more picks.

The difference between the thick and thin.

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This is my response to an e-mailed I received from a member with questions about the elements in the pictures, what is the part number of the element that I am going to use and why, and what "exactly" I was going to do to the pump to prepare it for the modified 10mm elements.

I thought I would post my response.

First the element that I am using is not pictured, as it has been modified and I am not ready to go public with what I "actually" did to it yet. There are a few pump shops that are working with some members here and over at STD that are, or are looking into, moding these pumps, and I do not want to give them anymore ideas, because I am thinking about doing some additional MWs and auctioning them off if I am happy with my concepts results.

Also I am not going to release the part number for the element that I have chosen, or exactly why I chose that particular one. I will say that it is out of a PS pump and is a thick type.

Second, regarding the modifications to the Pump Cam, Case, Governor, Plunger Springs, Etc., I also am going to keep the "Specifics" to my self for the previously stated reasons, consider that information as proprietary.

I will say that I am going to modify the cam and use different plunger return springs.

The questions in the e-mail seemed more inquisitive as to specifics than the normal questions about general concepts or ideas. I got the impression that I was being asked questions by someone who is interested in doing it, and had the knowledge and equipment to do it as well, but didn't want to do their own research and testing. I get that, no big deal with asking, as, you never know if you don’t ask. If I were not thinking about my own "line" of MW pumps, (for lack of a better term), then I would be more willing to share. I hope all understand. My experiences in the racing world has taught me that ideas are best kept secret, unless they don't work.

Who knows, this effort may just result in an identification of a concept that doesn’t work.

Never hesitate to ask, you never know.

Hi Tom , do you have more of the holley 6.5 MW elements?

I have been following this post for a while, and doing some adjustments to the ip, and found some real improvement in drivability. I had intended to put a turbo on, but may not at this point, as I have mostly been able to get enough gains to suit my needs without it.

But still have some questions. If I did go to larger elements, and not put a turbo on would this likely just overfuel? So far with the rack limiter removed it does not make smoke, or at least not enough to see in the mirror.

The other question is in regards to an earlier statement about governor settings, mostly idle speed, "The result is, in the case of a 616, that the dash idle control is not needed, even with the A/C on. Improved bottom end / mid range torque and throttle response, with a stronger high end pull."

What adjustments did you do that accomplished this?

__________________
1977 240D turbo

Hi,

I have to check but I don't think so.
I am still waiting for my M 5 with Floyd 7.5mm elements and turbo governor to compare it in sense of engine run.
To start a new production run for MW Holly 6.5 I need to order min. 3 sets.
I need some time to do the delivery valve tests to get smokeless power and then I really think of doing larger diameter MW.

Summary: Find 2 other customers for Holly 6.5 and I start the production run.
Delivery time: ? end of February?
Wait for Super-Holly (whatever diameter this will be), estimated in spring/early summer.

Tom

Larger elements will deliver a larger quantity of fuel for a given plunger stroke when compared to a smaller element, (directly related to a period of time the crank is turning)( and could result in the over fueling you speak of)) and or, they can deliver the same quantity of fuel that your 5.5mm elements can, with a shorter plunger stroke, (length of time required to inject a given amount of fuel will be less, and end of delivery will be sooner, increasing the number of crankshaft degrees BTDC after the end of injection).

The earlier the entire fuel charge can be completely injected, (BTDC), the better, (generally speaking as there is a point where its too much too soon), because the additional time BTDC will be used to burn the fuel and produce pressure that will result in work. This will also result in lower EGTs given the same volume of fuel injected as a 5.5mm element, because the 5.5mm element requires more time to inject a quantity of fuel, resulting in the end of injection being closer to TDC, and less time for the fuel to burn, resulting in un burnt or partially burnt fuel being burnt during the exhaust stroke and in the exhaust, causing high EGTs and smoke.

You can adjust the IP to deliver the same quantity of fuel with larger elements, as the 5.5mm elements do currently, that way you would get the benefit of a shorter delivery time, (Pulse width), with out over fueling.


Because the IPs are mechanically controlled, each one really needed to be individually tuned to operate properly, where as an electronic system has the ability to learn and adapt to achieve the desired outcome.

There are Three different governed controls that are each adjustable. Each can have an effect, or limit, the other.

The Idle governors on a 616 are set week, and rely on the throttle to set the idle. The dash pot moves the throttle. Because the throttle has a large hand in the idle speed, the Idle Governor can not, or has very limited ability to, regulate fuel to add or reduce power to maintain a constant idle speed, and insure a confident return to idle. (when the dash pot is turned up and the engine is warn the engine will not have a confident return to idle, as in you are not confident it will return to idle)

A properly set Idle governor will be able to control the Idle with the engine is cold, warm, hot, A/C on-off, lights on, etc.

The Idle Governor adjustment is inside the IP and is accessible with the back cover off. The adjustment screw turns VERY easily and it is VERY POSSIBLE that when the lock nut is loosened, the screw will turn as well, and you will loose the start point. Same for tightening the lock nut, the screw can/will turn and you will be chasing the setting until it is so far out you will have to take it to a shop. I can say this with confidence, because I have had two separate cars towed up here for me to get straightened out. I made special tools and developed a process to keep track and control of the actual screw position before, during, and after the adjustment.

In the case of a OM616, the Idle screw needs to be turned in, (CW), to increase the Idle Governor Spring Tension, which will increase the Idle governors strength, and ability to push the counter weights back with out the assistance from the throttle. If the strength is increased too much, the engine will want to "buck" when in a low gear and putting through a parking lot or in stop and go traffic.

The mid range power is controlled by the Torque Control Governor, and is adjusted by turning the Torque Control Capsule. (special tools are again required, and this one is very difficult to control during lock nut loosening and tightening. This one is the most bang for the buck, but you can get into a lot of trouble if you do not know what you are doing.)

If a Torque Control Capsule adjustment is made, I would strongly recommend that the Rack limiter is put back into operation, because right now, you either have a restricted fuel system, bad pressure relief spring, bad lift pump, or the Governor settings are such that they are limiting the fuel as you have no smoke. The explanation as to how and why the Governors are limiting the fuel is very long.

Note: most forums have information on how to make a Torque Control adjustment and state that the Idle Governor Spring Tension must be reduced the same number of turns as the Torque Control Capsule as turned. For a RW Governor, (used on MW IPs), this is very bad information that can/will result in a non confident, or no return to idle). I have fixed a few of those as well.

Additionally the High Speed Governor has final say. If it is set too soft, it can counter act a Torque Control Capsule adjustment, making it seem like it did very little or nothing at all. The Risk in turning up the High Speed Governor setting is that the max engine speed will be increased and some people are uncomfortable with that.

Finally, after any "internal" Governor adjustment, there are some precautionary steps that should be followed before and during start up to prevent unintentional run away after start up, and give you control of the engine so you can tell if the adjustment was incorrect, resulting in the engine wanting to take off. I have a process that I go though to prepare for start up, and after start up.

I do not encourage anyone who does not do this type of work regularly, to get into fine tuning the Governors. It is good to have an understanding of what is going on so you can communicate what you want to a tec that can make the adjustments necessary to achieve a present outcome.

Thank you for your well detailed answer.

When you are adjusting the idle screw what increment do you turn it each time? It would appear from your description that very small movements are all that is needed. I have been using Lance Newcomb's instructions from superturbo diesel. I am assuming you are referring to the "course idle screw", and not the "idle regulation bumper spring" as the screw to be adjusted?

__________________
1977 240D turbo

The problem is there was not nearly sufficient detail to support an adjustment of any kind, just enough information to get into trouble. I am not gifted enough to be able to condense several pages of a detailed service manual into a few crude paragraphs.

Now you have me very nervous. I do not want to use any terminology from a different source, (even in reference), as it could be interpreted, (implied), that I agree with the information, and or, support its use.

The, (my terminology), Idle Governor Spring Tension adjustment, (it is a slotted screw with a lock nut), on a RW governor is located in the lower cavity, (the top cavity is where the Max Speed adjustment is, and where the Shut off actuator goes in), directly bellow the Max Speed Governor Spring tension screw.

I am very much aware of how I am coming off here, but I see no benefit in tip towing around, as last time I tried that I ended up a defendant in a law suit in regards to this very subject in fact. As a result I feel compelled to cover my behind as completely as possible.

Several forums have posted limited information regarding MW and M IP adjustments. To isolate myself of any liability, I formally state that I do not indorse ANY adjustment information on ANY FORUM. I further do not recommend that ANY INFORMATION on ANY FORUM be used as a bases to proceed with an IP adjustment.

In my opinion, information posted or referenced on any forum is for entertainment purposes only, and is not to be used to make a determination as to; how a particular adjustment is made, any subsequent adjustments that "may" be needed to achieve a proper operating engine, as well as the names of adjustment points.

47dodge, I get the impression that you feel confident to get into the IP and turn some screws. I applaud that. Don't get me wrong, it is not my intention or desire to save people from them selves, or others for that matter, I just don't want to be mixed in with anyone else’s postings, as I said I am covering my butt.

A genuine question; (I prefer to not speak of someone who can not defend himself, but), Have you asked lance about making adjustments?

No I have not asked Lance. It was your comment about being able to adjust the idle quality that I qouted previously, that has brought me to ask you about tuning. I have felt that my 300d idles just fine hot or cold why would the 240d need a manuel adjustment. After all they have the same pump. So yes I am confident about getting into the pump and "turning screws". Please do understand I have many years as a diesel mechanic, and at least basic IP experiance. I would really like to advance my knowledge so I can fine tune the IP.

I understand your reluctance to say to much for fear of lawsuits. They are an unfortunate fact of life, and I know what it is like to be at the wrong end of one. Lawyers are the only ones that win. I must also say that if everyone closes up for fear of lawsuits then we all loose.

I am not trying to push you to say more, I think you have said enough for me to find the way at this point, and I really do appreciate that.

__________________
1977 240D turbo

PM sent

oh No This is disconcerting. I un wrapped mine (6.5 holley) that you sent me last monday and was examining after looking at OM616 pics.
There was something troubling about one of the assemblies--The flange is bent from being torqued down in a pump--The flange was inconsistant thickness with the rest , I took them down to Able Diesel Fuel injection in Lewisville Tx on Tuesday and the teck mich-ed them and pointed to the bolt sholder marks on the assembly that had been used-- he said it did not work for someone and was taken out -Wre-wrapped and was sent to you apparantly--
Im not saying you were aware of this unit being bad. But the tech said -No way they could use an assembly like that in a pump--The bad assembly was not only thinner flanged--one side was thinner that the other side of this flange -and that would or did cause it to seize and not work. I have the measurements he read with the mich's.
At this point I have $530.00 of useless equipment unless I get the last good element __I just need to know you will honor your supplied parts and help me get thre replacement. Thanks

The four good assemblys all had consistantly 225 thousandths thick flanges

the bad one has a flange that is .219 on its thicker side and .205 on its skinnier side. So what is supposed to be .225 has gone to .205 which caused it to bend because it was not robust enough.

The tech said it had definately been installed and removed because it was bad and it could not be used.

Able is the only reputable shop in the metroplex . there is a outlaw shop called lonestar in Ft worth that burned me yrs ago on my first bad experience with diesel fuel injection--I advise NO one to ever go to lonestar fuel injection for even lawn mower repair.

I am waiting for Tom to tell me he will honor his merchandise and get me a good assembly............

Im sending the element assemblys back to Toms colleague Peter for a refund. Looks like 2 mos wait for more MW parts.

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That is unfortunate.

A customer of mine is considering having me build him a MW with 8mm elements. Would you be interested in trying those? They would be from the same manufacturer I got the 10mm elements I am using, (China).

I would mark them up quite a bit, (your cost would be around $50.00 ea), so it would be cheaper if you ordered them yourself.

Not sure when or if he will pull the trigger, or if and when he does will the 8s be in stock. Just thought I would through it out there.