Aluminum injector caps

[Smokininmo]

Unaffordable nightmare? Merely making the caps stationary would solve about 90% of return line leaks.

My caps seal, right until the cap gets moved, then they leak. A different designed cap, that seals with crush washers on the existing shelves on the injector, tensioned by the fuel line would IMO eliminate the problems with the return lines.

Otherwise, you could just add a spacer to the top so the fuel line holds the cap stationary.

I do not believe the problem is the cap's quality as much as those dang things move all over everywhere. These o-rings aren't meant to seal moving objects. They aren't a shaft seal.

The reasoning behind the manifold is. (If it is in fact the caps moving all over the place that is causing the leaks) a 1 piece manifold will mitigate that movement in which case they SHOULD take MUCH longer to go bad. IE By the time one goes bad just replace them all. and you also never have all those caps and fuel lines and clamps to replace again. Also If you pull a cap for a oring replacement then you essentially disturb the caps to either side when removing the hose. I love the idea of aluminum caps and I think they would be a huge improvement. The manifold idea came about as a product of listening to the problems people are having and trying to come up with the most reliable cost effective way to fix the problem. Like I said I'm just thinking out loud.

 

[OLDBULL8]

This info should go along with the design of any configuration of caps, wether it be a manifold or individual. The temperature toleration of the o-ring is the largest factor of life of the o-ring. A Buna-N o-ring is rated at 180* max as apposed to a Viton, depending on what color used can be as high as 400*. The minimal squeeze factor is .007 for static installation. Just maybe I and others are under the wrong impression that the installation lube (Vasoline) is a good lube. According to Parker, a thin lube coating is sufficient and preferred, there are dedicated o-ring lube's that are silicone based.

Take this for what it's worth, but with all the 100's of post's of leaking/air intrusion fuel return lines, maybe it's something that should be considered.

http://www.parker.com/literature/ORD 5700 Parker_O-Ring_Handbook.pdf

 

[Smokininmo]

So the questions we all want answered are:
1)What is the cost to produce a set of aluminum oring caps? (Lets just assume there are eight caps with two barbs each.)
2)Will they improve reliability enough to offset that cost? (And yes we will all acknowledge that we will pay a certain amount for the cool factor whether they help or not)

Assuming that the injector mounting tolerances on IDI heads are tight enough to facilitate a one piece manifold on each side:
3) What is the cost to produce a pair of manifolds?
4)How does that compare to a full set of caps?
5)Is that improvement a simpler more effective way to solve the problem.

And the mother of all the Questions

Will the O rings just go bad anyway and so we wont have solved a damn thing or is it in fact the cap that is the problem?
My money is on the cap.

 

[laserjock]

That seems like a pretty reasonable summary. I might throw out there that there are other choices of o-ring materials. If like OLDBULL said, the main enemy is heat, then silicone (not sure if silicone is diesel rated or not... have to look that up) or something like a Kal-Rez fluoroelastomer would be better choices. Now Kal-Rez is the top of the line Dupont Fluoroelastomer and it is not cheap but it is resistant to nearly everything and good to over 600 F if I recall correctly. There are other considerations I can think of too regarding the o-rings. My issue with viton (while superior in most ways to buna) is that like most fluorinated elastomers, they are prone to compression setting (i.e. they loose their squishyness to use the technical term). Once they loose they take a compression set, the elastomeric tension is reduced and hence a small movement causes a leak. I agree whole heartily that minimizing or eliminating the movement of the cap should reduce the probablity of leak but we may need to look at the entire package. There is a lot of vibration to deal with here too. Not just tugging or hoses via fuel line movements.

 

[NO_SPRK]

Have you thought about making injector caps that bolt to a hard return line... maybe use 4 cylinder engine lines.. id rather convert to the VW/mercerdes/GM style

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[Smokininmo]

Have you thought about making injector caps that bolt to a hard return line... maybe use 4 cylinder engine lines.. id rather convert to the VW/mercerdes/GM style

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What do those look like?

 

[NO_SPRK]

Mbz vw gm use nipples with braided rubber line.

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Cummins and alot of other industrial engines use hard lines.

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[ADV]

solid lines or a manifold that fits over all 4 injectors is that going to be any better than a good quality cap with a good quality fuel line? I put the aluminum set on my truck on 7-17-2012 and had 188750 miles. Now more than a year later truck has 218002 miles so 29252 miles problem free. I run a strong MWO blend some time other times straight diesel it has seen outside temperatures from -8 to 103 truck starts and runs with no issue. I run the glow plugs for 10-12 seconds and its running in less than 3 seconds of cranking.

As of right now I do not have the time to do all the measurements and everything required to make a solid manifold. I am not saying it cant be done I am sure that it could but at this time I cant help out with that.

 

[opusd2]

I tell you what. I have been fighting one injector for the longest time, and I really wish I had GM style returns like my 84 M1009 does. Would make things so much simpler, I have NEVER had a return problem on that Chevy. Except for the crappy OEM filter setup I have yet to change out.

 

[NO_SPRK]

I measured the distance between each injector on a 6bt 12v VE pump cummins and a 7.3 idi. The distance between the injectors is pretty close. Id need a idi head or engine outside of a truck and without return lines for proper measurement

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[NO_SPRK]

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My mind is thinking of a style like this. You would use aluminum or steel caps but instead of the inline rubber lines you would have one bolt hole like the 4bt/6bt with a copper double crush washer. Id would bolt on either side of the injectors.

With so many HD big inline 4 diesel engines we could rob parts from them.

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[typ4]

Before I got in the viton biz, I talked with the oring suppliers and they all agreed that viton was the best all around for the temp ranges of our engines, on both ends of the scale you give up so either some elasticity or shrink resistance, so there is no 1 "perfect" solution for the orings. I dont know why some folks have such trouble, Maybe a bad injector top?
And as far as lube goes, Super lube is the recommended by all oring folks that I have talked to.


http://www.amazon.com/Synthetic-Gre...42&sr=8-2&keywords=superlube+synthetic+grease

This is the supplied lube in a Caterpillar brake rotochamber rebuild kit. And it is some slippery stuff. I used it on my returns last month or so ago and the caps slid right on, no snap , just went on.

 

[OLDBULL8]

I wish people would stop cluttering up this thread with all the redesign crap. The guy has designed and manufactured a cap that he has proved to be capable of many miles without leaks. If he is going to sell them, ya pays your money, take your chance. Ya did on the plastic caps didn't ya?

 

[NO_SPRK]

Heres the thing. Ive never actually had problems with return line kits ive put on. Personal or other. but I live one of the most neutral climates.

I think the oem design is flawed in several way and the aluminum caps are a great help but the hose connections are also a issue.

How many other light duty diesel engines have these return line issues?

I have no idea why IH/Ford did not use the MBZ/GM/VW style return lines. Is this a Stanadyne thing?

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[opusd2]

That's like the GM style on my 6.2s.

But the Aluminum caps are the real deal! They do a GREAT job of solving some inevitable problems. I'm with OldBull8, the thing is to appreciate the great solution someone went to great length to address a common problem, do the time to measure with great detail, and program a means of cutting a set of aluminum caps on a CNC along with all his work hours. We should appreciate it for all the work he did! There's nothing wrong with wondering about other methods, but give the guy his due! I think he did what a LOT of us wanted to do. And he should benefit from it, as we appreciate the great companies who give us great ways of making our trucks even better.

Thanks to an entrepreneur who deserves to be appreciated for his hard work. Thanks!