Hello all, we have a D11n #74z00648 with the 3508 Mechanical engine that has I believe a governor issue, the symptoms are lack of power and slow acceleration. We use it it for deep ripping and if you get moving and the rpms up before the ripper is lowered it seems to keep power but once it slows down enough you can feel it lose power and it won’t speed up to full rpm until you raise the ripper. I thought I found the problem and replaced the diaphragm on top of the governor with the cat rebuild kit and it ran great for a month, then same symptoms came back. Replace it again and it ran great for a few days, replaced it a third time it ran good for half a day. Finally I took out the governor diaphragm and put some oil on it and it ran great for a few hours then back to the low power if the engine is under load at low rpm. We have changed fuel filters and the transfer pump, checked fuel rail pressure. Quinn Cat came out and couldn’t help. Any suggestions would be greatly appreciated.
Does anyone have any ideas of what my next step should be?
This may sound simplistic. But, if you have gone through the governor three times... I would check compression.
This thread is a lot different than the typical “ my 50 year old neglected backhoe is low on power, please help” thread. In on page one!
Holy Cow! Ripper Cat down! Don’t panic! We totally got this. I would start ruling some other things out before messing with the gov any more. Sounds like you are messing with the AFR control diagram. Which may help temporarily, if you are dealing with a low boost issue. I’d check and record converter stall speed, boost pressure and take cylinder temp readings, exhaust temp readings and compare to the test specs in the TMI. Make sure you have full rack travel and not a bunch of worn out linkage. I would look carefully for a boost leak. Nige will be along shortly to straighten this mess out.
I beat you to the thread, Coaldust, but I think you beat me in the diagnostic advice. I doubt that it is a boost issue. The n series has two double sets of silicone orings in the adapter between the turbo and intake. The weak link is the paper gasket on the intake and the serious chance of the bolts holding it in place coming out. But, if he spent that quality time with his injection pump; he would have seen that failure. I am with you on the converter. Rhipper ? I am a little confused by the original post. You say ripper up.and ripper down. I assume ripper down means fully engaged in the dirt and rock. So if there isn't a load on it with the ripper down; you can still build up rpms and power? But it all fails when you try to go?
Thank you guys, yes I checked that I have full rack travel. And I’ve already replaced the (very expensive) silicone o-rings on the turbo pressure side. (That’s what’s the guy from Quinn recommended). I haven’t spent much time on the governor, the diagram I’ve changed is a 10 minute job, that I can change with it in the machine, Is there a common internal failure point in them? Mobilewrench , I meant that if I hit a hard spot in the ground while ripping, if it losses enough rpms it won’t build rpms and power even after I’m through the hard spot. I have to raise the ripper almost completely out of the ground, then it will rev up and I can start over. Basically it probably makes 80% power, if I pull 90% it cuts back to 50% until I reduce the load to 15% then it’s back to 80% if that makes sense.
G'day folks. First question is did the dealer guy who came out to the machine measure the boost pressure.? I'd like to see some boost numbers first and then start to have a bit of a think about it. Are we chasing a boost leak or a lack of fuel.? The above aside, the 3500 MUI engines have a convoluted linkage connecting the Woodward governor to the injectors, especially for the left side of the engine (governor is mounted on the right front corner). Those linkages have more joints in them than you can shake a stick at. It might pay to start pulling covers off and taking a good close look for play in the linkages. When it comes to checking/adjusting the governor itself (and the injector rack linkages) you need a genset engine guy, because most mechanical gensets have 3161 Woodward governors installed, just like this engine. The added complication on this particular engine installation is that it is not designed to run at a constant speed like a genset engine. DO NOT try to make adjustments to the governor. EDIT: How many operating hours does the engine have on it, both total accumulated hours and hours since the last time it was rebuilt.?
This is what you're up against. If that sight does not frighten you then nothing will........... All that lot has to be correctly adjusted AND with zero play in it before you even get to setting up the injectors. And we haven't even mentioned the governor yet...... It's not something you can do with a manual. It's more of an art form with a bit of witchcraft thrown in. Linkages like these were in the 3516 MUI engine in the first model 994s. In the dealership we had a couple of guys from the fuel injection shop who would go to site and do the adjustments/settings on every MUI engine that went out after rebuiid (and that was in spite of the fact that every engine was dyno run). I remember one of them telling me that the "settings from the manual" were just a starting point for setting it up in a machine as far as he was concerned, because every machine behaved just a bit different. One of the difficulties as I recall was to get the left bank of the engine (opposite side to the governor and operated via the cross-shaft) to respond the same way as the right bank.
If I understand the OP correctly he gets in a position with the ripper in the dirt where the engine RPM dies (for whatever reason) and will not recover unless he raises the ripper out of the ground. Once the RPM has sufficiently recovered he can drop the hook again. Question to the OP. When the engine loses RPM with the hook in the ground does it black smoke like a sunamabitch.? Also how many hours on the injectors and when were they last set/adjusted.? Hours on turbos.?
Nige, yes boost was ok when it was making power, I forget the exact Number, 27lbs maybe? When it would lose power it would of course lose boost as well. As far as hours I’m not sure. Meter shows 17k, engine was rebuilt by Empire Cat in 2006.
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No, there is very little smoke. When it loses power.
99W01763 - that's the original engine from when the tractor was built in 1989. If that machine only has 17k on it by now I'll eat my hat. If it was in Empire's territory in January 2006 it was most likely working in one of the copper mines in Arizona working 24/7 and clocking around 7k hours a year. I'd be surprised if both the machine and the engine are not closing in on (or past) 100k hours by now. Even if the number of 17k is only since the last rebuild/dyno test by Empire and is a good number that engine ought to be weil tired by now. 27 psi (maybe) of boost doesn't cut it I'm afraid. Can you ask whoever came out to it for a hard number.? Full load boost spec is 43.3psi and at converter stall (which is how I assume the Quinn tech measured it) the spec is 39.7psi with an absolute minimum of 33.7psi. I think you are missing a significant slice of boost somewhere.............
Yes it came from Arizona, and I’m sure it has tons of frame hrs, we had service records from the mine but they got misplaced in a move... I will try and get good boost readings. Thank you! Edit. I was pretty sure that the boost numbers were within spec...
And the engine is the original S/No, so at least some parts of it must have the same hours as the frame surely.?
Yeah, I didn’t realize it was the original engine block. So It was actually Holt that came out and they did not record any boost readings. I will try to get it tested again next week. Also, one other thing, if it’s not started for a few days it will smoke white smoke out of the left exhaust just until it warms up. No excessive smoke after it’s warm.
Not unusual. What did I say above regarding the convoluted control linkage from the governor via the cross-shaft to the left side of the engine..? It sounds to me as though the first thing it needs is: - 1. Injector control linkages (see post #9 above) inspected, joints checked for wear, then correctly adjusted. 2. Injectors set. And they need doing in that order. There is no point trying to set the injector adjustment until the linkages are correctly set. My doubt regarding the injectors at the moment with the last time that engine was rebuilt apparently being in 2006 by Empire, and with probably 17k hours on them since that rebuild is that they are fcuked.......... If CORRECT adjustment as above does not sort the smoking issue then you're probably going to be in for 8 injectors @ $700+ each Reman or $1400 each new. FYI a replacement Woodward governor is $14k and there is no Reman option any more. TBH the whole engine is probably ready for rebuild with those hours on it. You really need to find a good genset fuel injection guy, because this would be right up his street. AFAIK there are still a load of emergency generators around with 3500 MUI engines installed in them. As I mentioned above setting up that fuel control system is a cross somewhere between an art form & witchcraft. There are two chances of a Cat dealer these days having a technician familar with this setup - Slim & none. And Slim just left town.
Forgot to ask. When was the last time that the engine valve and fuel injector adjustments were performed.?
Thank you Nige. Yeah the cat guys don’t much experience with them... I did the valve adjustment about 500 hrs ago. We’ve never adjusted the injectors.
Well at least that gives you a starting point. I have no idea where you might be able to find someone capable of setting the linkage, racks, & injectors, maybe one of our CA members knows somebody.?
I have a question about the boost readings. All the specs for boost that I've run over my career have been in inches of mercury and not PSI. I've never run into a diesel engine that could run the PSI stated earlier. I seem to recall the twin turbo K Cummins in the 50 ton Haulpak trucks running in the 60" range when pulling 750 horses. Am I missing something? I agree with Nige on the condition of the engine and the need for adjustments at a minimum.
Well spotted John. The boost specs I quoted on Page 1 are indeed listed in inches of mercury. My apologies for that, I did not check my computer settings. Specifications translated to psi. Full load boost - 21.3 psi Torque converter stall boost - 19.5 psi with an absolute minimum of 16.6 psi to stay within the 0T Performance Specification.
that cross shaft and linkage is nightmarish. It reminds me of the twin carb MBG's and the venturi gauge for setting idle, only so much more.
Thanks for the updated specs. I measured boost and it is as follows. All tests were done with the service brakes as the job were on is done. Engine temp 175-180f High idle first gear slowly applying brakes to full load,max boost 17 psi. Low idle first gear, brakes locked, going to WOT, 9psi. (It takes 30 seconds to reach 8psi). High idle first gear, slowly applying brakes until machine stops, it holds 16psi after its stopped. Sounds like I’m low on boost...
I would say so. Your 3rd test result is the indicator. That is basically a converter stall test. You should be around 19 psi boost. How accurate is the gauge you are using would be the next question. The second test accelerating from Low Idle is also interesting. The fact it takes 30 seconds to pick up boost is the old Catch-22. You can't get boost without RPM, you can't get RPM without boost. Try doing the same test with the transmission in 3rd speed and see if the results are any different.
Ok, I’m heading back out there and will report back soon
I've always done torque converter stall tests in third gear forward and done the boost pressures at the same time. I lock up the service brakes first, open the throttle wide open and then drop the transmission in third gear forward and watch the boost pressure come up. If there is a problem, the boost will not build to spec from that level and the engine will drop below the specified RPM. There are many reasons why an engine would not build the proper boost when trying to bring on power from the bottom of the torque range. Design, altitude, air filters, fuel supply, governor problems, fuel ratio control valves, torque converter problems, other parasitic power draws like hydraulic pumps and so on. I was in a Cummins school years ago where the instructor was able describe troubleshooting a bad torque converter when the engine would not get full speed under load. There was a formula used to determine boost pressure when the engine was far below full stall rpm. I wish I could find those notes now.
In 1st 2nd or 3rd boost was the same.
And I bet it wasn't smoking hard when you performed the tests..? TBH I'd still suggest getting the racks, linkages, injectors, & governor set up first. At least you now have some "before" numbers that you can use to compare with when all the adjustments have been completed.
If the brakes are locked how would it make any difference what gear it was in?
It doesn't make any difference other than it is easier and safer to hold the machine in third gear. It is also easier on the drive train to drop into third and not get a few million pounds of torque slamming into all that metal.
Correct, very little smoke. ok, I will try to find someone with experience with them.
John, ok yes that makes sense.
Do you have to copy and paste to quote someone? I highlighted it the presses the +quote button but it didn’t work.
First you need to click the "+quote". If you do that then when you go to write a reply you'll find a blue "Insert Quotes" button under the bottom left corner of the reply box. You need to click on that to insert the quote.
Here's a question that came up in conversation offline. How is the governmor oil level.? Have you checked it recently.? And another that just came to mind. Has anyone inspected the linkage between the control lever in the cab and the shaft on the governor for worn joints, loose hardware, etc.? I've circled some of the obvious ones, there may be others.
Thanks! No I haven’t, I didn’t realize it had separate oil.. yes I have checked the linkage from cab to governor.
Be careful. The governor takes a special synthetic oil. Extract from manual below......... The 3161 Governor uses a self contained lubrication system. Governors on new engines are factory filled with a high quality synthetic oil hat will perform through the life of the governor. The oil has an ambient temperature operating range down to -40°C (-40°F) and will not oxidize over time. A sight gage shows the oil level in the governor. Proper level is within 25.4 mm (1.00 in) of top cover gasket with engine running. If filling is necessary, it is recommended that 136-9642 Caterpillar Governor Oil is used to maintain peak governor performance.
That’s a big help, I will check the level and also change the oil if it’s full. I tried to order oil but CAT doesn’t have any, anywhere. He’s going to try and find some... I did find some on eBay though.
TBH I'd have a look-see at the level first before buying some. Checking the oil level in a governor is not something that is normally done as a regular maintenance task and TBH I'd forgotten about it. A governor would normally be filled when it's built and that should last until the next time it's rebuilt. The suggestion is as part of the box-ticking exercise that will eventually lead to the root cause of the problem.
Before going out to buy oil.......... Take a look at your governor. Can you locate the fill plug (1), oil level sight glass (2), and drain plug (3) on it.? Reason I ask is that older governors were lubricated by engine oil and did not have the three items mentioned above. BTW if you do need oil it is nothing more exotic than an API CF-4 full synthetic SAE 0W-40 engine oil.
That’s a good idea. I don’t remember seeing a sight glass on ours... I will check. Ok, thanks, that should be easy enough to find.
So I go to look for the sight glass and lo and behold it is broken off.... full of dirt.
Nige, do you have the part # for (2) in your last photo? My parts book seems to show a slightly different governor without the sight glass.
Oh that's not good.......... not just the dirt but the fact that there is supposed to be about 1" of oil showing in the sight glass. So obviously it's low on oil and also the oil that is left in it is most likely contaminated. Also not good. I have a baaaad feeling about the internal condition of your governor. The service 1997/98 magazine article regarding the updated governors spoke thusly ........ "New basic governor groups (Woodward 3161) are used on the 3500 engines in these machines and the remanufactured 3500 engines for these machines. These new 3161 Governors have a self-contained oil supply. The former 3161 Governors were connected into the engine's oil system. This could allow engine contaminants to collect inside the governor cavity and could shorten the governor service life. The use of a self-contained oil supply should result in increased governor service life." Your parts book likely was printed in the time when the former governors that used engine oil for lubrication were the only ones used. Also looking at your Parts Manual photo there were no less than four different governors used AFTER the 9Y-6679 that is listed for engines 99W984-Up in your photo. 9Y-6679 covers engines 99W984-1689, 9Y-9122 covers 99W1690-2157 (includes yours), 7E-7250 covers 99W2158-3188, and 6I-0661 covers engines 99W3189-Up. And ALL of those Part Numbers used engine oil for governor lubrication. That's the risk you run when using an out-of-date Parts Manual. I show the governor with self-contained oil supply for a D11N as Part Number 124-3171 or Reman 0R-8309. Can you get a Part Number from the tag that is visible in your photo showing the broken sight glass elbow to confirm.? My suspicions are that Empire would have installed a Reman governor when they rebuilt the engine. At that time i worked for a dealer that was on a par with Empire as regards size, facilities, etc, and we didn't have anyone who could rebuild them so used Reman on all rebuilt MUI engines. Even in those days there were not too many 3500 MUI engines around, most were 1st Gen EUI. EDIT: At least for the latest governor Part Number there is a Reman available at $9k. Better than $14k for a new one.
That’s very interesting. Thank you for taking the time to figure all that out. I drained the oil, and got about 20oz of ok looking oil. Yes it’s a reman, part # 0r-0309. Date code 04-08. WG CO part #A854-573C. WG CO serial #2500150. Also the top left of the plate is stamped 21 604. Do you know what the oil capacity is?
The WG numbers will all be extremely useful if you get an independent guy with access to Woodward data to work on it. I'm afraid not, but it has to be more than 20oz because as I said above the correct oil level should be about 1" up the sight glass. TBH I'm more worried about what the dirt entry has done to cause wear in the mechanical parts of the governor. I have no idea if something like kerosene could be used to flush the governor out before adding new oil. Regarding the sight glass I have two Part Numbers for you. Refs 9 & 11 on the illustration below.. 129-3096 which sells at $220 (ouch!) which I think is the complete sight glass assembly including the elbow. See below. That's how it appears in the Parts system. I also found 131-4345 which appears to be just a replacement glass. Now here's the kicker. I can't tell whether the 129-3096 comes complete with a glass, or if it's no more than the body of the assembly minus the glass. Either way the 131-4345 is only priced at $7.
Nige knocks it out of the park, again.
I had help, don't you worry.......... take a bow Cmark. Another thought. Take off the cap (Ref 1 in the illustration in post #43) and see if the atmospheric breather in it still works....... I'll bet you find it's plugged. A replacement cap is a 123-9693 (replaced by 1 x 5P-1838 & 1 x 171-5286) priced at around $20 for the pair. Still on the subject of the latest type of oil-filled governor, every piece of information I've found on them since we started delving down that particular rabbit hole has been related to generator sets. Apart from the Service Mag announcing the change in governor lubrication from engine oil to self-contained which was listed under 74Z D11N all the other service info has been generator set related. Hence my comment from earlier about your best bet to locate a governor expert.
I’m going to hope and pray that low oil was all that’s wrong with it. I should have both of the parts in the morning, hopefully one or both of them fit. I think I will just use the specified oil and change it a few times to clean it out. That’s for sure, I’ve been reading on here for years and the main reason I signed up was in hope that Nige would be able to help me figure this out.
Should be 1.8L. (2 qt)
I’m not a 3161 guy. But, I recall using diesel to flush them, after retrieving engines from Davey Jones Locker. Your oil idea sounds great. I wouldn’t know where to look to find a 3161 guy. I bet NC Power Systems in Dutch Harbor has one or two. I used to use a Shop in Seattle.
That's 68 ounces in your language. I'd say you were more than a hair low..........
Just out of nostalgia I went back and took a look at our fleet list from round about the time Empire rebuilt the OP's engine. In the dealership we had forty-two D11s on the books and no less than 125 of various iterations of D10's. Even 15 years ago only two of the D11's were N's and both of them had been converted to electronic engines. From the next life after the above. 17 brand-new D11R's just about to be handed over to a customer in Colombia.
Marine is one option I hadn't considered. All depends how far the OP is from the sea i guess.
Awesome, thanks! Yeah, very low. I didn’t see any shavings in the oil so hopefully it’s ok. I will take a look at the breather.
Were the mechanical 3500s a problem child? It sure seems they changed governors often.. wow I wouldn’t mind having one of those!
I'm not sure I would describe them as a problem child, but would say that Woodward governors are far more suited to controlling engines that run at a relatively constant speed (think gensets, marine engines, industrial applications), as opposed to a machine engine where a varying RPM requirement as a result of changing throttle pedal inputs are normal. The 3500 MUI engines were only installed in a few machine models before the first electronically-controlled 3500s came on the scene. However at the time of first introduction of the "big" models there was no electronic engine option available. From memory there was the D11N, 8GB-prefix 785, 9ZC-prefix 789, 3SJ-prefix 793, and the 9YF-prefix 994. Forget the 994 though because it was run more like a genset. You engaged high idle and ran it on the left pedal. After the advent of the electronically-controlled 3500 engine Caterpillar very quickly made retrofit kits available for all the above-mentioned truck models plus the D11N to remove the MUI engine and replace it with an EUI engine. See below for your D11N and the instruction for retrofitting an EUI engine.
I see, very interesting. What’s the overall consensus on the 3508 vs the C32? Quinn has been trying to get us to repower it with a tier 3 C32.
Can't comment on the ins and outs of that particular repower but the C32 is the latest version of the 3412. A whole class smaller than the 3500 series. 3400 series is 5.4" bore. 3500 series is 6.7" bore.
So the C32 is basically a stroked C27/3412? I talked to one of the Quinn techs and he was saying that you lose a few thousand pounds of weight going from 3508 to C32 Which would be a problem for us as we’re already light in the front because we don’t have the blade on.
Basically, yes. C32 is 5.7 x 6.4" V12. C27 is 5.4 x 6.0" V12. Both (as far as I'm aware) share the same platform.
C32 is the engine model used in the current model D11T tractor. I haven't been around one yet so I have no idea how it performs compared to the former 3508C engine. (We had C32s in 777F trucks and they seemed to go OK, but a tractor application is a totally different ball game.) The D10T uses a C27 which is the latter-day equivalent of the venerable 3412 which of course is what the D10N & R models had. Plenty of experience with them and they seem to run pretty well. TBH the investment required IMHO to install all the electronics necessary to run a C32 in a 30 y/o tractor ought to be a non-starter from a cost perspective. Surmising...... I would have expected with the level of electronics on a C32 that it would really interface better with an electronically-controlled transmission, not the cable-controlled one on your particular tractor. Furthermore I don't see any documentation in the system to support a 3508 MUI-C32 engine conversion in a D11N. Ask Quinn to show you the "Special Instruction" detailing the conversion. I posted the conversion information for a 3508 EUI a few posts back. That ought to be a better route I would have thought because the EUI engine could be built exactly the same way as the MUI and mechanically would pretty much be a straight drop in replacement. Obviously the engine electrical system and its connections would change a bit.
Yes, the repower is very expensive, it only makes sense if you get a grant from the state for lower emissions, and it’s still expensive... I thought I had found online a while ago a cat teir 2 3508b conversation for the d11n, do you see that? Or just the tier 1 you posted? Ok I will ask about the special instruction. We have repowerd one of our D10Ns 2yd with a c27 and they did not change any transmission controls. Everything seams to work ok with it.
I assume the later d11Rs were tier 2? Does anyone know if cat made a tier 3 3508?
I'm not sure even if the latest generation of the D11R was Tier 2. I get the impression they were Tier 1 but I'll need to dig a bit more to confirm that. The reason I say that is the last generation of 11Rs (before the T model came along) that were built with an electronic 3508 engine from the get-go have a C32 retrofit available, but that retrofit is only a Tier 2. Now that would not make much sense to me if the original engine was also a Tier 2 because the usual reason for a retrofit is to install an engine meeting a higher EPA emissions level, not one the same as the original engine. EDIT: Well that didn't take very long. Even the current model D11T tractor is only rated EPA Tier 2, probably because of the 850BHP power output. I confirmed this from the EPA standards. Engines rated above 750 BHP (which include the OP's D11N but interestingly enough not his 650BHP D10N machines) were required to meet EPA Tier 1 from 2000-onwards and EPA Tier 2 from 2006-onwards. Since 2006 nothing has changed regarding the emissions requirements they have to meet. https://dieselnet.com/standards/us/nonroad.php All electronic D11R tractors were rated EPA Tier 1, and the C32 retrofit is designed to take them to the same Tier 2 emissions level as the latest D11T. I have searched again and can find nothing regarding a C32 retrofit for a D11N. Also, with your 11N having been originally built in 1989 it pre-dates emissions regulations by about a decade and I guess could be regarded as being Tier "0" emissions, hence the upgrade retrofit to a Tier 1 electronic 3508 engine that was offered back in the day.
That’s interesting, maybe the c32 they offer is a tier 2. Or maybe tier 2 and 3 for the c32 is the same thing? I did find this online, it seems to say cat make two models of the d11t, one tier 2 and one teir 4 with DOC.
Easily explained. Only countries such as the USA where emissions regulations exist require "the whole hog" as regards exhuast emissions control. Export markets such as the ones I've worked in all my career are classed as LRC (Less-Regulated Countries) from the emissions standpoint and therefore get an engine which does not have any emissions control or exhaust aftertreatment system installed. Basically its emissions are a result of engine design and there is nothing tagged on the back end to clean up the exhaust. The snapshot you posted from the specalog alludes to that - RH side top of the page. It seems as though the info I linked above was not up to date. New nonroad engines with power ratings from 750-1200 BHP (560-900 Kw) were required to meet Tier 4 interim from 2011 and Tier 4 Final from 2015 onwards. https://nepis.epa.gov/Exe/ZyPDF.cgi?Dockey=P100OA05.pdf I suspect there is no Tier 3 version of the C32. Why.? Well if you look at the link I posted the emissions standard for engines 750-1200 BHP jumped straight from Tier 2 to Tier 4 interim. With that power range being the logical one for the C32 engine to fall into (whatever machine installation it was built for) it would seem logical that it also went the same way in regards to emission ratings. An interesting aside. I looked at the Specalog for the 777G haul truck which is also powered by a C32. The Tier 2 (export) version has a nominal rated payload 1.6 tons more that the equivalent Tier 4 version of the truck. That'll be the exhaust aftertreatment system then......... I didn't look at respective fuel consumption figures for the two engines, it would be too depressing. EDIT: The previous 777F model with C32 only had one engine option - Tier 2. Strangely enough there is a Tier 4 final engine repower retrofit kit available for it.
Can't wait to find out what a full compliment of new synthetic oil does for that governor!
That’s one heavy DOC!! I got the parts installed and new oil in. I’m warming the machine up right now.
Well, I added fresh oil warmed it up then drained oil and refilled. Here are my new numbers. 175f engine. Where before I had 17psi at full load i now have 18. Before I had 9psi accelerating from idle with brakes locked I now have 16.5. (And it takes 15 seconds to reach 8 psi instead of 36 before) Before I had 16 psi slowly applying brakes until machine stops. I now have 16.5. Which is all wonderful, except once engine reaches 190f, the max boost is still there but the acceleration test is back down to 8 psi.... so I think it is definitely better but it still might need additional adjustments. We will have to wait till we get it on another job and see real life ripping performance. A big thank you to all the help and info!
Linkages, racks, & injector settings next step then......... I take it that it still doesn't smoke heavily under acceleration.?
Correct, not noticeably more smoke.
Still short of fuel by the sounds of it IMHO. Under sharp acceleration from idle it ought to give a distinct puff of black smoke like somebody threw a shovel full of coal on the fire.
I wonder if the AFR diaphragm I changed in the past was for the old style governor, and if the updated governor takes a different one... the kit part number I used was #4P-6869.
Sorry, no. 4P-6869 is the repair kit listed for the A/F ratio control on the 0R-8309 govenor currently installed on your engine.
I see, ok well thanks for checking.
Hello all, So I looked at the turbos today. My book shows a end play spec of .0065” (+-.0025) the right side one seems about right but the left one has end play of about .030” could excessive end play cause low boost when warmed up? I’m thinking I need a new turbo..
If you go back to page 1 you responded to one of my questions that when the RPM dies the engines DOES NOT smoke heavily until the RPM recovers. That lack of smoke indicates to me a lack of fuel, not a lack of boost. As a comment on your turbos. The one with the higher-than-spec end float probably does need replacing but on an engine like that one I would always recommend replacing turbos in pairs unless there was a really good reason not to such as a low-hour (after rebuild) turbo failure. Sorry for harking back to it but the first thing that engine needs IMO is to have all the injector control linkages (see Page 1) checked and adjusted if necessary, followed by an injector set. If that doesn't solve the problem my gut feeling is, that with 17k hours on it since the last time it was rebuilt, it's just plain tired and needs rebuilding again. Again repeating myself, your challenge is to find a guy who actually knows how to adjust the MUI rack controls.
Yes that makes sense, Quinn supposedly has someone with experience adjusting them, he’s supposed to be giving me a call. Thanks again
Well, the Quinn tech came out and adjusted the valves, injector height, injector rack settings and checked the governor fuel setting. The rack settings were the only thing that needed much adjustment. But after all that it still isn’t running right. Maybe a little better but still not revving up like it should and still very little smoke. He checked the turbo and said he recommended replacement of that first then the injectors. The injectors seem to leaking, the oil under the valve covers had fuel mixed in with it. But we took a engine oil sample and it came but with no fuel in the oil...,
Well, I installed a Reman turbo. No improvement.
Well, good news! Its fixed. I took the governor diaphragm off again looking for clues and I realized the gasket under the diaphragm cover had one small hole, but the gasket was rotated so the the gasket was blocking the hole in the governor housing that allows boost pressure to operate the diaphragm. So I rotated the gasket to align with the small hole and now with the shank 6’ in the ground at low idle it takes 5 seconds to get moving and reach 20psi boost. Now I only changed the diaphragm after I was having problems, so it wasn’t the original issue, ( it must have been the turbo or the injector settings) but I’m happy to be done with it. A big thank you to all who helped me sort it out!
Glad to hear that you got it sorted.
This has been an amazing thread. I know squat (basically zilch) about dozers...ten years ago my son and I got my uncle's D7 cranked after many years of no-go. It ran great but took a 40-acre field to maneuver it back to its start point. I hope to try to resurrect it again before too long. I gotta feeling you guys here will be able to give us good input on how to make that beast steerable when we try again. Thanks to the OP for following thru on how you got it running right...and to Nige and the minions that helped this along.