gallery.

Re: 327 Not Breathing Right?!?!
 

So without the road draft tube the only other option is to ventilate the valve covers and run the vacuum lines as usual?

Re: 327 Not Breathing Right?!?!
 

Correct...

Re: 327 Not Breathing Right?!?!
 

Here's what I was talking about. Someone must have put an inch and a quarter freeze plug in your block where this went?

http://i249.photobucket.com/albums/g...t/CIMG2970.jpg

Re: 327 Not Breathing Right?!?!
 

One of these on the back end of each valve cover should cure my issue. And will look pretty slick while maintaining the integrity of the factory script valve covers that I am running. The hole should be drilled as high as possible on the vc's to allow for inertia oil movement upon acceleration.
http://www.summitracing.com/parts/SUM-440332/

Re: 327 Not Breathing Right?!?!
 

Kinda strange, but there is absolutely no signs of the block even being machined in that area from the factory. The casting numbers show it is a 1966 Corvette block so it may have never had one to begin with.

Re: 327 Not Breathing Right?!?!
 

Another thought, how much oil accumulates in the valve covers that could possible slosh to the rear inside valve cover? I do not see it being enough to cause any issues, but I could be wrong!!! It is not a race truck so no huge takeoffs from the line, just a weekend driver show truck.

Re: 327 Not Breathing Right?!?!
 

here is a pic of the back of the block with the thingy in it:lol: and check out this threadhttp://67-72chevytrucks.com/vboard/s...d.php?t=366853

Re: 327 Not Breathing Right?!?!
 

Check out PMC valve covers. They look like the old school chevrolet but have holes in the side so you can vent and use a pcv valve. They are cast aluminum with the chevrolet script.

Re: 327 Not Breathing Right?!?!
 

This is toooo cool and I would not mind that at all...........but, I don't have the hole for the thingy in my block. The block is solid there and has not been filled in. I actually found that thread while researching this problem and wanted to look at it again...Thanks!!!

Couldn't find the PMC valve covers, do you have a url? They sound cool and I would like to check into them.

Re: 327 Not Breathing Right?!?!
 

I gotta keep these valve covers if I can simply because I think they just look super cool. I hate to drill in the back of them, but it is for the greater good of the engine.
Attachment 797762

Re: 327 Not Breathing Right?!?!
 

I thought the set-up in the pic that 'rsavage' showed were used up to 1967 on 283 & 327, so why would a 1966 motor not have the hole unless there was something different with the Corvette motors like, maybe it was once a fuel injection factory set-up. But that's now going way out of my league.

Re: 327 Not Breathing Right?!?!
 

Way outta my league too. In the end if the engine breaths right I'll be happy. I have some valve covers with holes in them so I am going to try those on to see if it makes a huge difference. It should. I will post pics of what I am trying before I tap holes into the valve covers I am using.

Re: 327 Not Breathing Right?!?!
 

:lol:try some nasal strips.....that should get her breathin right....haha:lol:

Re: 327 Not Breathing Right?!?!
 

Funny guy huh! She sounds alot better than she did. Routed the oil filler to the carb, the power booster to the manifold and the trans to the front of the carb on the small tube. It seems to be fine now, we'll see after I run it a little bit.

Re: 327 Not Breathing Right?!?!
 

i hope it works out i love the look of those valve covers on it :metal:

Re: 327 Not Breathing Right?!?!
 

Thanks dude! I think they look right at home on it too. No holes is even better.

Re: 327 Not Breathing Right?!?!
 

Slick67, love that engine, it is sharp!

I'm a little confused, unless I'm reading the above wrong, you ran the filler tube cap to one of the large carb "vacuum" sources and swapped the booster to the manifold source. also you're now running the tranny off one of the smaller carb sources.

If that's the case, as far as your crankcase ventilation goes, I don't see where you changed anything. And if you now have the tranny hooked to the passenger side port on the front of the carb it is no longer getting a vacuum signal at idle.

it appears to me you are still pulling a low pressure on the crankcase with no cross ventilation.

Sorry, I may be missing something

Re: 327 Not Breathing Right?!?!
 

Thanks! The trans is going to be hooked to the small driver side tube on the front of the carb. The booster is hooked to the manifold, which is correct according to other vehicles. But I am still questioning the ventilation also. There should be a entrance for fresh air, correct?

Re: 327 Not Breathing Right?!?!
 

valve covers cool?

without a proper PVC system the old school result was SLUDGE heavy thick and grimey NOT COOL

Re: 327 Not Breathing Right?!?!
 

I will cut them if needed to avoid the sludge issue. If I do this, it has to be exactly what the engine needs. Holes in the vc's is a major step that I do not want to make a mistake on.

Re: 327 Not Breathing Right?!?!
 

I had another thought. If the PCV valve you have (had) is made to function opposite how it was installed it would explain why the cap blew off in the first place and why the current set up runs better.

I ran into this when trying to fit a system to my tri-power intake.

Re: 327 Not Breathing Right?!?!
 

The real issue here is that you are not allowing "incoming" air. You have the oil filler tube connected to vacuum, which will produce a vacuum inside the crank case. If you do not have some kind of filtered way to let air in, it will suck in a gasket somewhere. Must likely it will be one of the intake end seals or valve cover gaskets.
The whole point of the PVC system is that it does indeed draw out fumes, but it has another tube connected to the air cleaner to allow air in from the other side. That's the bigger heater hose sized tube that goes to the stock air cleaner housing. Most times when the stock unit is removed, a simple vent is installed in place of that tube.

If you want to keep the valve covers un-touched, you are going to have to find an alternative way to let air in. You could drill and tap a hole near the back of the intake manifold, behind the runners, that would get to the lifter valley. This would allow you to put a hose on it, allowing a "remote" breather. It's not an ideal thing because the intake air and PVC draw would both be in the lifter valley. It probably wouldn't pull fumes from the valve covers as well as the "correct" set-up, but it will eliminate the gasket sucking problem.

Re: 327 Not Breathing Right?!?!
 

Yes, and just drilling a hole in the valve cover for the PCV valve is not enough since there won't be a baffle present. There is a baffled gromment you can get to take care of that issue. If you want to go that route I'll find the link for the gromment (I saw one not long ago)

Re: 327 Not Breathing Right?!?!
 

That sounds like a good alternative, would it still allow the engine to breath properly enough to eliminate the sludge issue? Also, with the PCV valve on the same runner would it still have enough vacuum?

I have purchased the baffled grommets that can be installed on the rear of the valve cover, but that is a last resort. Although it seems that it would be easier and more effective than drilling into the intake at this point. This is what I purchased.
http://www.summitracing.com/parts/SUM-440332/
Attachment 802246

Re: 327 Not Breathing Right?!?!
 

Slick67, you may have misunderstood Longhair, the hole he's talking about would not go into the intake runner, it would go into a place on the manifold that goes into the lifter valley. that's what I did on the tri-power.

Re: 327 Not Breathing Right?!?!
 

Understood. Do you have a pic of where you drilled? Did you istall a PCV or some other attachment?

Re: 327 Not Breathing Right?!?!
 

these are exactly what i was looking at in JEGS to use on mine, and just put them at the very back , run one of the square breathers turned sideways ?? just what i was thinking of doing

Re: 327 Not Breathing Right?!?!
 

When you drill into the back of the v/c's make sure these don't stick to far in and hit the rocker arms or lifters. I had to make mine shorter than I wanted to because of this issue. When I made my tubes (for the v/c's) I built two baffler in each to try and keep the oil from slinging up into the tube but still allow air movement. I also built a "catch can" type box to house the pcv and the breather. In theory my motor should pull in air from the old oil filler tube (it's been modified) and from the breather and the pcv "should" pull the fumes....should. I've only had it running for a little while and I'm still working the bugs out (other issuse not related) so I will report back after I get some miles under her. Here's some pics of what I did....

Re: 327 Not Breathing Right?!?!
 

Slick67, yes I installed an inline PCV valve. I'm seriously thinking that the valve you were using is designed to thread into the oil galley something like the fitting I have below threaded into my manifold. if so, the manifold vacuum it was hooked to was actually pulling the valve closed and your system was building pressure. Am I making any sense? if that's what was happening, then you could use that valve (in the proper location), plumbed to the carb vacuum source and a regular breather on the oil fill.

Here's the inline PCV valve
http://i647.photobucket.com/albums/u...y/100_0303.jpg

here's the manifold location (this is just a fitting, not a PCV valve)
http://i647.photobucket.com/albums/u...y/100_0302.jpg

and the "vacuum source"
http://i647.photobucket.com/albums/u...y/100_0304.jpg

drawing from the oil galley has the drawback of not being baffled. I don't know if that's a problem as it would be with valve covers. and, as Longhair mentioned, in your case if you use the oil fill for the breather, you won't be drawing from the valve covers. it would still be better than no crankcase ventilation or the situation you may have now where manifold vacuum is apparently creating a low pressure situation.

Re: 327 Not Breathing Right?!?!
 

I picked mine up from Wild West Rods on eBay for $15 bucks each. So if you are still thinking this direction is right for you here is a way to save a few bucks!

I am going to measure to make sure before any cutting happens. That is a really cool settup you have there! This is starting to sound like I may have cured the problem with the vacuum by rerouting the hoses, but now I need fresh air. Eventually this will all be clear to me and correctly done.

I think the settup you have is essentially what I have. The engine does not seem to be building up any pressure since I rerouted the the oil filler hose to the carb and it seems to run better. But I have to see what is happening with my settup first.

Re: 327 Not Breathing Right?!?!
 

i was looking at my speedway catalog this morning and i noticed , Offeanuser (sure i didnt spell that right) has a breather that mount to the side of your valve covers and comes up looks pretty cool i think but $75 bucks apiece

Re: 327 Not Breathing Right?!?!
 

Ouch. That is a little TOO pricey. This is just another opportunity to be creative and come up with something cool that noone else has. I am not seeing any signs of leakage since I rerouted my vacuum from the oil filler to the front of the carb. This seems to have resolved the issue, maybe not for good but I will be keeping a close eye on all of my gaskets and running it very little for now.

Re: 327 Not Breathing Right?!?!
 

I understand you don't have the hole for the road draft provision anymore but here is a pic I found off of the web that someone had done for their 283 with stock valve covers. I wish I had more information.

Keith

Re: 327 Not Breathing Right?!?!
 

Still have not cut the valve covers and waited to see what happened with the re-routing of the vacuum lines. It looks like I will have to cut the vc's to avoid drilling into the intake since it is still not acting right when it runs. Also noticed a little oil around the #5 spark plug which is a sure sign of oil getting through the rings because of the built up pressure in the engine. Is that a correct assumption???