High RPM governor springs.

[Mandrewoid]

52 minutes ago, JoeH said:

So all Mandrewoid needs to do is turn that screw a turn or two one way or the other to get to 2100 rpm I figure.

No this is incorrect. You can set the high idle screw to 2300 rpm all you want, but if you have 1800rpm governor springs, you will only make idle power at 2300rpm. 

What you can do is put 3000rpm governor springs in and then turn the high idle screw down so you don't exceed 2200 rpm. At that point it will likely behave a little bit like a farm tractor. As soon as the engine rpm drops to 2100, all the horsepower will be available. You won't have to wait to drop down to 1700rpm. 

[mechohaulic]

had ole number one R607T  1001 =end673  running today . brought tears (almost) to my eyes. not only the sound but more important are the memories . simpler days. next to it is a $ 300k KW triaxle has been down for 3 weeks waiting for parts. 

[JoeH]

1 hour ago, Mandrewoid said:

No this is incorrect. You can set the high idle screw to 2300 rpm all you want, but if you have 1800rpm governor springs, you will only make idle power at 2300rpm. 

What you can do is put 3000rpm governor springs in and then turn the high idle screw down so you don't exceed 2200 rpm. At that point it will likely behave a little bit like a farm tractor. As soon as the engine rpm drops to 2100, all the horsepower will be available. You won't have to wait to drop down to 1700rpm. 

Let us know what you do and how it turns out, I'd just hate to see the motor take a hit if it gets over revved. My experience with fuel pumps is very limited.

[JoeH]

On 12/11/2023 at 1:02 PM, Mandrewoid said:

Or possibly the spring out of an E6-350, or maybe even just a 285 non-L

You did mention you have a spare motor. What is it exactly? And is your current motor an E6-275L or an EM6-275L? Knowing if they have the M in there is important.

I'm thinking your best spring change would be like you said, swap either just springs from your spare motor or swap the whole fuel pump.  For a pump swap it'll need to be an EM6 pump not an E6 pump because it sounds like you have very tall gearing. The EM6 motors make 90%+ of peak torque from 900-1100 rpms all the way to the governor, whereas a standard E6 has a much smaller power band.

 

[Mandrewoid]

It is an EM6-275L for sure. I believe the other one is an EM6-350 but I will definitely check. It only has a 9 speed so my assumption is that it has the same large power band. Especially when I talk to the old owner of that truck and he describes driving it. 

The 350 had a massive air to air in front of the radiator, and my 275 is a tip-turbine with water to air. 

I saw on here somewhere that they did make a tip-turbine 350 with water to air. Would that be the same motor internally as mine, or did Mack do crazy things like put different valve springs and pistons in depending on the horsepower designation of the engine? 

 

It would make sense to me to keep all that stuff common for ease of manufacture and parts supply... But I know other engine manufacturers did not do that. 

[mrsmackpaul]

Im sure there was minor differences to the blocks thru out the years

But as far as I know the main difference in E6 blocks was between Maxidyne and Thermodyne 

Maxidyne I believe had more webbing cast into the block

To make the motor rev harder you need to increase the tension on the fly weights 

I believe that this is achieved by pulling out the shims that I pointed to in a picture earlier 

This makes the motor rev harder before the rack starts to close the injector pumps off as the fly weights have more pressure against them so move out at higher revs 

 

Paul 

[JoeH]

I'm not sure there is an em6-350, I think the Maxidynes tapped out at 300.  If it's a 350 then I'd expect it to be an e6-350. I drive an E7-350 triaxle with an 8LL most days, 8 gears will get it to 70+ mph.

If the 350 runs, you might be happier dropping that and the 9 speed transmission into the truck.  That will give you much better gearing for what you're trying to do.

[JoeH]

I would expect block and internals to be the same, only differences I would think are injectors, turbo, and fuel pump. I'd expect valve springs to be the same, only reason to put heavier springs in would be to avoid valve float while running higher rpms.

Edited December 13, 2023 by JoeH

[JoeH]

One more spitball idea, throw a butterfly engine brake in the exhaust pipe for upshifting. It'll make the truck a whole different animal. It'll cut your engine speed down much faster so you'll be getting into gear closer to 1100 or 1200 rpms. We had a jake brake on one of our Maxidynes for decades, and it made the truck faaast.

[JoeH]

If you put a butterfly valve on, you'd need to use it constantly for shifting and probably clean it every so often. Lack of use the soot will jam up the butterfly valve and it can jam when it engages and not release. As far as using it as a brake for the truck, I'm not sure the exhaust valves can handle the back pressure. Fine when shifting, but on actual braking it may generate too much pressure any closed valve springs.

[Mandrewoid]

 

1 minute ago, JoeH said:

One more spitball idea, throw a butterfly engine brake in the exhaust pipe for upshifting. It'll make the truck a whole different animal. It'll cut your engine speed down much faster so you'll be getting into gear closer to 1100 or 1200 rpms. We had a jake brake on one of our Maxidynes for decades, and it made the truck faaast.

I like this idea. But I'm also afraid of valve float from exhaust back pressure. I never really thought of it before, but two valves have much more surface areas and fewer valve springs to hold them shut. I'm pretty sure my engine is a 2 valve, I have had the covers off in the past. 

[Mandrewoid]

A guy might be able to get away with 30 PSI of exhaust back pressure. Because that's about the same pressure as your turbine drive pressure under hard loading conditions would be. I have looked for these butterflies before and I've seen them for RV purposes but I've never really seen one that I thought was big enough to use on an e6 Mack?

[Mandrewoid]

I have also toyed with the idea of using my massive live PTO as a hydraulic retarder. All I have to do for that is install a check valve and a 4000 PSI relief valve. It would dump a lot of heat into the oil but at maximum rpm it would give me 150 horsepower of braking force. I never thought of using it as a shift assist though because the delay from hydraulic valve activation to pressure actually building is probably about half of the amount that you'd need to make a good shift anyway. Unless I had the oil always pumping and just threw a directional valve in order to activate the breaking then it would be immediate but if I screw it up I'd end up with 300 gallons of manure on the road.

 

My tanker unloads 6,000 US gallons in one minute and 30 seconds

[Mandrewoid]

Another fun experiment that I'm not sure anyone has ever tried before. You could link up your throttle pedal and a boost sensor to a 1-in airline going to your exhaust manifold on the pre-turbo side. Then when you stomp on the throttle at 900 RPM and have no boost yet. Dump compressed air from your air tanks into the exhaust manifold to light up the turbo faster. If you want to get real fancy you can also stick a fuel injector in the exhaust manifold so when you dump this cold air in then you light it on fire. And you have a jet powered turbocharger for a quarter of a second every time you step on the throttle until boost builds. 

[JoeH]

You don't need 150hp of braking power to slow the engine down.  You may be stalling that thing out doing that.  Typical Jake's have an electric switch on the clutch pedal, another on the throttle lever on the pump. Then there's a manual system hi/lo/off switch on the dash.  Hi/lo is two heads/one head. If you were going to run your pump as a brake I'd build it into your pedals so it's instantly on or off.

[JoeH]

Hydraulic oil doesn't compress, so the response time could be better than you're thinking. Don't think you'd build all that much heat if you just used it as a shift assist, you're talking about 1-2 seconds of braking time per shift. It will mean more wear and perhaps shock load on your hydraulic system, mostly I'm thinking about the pump drive shaft.

[JoeH]

Not sure how big your pump is but I'll take a wager that 1,000-2,000 psi pressure relief will probably get the job done on shifting. If you go this route I'd start on the low side pressure relief setting and build up to the sweet spot.

[Mandrewoid]

The pump is an Eaton hydrostatic pump. 5.4 cubic inches. 40gpm@1800. But it's a variable displacement pump. The response time would be because the pump has to swing the s wash plate before it starts pumping. Although maybe if I put an air cylinder on it it would move faster than the current 1/8" hydraulic cylinder that activates the control lever.   

I could put a button on the shifter that would be kinda cool. 

[JoeH]

We have a pump like that on one of our trucks, it's a piece of sh*t in our application, but the swash plate adjusts very fast on ours.

Our system requires multiple hydraulic valves to need to be synchronized, and the type of control valves don't allow for it well.

[Mandrewoid]

4 minutes ago, JoeH said:

We have a pump like that on one of our trucks, it's a piece of sh*t in our application, but the swash plate adjusts very fast on ours.

Our system requires multiple hydraulic valves to need to be synchronized, and the type of control valves don't allow for it well.

What kind of application is that? Mine has a second pump on the front for running aux functions but I have it just pumping oil through the filter and back to tank. 

[JoeH]

Volumetric concrete mixer. Has to run hydraulic water pump, conveyor, mixing auger all at certain speeds to maintain the right material ratios.  We had a hydraulic company design the system for us, it's garbage.  Section pumps are the way these trucks need to be set up.

[JoeH]

We had to add Prince pressure compensating valves to the auger and conveyor to balance the flow properly.

[Mandrewoid]

Ohhh yes I know that equipment. Live less than a mile from Quinte Mobile concrete. They've got tons of volumetric mixers. The older ones run a big crank mounted gear pump like a garbage truck, and then use pressure/flow compensating valves, and the newer ones are Allison autos with REPTO. 

.... Kinda jealous of those new trucks 😂. They have a few international and a few Mack.