TIH setup

For discussing the modifications needed for diesel vehicles to run with 2 tank veggie oil conversions.

Moderators: SunWizard, coachgeo

Postby SunWizard » Fri Nov 21, 2008 9:00 am

coachgeo wrote:Sun.. what about yours in same senarios?

Mine starts fine no matter how cold it gets (-10F is the coldest in 3 years here), without using the block heater. Warm up time until switchover gets slightly longer the colder it gets.
YVORMV - Your veg. oil results may vary.
95 Dodge Cummins 4x4 SVO WVO conversion.
81 Mercedes 300D- stock and happy on V80/D20 blend.
Low fossil net zero house- 100% solar power and heat.
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Postby tubular031 » Fri Nov 21, 2008 9:25 am

John Galt wrote: Here it routinely gets to minus thirty and insulated HOH + FPHE works fine at those temperatures ....


Hey John-
Since you seem to know your stuff on the HOH setup, can you answer a question for me?

What is the best way to transfer the heat from the coolant hoses to the fuel hose? I know aluminum is better for heat xfer, so do you have the heater hoses bundled with fuel line or aluminum line? I would think using rubber fuel line would not be as efficient as a aluminum fuel line.

What are you using to insulate the HOH bundle? That pipe insulation that homedepot and lowes sell or something else? I have seen rubber like insulation at the hardware store and I have also seen plastic like foam insulation. Any pointers on what is better?

I live in north texas and seeing less then 30 deg is not very common. I am getting a tank with a hotfox pick up in it and going to be using a FPHE. Plus I have a 7.3 PSD and the common rule is get the oil there and the heads heat it up the rest of the way. I would like the fuel to be hot enough so the heads dont have to heat any....
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Postby WD8CDH » Fri Nov 21, 2008 11:07 am

John Galt wrote:Why would you want to use an obsolete and unreliable method, when knowledgeable and experienced people use insulated HOH or TOH?


John,

I am going to have to disagree with you here. With some engines and their particular coolant flows and heat output, and some oils, it may be enough that you couldn't tell the difference. With your cold upflow oil processing (removing the PHO and Fats), you could usually get by with HOH, especially on a truck. With all the PHO and Fats left in (I don't want to waste usable fuel) HOH may be adequite but still with somewhat longer warm-up times than a proper aluminum tube/rubber hose TIH.

In most cases, especially in limited spaces like in cars, TIH is easier to run than insulated HOH because of less bulk.

History has shown that properly built TIH has better long term reliability than HOH/TOH unless you go to either aluminum or Viton for the fuel line in the HOH/TOH. Viton, of course is quite expensive and aluminum makes for a bulkier TOH assembly than it would as TIH with poorer thermal properties than TIH. You can make up for the poorer heat transfer of HOH/TOH by using parallel coolant flow but parallel coolant flow is more susceptible to fuel tank overheating with long operating times in warm weather than series counter-flow operation.

Unless you delay your switch over to VO, having the FPHE before the filter will give you a slug of not hot enough oil from the filter to the engine when it is the most vulnerable. Insulating the fuel filter (if you have the room to do so) will not eliminate the cool oil slug. An FPHE, due to it's distributed heat and low thermal mass heats all of it's oil simultaneously preventing a slug of cool oil if it is the last heat exchanger. I like to design my systems so they prolong the life of the engine, not put more strain on it.

Older Mercedes, Toyota and Isuzu engines are more tolerant of sub-optimal design but in general, a Heated Fuel Pickup > Aluminum TIH > Heated Fuel Filter > FPHE with series counter flow coolant configuration is the best performing, most reliable, more cost effective and easier to install system with the widest climate range, widest range of fuels and widest variety of engines. Sure, you can build a good system with HOH if you are careful, but you can build a better system with TIH.
Ron Schroeder
WD8CDH
'85 MB 300DT 2 Tank
Since '81 former WVO conversions:
'83 240D
'80 Audi 4000D
'83 Isuzu Pup
'86 Golf
'76 Honda Civic with Kubota engine
Prior to the cars, several generators
Kubota Tractor
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Postby John Galt » Fri Nov 21, 2008 1:45 pm

tubular031 wrote:
John Galt wrote: Here it routinely gets to minus thirty and insulated HOH + FPHE works fine at those temperatures ....


What is the best way to transfer the heat from the coolant hoses to the fuel hose? I know aluminum is better for heat xfer, so do you have the heater hoses bundled with fuel line or aluminum line? I would think using rubber fuel line would not be as efficient as a aluminum fuel line.
What are you using to insulate the HOH bundle? That pipe insulation that homedepot and lowes sell or something else? I have seen rubber like insulation at the hardware store and I have also seen plastic like foam insulation. Any pointers on what is better? ...


PEX tube for the VO fuel bundled with coolant hose, and insulated with common foam pipe insulation. One could also use Armaflex insulation from refrigeration contractors but it's rather expensive.

having the FPHE before the filter will give you a slug of not hot enough oil from the filter.


Not going to happen if the filter is preheated and the start-up fuel is run through the filter. I don't see the point of a separate filter for the VO. If the VO is processed correctly the OEM fuel filter should be adequate. I use one FPHE for all fuel, didn't add a 2nd filter and have never experienced ANY filter clogging problems. I just make sure that all fuel going into the tank is correctly filtered to 5µ. I operate in much colder temperatures than those in the lower 48 experience and I've engineered the fuel system for simplicity and maximum reliability. When you live and work in the cold North you soon learn that complex systems fail at the least convenient times and usually at very cold temperatures, far from home.

This has been a good, informative discussion. Each user has to evaluate the options and make the choice that works best for their situation. The "best" method depends on individual circumstances and there are no right vs wrong answers.

If you choose to use aluminum TIH be VERY careful how you route and secure the assembly so that it does not bridge between two components which will vibrate differently, or the aluminum will be subjected to stress cracking from the vibration.
Last edited by John Galt on Sun Nov 23, 2008 2:06 pm, edited 1 time in total.
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Postby WD8CDH » Fri Nov 21, 2008 4:48 pm

John Galt wrote:
tubular031 wrote:
John Galt wrote:
having the FPHE before the filter will give you a slug of not hot enough oil from the filter.


Not going to happen if the filter is preheated and the start-up fuel is run through the filter. I don't see the point of a separate filter for the VO. If the VO is processed correctly the OEM fuel filter should be adequate. I use one FPHE for all fuel, didn't add a 2nd filter and have never experienced ANY filter clogging problems. I just make sure that all fuel going into the tank is correctly filtered to 5µ. I operate in much colder temperatures than those in the lower 48 experience and I've engineered the fuel system for simplicity and maximum reliability. When you live and work in the cold North you soon learn that complex systems fail at the least convenient times and usually at very cold temperatures, far from home.

This has been a good, informative discussion. Each user has to evaluate the options and make the choice that works best for their situation. The "best" method depends on individual circumstances and there are no right vs wrong answers, regardless of how emotionally attached some people might be about one method vs others.

If you choose to use aluminum TIH be VERY careful how you route and secure the assembly so that it does not bridge between two components which will vibrate differently, or the aluminum will be subjected to stress cracking from the vibration.


Hi John,

The point of two filters is reduce diesel fuel usage during switchover and during purge. Separate filters also allow much faster purge. And lastly separate filters allow redundancy. With my daily drive cycle, a single filter would more than double my diesel usage. Not a big deal if most of your driving is long cruises.

You are right that if the VO is processed correctly the OEM fuel filter should be adequate. In fact, I use the same OEM element type on both my diesel side and my WVO side but they are two separate filters. Because I properly de-water and filter my oil, I have NEVER had to change a WVO filter from plugging in over 30 years but I have been forced to change diesel filters on the road a number of times. At least I only need to carry one type of filter.

I prefer to not run the diesel fuel thru the FPHE so I can run diesel for extended periods of time without more rapidly degrading the engine from loss of lubricity with heated diesel fuel. Of course, you could eliminate that problem by turning off the heat in the FPHE during extended diesel fuel usage but that would add complexity.

Of course you shouldn't run aluminum fuel line from the body/frame to the motor because of relative movement but with normal mounting, I have never seen an aluminum TIH fail. By far, most of my conversions and most of the conversions that I have seen have been 3003-O series aluminum TIH but all of the heated fuel line failures that I have seen have been PEX or other non-metallic fuel lines.
Last edited by WD8CDH on Tue Nov 25, 2008 7:14 am, edited 1 time in total.
Ron Schroeder
WD8CDH
'85 MB 300DT 2 Tank
Since '81 former WVO conversions:
'83 240D
'80 Audi 4000D
'83 Isuzu Pup
'86 Golf
'76 Honda Civic with Kubota engine
Prior to the cars, several generators
Kubota Tractor
WD8CDH
 
Posts: 103
Joined: Tue May 27, 2008 11:44 am
Location: NY

Postby SunWizard » Fri Nov 21, 2008 5:00 pm

John Galt wrote:I use one FPHE for all fuel, didn't add a 2nd filter and have never experienced ANY filter clogging problems. I just make sure that all fuel going into the tank is correctly filtered to 5µ. I operate in much colder temperatures than those in the lower 48 experience and I've engineered the fuel system for simplicity and maximum reliability.

Are you still blending with only 20% VO and being very careful to have no PHO? The amount of heat needed to run that fuel blend through a filter is far different than for 100% PHO.
YVORMV - Your veg. oil results may vary.
95 Dodge Cummins 4x4 SVO WVO conversion.
81 Mercedes 300D- stock and happy on V80/D20 blend.
Low fossil net zero house- 100% solar power and heat.
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Postby John Galt » Fri Nov 21, 2008 8:03 pm

My comments arise from seeing what works and what doesn't work with a variety of VO fuel systems, including heated and unheated single tank blends as well as differently configured two tank systems. If you live in a warm climate then almost anything will work, even bad designs. Colder climates require better designs with fewer components to leak or fail if long term reliable operation is desired. Design faults will always fail at the coldest temperature, in the most remote locations. That's Murphy's Law: Whatever can go wrong, will go wrong, at the worst possible time and place. Murphy lives in the cold harsh North.

If someone wants to use aluminum TIH or HIH, then be prepared for more joints to leak fuel, coolant or introduce air, and realize that failure of the inner aluminum tube will lead to catastrophic results before the problem is discovered. Some people are comfortable with that, others are not. It's a matter of individual choice and individual risk tolerance.

It's my personal belief that it's irresponsible to tell people that aluminum TIH is as reliable and potentially trouble free as a simple TOH or HOH system.
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Postby veggiesub » Sat Nov 22, 2008 7:57 pm

John,
Have you seen or heard of a TIH failure?
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Postby John Galt » Sun Nov 23, 2008 1:12 am

In the past forty years or so I've seen numerous examples of vibration induced metal fatigue stress fractures in a variety of metallic tubes used in ships, vehicles, aircraft, and industrial machinery. The various materials have included alloys mainly consisting of copper, aluminum or steel. Many of these failures required years to develop, and in quite a few cases the failure was induced by altering or removing tubing support as originally designed. On various VO fuel forums I have read about similar failures in bare tube, hose on tube, and tube in hose configurations which were consistent with the failures I had seen myself. In most cases the leaks were readily apparent and remedial action was taken before too much damage occurred. The failures with TIH caused the most damage since the leak remains hidden until significant damage to other components occur or the tube separates completely and the vehicle stops. The failure usually occurs where the tube connects to the compression fitting, or at the point of last support in a freely vibrating TIH assembly or a TIH assembly bridging across two differently vibrating components like a frame and body or a frame and engine. As mentioned, these failures often happen only after a number of years of apparently trouble free operation. In my opinion many of the TIH applications in VO fuel systems have not paid attention to necessary installation details, and will ultimately result in failure of the metallic tube within the hose part of the assembly. Many of these are like ticking time bombs.

One could no doubt adapt a wooden spoke wagon wheel to a truck, and it might appear to work fine for a while. That does not mean it's a good choice for that application. Technology advances; simpler more reliable systems are developed and applied, and these also evolve. That's the nature of R&D; nobody credible expects it to stop and stagnate when the first solution to a problem is developed. Consider the limitations and risks of any design, and accept the risks or change the design.

I don't sell kits or designs using TIH applications, nor do I have any TIH assemblies on any of my vehicles or vehicles I've worked on; I have no vested interest in the success or failure of TIH applications. I'm merely sharing my experience, take it for whatever you think it's worth; I don't care one way or the other. I'm here to share information and encourage technical discussion, not to change anyone's preconceived ideas.
Last edited by John Galt on Sun Nov 23, 2008 1:42 pm, edited 1 time in total.
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Postby veggiesub » Sun Nov 23, 2008 10:55 am

IH can indeed be troublesome if improperly installed, but they transfer heat better than OH systems. There are certainly pros and cons to each. I think it is misleading to tell new folks that the community has left TIH behind. You have, but I suspect that most have not.
Last edited by veggiesub on Sun Nov 23, 2008 4:43 pm, edited 1 time in total.
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Postby John Galt » Sun Nov 23, 2008 1:53 pm

There's no doubt that TIH transfers more heat. However I question whether or not that extra heat transfer is really needed at that point in a correctly designed fuel heating system. The temperature of the fuel pick-up in the tank and the lines to the heat exchanger only needs to be warm enough to keep the fuel fluid. Insulated HOH or TOH will accomplish this with none of the problems inherent in TIH assemblies. If the heat exchanger is correctly sized, and correctly connected to the coolant and fuel systems than it should provide adequate heating to the fuel.

TIH requires more components and much more attention to detail to operate reliably. If someone is willing to invest that care and attention, then they can probably make it work adequately for their needs.
Last edited by John Galt on Sun Nov 23, 2008 2:16 pm, edited 1 time in total.
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Postby John Galt » Sun Nov 23, 2008 2:11 pm

Regarding the personal comments: I've edited my messages to remove any potentially inflammatory statements. Unlike the Frybird forum there have been no inflammatory personal attacks here and I shouldn't have let my irritation from being provoked there influence the replies I make here. Thanks for bringing this to my attention.
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Postby veggiesub » Sun Nov 23, 2008 4:42 pm

Thanks John. I agree that this forum is a refreshing change. I edited as well.
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Postby tubular031 » Mon Nov 24, 2008 8:29 am

John Galt wrote:Regarding the personal comments: I've edited my messages to remove any potentially inflammatory statements. Unlike the Frybird forum there have been no inflammatory personal attacks here and I shouldn't have let my irritation from being provoked there influence the replies I make here. Thanks for bringing this to my attention.


veggiesub wrote:Thanks John. I agree that this forum is a refreshing change. I edited as well.


I read this after you guys edited your comments and thanks for your input. I agree stick to the facts and leave the personal junk out of it. we are here to learn, not fight. I am glad you 2 came to that conclusion and I admire that.

John - After studding the vegiestroke setup and reading your input, I am going to build my first kit for my truck using HOH with a bunch of insulation.

Thanks again guys!!!
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Postby WD8CDH » Wed Nov 26, 2008 12:13 pm

John Galt wrote:Insulated HOH does everything that HIH does, but better with less cost and greater reliability, so we will just have to agree to disagree.


Hi John,

The above is mostly misinformation. While I don't consider HOH "bad", my over 3 decades of experience, most other's experience and scientific analysis show TIH to usually perform better than HOH.

As far as cost, TIH can be marginally more expensive or cheaper than HOH. For example, The 3003-O aluminum tubing usually used in TIH is about $1.00/foot. PEX is only $.60/foot but other tubing like Viton is as much as $5.00/ foot. PEX won't last as long as aluminum because of deterioration from WVO and to some extent vibration so with PEX, you would be trading a slightly lower cost for shorter life and less reliability. Going to Viton or any other tubing with the same life as aluminum would be from 2X to 5X or more per foot. The fittings for each end of a TIH would be between $5 and $10 each so except for a very short run, aluminum/rubber TIH would be cheaper than Viton/rubber HOH.

While an internal leak in a TIH could potentially cause engine damage, the mechanism for that failure is about the least likely failure of TIH. Vibration can cause metal fatigue but in the application where we are using TIH, the tubing is surrounded by and filled with liquid dampening that vibration to well below the fatigue stress point. An exposed metal tube like the examples of vibration induced metal fatigue stress fractures in a variety of metallic tubes used in ships, vehicles, aircraft, and industrial machinery is a far different and a much more severe vibration profile than the vibration internal to a TIH so that type of failure in a TIH is practically non-existent. The most likely, but still extremely rare, point of failure is where the inner tube exits the compression fitting. Failure at that point has no risk of engine damage from coolant contaminating the fuel. Calling TIH a ticking time bomb is quite a contradiction to long term existing experience and R & D.

3003-O aluminum tubing has been the material of choice for fuel lines in the Racing and Aviation industries for many years because of it's long term safety and reliability.

While for you and your driving cycle, using a single filter overcomes the decrease in thermal performance of HOH compared to TIH, I would suspect that many users would not tolerate the increase in switchover times, purge times, fuel cross contamination and petro fuel usage compared to separate filters.

I am glad that HOH and a single filter works for you, but it is not the best design for everybody or all conditions.
Ron Schroeder
WD8CDH
'85 MB 300DT 2 Tank
Since '81 former WVO conversions:
'83 240D
'80 Audi 4000D
'83 Isuzu Pup
'86 Golf
'76 Honda Civic with Kubota engine
Prior to the cars, several generators
Kubota Tractor
WD8CDH
 
Posts: 103
Joined: Tue May 27, 2008 11:44 am
Location: NY

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