Fuel Leaks are one of the main causes of engine fires. The original hose end injector design used by Volkswagen (and all other manufactures at the time) helped cause these fires. Lets go over the leak points using the original design vs switching to an injector using an o-ring to seal the connection between fuel rail and fuel injector. I decided to write this due to a conversation I saw on the samba forum. In the thread, our fuel rails were brought up. However, the moderator there decided to censor the topic. There was also another guy, who talked to a guy that works on VW’s who likes the original way better too. This makes our rails junk. That moderator praised the VW mechanic because he agreed with him. It appears his personal view is that of a few others as well: “VW spent millions on R&D so it must be the best”.
They are not wrong. However, VW spent millions to SAVE Ten’s of millions. Not to make the absolute best thing available. That is absolutely ridiculous to think otherwise. Volkswagen designed the rail around the fuel injectors being produced by Bosch at that point in time.
There is fear in the waters
I had someone show me one of the funniest things lately. It was a competitor that sells fuel injectors from the 90’s that are painted all pretty, at an incredible mark-up to $289 a set of 4. In the video they were hitting their fuel rail with a hammer. LOL. I can only assume this was in response to knowing we have something way better. Because of that, they need to try to convince people as to why people should stick with purchasing their injectors and using an outdated connection method.
The stock plastic rail
In this video, we see the stock rail being used as the example. Lets go through what this competitor said and did.
He took a ball peen hammer (that looks to be a 16oz size or less )and dropped it from a few inches above the plastic fuel rail. I should be impressed, because that was the intention of this video. However, around 5th or 6th grade I learned that bridges are build with arches because that allows the load to be spread vs absorbing the impact straight down. So I am not sure what this video actually proves besides why the original rail design was ROUND. I would be more impressed if the rail was held in place and the nipples the hoses attached to were put under stress or hit by a hammer. Even if that same 16oz (?) hammer were dropped directly on the nipples, that would have proven more of a point. Especially since so many of us know the feeling of tightening the hose on the rail only to snap it off or crack it.
There was a challenge in the video: “Show me another car you can whack the fuel injection rail with a hammer and it still runs”. As it turns out, I haven’t been able to find a car that doesn’t continue to run. Much of that has to do with the entire automotive industry moving away from hose-end injectors. I challenge back to go find a vehicle you couldn’t do this to.
It can only be assumed that the question “So, who needs injectors?” is because they feel they proved the rail is durable? Okay. But, durable and prone to leaking and engine fires are two different things. We have already gone over this several times and put videos together showing the spray pattern difference between the EV1 fuel injectors vs the EV14 fuel injectors in our Vanagon Fuel Rail Kit. In addition, if you want hose end still, we offer you a DIY kit to make the same modifications they do, at your garage.
Leaking points with upgraded aluminum fuel rail
Before the thread was scrubbed, the number of points of possible leaking was discussed on the samba. I completely disagree with the assessment from a few of the possible leak points. The statement was made there was a net zero difference because you are only trading an o-ring for a hose. This is simply not true. Lets take a look at an option of what has been accepted in the community as an upgrade over the OEM plastic rail.
The points where a leak can occur are marked with a drop.
Starting on the rail, each nipple has a thread where a leak can occur. (4 points)
More failure points can be found where each nipple is sealed with a clamp. (4 points)
Each hose itself connecting the rail to the fuel injector could be a point of failure. (2 points)
Injectors use a barb that connect to the hose, sealed with a clamp, which can leak. (2 points)
Bosch EV1 injectors have a metal body with a plastic molding for electrical connection. It is not uncommon for this to leak. Because of the ethanol content of fuels used today vs in the 70’s and 80’s, the material internally was not designed to withstand the same conditions. This is not anything new, it has been happening for years. This issue is partially why Bosch and other companies moved away from the EV1 metal body design.
There are 14 total possible points of failure where a leak can occur using the EV1 Hose end connection fuel injection system. If you were to eliminate the threaded nipple rail and swap it for a welded style, it saves 4 possible leak points.
Injector-Rehab fuel rail system possible leak points
Not taking in account the latest injectors being far superior to the technology available “back then”, lets talk about the benefits of the VW Vanagon fuel rail system we are bringing to market. How many points of failure are there? Lets take a look.
We are only replacing a portion of the system. Because of this, we are still going to have points of possible leaking. However, they are greatly reduced from the previous method.
Starting at the outer most and working towards the injectors, we have 2 barbed fittings to tie the system into the existing system’s feed and return lines. (2 points)
The next connection is an “AN fitting”. This stands for Army Navy as these two agencies agreed on this method as the standard back in WWII. Unlike hose end injectors, this method of joining 2 connections has stood the test of time and is still used today and is regulated under Aerospace Standards specification AS4842, AS4843, and AS4875. (2 Points)
Adapting the AN fitting to the anodized fuel rail is a tapered NPT (National Pipe Thread) as this type of thread provides rigidity and a pressure tight seal. (2 Points)
Last but not least, the injector o-rings. Again, the method the entire automotive industry (including VW) has used since the mid 80’s. (2 points)
This gives us 8 total points a fuel leak would be possible in your Volkswagen, Hans.
If my math is correct, this would be Six (6) less points than with using a threaded aluminum rail. Two less points than using a welded nipple rail. This is just by sheer number of points of possible leaking. However, it does not take into account the likelihood of the leaking because of the TYPE of connection or point of failure we are calculating.
Still want to use a hose-end as Hans originally designed?
Knock yourself out! The Chinese still use chopsticks even though they’ve seen a fork before. Who’s to stop you?!
The plastic OEM rail and hose end injectors are replaced with an anodized fuel rail which accepts injectors which seal in the system via an o-ring. Bosch, along with the rest of the automotive industry, moved to this method of fuel delivery shortly after electronic fuel injection was introduced. O-rings have been used for longer than hose-end injectors were in electronic FI’s infancy. And, o-rings have been used in the next phase of advancement in fuel injection technology in the GDI (Gasoline Direct Injection) applications. These systems run at 3000+ PSI. Pretty sure they will hold up in your VW system.
We get it though. The VW waterboxer is such an engineering marvel, you want to keep the hose-end style injectors. Do it!
Want to make your own like the other retailers do? Want to use the same “magic” injector? We’ve got you covered! Fully Cleaned and flow tested kits available that anyone with some wrenching capability and basic tools can make a set themselves.
Here is a quick video showing you how to “make” your own at a fraction of the price.