[jpiper]

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 goes. Can someone help me out?

Thanx

Jpiper

 

[Gary]

The large hole connects directly to the air cleaner (No PCV valve) The small one connects to a metered orifice located on the intake either at the engine side below the carb base or is part of the brake booster vacuum fitting.

Make sure the fitting has a small opening (~ 1/16 inch) or you will get too much vacuum to the engine.

Running your 1.9 without this connected will cause pressure build up inside the motor and cause all kinds of oil leaks.

 

[jpiper]

Well the last statement explains some of the new leaks. Gary you are saying there is no PCV valve, but in my manual it states there is one and there has always been one in the hose since I have had the car. What is your reasoning for removal. If I didn't have the valve in the hose how could I get the hose to connect to the cover? Can you recommend fittings that would provide a means of connecting the hoses to the valve cover?

Thanx :

 

[Gary]

What year Opel do you have? On the early ones, both hoses just pushed into the valve cover. No fittings.

 

[kwilford]

Crankcase Ventilation in a GT, and Holley Carbs

JM,

This is one of Opel's little mysteries that wasn't solved for me until I started hanging around these Opel sites. Actually it was the [email protected] site, and I think it was Otto Bartsch who provided the answer. Opel GT's do not have a PCV (Positive Crankcase Ventilation) valve, so if yours has one, it was installed by a PO (Previous Owner). Possibly created ALL kinds of engine leaks when he did that.

Instead, a small vacuum hose is meant to suck crankcase fumes OUT of the engine, and the big hose allows filtered air IN to the valve cover to replace air in excess of blowby gas.

This is what happens in detail. Opel uses a metered vacuum port on the side of the intake manifold, just below the brake booster vacuum hose. But NOT the small one that angles back to the rear, which is the distributor vacuum retard (versus the vacuum advance, which is attached to the carb base; on the Solex, it is outboard, while my Weber is inboard; not sure where it is on your Holley). This small vacuum hose (1/8 inch ID on my GT) connects to the small hole in the top of the valve cover.

The metered vacuum port sucks crankcase fumes into the manifold to be combusted. But the engine case would also be subjected to a "vacuum", except there is a big hose (probably where your PCV valve is connected) that draws air into the valve cover. (By the way, a PCV valve is a check valve, which is designed to only allow crankcase fumes to flow OUT of the valve cover. OPPOSITE to what an Opel system should do). This big hose should be connected to the "inside" of the filter housing so that it draws filtered air in, but that can be tricky on an aftermarket filter housing. On my GT, I drilled a hole in the filter base and installed a right angle fitting and a barbed connection, and then used 3/8 inch hose. I tapped the valve cover with a 1/2 inch NPT tapered tap and bought a 1/2 by 3/8 brass barb fitting to connect the hose to. I did the same with the vacuum hose (1/8 by 1/4 I think). But I believe the factory solution is to just jam the hoses into the valve cover holes. Sorry I can't just show you a picture, but the digital camera hasn't been approved yet by management.

I hope that helps. But I now have a question about the carb you are using. Common wisdom around here is to replace the stock Solex (aka "Slowex", or more often "Piece of S--t") with a Weber, usually a 32/36 DGAV (water choke) or DGEV (electric choke) with a progressive mechanical secondary. The serious folks with high compression pistons, wilder cams and more displacement (2.0, 2.2 and even 2.4 litre) use the 38 DGAS, which opens both barrels simultaneously.

I happened to find and install a Weber 32/36 DFM (manual choke), which has a reversed throttle, and requires some fancy linkage modifications. But I believe the reversed orientation may result in cylinder leaning, especially the middle two cylinders. The same problem exists with the Ford Webers ('70-71 Cortina GT with a Weber DFAV?) and Pinto carbs. But I hadn't heard about the Holley from the ubiquitous 2.2 litre Caravan. Tell us about it, and how did you connect the cable versus the standard mechanical linkage? Do you happen to know which model it is? How well does it work, or have you really tried it out yet ? Curious minds, especially those with the crummy old Solex, want to know!

 

[kwilford]

Holley Carbs and Memory Lapses

Or did I get my Canadian Opels mixed up. Was it JM in Ontario. or RedOpelGT in Winnipeg who installed a Holley Carb from a 2.2 litre Caravan? Whovever it was, please tell us a story.

 

[jpiper]

In response to your questions, I have a 1971 GT still with a SOLEX carb. It must be RedOpelGT that has the Holley carb. I must be the only Opeler with the original Solex carb still in use! I too would be interested in hearing more about the above carb installation and make the move on replacing my Solex.

PCV
Is there a problem with leaving the PCV valve inserted as long as it is installed in the proper direction, so that it will allow air into the crankcase and stop the contaminated gases from coming back and entering into the carb? Do you think it will restrict the amount of air flow required into the crankcase?
Regarding the other vacuum line, I located the intake manifold connection for the brake booster and the distributor vacuum retard lines yesterday but could not see where this vacuum line would connect. I will look again today (Can use the Father's Day excuse to get permission from "management").

Just a note to let you know that I wasn't dreaming the whole thing up, Chilton's Opel 71-75 Repair and Tune-up Guide (ISBN 0-8019-6575-6) Page 86, Chapter 4 Emission Controls and Fuel Systems, refers to the PCV valve in the air hose from the filter. I must add though that no mention is made in either my 1971 or 1972 Opel Service Manuals about PCV valves. That tells me something there.

Thanx again for the help.

 

[kwilford]

Carbs and PCV System

John,

Sorry about the carb mixup, it must have been RedOpelGt in Winnipeg. So hopelfully he will respond with regards to the Holley conversion. I looked up my Weber, and it is actually a 32 DFM versus 32/36, so same size secondary as primary. And according to the Haynes Weber book I have, it is the same family of carbs as the DGV and DGS, but I remember having to switch the rotation of the bell crank, which I also had to do with the 32/36 DFAV that I installed years ago on my wife's GT. It came via a recycler off a '70 Ford Cortina GT, and worked great. A Solex can be made to work, but is tricky to set up. Throttle plate idle position has to be set up by vacuum (1 to 6 inches of water) and THEN idle speed is adjusted by the air speed screw, AFTER the idle mixture screw is adjusted. But mine had VERY poor throttle transition when it was in between hot and cold, and bogged no matter how many times I rebuilt and adjusted it. I have been told there are internal passages prone to plugging, and also internal check valves that can't readily be repaired, so often the only recourse is to change it out. The Weber was the best thing I ever did to my GT in 25 years of owning it.

As for the PCV valve, I have the same Chiltons Opel manual and it does refer to a PCV valve, but it also describes the metered orifice as the PCV valve. It mentions that the "valve" needs to be serviced, but really you just need to ensure that the orifice (which apparently is in the metal tube that is inserted in the manifold) is simply open. What you are looking for is a tube on the intake manifold just below the carb base. There should be a fitting screwed into the manifold of approximately 5/8 inch diameter, which is the booster hose connection. The distributor retard connection is on the side of this fitting. The metered PCV orifice is a separate metal tube just below the booster fitting, attached directly to the manifold. It is approximately 3/16 inch in diameter and 3/4 inch long.

I looked up the operation of a PCV valve in my big Chiltons book, and it describes the operation as follows. The PVC valve allows crankcase vapours to be drawn in to the manifold to be burnt. Replacement air is drawn in to the engine via the breather cap (oil filler caps that have internal filters), or sometimes from the air filter housing (the little filter on the side of some filter housings). (Opels use a sealed oil filler cap, so hence the need for a separate air inlet). American V-8 engines usually have a breather on one side, and the PCV valve on the other, while inline engines have the breather at one end and the PCV at the other. The PCV valve is spring loaded (not sure if this is true of ALL manufacturers?) to allow it to open at low manifold vacuum (open throttle or under acceleration), while high manifold vacuum (at idle or while decelerating) actually causes it to close. It also closes during engine backfires, to prevent combustion and explosion of the crankcase vapours, so it can close with high flow in EITHER direction.

This feature in itself might suggest that you don't use it, since a given PCV valve is probably calibrated to specific operating vacuum conditions. And I suspect that the stock Opel system actually pulls crankcase vapours from the big hose duriing full throttle operation, since there will be a slight vacuum present in the air filter housing and manifold vacuum (below the throttle plate) will be very low. So my suggestion is to forgo the PCV valve, or at least disable it by removing the internals.

HTH

 

[jpiper]

Keith;
I spent an hour this afternoon in the garage determined to find the intake manifold fitting and was finally successfull in finding the "puppy". It was located directly under the brake booster and timing retard connections and from looking directly down over the top, it was hard to see. I "shoved" a hose in the cover and connected the other end of the hose to the intake fitting. I took your advice and removed the PCV valve that was installed. There was no way air was getting thorugh there. Now I will search for a new line and fitting.
I didn't have an opportunity to start the engine due to the rainy weather we are having and besides the rear is on jacks due to a brake overhaul and the system needs to be bled.
From searching for this connection I also found that the timing retard line doesn't exist anymore. The fitting on the manifold is plugged off and the fitting on the vaccum advance unit is open. What are the effects of this? The engine has always started and run well, although in the past 10 years it was only driven around the block a few times and run outside the garage.
Thanks for the helpful tips and great explanations, they definitely helped a lot.
I will be watching the forum for more info.

Thanx.

 

[Gary]

Great thread guys!!

jpiper, When you start a thread or reply to a post, if you check the "Email Notification" box in the "options:" section below your reply, you will be notified by email whenever a response is posted to that thread.

 

[kwilford]

Crankcase Ventilation

Thanks Gary, just a couple of Canadians trying to keep our lonely old Opels running in a sea of Japanese iron. At least around MY house!

Eventually, this forum stuff is going to have caused me to have read all four Opel manuals I own, including all 591 pages of the Opel Factory Service Manual. Well, maybe I'll skip the 109 pages on the automatic transmission. Never did like those contraptions.

So, while casually fliiping through the 1972 Factory Manual, I noticed that, on page 00-10, under maintenance section 00-12, it recommends the following every 6000 miles. "Crankcase Ventilator Metered Orifice: Remove rubber hose from metered orifice and supply air pressure to orfice (sic) to remove any foreign particles that may be trapped."

So, my GT has 102,000 miles, so I guess I should promptly go out and perform this service 17 times, just to catch up. Did these Opel manual writers (CAN'T be engineers to blame!) think we had nothing better to do than to blow out our orifices? (NO JOKES HERE!!!) And for that matter, the same section recommends that, after checking all brake pads and linings at the same interval, the front wheel bearings be repacked and adjusted.

No wonder my car needs to be restored after only 102,000 miles. I clearly neglected it!

 

[redopelgt]

carbatooter

Yes, Keith, it was I that installed a cable operated holley from a caravan 2.2l motor. I had one kicking around at work, back in 1985, saw that the base bolt pattern was the same as on my intake. I installed it and it worked. To convert from manual linkage to cable, I removed a gas pedal from a caravan. Haven't installed it yet on the GT, but plan to do so this summer. It will just be bolted to the firewall. It comes with a mounting plate as part of the gas pedal assembly. Looks a cinch. I have a lot of work ahead due to the local squirrel population using the Gt as a condominium. A real mess.

 

[Thom71GT]

Is it possible???

That he meant PVC? on the base of the Weber, there is a small plastic 90 degree pipe that comes out and looks to have a hose attached to. Looks like a small piece of pvc pipe.

Is that where that hose connects too?

Also, for the little hole. On the small "nipple" at the base of the intake manifold, I have that going to the connector on the otherside of the distributor. Is that not where it goes?

 

[jpiper]

VoodooU;
No, I was talking about a "PCV valve" (one way check valve) that was installed in the air hose from the air filter to the cover and Keith was correct, it shouldn't be there. As far as the other connection there is one that goes to you distributor (vacuum diaphram). This one connects at a "Y" type fitting where your vacuum line from you brake booster connects. I am going to try to borrow a digital camera this weekend and hopefully provide some pics.
Thanx to RedOpelGt for replying about the Holley carb.

 

[kwilford]

Distributor Vacuum Retard

One question that was asked and not answered was regarding the distributor vacuum retard connecton. I believe this feature only came with slightly later Opels (1970 and on?) and is an emission control feature. To use the term "feature" a bit optimistically.

In short, the vacuum retard only funtions with a fully closed throttle, retarding the timing 4 to 7 degrees. It helps reduce hydrocarbons and CO (carbon monoxide) emissions during idling and deceleration. It is supplied directly by the intake manifold, NOT the port on the carb base, and the following explains WHY this is important.

As soon as the throttle plate opens slightly, it uncovers the vacuum ADVANCE port in the carb base, which overcomes the RETARD. As the throttle plate continues to open, the vacuum advance begins at between 2.9 and 4.1 inches water vacuum, and maxes out with 7 to 10 degrees advance at 5.6 to 6.4 inches water vacuum.

Remember, this is in ADDITION to the mechanical centrifugal advance, which advances the timing, beginning at 1100-1200 rpm. The factory spec is between 7.5-15 degrees of advance at 1400 rpm and it maxes out at 28-32 degrees advance at 3600 rpm. All of the above can be checked if you own a vacuum guage (or can assemble a water manometer) and a variable degree timing light. Above all else, it emphasizes the need to REMOVE the vacuum lines when setting the engine timing, and to set the timing while idling under 1100 rpm.

As for the importance of the vacuum retard sytem, so long as the port is properly sealed, it will not detrimentally affect engine operation without it. In fact, the engnie will probably idle better (less gas consumption) with it disconnected. But in smoggy old California, I bet that it will cause a FAIL in an emissions test.

HTH

 

[Gary]

Great description, Keith. The "Early" GT's had a "Dual Can" distributor with a separate diaphram for the retard.

 

[RallyBob]

Keith, that was very well stated and explains the functions of the mech/advance distributors well. Keep in mind that althought the 1971-1974 distributors were essentially the same in regards to mechanical advance, through the years the vacuum advance was reduced so that by the time 1974 rolled around, there was only 1-3 degrees of vacuum-induced advance! All in the name of reduced emissions.....
By 1975, the mechanical advance-only distributor (which retained a vacuum retard feature BTW) was reduced to a mere 25 degrees of mechanical advance, plus the baseline setting of 5 degrees for a total advance of only 30 degrees. By comparison, a 1971 distributor had anywhere from 28-32 mechanical (as Keith noted), and 11-13 of vacuum advance for a total of anywhere from 39 to 45 degrees. On the old-style distributors, you might see as much as 51 degrees of total timing. Is it any wonder those old 9:1 motors with 51 degrees of timing will ping on today's pump gas.....

Bob

 

[Gary]

Is it any wonder those old 9:1 motors with 51 degrees of timing will ping on today's pump gas.....

I can attest to that! My rebuilt '69 motor pinged like crazy until RallyBob worked his magic at the "Weber Jetting Party". No Vac advance now. 10 deg baseline, 35 total using a distriibutor from a '73 automatic.

BTW Bob, I did pick up an advance timing light for $32.00 on eBay.

 

[jpiper]

VoodooU
Here is the pic I promised pertaining to the PCV metering orifice and the vacuum lines. It is in jpeg format. Hope this will be of additional help to you.

 

[jpiper]

Sorry, forgot to add the picture!! Here it is! I had to alter the original pic size in order to send it so if the pic is not clear enough let me know and I will try to get it to you another way.