[Opel_convert]

I have an Opel GT with a 10 bolt head modified by OGTS to fit the 2.0 Liter Pistons.
I also have the chrome long tube header from OGTS.
The cam is new and is the street strip model form OGTS.
I will be running a brand new 32/36 Webber carb.
My valve cover is chromed as well as the oil pan.
I am concerned about heat soak that I am reading so much about on this website.

I have a new mechanical fuel pump to put in it but I have read that everyone is going to electric fuel pumps.
Questions:
1. What is the recommended fuel pump I should purchase?
2. If I go with an electrical pump, do I need to make a return fuel line back to the tank?
3. If there needs to be a return line, how does it get back to the tank? a new hole or bung added? or plumb it to one of the vent hose inlets?
4. how many are using a fuel pressure regulator with the Webber Carb?
5. What should the regulator pressure be set to if using one.

Once my cam gets broken in, Gil mentioned I should buy a larger Webber 36/38. (I think)
What are everyone's opinion going to the larger carb?

Any help is most appreciated!

 

[Manta Rallier]

#2.... Not necessary to put in a return line; that's optional. The idea is to keep more fuel flowing around and around and thus the fuel getting to carb when running is cooler. This is often done with a fuel filter that has a 3rd port on it to let excess fuel return. Once the engine is shut off, it does not help with any problems stemming from the carb absorbing heat when not running.

 

[Knorm65]

My video should answer all your questions.

The link to a good fuel pump is in the video description.

Just start with a Weber 38DGAS from the get go. It would be silly to have to swap after cam break in.

 

[Opel_convert]

i will watch but first I wanted to say...
Thanks for your reply.
I already bought the Weber although it is not installed. That was one of the first things I bought ( 8years ago) when I started this restoration. The engine restoration was only supposed to be a carb change in the beginning of this project. But you know how that goes...… one thing leads to another until every bolt is shiny!!!

 

[kwilford]

I have an Opel GT with a 10 bolt head modified by OGTS to fit the 2.0 Liter Pistons.
I also have the chrome long tube header from OGTS.
The cam is new and is the street strip model form OGTS.
I will be running a brand new 32/36 Webber carb.
My valve cover is chromed as well as the oil pan.
I am concerned about heat soak that I am reading so much about on this website.

I have a new mechanical fuel pump to put in it but I have read that everyone is going to electric fuel pumps.
Questions:
1. What is the recommended fuel pump I should purchase?
2. If I go with an electrical pump, do I need to make a return fuel line back to the tank?
3. If there needs to be a return line, how does it get back to the tank? a new hole or bung added? or plumb it to one of the vent hose inlets?
4. how many are using a fuel pressure regulator with the Webber Carb?
5. What should the regulator pressure be set to if using one.

Once my cam gets broken in, Gil mentioned I should buy a larger Webber 36/38. (I think)
What are everyone's opinion going to the larger carb?

Any help is most appreciated!

MODERATOR'S NOTE:
I moved this thread to the Fuel Pump Forum from the Exhaust Forum, in case you are looking for it.

A couple of comment/questions:

Not everyone likes electric fuel pumps. I do, and if properly spec'd and installed, they work VERY well. But so can the stock mechanical pump.

An Opel CIH head (any CIH head, 10 bolt or 12 bolt) isn't modified to fit the 2.0 (ie 95 mm) pistons. The larger pistons require a different head gasket. Not sure what you mean by that.

Weber has one "b". Sorry, I am just being silly...

I don't know what a "street strip cam from OGTS" is. Is it a "Torquer", or a "Combo", or something else? any idea what power your engine puts out? Relevant for the carb question.

Is the valve cover and oil pan chromed or polished? Totally irrelevant to a fuel pump question, but now I need to know. Aluminum can be chromed, but is more typically polished.

OK, heat soak on these engines is a real problem, and often can be solved, or at least reduced, by an electric fuel pump, properly specified and properly located. A heat shield below the carb works wonders. The header is a big help, as it eliminates the heat stove connection from the exhaust manifold to the inlet manifold

I like to re-route the fuel line away from the engine. My latest version has the fuel line run down the frame rail, around the front of the radiator, BELOW the radiator in the belly pan area, then up along PS fender, and a short jump to the carb. A clear fuel filter next to the air filter housing provides an excellent visual reference if you have fuel flow, and the carb needs to have the inlet on the outboard side, versus the typical inboard location.

There are numerous electric fuel pump choices. The key aspect is the maximum outlet pressure. Make sure the one you buy has a max outlet pressure no greater than 4 psi. 3 psi works fine. A regulator is ONLY required if you have chose a pump that puts out greater than 4 psi. Opel GT Source sells a nice one. My favorite is the Carter P60504 rotary pump, much discussed on relevant threads in the Fuel Pump Forum. That # has been changed up to P90091. I just bought a couple of the slightly lower pressure pumps (P60430, 3 psi) from Rock Auto for $30USD each.

I suspect that you have a 32/36 DGEV or 32/36 DGAV, the most common Weber carb used on these engines. Gil may have suggested that an upgraded carb to consider is a 38 DGAS (or more likely a DGES, electric choke ("E") vs water ("A) ). Your existing carb should be sufficient for the engine as described, but the 38 DGEV , if properly jetted, will provide a few extra HP, and better throttle response, since it is a "synchronous" (both throats open at the same time). I have one on my GT, but that engine has been upgraded to at least 110 HP from 78 HP, and the 38 DGEV still needs careful jetting to work well.

HTH

 

[First opel 1981]

Buy two electric fuel pumps. They often fail with no warning.

An electric fuel pump DOES help with the boil-out problem. After the car cools down you don't have to crank it to refill the bowl.

 

[Manta Rallier]

Buy two electric fuel pumps. They often fail with no warning.

An electric fuel pump DOES help with the boil-out problem. After the car cools down you don't have to crank it to refill the bowl.

Yes, it does not suffer vapor-lock in the lines to the mechanical pump in the engine compartment and can refill the bowl quickly.

I wanted the OP to know that fuel boiling within and possibly out of the carb after stopping is a different issue not addressed by a pump change. So there is more to be aware of here. And if the hot carb wants to boil out the fuel and if that fuel goes into the intake manifold when stopped, and then down into cylinders, it can wash oil off the cylinder walls, dilute the oil, and cylinder and other engine wear results. That matter rarely gets into these discussions.

To your point about electric pump sudden failures, I would run 2 electric pumps in my rally car and have both an electric switchover and a fuel transfer valve to switch to the back up pump.

 

[Opel_convert]

MODERATOR'S NOTE:
I moved this thread to the Fuel Pump Forum from the Exhaust Forum, in case you are looking for it.

A couple of comment/questions:

Not everyone likes electric fuel pumps. I do, and if properly spec'd and installed, they work VERY well. But so can the stock mechanical pump.

An Opel CIH head (any CIH head, 10 bolt or 12 bolt) isn't modified to fit the 2.0 (ie 95 mm) pistons. The larger pistons require a different head gasket. Not sure what you mean by that.

Weber has one "b". Sorry, I am just being silly...

I don't know what a "street strip cam from OGTS" is. Is it a "Torquer", or a "Combo", or something else? any idea what power your engine puts out? Relevant for the carb question.

Is the valve cover and oil pan chromed or polished? Totally irrelevant to a fuel pump question, but now I need to know. Aluminum can be chromed, but is more typically polished.

OK, heat soak on these engines is a real problem, and often can be solved, or at least reduced, by an electric fuel pump, properly specified and properly located. A heat shield below the carb works wonders. The header is a big help, as it eliminates the heat stove connection from the exhaust manifold to the inlet manifold

I like to re-route the fuel line away from the engine. My latest version has the fuel line run down the frame rail, around the front of the radiator, BELOW the radiator in the belly pan area, then up along PS fender, and a short jump to the carb. A clear fuel filter next to the air filter housing provides an excellent visual reference if you have fuel flow, and the carb needs to have the inlet on the outboard side, versus the typical inboard location.

There are numerous electric fuel pump choices. The key aspect is the maximum outlet pressure. Make sure the one you buy has a max outlet pressure no greater than 4 psi. 3 psi works fine. A regulator is ONLY required if you have chose a pump that puts out greater than 4 psi. Opel GT Source sells a nice one. My favorite is the Carter P60504 rotary pump, much discussed on relevant threads in the Fuel Pump Forum. That # has been changed up to P90091. I just bought a couple of the slightly lower pressure pumps (P60430, 3 psi) from Rock Auto for $30USD each.

I suspect that you have a 32/36 DGEV or 32/36 DGAV, the most common Weber carb used on these engines. Gil may have suggested that an upgraded carb to consider is a 38 DGAS (or more likely a DGES, electric choke ("E") vs water ("A) ). Your existing carb should be sufficient for the engine as described, but the 38 DGEV , if properly jetted, will provide a few extra HP, and better throttle response, since it is a "synchronous" (both throats open at the same time). I have one on my GT, but that engine has been upgraded to at least 110 HP from 78 HP, and the 38 DGEV still needs careful jetting to work well.

HTH

Keith,
1. The head is one from OGTS that has been rebuilt with the double springs, new cam bearing etc.. The one they sell for about $1k
2. I bought the 2.0L pistons from OGTS and the 2.0 L engine gasket kit.
3. I had my engine machined and had new main and rod bearings installed.
4. I was planning to reuse my cam but the engine builder said it had a bad lobe and recommended it be replaced.
I purchased the Combo from OGTS.
5. Eight years or so ago I bought a new weber with the electric choke it is the 32/36 DGEV model. Not the water cooled. I also bought a stock mechanical fuel pump. Back then I was only planning to replace the carb and fuel pump but the restoration lead from one thing to another and pockets of time to work on the car have proven to be the largest challenge.
6. I sent my valve cover and oil pan to be chrome plated not polished. Used Librandi's in Harrisburg PA. I also had a second valve cover done at the same time. They turned out very nice.
The car is 85% complete and my engine is still on the engine stand. I never heard the car run, ever. I bought it not running.
I am at a point where I need to decide if I want to put the 32/36 carb on or try to sell it. I als need to determine if I and going to install the mech fuel pump or sell it.

My last question would be if I install a new Weber 38DGES carb and alternator while the engine is on the engine stand, is it still possible to install the engine form the bottom of the car? I really don't want to remove and reinstall the long tube headers after the engine is in the car.

 

[The Scifi Guy]

I sent you a reply to your engine install query.

I have tested many electric fuel pumps in the different styles and I have found the red Edelbrock 3-5psi pumps to be the best and quietest. No return line needed. I don't personally feel the need, nor have I experienced the need in 40 years of GT driving, to have a fuel pressure regulator installed on a carbed car, if you're using the appropriate 3-5psi pump. Install the pump and filter just in front of the left rear tire in the nice pocket in that vicinity where the oem fuel line runs(pic below). I drill a 1/4" hole in the floor there, under the luggage shelf, install a rubber grommet, and route the power and ground into the car from there. Removing the luggage shelf to do that also gives you access to the two mounting holes you'll need to install the shock/vibration isolators that the electric pumps come with. Route the power wire to somewhere that's gets power when the ignition switch is turned to Run. Off the top of my head I can't recall which fuse would be best for that.

 

[kwilford]

My last question would be if I install a new Weber 38DGES carb and alternator while the engine is on the engine stand, is it still possible to install the engine form the bottom of the car? I really don't want to remove and reinstall the long tube headers after the engine is in the car.

Thanks for the clarifications.

IMHO, and the factory Service Manual, the alternator and distributor should be removed to install the engine (and from the bottom is the only way to do it correctly, again IMHO).

I do NOT have the carb nor intake manifold installed during the engine install. Too easy to damage it. The long-style header should be "in place" when the engine is lifted, but I prefer to not have it attached to the engine.

 

[P.J. Romano]

To your point about electric pump sudden failures, I would run 2 electric pumps in my rally car and have both an electric switchover and a fuel transfer valve to switch to the back up pump.

I am running such setup in my GT for a long time. If anybody has ever been involved in replacing fuel pump on the side of the road, he would know how difficult it is to do it without proper tools and the gas lines that became hard as bone.

Also, let us not forget the safety, electrical pump should have some kind of cut-off switch that would disengage the pump in the case of accident. Switch could be managed by the oil pressure or as in my case by inertia cut-off switch (I am using Ford inertia cut-off switch).

 

[First opel 1981]

Do you frequently switch between pumps to keep the "idle" one from getting gunky?

 

[P.J. Romano]

Good question. I flip the switch every couple months or whenever I remember to be sure that both pumps are in good working condition. I started doing that since stand-by pump went bad after not being activated for a long time. Ethanol and water in fuel are not doing any good to the fuel system.

 

[Manta Rallier]

OP, I know you are not quite at this point yet, but as for your carb choices, it sounds like both are new. The one of the riskiest things you can do is put on any new or untried carb or ignition when you are starting a new engine with a new flat tappet cam. The engine needs to start and run immediately up to the 2000-2500 RPM range for 20-25 minutes, to get copious oil to the cam to get it and the new lifters broken in. A lot of cranking and/or stopping and starting with a new flat tappet cam is inviting a damaged cam lobe.

Since it sounds like both carbs are new, IMHO the 32/36 is probably the better carb choice as it is more likely to start and run well out of the box. Others ought to comment on that vs the larger carb, but that mey be why Gil recommended the carb change after break-in.

Some other things for the break-in are to understand the matter of ZDDP levels in your oil, and setting the initial ignition timing for break-in. Those can be discussed now or when you get closer.

 

[The Scifi Guy]

I agree, an Opel rookie should start with a 32/36. It's a great carb to learn the nuances of Opel engine tuning on and they have a very friendly and generous adjustment range with room for error. A Weber 38/38 is a whole lot of fun to drive with, but they can be maddeningly fussy to tune and have a very narrow adjustment window.

 

[Opel_convert]

OP, I know you are not quite at this point yet, but as for your carb choices, it sounds like both are new. The one of the riskiest things you can do is put on any new or untried carb or ignition when you are starting a new engine with a new flat tappet cam. The engine needs to start and run immediately up to the 2000-2500 RPM range for 20-25 minutes, to get copious oil to the cam to get it and the new lifters broken in. A lot of cranking and/or stopping and starting with a new flat tappet cam is inviting a damaged cam lobe.

Since it sounds like both carbs are new, IMHO the 32/36 is probably the better carb choice as it is more likely to start and run well out of the box. Others ought to comment on that vs the larger carb, but that mey be why Gil recommended the carb change after break-in.

Some other things for the break-in are to understand the matter of ZDDP levels in your oil, and setting the initial ignition timing for break-in. Those can be discussed now or when you get closer.

All great points! I was told about the break in period from the engine builder as well as from Gil; however, I was concerned how I was going to manage tuning the carb, checking the timing from the passenger side when the Dizzy is on the drivers and my head was turned on it's ear just to look into the pointer window. What a crazy place for the timing pointer. And keeping the engine running for 20-25 minutes at 2k rpm.

I am using break in oil Driven BR-40.

 

[Opel_convert]

I sent you a reply to your engine install query.

I have tested many electric fuel pumps in the different styles and I have found the red Edelbrock 3-5psi pumps to be the best and quietest. No return line needed. I don't personally feel the need, nor have I experienced the need in 40 years of GT driving, to have a fuel pressure regulator installed on a carbed car, if you're using the appropriate 3-5psi pump. Install the pump and filter just in front of the left rear tire in the nice pocket in that vicinity where the oem fuel line runs(pic below). I drill a 1/4" hole in the floor there, under the luggage shelf, install a rubber grommet, and route the power and ground into the car from there. Removing the luggage shelf to do that also gives you access to the two mounting holes you'll need to install the shock/vibration isolators that the electric pumps come with. Route the power wire to somewhere that's gets power when the ignition switch is turned to Run. Off the top of my head I can't recall which fuse would be best for that.

View attachment 425079 View attachment 425080

Do you like this pump more than the carter P60504. I saw in one of your other emails you preferred the carter over the loud ticking unit from OGTS.

 

[Opel_convert]

Why cant I post pictures in my reply's to you guys? when I try it says contact the administrator...

 

[The Scifi Guy]

The Carters are a military spec pump from the Korean war era, they are about as old school as you can get with electric pumps. They are designed for quick and easy replacement in the field. Apparently, all the dudes that think you should carry an extra fuel pump in your car at all times in case your pump fails use Carters. I personally have never had an electric fuel pump in my GT's fail in 35 years and 225K+ miles of driving in my GT's. I had some sort of rotary pump, whose name I don't recall, during most of that time. When I got back into Opels about 12 years ago I started using diaphragm-style Posiflows, but I disliked the click sound they made, so I tried out a Carter. It was quieter, but sounded like I had a dremel under my car. Then I tried the red Edelbrock and I was even happier with it's lower sound.

On a side note: My new FI conversion returnless fuel pump system uses the low pressure Edelbrock pump to bring the fuel from the tank to the high pressure Edelbrock pump in the engine compartment. Frankly, the high pressure pump is even quieter than the low pressure one!

 

[The Scifi Guy]

Hey man, did you get the link I sent you in a private message? Click on your "O" avatar pic on the right side at the top of any page and select "Discussions". Your "O" should have a red dot on it to indicate you have a message. This is not the same "O" as your avatar in a post, it's the one that shows up only at the top of a page. I don't know if clicking a post avatar will do the same thing.