Hey Everybody. I have been searching for an hour with no luck. I have a 1976 914/4 that I have converted over to 44mm Empi's. Now I am setting up the fuel system, new low pressure pump, stainless lines, presure regulator, etc. what I can't figure out is what to do with the extra line I have on the fuel tank. Should I cap it? Vent it? I did run both stainless line back to the engine bay so I could t them in or what ever. I just need some guidance.

Thanks in advance.
Robin

Just cap it. It's needed as a return line for the FI.

www.914world.com/specs/SirAndyCarbFuelPumpRelay.php

here is some information for wiring of the fuel pump

Put the pressure regulator in the return line of a loop past the carbs.
So.....tank to pump (front mount) to carb 1 to carb 2 to regulator to return.
You already did most of the work.
OR.... with a low pressure pump, feed from pump to a T between the carbs and cap the return line.

Excellent! Thanks for the replies, I will just cap it. Yes I have already put all of the lines in so it is T-ed and ready to go. So I guess I will post a couple of pictures. I have had this car for 5 years but it sat for 3 of those because of working out of state. Now I am trying to get back on it and get it going again. This is not my first Porsche but it is my first air cooled boxer.

What have I done so far? Motor rebuild with big bore kit. Ported and polished the heads myself. 901 (I think that was the number, it's supposed to be THE distributor for a type 4 motor) distributor, electronic pick up, MSD 6A ignition box, flame thrower coil. So as soon as I get the fuel all situated and working I will get the ignition system set up and see if I can make it run for the first time in 5 years. Have done some work to the body, fiberglass front airdam, reworking ugly bumpers into the car... Then, the fun part. Making all of the rest work and look good.

Robin
1976 Porsche 914 2.0 (before the kit)
2003 Victory V92DC
1964 BSA A65
1982 Yamaha Vision 550 twin

Excellent!!! I didn't think of this, I just wired the new fuel pump to the wires for the old. This help a lot when I was wondering why I wasn't getting fuel! Thank you!

Looks like you don't have the thermostat flaps. YOU NEED THOSE FLAPS. Your engine will run way too hot without them.

--DD

Also, using the return line is beneficial on a carbed engine. The constant fuel flow through the lines helps preventing the fuel from getting too hot.

I also agree and highly recommend using pump around method so keep return line in use. Use Holley regulator made for return to tank installed after carbs, not the dead head model before carbs. Set at 3.5 PSI

Man you are good noticing those were gone. I have actually re-engineered some of the ducting to eliminate the flaps. They were in really bad shape so I have opened up the bottom and will be hand making air diverters to hopefully combat the problem. I have also thought about adding some external fans but haven't thought through that one totally.

I like the idea of using the return line. Not sure about buying a Holley regulator but I can see the benefit of constant fuel flow. Hell all of the lines are all ready in it's just a matter of adding another T and doing a little rerouting. Thanks for all the advice! It is very helpful!

R

Get your fuel lines off of the engine! It only serves to heat the gas up. If you look at the rear verticle engine tin you can run the line to dr side with a split piece of vacuum hose wrapped around the fuel line and secure the affair with 2 line holders. For me, the linkage on the rear of the carbs was less than optimal. You need to figure out how you're going to deal with the vapors from the open tube on the oil fill tower. Your engine compartment will wind up an oily mess. Rethink your position on the cooling flaps. They are simple and do the job. A rotary pump (the filter should be prior to your pump) verified at the correct pressure, eliminates the regulator and gauge. fewer fuel line connections and clamps equals less leak potential. Especially, when in all probability it will happen over the top of the engine, while you're driving and then you can watch your car burn up.

PS one filter will do the job. Get a stock FI filter with the same size fittings on either side.

PSS I noticed in your sig you have a Vision. I had one. Fun bike but a bit futuristic for it's time.

Your carbs are configured for flow through fuel feed.
All you need is one more nipple per carb across from the present feed.
I also agree that a regulator is unnecessary if you use a pump designed for carbs.
There is a Pierburg rotary pump available recently.
A rotary is modern, quiet, low vibration and dependable.

Did you change the cam to a carb compatible one when you overhauled the engine?

Good advice. I was thinking of a different way to route the lines, I am sure I can get them off the engine. The vent will be taken care of, just not there yet. I actually have the stock EFI filter before the pump, the Empi filters were more for looks and to verify flow. Maybe I will just delete them all together. I will look into the rotary pump but I just installed a new 9psi "noisy" pump and that one sounds expensive.

I do not have the cooling flaps anymore between the two moves over the last 3 years they have been misplaced/lost. Do they really do that much? It seems to me they would decrease air flow causing more issues. I have change out the stock heavy heat soaking exhaust manifolds for headers to get that heat dispersed faster.

Heater? Going with a 12 volt one custom installed. It's south Georgia, don't need heat very often.

Oh yes, I have one of the original Victory's. Yellow and black 03 Deluxe Cruiser. I was lead chassis designer for Victory from 98-01.

Ummm, this is the first I have heard of a EFI cam not working fine for a Carb motor. I looked into more performance cams to go with the jugs and pistons I put in but there was, as always, budget concerns.

Change the cam or be sure not to toss the F.I. parts. You will regret it. Also go to the classifieds and post a WTB: ad for all the correct ducting. There have been many an engine builder (some who charge 10K+ as a starting build price and have done lots of dyno time) who have tried and failed to make a better cooling system than the Porsche engineers. You will also need the NLA T-Stat.

Oh.. and

It would appear that you have 12 fuel line connection points in the engine bay alone. A tad excessive.

Carbs can be made to work with a FI grind cam.

It works better with the t-stat, but the cooling system will still work without it. It will take longer to warm up, of course. But leaving the flaps out sill keep the air from going the places that it is supposed to go, and your engine will not like you for it.

We have seen these engines go from "TOO DAMN HOT" to "normal operating temps" just by installing those flaps.

--DD

Without a thermostat the cooling flaps will simply sit in the "full cooling" position which is OK if you're fine with the longer warmup times.

However, running an engine without the cooling flaps will result in a quick and ugly heatstroke death.
Among other things, running without the flaps means you will have NO air going through your oil cooler.

It's a sure way to turn that engine into a boat anchor.

Here's a pic of what the flaps look like when in the full cooling position.

Note that the passenger side flap is pointing down to direct air into the oil cooler.
Without that flap down like that (or no flap at all) none of the air would be forced through the oil cooler.

Okay, heat flaps it is. What does the T-Stat look like (I am sure it doesn't look anything like the ones in my Fords and Dodges)? I have built a few engines in my day even some air cooled engines but more in the V-Twin and Vertical twin variety which means I am a little bit of a novice here. How hard is it going to be to install the flaps with the engine in the car or should I just plan on dropping it again?

Thanks for all the advice guys.
Robin

I believe you can install the flaps with the engine in the car (although I did it with engine out, so I could be wrong). You basically need to remove all the top tin which is the challenge.

The thermostat "bellows" looks like this (although this picture may be from a Type I, but it's basically the same thing):



When cool, it's compressed like in the picture above. It's mounted to the bottom of the engine case near oil pan on driver side. When warm, it expands. There's a wire attached to it that feeds around a pulley and up a hole in the tin topside. As it expands it lets more wire out and that allows the springs to open the flaps into their cooling position. After shutdown, as it cools down, the bellows contract again. If you get one make sure you get one that fails in the full cooling position. There are versions out there that apparently fail in the cold position (less cooling). There is a guy that manufactures them: Awesome Powdercoat.

Rube Goldberg would be proud.

Here's a close up picture of my engine topside. In the white circle you can see the wire that comes up through a hole in the tin. It attaches to that clamp which is spring loaded and mounted to the cooling flaps rod. The rod is partially held in place by that little flat piece next to the spring (I had to fabricate one because I was missing mine). This picture was taken with a cold engine. When it warms up that clamp will rotate, I dunno, maybe 60 degrees (?) CCW (from the direction this picture was taken). As others have said it's not strictly necessary to have the thermostat in place. It's not GOOD for the engine or your gas mileage but you won't have a catastrophic failure necessarily, like you can expect at some point without cooling flaps.

Click to view attachment

Thanks again for your help and the pictures were HUGE! I am going to go through the boxes of stuff I have and see how much of this I still have. It's been a few years and I'm old enough I have CRS (Can't Remember Shit).

At least if I have to drop the engine it's easy enough to do!

Thanks again for everything guys.

R

SirAndy, good picture and explanation. I think it is a common misunderstanding that removal of the flaps will result in less interference to airflow and therefor better cooling. But, as you noted, removal of the flap which directs air to the oil cooler results in the oil cooler no longer doing its job.

Has anyone considered lowering the operating temp of the tstat for carbs? Typical tstats say 85-90 for fi, and mention a lower temp for vw's running carbs.

I looked at the system for a long time and swore that the pass side flap in that position will direct the least air flow over the oil cooler.
In that position the oil cooler air flow is almost completely blocked.

When I removed my cooler entirely, I riveted the door DOWN in that position to stop air flow to the cooler.
Is that the incorrect method to stop flow to the cooler?

Take a look at this pic with the flaps only partially open. That passenger side flap has a flange that curves down into the fan housing. When the flaps are all the way open, like in SirAndy's pic, that flange directs some of the air right to the oil cooler, while most of the air goes over it to the cylinders.

Yes, but if you close that flap (all the way down) I dont see how that directs MORE air over the cooler. It seems that is the position that has the least flow to the cooler.

Because when it's completely closed there is no air going to the oil cooler. Flap up (cold) is closed. Flap down (hot) is open.

Sorry for the hijack.
If the flap is in the position shown on the right, I believe this blocks flow to the cooler and provides max flow over the cylinders.
It is hard to visualize because the engine tin that covers the cooler is missing in that pic.
But I believe the flap blocks all flow to the cooler when pressed down all the way.

Here's a drawing I found online that illustrates what is happening with the flaps. Does that make sense now? See how the air goes under the flap to the cooler?

That drawing is a great find! Hopefully it puts to rest the controversy over how air gets to the oil cooler. I was skeptical myself until I took the system apart and saw how the vane works. Ingenious.

Another fuel tank related item you may want to consider when running carbs is a vacuum relief. I never had one on mine and then one day after a long drive I had fuel starvation. I opened fuel filler to confirm there was fuel in tank and heard a large rush of air in tank and sounds of the metal fuel tank relaxing from being under strong vacuum. I later found some posts about this and added a relief valve on my car. I am sure some others that have more experience can provide their thoughts.

Jim

Thanks!

Great!, I guess I need to get under my car and see if I can close the slot where air is now blowing onto my oil cooler that is no longer there....

You can remove one fuel filter and put one only in the pressure line before the tee fitting,I wouldn't feel happy with the screw type hose clamps you have,get the correct band type fuel hose ones as they don't cut the hose up when tightened.
As mentioned ditch that pressure regulator they don't work well and are known to leak,the holley low pressure one is cheap and cheerful,I say this because I have had experience with both bad and good in that order.
Have you speced these carbs for your engine size? ,make sure the venturies aren't too large many of these larger carbs are sold like that,it causes a huge flat spot in the lower rpm range and makes the car miserable to drive.
Aircooled.net have a good basic set-up guide if you haven't been there yet.
Good advise given so far on the cooling flaps,when you have done that you can get some rubber grommets and plug all the unused holes in your engine bay....every bit helps to make a cooler running engine.
Good luck getting it running.

Very useful, thanks for the drawing.

Is there any way to test this system with the engine in the car? I have a terrible problem with high oil temps in the summer time (like "260-270+ terrible", verified with the dipstick thermometer). Runs great today (45*) but some summer time (80-90+) I gotta keep movin'...

I have verified from underneath (I have a lift) that the bellows is working (used a home propane torch to test it), and I can hear some items "clank" at full travel either way. But I'm not seein' a way to verify position of these flaps without having to dig down into the engine covers.

The bar that the flaps are attached to can be seen from above the engine. (Don't pay attention to the red circles. I pulled this image off google.) On the left side near the spring is a little tab. You can manually turn the flaps if you disconnect the cable and see that they're at full open or closed. Default position is at full open in case the cable or thermostat breaks.
I suppose it's possible that the individual flaps themselves may be out of whack. The only way to know would be to remove the cooling tins.

High oil temps could also be due to a worn oil pressure release valve. The stock valve has an oil cooler bypass function for warm up that can wear out over time and allow too much oil to bypass the cooler. If you get the upgraded one from Tangerine Racing it'll eliminate that problem.

Having BTDT, the best advice I could give is this: Go back to the original fuel injection as it is a dependable and fine performing setup. Carburetion that is poorly setup (combined with disabled cooling system) will lead to quick demise of your poor engine. I have never seen a street 914 improved by removing the FI, but have seen several with the opposite result.

The FI will run smoother and more reliably on a 914. The carb linkage is affected by the engine heating and cooling, and the carbs get out of sync easily. So unless you have a big motor with lots of cam, the FI works better.

That being said, if you cant find your set of cooling flaps, I have a LOT of them. You can have one set for the cost of shipping.

I had another 914 owner who's rebuilding his engine take a couple pics of the flap with the shroud disassembled.

i actually need a set for a motor i am building here.

Wish I would have seen this earlier. I just got a set off of eBay and that set me back 75 bucks. As far as the EFI, I sold it because I was lead to believe that since I put a big bore kit in it that the EFI being a closed system wouldn't work. Also I am very old school and am much better with carbs.

Not meant to insult, but if you got a set of carbs for $75, I'm betting you'll have a bunch of trouble. You may have gotten lucky, or you may have gotten someone else's problems. A mild bump in displacement won't really be a problem with the FI system. You may need to dial it in with a wide band O2 sensor, but it should work fine. All of the advice you are getting to keep the FI is with and for good reason.

He said he got a set of cooling flaps for $75.
And he already sold the FI system.

Fuel Injection is definitely the way to go if your going to stay stock or almost stock as many will attest to on the site......

There are many great sites that will help with identifying the parts you will need and more importantly what you will need as a complete system to work.

The ECU/brain, injectors, TPS and the other items are not necessarily interchangeable. Identification has more to do with your engines displacement.

Good Luck!

Wow. A month ago you literally didn't know the difference between fuel injection and carbs and now you're an "internet expert," giving other people advice... and all without even learning how to use the "search" function. This whole interweb thing is pretty amazing.

I am confused with this discussion of flaps or no flaps. I have been running my 2.2L carbed 4 with flaps set at full open/no thermostat for thousands of miles; some at top speeds over long hauls across the Arizona desert, California mountains, from the beach up to Flagstaff in a downpour then a driving snowstorm (without any heater - much less engine coolers), and I have a cool running engine that takes longer to heat up to running temp but is far from fried or frying.... i am fully appreciative of Dave's acumen in the annals of 914 lore but i remain .

The other day, it was 119 degrees in the desert and the car went from 68 at the beach to 119 and back.... and ran like a top.... ////way

Removing only the thermostat is just going to cause the engine to warm up more slowly.

People have been doing this in places like California for decades. Some because they think it will keep the engine cooler in hot summers, or "just in case" they fail closed. Both cases are false economy.

The best is to have the thermostat installed and properly adjusted.

The cooling flaps must be installed. I would consider it critical in any aircooled engine and even more so with the type 4.