@@staym925 I replaced the injectors.

Your cpl shows that you're running an NTC-300 big cam IV. It shows me that the injectors you're running should be top stop injectors. I would have thought your motor would have come from factory with a dual entry turbo such as an HT3B, but came with a single entry turbo instead; interesting. Your motor is not STC controlled correct? This CPL is honestly a little tricky as your motor is a pre big cam IV 88/89. The sets I'm seeing that you can run with a dual entry turbo would be a 401B or 425A heads. Your lash for the 401B would be set at your typical .018". You would have to but new injector adjusting screws for the 425As and they would be adjusted to .018" as well. From the Jacobs master application guide they say to use a 425A configuration, but thats going off your cpl which would have a single entry turbo. By putting on a dual entry turbo you would be changing the cpl. I wouldn't know what your new cpl would be other than these two head configurations would be compatible to a pre-88, FIXED timed, dual entry, big cam IV engine. Here are the links to some Jake manuals that I would highly recommend reading. They are for the 401, 420/425, and 430 series. Hope this helped! www.jacobsvehiclesystems.com/sites/default/files/2021-08/Installation_Manual_for_Model_401A_401B_401C.pdf www.jacobsvehiclesystems.com/sites/default/files/service_literature/015626.pdf www.jacobsvehiclesystems.com/sites/default/files/service_literature/015864.pdf

@@jimhurricane5831 thank very much for all of this information. With my injectors being stop top; would I be able to run normal injectors as well if I wanted too ? Also, what is the draw back to me operating off of the single turbo entry ? I intend to convert over to an air to air system on this motor along with a high flow conversion. I mentioned this to get your input on me doing something like this using my cpl platform. I’ve also got a pt pump and matching injectors from a big cam 1 flowed to 425hp to also throw at the motor.

Not a problem hope it helped you get going I’m the right direction. With your truck being fixed time it takes the stop top injectors so you can put “larger injectors” in it if you wanted. You’re not running an STC system so you can have your original injectors built over or buy different ones to instal. You would be putting the cart before the horse a little though. Your cam has a different cam code than a 425HP motor let alone a 400HP motor. If you were to do as your saying and start ramping up the horse power you would either need to pull the cam and replace it with one built for running 400 plus HP and time it at the right cam code or see if your original cam could be set to the timing code of a 400HP cpl. motor. Don’t know how well the last stated method would work. It might not as the cam profiles are different and might not be able to achieve the timing needed. I wouldn’t be to concerned if you just wanted 25-50HP more but to go 100 HP + you would be looking at cam timing (most likely replacing it), injectors, turbo, exhaust manifold if you don’t have a pulse manifold, pump work, and a new set of jakes. Air to air isn’t necessary but helps a lot! You could stay with the low flow cooling system, as I have seen many built 425 and had no heating issues. Can’t go any over that though as the cooling system just can’t keep up!! To answer the turbo question you would need to update to a dual entry if you wanted to build a 400HP plus motor. Put simply they just build better boost than a single entry turbo. That’s just my advice, someone else might have better insight on building hp out of these motors than what I’m telling you. Personally if I was building a IV and converting it to a high flow cooling system, and adding an air-to-air intake I would build it to an 0625 CPL. If it was a strong running motor I wouldn’t swap out pistons or liners to a 0625 cpl but role rods and mains in it, new cam bearings swap the cam/time it, new cam followers, instal injectors for an 0625 cpl, have the pump turned up, new HT3B with a new pulse manifold, new 425A jake heads, and I’d have a rippen motor. A lot of work though! Good luck and hope you get the motor your looking for!

Yes it is👍

Great question and unfortunately these parts are not that close. I ended up adding more shims to hit the timing readings I needed. Could it have been close enough to get away with; possibly. Wouldn’t have been right or the timing code my cpl required but would it have run; probably. When doing a rebuild a maybe vs. a dead on is the difference from one running a long time to one possibly not👍

I agree. Knowing is always better then guessing. Hey. You wouldn't have a part number for that cam bearing install/removal tool? And especially that #7 cam bearing removal tool? TIA

I unfortunately don’t off hand. I was lent that tool by a friend, as well as the timing jig.

It’s surprising I know!

Dylan you are correct 30 and 30E heads are not the correct heads for a big cam 3 with a dual entry turbo. 30 and early 30E heads had a 3/8” slave piston adjusting screw and according to Jacobs are not upgradable nor comparable for your setup. The late 30E heads had a 1/2” slave piston adjusting screw which did make them upgradable by replacing the hard 3/8”adjusting screw with a P/n3871407 Autolash screw. This converted the 30E to a 400H, which is compatible for a big cam 3 engines running a dual entry turbo. That being said. I have heard of people drilling and tapping the 3/8” hole to a 1/2” hole to be able to receive an auto lash screw. I don’t recommend it, but people have done it. You don’t have to get 425s. You can get 400H heads; or you can find 30E, 44B, or 400 heads and update them to a 400H by installing the correct auto lash screw designed for those heads Hope this helps👍

@@jimhurricane5831 okay, are the auto lash screws readily available yet? Maybe my best option is to find one more 30 e head to replace the one early model 30 that is on the truck and then convert them all to model 400h, are the 425s different or better than say a set of 400h jakes? Thanks for the help, I really appreciate it

@@Dylanstc yes, the auto lash screws are still available. If you buy 30E heads make sure they have the 1/2 adjusting screws. The early heads had 3/8 and later heads had 1/2. A 425 head has no difference in braking power. As far as durability I wouldn’t be able to say which one holds up longer between a 425 or 30. If the other 30E heads look good and they have the 1/2” solid adjusting screw I myself would be looking for another 30E to update👍 Good luck and hope this helps.

@@jimhurricane5831 okay sounds good! Thanks again for the help!

Depends what model of equalizing beam suspension is under your truck.

Same

@@jresquivel4499 The center bushing I used on this project was a 49600-000L and the end bushing kit were a part number of a 45000-007L.

Ty

Fuel supply/pressure won't affect you on your engine braking, and it all depends on what Jake models you're running/auto lash screws you have. If your running older Jake heads that came with the motor factory then you may run into some issues.If the heads had been replaced in its life and updated at some point, let's say with 425s, and the right auto lash screws installed you'd be good to go! If they're model 25 or 30's then thats not good. I don't know anything about a fuel screw on a Big Cam unless you're running a different governor/fuel pump configuration I am unaware of. I've always just set fuel pressure/delivery by shims, springs, and buttons on the back side of the governor. Regardless of how you pumped the fuel pump up, it won't effect your engine UNDER braking applications. Don't get me wrong the pulse manifold and turbo will for sure!! Just not the fuel side. You can build 40 pounds of boost while UNDER LOAD on these motors all day with no issues! I know many individuals who have had turbos built to achieve that amount. The only time high boost, I am aware of, will hurt the motor is when UNDER ENGINE BRAKING. If you were to force 40 pounds of boost in the cylinders under a braking application there would be so much pressure that when the injector rocker went to move the master piston on the Jake Head assembly it would come up hard on the slave piston end, because it couldn't fiscally push down the exhaust bridge to open the exhaust valves on the motor. All that said 19 pounds at 2100 rpm as I stated in another post is what I have seen on several of our big cams, and that's with all the correct hardware while Jakeing. We build about 25-28 under load stock. Thats a big cam though not a small cam. Hope this helps and sorry for the long post!

If you swapped turbo housings you would lose an incredible amount of performance on the HT60 as it was designed or "mapped" rather to have a dual entry on the exhaust housing.The HT3B turbo charger came at one point with a dual entry, as well as a single entry. This affected boost results; when an H3TB turbo "single entry" was used as a replacement for a T50, HT4B, T46B, ST50, or VT50 (single entry design) there was no need for any engine brake upgrade or modification as there was no over boosting the engine while engine braking. I could be very wrong about the HT6O but single entry turbos just don't build boost as well as a divided entry turbos plain and simple. Now as far as the 25B engine brake goes they are non-upgradable; UNLESS!!!! you have a small cam III. The cummins application guide states that with a small cam III with a dual entry turbo you can replace the slave piston adjusting screw p/n 009916 with an auto lash screw p/n 013369. If you don't have a small cam III then you would be looking at putting a different model heads on, like the 425s. I would want to do a little more homework on this as I found this upgrade in an old manual when only 401A, 401B, and 401C heads were the latest and greatest on the market. If you give me your engine cpl, and KNOW that your engine was and or is built to that cpl I could do some more digging. As far as swapping housing i have no idea if that would work as a fix or would really even recommend one doing so. Hope this helps.

@@jimhurricane5831 built 11-74 ntf365 out of a fire engine cpl 0155 I have the serial if that helps, you don't know how much I appreciate your time and I will GLADLY pay you for your help

No worries! Couldn't find your cpl. Mathew please private message me at barnestruckingand [email protected]. I can help you more then.

That's great boost. Having 20 pounds of boost while using the exhaust breaks tells me you should have the right heads and auto lash screws for the master cylinders in the Jake heads. Single and dual entry doesn't matter as far as causing any damage to the motor; just performance. The problem is when the wrong Jacobs heads and turbos are match up incorrectly. This would cause an over boost senecio while jaking, and literally destroy the injector cam lobe, push rod, valvetrain, and more instantly in some cases or overtime. You should either have 400H, 401B, or a 425s on your motor. The auto lash screws will be different between models and the 401B are reset screws NOT auto lash screws. I would just verify if you have the right Jacob break models, as well as, lash screws for your motor, and you should be good to go. That information can be found on Jacobs website!

@@jimhurricane5831 I can’t really tell see the tag being worn but it don’t look good for me ‘I think’ it looks like they are 401C def 401 is visible but it’s either 401A or C but looks like C.. my turbo is HT60.. Jake’s work amazingly and it does build boost when jake-ing for sure. I’ll admit I’m concerned. I took off the original dual inlet turbo and put this one on. Max boost used to be about 22 lbs. but now it runs AWSOME so I hope I didn’t risk something.. thx so much for your response

401As and 401Cs are the wrong application for a divided entry turbo on a BIG CAM 3. For a BIG CAM 3 running a divided entry turbo it needs to be either 400H, 401B, or a 425. The 401As were made for a 475 twin turbo designed motor, but a 401B could be used in its place, but not the other way around. Can't use a 401A in place of a 401B. A 401A, 401B, and 401C have different diameter master pistons and cannot be intermixed, and unfortunately cannot be changed or modified/updated to change from an A to a B model or B to a C model break head. Most likely this is why your running 22 pounds of boost while your engine breaks are on. On a cummins motor, because the master piston is running off the injector cam lob, putting to much boost in the cylinders loads the valve train and causes the injector rockers to physically be unable to open/or is loaded beyond oem standards because of to much pressure in the cylinder. On other motors, like Cat , the more the boost the better while using your engine breaks, but for these old cummins motors to much is a bad thing. Somethings got to give right!? I have seen people run with that much boost and haven't, that I know of, have any problems. I have on the other hand been told anything over 15psi is starting to get high. That being said the trucks we have, as well as ones that I have worked (which all have correct/stock parts) have run around 18-20 psi at I want to say 2000-2100 rpm. I try to keep the rpm no more than 2000 myself.I also want to say that there is a difference in slave piston length and running a 401C in place of a B could cause an interference problem. (piston hitting valve) Now someone could correct me on that! Bottom line is I like to stay in factory specs. If you're running 401Cs on your motor Jacobs is saying that can cause some bad and unwanted things to happen to your motor. I hope this helps and sorry for the long message.

Yes, on the Jacob’s website and through various Cummins manuals. Takes some time to find but the information is still out there on the web to find and print off. Manuals seem to be harder to find there days though.

Damn

I have one that after a 2 or more tanks it will starts to bubble/boil the gas in the tank. It does the same vapor lock no start

That C.P.L of a 393 reads off of a Big Cam 1 NTC-400 if I'm not mistaken. You could update to a HT3B turbo, but I don't know what exhaust manifold you're running. If it's the old style it will be time to update to the newer style maniflod , as it's a more efficient manifold for exhaust flow and necessary when updating to a dual entry turbo. (that's if you want to see a real performance change in the turbo and motor) Inlet and outlet ports for oil should be ok, but to be honest it's been a long time sense I've worked on a Big Cam 1, let alone seen one! They are a little before my time!! The next question is what Jake Heads you have. If you throw a new turbo on there and don't install the correct auto-lash screws then you can cause engine damage. If you know the model of Jake Heads, model of turbo you want to put on, and model engine you have, then on one of the pages in this video will tell you what auto lash screws to get for your engine breaks. I want to say originally your engine would be running 30 or 30E heads, but if the turbo was updated or the heads it could have the 400 or 400H. Could have 425s or 401..... i don't know!!! Long post and I'm sorry. If you throw a HT3B turbo on there with the right exhaust changes you will see a more responsive motor, and one that has quite a bit more power especially on the bottom end. Your boost will build much better at lower rpm, but don't forget to put the right auto lash screws in the Jakes, if equipped , or bad things will happen . Hope this helps!

Long story short a H3TB turbo would be a good candidate if you wanted to do some updating to the trucks exhaust and Jake-Heads if equipped.

@@jimhurricane5831 it is the old style manifold. I have the 425 model Jacobs brakes with the auto lash adjusting screws. I just ran a fresh overhead a few days ago

@@jimhurricane5831 it is the big cam 1 ntc 400. Absolutely correct.

@@jimhurricane5831 and I genuinely appreciate the information you’ve given me. It’s very hard to find anyone with knowledge on the 855 big cam engines. This is my first Diesel engine to work on and it’s going well so far. Very thankful I went with Cummins. Very easy for the common man with mechanical skills to fix himself.

I enjoy running these saws as well. Haven’t ran one in a spell, but they can cut just the same as any other hand saw out there.

I love my mini macs. Their great little saws. Have a fury eager beav, 120, 110, 35, and a 25. All work great. Use the beav and the 25 mostly. That 25 is so light and rips. It's way smaller than the rest. So it's great for climbing.

Thank you!

It’s amazing that these manuals are almost non-existent anymore. They do have them on the Jacob’s website, but it is very difficult to work your way through their site to find them. It’s sad to say these motors will soon be gone, but the biggest loss will be those who had the knowledge and experience to work on them.

If you have a Jacobs part number any distributer should be able to order them. Kenworth, Frieghtliner, and so on. I have had the best luck with the local Pace Kenworth dealer in my area.

@@jimhurricane5831 Thank you

This walking movement is normal for the equalizing beam suspension. It's what caused the name to change from "equalizing beam" to "walking beam." What the issue is how much movement you have while in a turn, as well as, axles alignment when straightened out; that is front to back side to side. If your rear axles are moving out MORE than half a tire width that's a good indication things are starting to wear pretty good. I've seen the beam bushings so worn that the inner tires will wear on bolts on the frame rail or the frame rail directly. Most people won't replace their bushings unless there is severe wear and something of this nature starts to occur. Hendrickson litirliture says that after cornering if the tires do not stay in alignment, side to side from front to back, it's time to change the bushings. Long answer to your question but hope this helps. I've been told that these bushings will last in a dump truck application for about 5 years if rubber and 8 years if poly and found this to be fairly accurate. I install polyurethane bushings strictly unless asked to do otherwise.

Mine too wen I turn the corner one pops out more

@@jresquivel4499 this was a year ago. I still have my truck and run it daily. Since this time I got all new bushings on my rear suspension and I have absolutely no movement. It’s not supposed to move. When the tires start rubbing against frame or other suspension parts bushings need to be changed

Some play is the nature of the beast on the big cam/small cam engine. "Some play" for some people means very little, and to others means a whole lot! Is the accessory drive front seal leaking? That's an easy indicator that the bushing might need to be replaced. Some play is acceptable, but to much is defiantly a bad thing. I believe and don't quote me on this, but the max play for a Big Cam 1 is 16 thousandths. I couldn't find it in my literature and 16 thousandths is what I remember, but this is coming from my memory which is not at all the best. Not a very difficult job for some just time consuming by pulling the air compressor, if equipped, and fuel pump to access the bushing. You will remove the accessory drive pulley, after aligning the timing marks on the accessory drive gear to the gear train. There is a small plug under the accessory drive housing and that's where you align the marks. Make sure you do this as it is critical when reinstalling the gear that it is in time; as this sets the timing for the next valve/injector adjustments. In short if you don't align the marks you very easily can move the gear putting it out of time, and when you install your pulley your letters a, b, and c will not be clocked in the correct position when you make gear train adjustments. After removing the pulley, remove the front seal, then remove the nut and washer from the accessory gear, do not drop them in the front gear case or you just caused yourself a lot of work by now having to either fish them out with a magnet or having to remove the front gear cover! Once the nut and washer are off drive the shaft from the gear with the T-Puller. There will be a thrust washer in there behind the gear so don't loose it that either! Once the shaft is out drive the bushing out and install the new one and reverser order to put it back together. I would recommend getting a repair manual as it will have the torque specs and also more detailed info in doing this. There is a keyway seal that needs to be installed, as well as, a few other things that having the book would be a good thing instead of reading a KZfaq post! If the accessory drive bushing has spun inside the housing then your talking a big job. The rear gear train cover would have to be removed making you remove the cam. This means removing the gear train and followers which have to be shimmed correctly back in. I've been told this can happen but haven't seen it myself.

After saying I couldn’t find the measurements I found one. This is for a Big Cam 3 mind you which is 11 thousandths play for the accessory drive. I don’t know if the Big Cam 1 is different but this can give you an idea. Hope this was helpful.

@@jimhurricane5831 thank you so much sir. I believe I have just about the right play. No oil leak. So I should be good. Thanks again for the insight. Have a blessed day

Hello sir, another question. I’m trying to find out why the Big Cam engine needs to run at high rpm’s? If I cruise it around 14 1/2- to 15 1/2 rpm, am I damaging it? Or what’s the whole concept of this if you know? Thanks in advance.

Great question. This isn’t a short answer, but I will try to make it that way. What we’re dealing with is the torque band verses the actual horse power of the motor. The torque band or torque curve tells us, or shows us rather, where we obtain peak torque at what r.p.m. On a Big Cam 855 motor this curve starts at 1300 and starts dropping off after 1500 r.pm. I could get corrected here, but it’s between these to points we have peak torque. Every Big Cam I’ve ever driven I can’t run at that low r.p.m loaded, because the truck doesn’t have enough “horse power” to stay there; subsequently I have to raise my r.p.m to keep going. Max r.p.m for a Big Cam 855 Cummins is 2150 r.p.m I don’t like going that high, but it’s within the limits. I run around 1800-2000 trying to stay at 1900 on the high side, and only Jake up to 2100. What people do to run at lower r.p.m, and run in the torque band is having their engine work on. They raise the horse power of the truck and in return they have the horse power to run at a lower r.p.m where the motor is most efficient. They get to run in the torque band. One major benefit is fuel savings, but the down side is if you’re not paying attention with the added horse power you can damage the motor. Now to answer your question. If your able to run your motor at 1450 to 1550 and your exhaust temps are good then heck ya I would run it there👍 Going up to 1800-1900 only burns more fuel. If your exhaust temps are not good and high then your lugging it and you need to drop a gear to get back up to a the higher r.p.m’s. Hope this helps👍

Already sold just haven’t removed the video yet.

That's exactly what I was thinking..