smaller hole in valve cover

5431 Views 19 Replies 6 Participants Last post by tekenaar, Dec 23, 2003

opeldean

Discussion Starter · Jun 7, 2003

the smaller hole in my valve cover has no hose attached....
car is running fine...but this doesn't seem right as it comunicates to to valve area...

sholud I:
1)do nothing
2)plug it
3)run a hose to somewhere

PS:the larger hose/hole in valve cover goes to the weber 32-63 electric choke

photo attached

thanks!

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kwilford

· #2 · Jun 7, 2003 (Edited)

Nice valve cover.

It is a CRUCIAL part of the engine's Positive Crankcase Ventilation system (PCV), and should be hooked up to the "metering orifice tube", which is the small metal tube on the outside of the intake manifold just below the brake booster connection. This has been discussed ad nauseum, so do a search on "PCV" or at least go to:

http://opelgt.com/forums/showthread.php?s=&threadid=313

And especially look at the last posting, where John McInnis attached a picture. It's worth a thousand words....

kwilford

· #3 · Jun 7, 2003 (Edited)

And here is a link to larger version of the photo:

www.opelgt.com

Valve Cover PCV and Vacuum Connections

There are two outlets on the RH side of the valve cover for the 1.9 liter engine. The one at the rear of the cover is for the hose from the Air Cleaner to the PCV valve and the other goes where? I have looked in my manuals and cannot find a pic showing what hose is inserted there and where it...

www.opelgt.com

opeldean

Discussion Starter · #4 · Jun 7, 2003

which vacuum line do I "Y " to

do I attach a y connector at location A..next to intake or do I attach a Y on to B .. both next to intake

Note: "big A" leads to "small a "on vacuum advance on distributer

thank you...

maybe this expalins why it was so dirty inside the vale cover

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Travis

· #5 · Jun 7, 2003

Another option is to plug both of the holes in the valve cover(weld or pipe plug) and install a breather. Most auto parts stores carry valve cover breathers for american V8s. I just cut a hole in the side of my valve cover to accept the breather. While I was at it I removed the stock filter, the plate which held it in place and it's bosses. Now if I revove the oil fill cover I can see a few of rockers and surprisingly oil doesn't seems to splash out while running. If and when I am able to install my roller rockers I'll be able to show them off. It's a shame to not be able to see some of the really cool parts we install in our engines...

-Travis

kwilford

· #6 · Jun 7, 2003

"A" is the distributor vacuum advance (to the carb base, which is ported internally to just above the throttle plate when it is at the idle position). "B" is the distributor vacuum retard (which only retards the ignition at an idle, for NOX emission reduction, and which sees a vacuum when the throttle plate is closed). Do not hook the valve cover vent to either of these.

You are looking for another metal tube on the intake manifold, just below the big "Y" fitting that "B" and the brake booster hose are connected to. In John's photo, you can "just" see it, and it is pointed to with a red arrow from the words "PCV metering orifice directly below "Y" fitting" .

This tube has a very small hole (the "orifice") in it, which allows a small (metered) amount of air to be drawn into the intake manifold. This "sucks" crankcase fumes out of the valve cover at an idle. The big hose provides "makeup air" to prevent the crankcase from being pulled down to a vacuum at an idle, and flows OUT from the valve cover into the carb throat when the engine rpm is higher (when there is little on no manifold vacuum and lots of crankcase fumes).

HTH

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kwilford

· #7 · Jun 7, 2003

Personally, I prefer to burn crankcase vapours rather than vent them, so I am not a big fan of what Travis proposes. The stock setup is quite funtional, although it can be tricky to get the hoses to seal to the valve cover. My solution was to install barbed hose connectors such as this:

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opeldean

Discussion Starter · #8 · Jun 7, 2003

tube is missing

the tube is missing or plugged..are there other soluitons besides
modifying the valve cover as travis mentioned?

thanks

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kwilford

· #9 · Jun 7, 2003

Hmm...

This is what it should look like (if you have a '72 and older manifold). But if you have a later version, I believe the PCV metering orifice is on the engine side of the manifold (of which I don't have a photo handy). It should look similar, and will hook up the same way.

If a PO has just plugged the old hole (after, I presume, it was broken off), you can connect the small valve cover hole to a tee on the vacuum retard hose (they end up in the same place) and plug the PCV hose with a dowel, drilled out with an orifice. I checked mine, and it was a #53 drill bit, which is 0.059 inch. Close enough to 1/16 inch for me.

And make sure that there isn't still a hole there, since it will act like (and be!) a vacuum leak.

HTH

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Gary

· #10 · Jun 7, 2003

Great thread guys! The new max size for attachments makes it a lot clearer.

Travis

· #11 · Jun 7, 2003

kwilford said:
Personally, I prefer to burn crankcase vapours rather than vent them, so I am not a big fan of what Travis proposes.

To each his own. I prefer to limit what I take into the engine to cold clean air and fuel. The vapors can vent to the air with most of the particles getting trapped in the filter which I can easily replace in the future if needed. No need to remove the valve cover.

It's also nice to have two less hoses to have to look at/deal with. I already have enough hoses with the water choke.

-Travis

opeldean

Discussion Starter · #12 · Jun 7, 2003

wow...this was great help.

The car interior tends to smell gassy at idle..I guess this explains it.. am I corect? thank you again wilford..travis too

I will "T off the retard line and use the dowel with the hole in it on the valve cover"

thanks so much!

Travis

· #13 · Jun 7, 2003

Re: wow...this was great help.

bucky said:
The car interior tends to smell gassy at idle.

You shouldn't be getting a gassy smell out the valve cover unless you have excessive gas in your oil, which would be bad. It's more likely your gas tank vent lines...

-Travis

kwilford

· #14 · Jun 7, 2003

Yep, what Travis says...

Several good threads on this. Just search for "vent + tank", and also look at:

http://opelgt.com/forums/showthread.php?s=&threadid=856

HTH

jordan

· #15 · Jun 7, 2003

hey keith i see that your valve cover is very shiny and "chromey" did you have it nickel plated? if so does it have to be in immaculate condition fo it to look good? also how much $$ did it cost?

Travis

· #16 · Jun 7, 2003

Chrome plating on aluminum is generally a layer of nickel and then chrome. On steel they add a layer of copper as nickel doesn't bond to steel too well. OGTS offers this service as does Nu-Chrome. I've seen a valve cover that was done by Nu-Chrome and it was absolutely beautifull! Personally, I'd be afraid to work on my motor....

-Travis

kwilford

· #17 · Jun 7, 2003

It was polished, by the same folks (Advance Plating, in Medicine Hat, Alberta) who did my plating. They also polished my thermostat housing, and it cost $65 and $20 CAD respectively. That is about $42 and $13 in USD, so I couldn't pass it up. I am not sure how long it will last (once I get the engine and the rest of the car re-assembled!) since the aluminum is still prone to oxidation (there is no "coating" or anodizing). They told me it just needs to be waxed yearly and buffed up a bit. I have seen this done before, but I don't know the long term results.

opeldean

Discussion Starter · #18 · Jun 8, 2003

hose is routed...

I am finished with my repair.As an opel newbie I am allowed to make mistakes..as I was searching for the where the pipe should be..I could not find a plug,repair or break...my opel is a 70 gt...
so I remembered that keith said on some opels "the hook-up pipe to valve cover is found on the engine side of the intake''...

my hook up WAS easy to get to "on the engine side"... it had a ruuber plug for some odd reason...I went to oriely automotive
and bought 1/16 '' ID vacuum line and routed it..to a brass barb that I set with permatex and epoxy....

I think the repair is tight..but my vacuum line looks a little small.

If anyone thinks it needs to be larger .let me know

thanks a lot for the help..again

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tekenaar

· #19 · Nov 28, 2003

Engine side metered orifice use

kwilford said:
Hmm...

This is what it should look like (if you have a '72 and older manifold). But if you have a later version, I believe the PCV metering orifice is on the engine side of the manifold (of which I don't have a photo handy). It should look similar, and will hook up the same way.

If a PO has just plugged the old hole (after, I presume, it was broken off), you can connect the small valve cover hole to a tee on the vacuum retard hose (they end up in the same place) and plug the PCV hose with a dowel, drilled out with an orifice. I checked mine, and it was a #53 drill bit, which is 0.059 inch. Close enough to 1/16 inch for me.

And make sure that there isn't still a hole there, since it will act like (and be!) a vacuum leak.

HTH

My completely stock '69 Kadette has a 90° metered orifice fitting on the engine side of the manifold.

tekenaar

· #20 · Dec 23, 2003 (Edited)

Re: Engine side metered orifice use

tekenaar said:
My completely stock '69 Kadette has a 90° metered orifice fitting on the engine side of the manifold.

Originally posted by kwilford
Hmm...

. . .

I checked mine, and it was a #53 drill bit, which is 0.059 inch. Close enough to 1/16 inch for me.

. . .

BTW, ALL metered orifices on the engine side of the manifold are 90° "L" fittings that screw into the manifold (1/8" NPT), probably to permit cleaning. A point of interest is that I've found a 1/16" (0.0625") orifice to be just about right for the "small" valve cover hole which is always connected to a manifold vacuum source.

For "large" hose retention in the valve cover, I use a 1/2" piece of 1/2" rigid copper tubing shoved into the end of the vent hose that goes into the "large" valve cover breather hole. Retains well and NO LEAKS!

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