[TheCollector]

I just picked up this '70 GT two nights ago. The engine only has 2K miles on an overhaul and everything's in great shape.

EXCEPT that once it gets up to and has been at operating temperature for a while, it starts to chug at idle and seems to be loading up before it eventually dies, but the plugs show a good mixture.

I've replaced the plugs and wires (original wires) and swapped out the coil to verify it wasn't an ignition problem. I've adjusted the idle mixture and I'm pretty sure I've got it right.

It's got an electric choke and I've verified that the choke butterflies are fully open when warm and I've checked what seems to be an electrically actuated solenoid (anti-diesel?) for proper operation. I'm about to check that the choke cut-out diaprham is OK, but I'm betting it's fine.

It's almost like it's experiencing vaporlock, but I've verified that I've got pleny of fuel pressure at the carb.

I've got and maintain a number of classics (including a Brit w/a Weber DCOE), but this is my first Opel.

The records I received with the car indicate two carb rebuids over the past few years since the engine rebuild (it sat a lot) and I've already ordered a rebuild kit. But unless both prior mechanics screwed up the rebuilds, I don't hold out much hope for that fixing the problem.

Anybody got any clues where I should be looking?

Thanks,
-Bob

 

[OpelJim]

Is this the Yellow GT you purchased on eBay from a very nice man Richard ? from Pasadena ?

Hard to tell what the problem is (via email )
but if you can bring it to the Riverside county area there is an Opel repair shop just south of Corona.

They can fix it for you, I am sure.

 

[kwilford]

Maybe a vacuum leak? Opels are notorious for that. Especially where the manifold mates with the head, or between one of the base gaskets? Is there a thick phenolic gasket above the heat shield? Is there a heat shield? Without one, the bowl will boil, and seem like vapour lock. I presume it is actually a 32/36 DGEV (electric choke) rather than a DGAV (water choke).

 

[Gary]

Is the fuel line routed near the exhaust manifold? Does it enter the carb on the engine side? Do you have a heat shield between the carb and the intake manifold? Any of those could lead to a vapor lock condition.

 

[TheCollector]

Jim; Yes I did pick it up from Richard - and you're right - he's a great guy. I doubt that he drove it far enough in the past few years to warm it to the point of experiencing this problem.

It does NOT have a heat shield. I was wondering about that after placing the order for the carb kit yesterday. I'm sure it could benefit from one. If anyone knows where I can pick one up or has any specs for making one I'd be appreciative.

The fuel line enters the carb opposite the engine side, but the fuel line does run around the front of the valve cover - definately a heat source.

I have been able to hear a very slight hissing from the carb body after shutdown - leading me to believe that the fuel may be boiling. I have disassembled the choke mechanism and everything seems to be operating properly.

The metal tag attached to the carb does state that it is a DGAV.

I appreciate the replies and look forward to reading more.

-Bob

 

[Gary]

After I rebuilt the engine in my '69, I drove it 50 miles to the Opels on the Lawn show. When I arrived, it would not keep running and I had the pleasure of being pushed across the showfield. It ran fine once it cooled off. I did not have a heat shield under the Weber 32/36. Added one and never had that problem again.

My guess.... Save the carb kit for the future. Add the heat shield and give it a try. Follow OGTS gasket sequence W/the thick spacer.

Sometimes people will eliminate the thick spacer and heatshield in order to get the Weber-to-stock air filter adapter to clear the hood.

 

[TheCollector]

OK, it's sounding like I definitely need a heat shield. It looks like it's got the thick carb/manifold gasket and I've ordered one with the kit. I'll add a thin gasket to the order.

What is the "OGTS" gasket sequence?

Again, if anyone has any kind of heatshield template or even a photo showing one installed, it would help a bunch.

-Bob

 

[Gary]

What is the "OGTS" gasket sequence?

Gil has an instruction sheet for installing a Weber. It call for using permatex High Tack sealer on the intake and the smooth area of the 4 studs along with the gaskets. Then Thin gasket, heat shield, Thick gasket, Weber.

One other thing to check for as Keith mentioned is a vacuum leak. Warm up the car and spray carb cleaner around the mounting gaskets. If the idle speed increases, you found a leak.

Let us know how you make out.

 

[kwilford]

Heat Shield

The heat shields show up on ebay from time to time. But if you place a post here in the "Parts Wanted" section of the classified, one of the members will probably have one:

http://www.opelgt.com/ppc.php

or contact one of used Opel Parts dealers with links here:

http://www.opelgt.com/links

such as OpelJunkyard.com, Orphan Motorsports, Opels Unlimited (and be VERY patient) or even (gasp!) USA Opels (that was a free plug, Jim), I am sure that one of them will have one. They are pretty common, what with 103,000 of them made and maybe only 15,000 still in use.

And if you are still in a pinch, drop me a note. I think I know of a couple up here in Canada that I could pry free, but the shipping will be quite a bit less from within the U.S. of A.

HTH