So its been a long time that i have been chasing down this fuel issue and i am utterly stumped at this point. first I will give you the specs. threw my research I believe its a 1960 model year Cat 17A D7 Turbo. I bought the machine about 3 years ago and love it since day one strong like bull and dumb like one too ( nothing electric controlled). last summer, I had a sudden engine nock and loss of power and blew the dip stick clean out of the machine. I immediately shut her down and investigated. turns out I lost fuel pressure to #2 cylinder, dead cylinder. apon digging deeper I noticed the front half of the engine filling up with anti- freeze, I suspect when #2 went dead the compression had to go somewhere and it blew the dipstick out of the machine and across the yard about 15 feet and destroying the head gasket seal. Ok so simple fix I thought. All new head set all new gaskets everywhere tore it all down and solved that problem, re-lashed the valve train put in a new push rod and lifter because someone's jimmy rig fix from years ago in my opinion was Ludacris, did regular maintance rebuilt all the hydraulic cylinders up front with brand new rods and seals what not and then it was off to the fuel system to fix the misfire. Now this is where my Delma is I am at a loss I have replaced the injector nozzle and body, the line has no kinks or obstructions, I put a brand new piston pump on #2 high pressure pumps spot, the yoke was in spec so didn't change it, took apart the whole fuel system no contamination in the passage ports in the filter assembly transfer pump primary filter and both secondary filters are brand new, drained the entire fuel tank cleaned it no rust or dirt. played flip flop between a known firing cylinders injectors pump and injectors the problem always stays ay #2. So with all that I figured it has to be the cam shaft or lifter. so I follow the book bring #2 up to compression at TC bought a brand new micrometer for measuring depth, set the lifter up to spec of 1.733 " from deck to yoke that dose not solve the problem do the same test to #1 cylinder the values are equal. so then I measure the lift at full rise thinking the cam lobe is worn down, nope it is exactly the same amount to lift as #1 so then I do the measurement to see if at TC the lift is right for that duration on the lobe matches exactly to known working cylinder #1. When the engine is running it defiantly has a loud fuel nock and if you crack the injector lines will its running #1,3,4 all affect the engine idle negatively obviously bc its a no fuel scenario but when you crack #2 it dose not react like its running on only 3 cylinders of power currently. When you take the fuel lines off the Piston pump caps you can watch a steady fuel stream like a guizzer shooting up about 6 inches on #1,3,4 but #2 barely will squirt 3" and at the injector tip it will only dribble fuel barely no atomization. so now i am grasping at straws I get an idea maybe the lifter spring is broken and it works fine at slow speeds with the micrometer but as the RPM increases at engine running I get a "Valve Float" scenario like racecars at High RPM. causing my problems, so tonight I took the cam and lifters out of #2 and #1 no ware no scrapes nothing then springs feel identical resistance rollers are smooth the parts look brand new. So to sum it all up everything on that cylinders fuel system is either replaced or in spec the cam is fine the lifter looks good it has the right amount of lift and duration, the piston pump is brand new and if you swap in old one it dose not change the line is clear the injector tip and body is new. and I still have a dead cylinder. What could it possibly be left to investigate?
You could swap #2 pump and capsule with #3 to double check. But, it probably has a low compression problem on #2. Maybe a bent rod from the previous failure? When it hydro-locked with water. You could do a compression test or a leak down test. Use the old fuel capsule to make a custom adapter for your compression tester. Guaranteed to find the issue.
You can check for a bent rod by measuring piston height a TDC and compare to #3 running mate.
Yes, start by moving #2 capsule then #2 pump to another cylinder to check operation. Are you getting bubble free fuel flow when bleeding pumps and at the injectors?
ok so i have though about those scenario also, I did do a compression test in the cylinders last year to see if there was a bent rod or mechanical failure since yes it could have been hydro locked. I can't remember the exact psi but the values I do remember were within 10% from the problematic cylinder #2 to known working cylinder #3. I have played flip flop between all the cylinders cap pistons at this point now the problem always remains at cylinder #2 never moving the issue to another cylinder even with brand new cap and piston or used matched pair. I didn't check for bent rod Hight compared to #3 but when I had the head off last year I also had the inspection covers off to check the cam and crank shaft areas there was no obvious bend in the rod by looking at it no when I ran my hand up in side didn't feel like it was bent but obviously your eye and hand is not very scientific. lastly even if the root of my problem is the #2 cylinder has a engine failure of bent rod or something similar ( witch has not been fully ruled out as the main problem) it would not explain the poor fuel pressure always being a constant on #2 high pressure pump the High pressure pump and its fuel rack are completely independent of the engine its like its own motor in its own right. I wouldn't say there is bubbles in the line i would describe it more like that it is erratic. To describe this as best as i can when the starter is turning over the engine #1,3,4 cylinders pump and cap create a steady stream of fuel jumping up to a Hight of 6" with the line to the injector removed where as #2 cylinders pump and cap with either a brand new or used pump and cap always produces a stop and start like of stream never rising more then 3".
Always do your parts swapping w the FARTHEST away cyl. from your suspect cyl. If it’s 2.. swap w 4.. NOT 1 or 3. Just incase the problem has leeched to either cyl. beside it.. Is this injection pump the kind 1 that has single pump for each cyl.?? It sound like it.. Do u know that there is a TIMING SHIM below the pump.?? It’s possible that the shim stuck to the bottom of the old one and u didn’t notice it..?? It’s worth a glance.. I sure hope that’s ur problem..
These old pumps use an adjustable yoke to set pump stroke ,no shims. Bob
i have swapped piston cup 1, 3, 4 all on to the dead cylinder #2 never changes anything I just used #1 in my explanation because it is the easiest one to swap since #3, 4 are behind the turbo and are kind of a pain to remove unlike switching 1 and 2. and yes this is a piston and yoke style old set up very simple adjustability is done with a set nut and a depth finding micrometer set to TC on that cylinders compression stroke measurement of 1.733 +- 4 thou
also today i made a custom engine compression tester and custom fuel pressure tester with and little machining and an old injectors. if it stops snowing tomorrow i am going to put the pump back together retime all the cylinders and do a compression test on all cylinders again and now a fuel pressure test on all cylinders just before the injector at line pressure then i will know the exact values for everything and cross the next bridge. Just wanna make this old girl move some dirt again on all 4 cylinders of power.
Ok, so it is consistently #2 pump. Check the wear on #2 yoke. Lifter height may be correct but your not getting full plunger return stroke.
When you reinstalled pumps did you align the mark on the rack with the line on the sector gear on the pump?
I can't see it being a fuel issue , blowing the dipstick out means it had a sudden rise in pressure in the crankcase , I would think it would be a piston failed . With a head off and the plate for the third cylinder removed to give access to the bigend you can check the conrod after removing the rod and piston . I have seen a hole in the side of one of these motors near big enough to put your head where a broken rod came out the side .
Bad rod/piston or not, that doesn't explain why #2 pump is not performing.
I’m not convinced there is a problem with the #2 P&B or the capsule. I don’t think it possible to look at the squirt and quantitatively determine if it’s good or bad. The NOP is like 700 psi. The injection pressure is so low, the fuel doesn’t even really “atomize” on these antiques. The Op has done due diligence with the fuel system. I admire his persistent. The blown head gasket didn’t send the dipstick to orbit. It’s got a piston/liner/ring issue. Let’s just do a leak down test and settle this. Let’s stop talking about it and be about it. Pidder Padder, let’s get at er’.
If I understand hdsbc correctly, he had done a compression test, and #2 was within 10% of the others. He also had the head off, and a bad piston or liner would have been pretty obvious while the head was off. We haven't heard what those compression test numbers were. That might help us determine if the cyilinders are tired.
If everything he says is square has to be pump housing cam internal crack ect .
If it is direct start as a down and dirty compression test, you should hear a definite skip when it is turning over. A somewhat trained ear could hear/feel under pony start. That business of the dipstick shooting across the yard is worrisome. Changing the head gasket is not going to fix whatever caused that.
Man is there a wealth of knowledge on here!
The motor has serious blow by issues , if it could be called that firing a dip stick across a yard . Spending time and money on the fuel problem could be a waste . Can't say I've ever heard of a dip stick being fired out . Breather on the motor might need a clean out .
to answer everyone's responses 1st: i have checked the yoke it was still 1 thou within the books spec of tolerance not much but still there plus i tried to purchases an new one and come up unable to find. 2ed: yes i aligned the mark on the rack to the piston's rack gear thought of that also one cylinder could have been advanced or retarded fuel. But no this is not the case each piston plunger has a mark on the 5th tooth counting from the left that mates with the governor long rack indicator mark. 3rd: lets forget about the engine problem for a moment. yes i know we have not ruled out definitively that there is not a bent connecting rod i get it but that dose not explain why i have a problem with #2 pump injector system. Today is a much nicer day i am going to reassemble the pump and do another compression test on the motor to get the exact values this year compared to last year since i can't not remember the numbers. 4th: i also will be doing a all cylinders fuel pressure test today made a custom adaptor yesterday to do so. 5th" where would i look for a internal crack on the pump housing i have the cam out now and the lifter the are no physical sings of damage and i measured each lobe lift of the cam they are all the exact same the cam looks brand new for being 60 + years of service and the lifters are the same length from the roller to the top but that dose not matter since its on adjustable threaded yoke anyhow. 6th: yes when the engine is running it sounds like a misfire and you can watch the smoke out the pipe poof poof miss poof over and over again and a auditable knock like a dead cylinder. 7th: i do not have the original pony start motor when i purchased the machine someone had already removed it and installed an electric starter. 8th: i know the motor had a problem yes the dipstick blew out but it only did it 1 time, since then the engine has run for about a hours time like this trying to diagnose problems and having mechanics stop by and give there personal input. but again since then i have take the head off checked the piston rings and cylinder liner for physical damage, had the inspection cover off the cam shaft area and replaced a lifter and push rod, had the cover off the bottom and and looked for damage to the rod and crank if there was a hole in the liner or block i most likely would have seen it by now and that cylinder would be seriously low on compression. the motor still turns over and runs fine every time i start it there is no anit-freeze in the front cylinders anymore it had to be a fluke scenario were #2 lost fuel because the pump failed over pressurized the cylinder blew the head gasket and that compression had to go somewhere strait past the rings into the crank case and shot the dipstick out. i know its worry some thing but i have to fix one thing at a time nonsense of trying to remedy 7 things at the same time or else your never going to find the root of the problem to begin with. To sum up I have to get #2 injector pump working properly to the specs of the adjacent cylinders to definitively rule out fuel is not the issue. once i know this for sure no doubt then it will be time to do an engine overhaul. In my mind this machine is paid for what i have done with in 3 years and i will never get another one in this good of shape for the money i have into it so if have have to cross that bridge i will. to me saving something this old and easy to work on is worth keeping rather then turning to scrap metal.
What does the crankcase blow-by look like? Any puffing while the engine is running ? I have witnessed a D9 blowing the dipstick out of it's tube. But, it had a blown piston.
working right now on putting the injection pump back together so making progress coffee time haha. i can put my hand over the crank case breather and it dose not have any puffing coming out when the engine is hot and running its just a steady steam rising out of the breather. nothing out of the ordinary and the steam dose not puff it just continuously rises like a large slow kettle.
Your on the right track. Get the #2 pump sorted out as it is probably the root cause of it all. Running a cylinder on inadequate fuel supply (lean burn) can lead to all sorts of problems as witnessed by engine knock, inadequately atomized fuel, cylinder wash down, piston and ring damage etc. I've witnessed an extreme case where conditions actually got to the point of crankcase explosion. Check these pistons for damage when injection goes afoul...
You stated that your not seeing bubbles in the fuel but while your at it make this check. With the lines disconnected to the injectors, put a few drops of oil in the injector opening. Crank the engine and see if the oil is blown out of the inlet. This will give you a check on whether there is any compression leakage past the nozzle seat. Any leakage here can result in displacing fuel in the injection pumps.
Ok so here goes for my findings. I have reassembled the machine back ready for compression and fuel pressure check but that will have wait till tomorrow weather turned for the worse little bit of a blizzard. so i did a spring compression test on all the lifters #1 36.5 lbs #2 38 lbs #3 37lbs #4 37 lbs so the spring is defiantly not the problem. turns out the cylinder in question has the highest rebound force anyhow and all the lifter bores were not scored and the lifters moved easily up and down no evidence of cracking. by take a picture and looking at the picture. Lifter length from roller to top #1 3.586 #2 3.587 #3 3.585 #4 3.585 so lifters are all practically the same could be a little human error because i had to use a caliper, micrometer wouldn't fit since the jaw was not deep enough. Piston plunger length book says spec is 2.6575 - 2.6577 #1 2.6576 #2 2.6577 #3 2.6576 #4 26576 all within spec brand new one book says no spec on yoke but if uneven ware replace like the picture that was earlier posted. There all perfectly flat and when you put the yoke on the plungers they all have hardly any slop I would say there all within tolerances. since i removed the cam entirely i had to set all the lifters back up so did just as the book says started at #4 just because that's where i was on compression stroke anyhow took the valve cover off made sure both valves were closed spun the engine in direction of rotation found mark for (1-4) TC didn't go past it and if i did i would back track at least 60degrees of rotation to eliminate black lash on timing gears then return to timing mark. set micrometer to 1.733 and set the lock nut continue on threw the firing order using the (2-3) TC mark next still all were set book says spec is + or - 4 thou i got each one set to right on the money or 0.5 of a thou out well within specs. moved all the components from #3 cylinder i.e pump cap piston plunger yoke lifter spring to #2 if the problem moves to #3 cylinder now i know for sure its something wrong most likely the yoke with #2. yes Old magnet totally agree with you I want to solve the root of the problem before getting knee deep in tearing down this old engine no point in dropping the skid and pan to change a rod if the problem is just going to happen again to a new rod that in my mind is wasteful. tomorrow i will most defiantly do that oil on the injector trick well i am doing a compression test. So if the problem moves to #3 with low fuel pressure then i know its the fuel pump if it stays in #2 and compression test yields low then i know i am rebuilding part of the engine.
Sorry the pictures are not in order of reassembly
How are you going about checking injection pressure. Do not dead head test. If you test use a pressure relief valve set at some reasonable pressure, maybe 750 psi or so or something could get busted. What's the part number on your new replacement pump?
my plan was to loosen all the injector lines at the pump so no fuel can reach the motor, then screw a fuel line 1 cap at a time to my custom tool i made. I drilled out the body of an old injector removed the tip cut off the end and thread it for a adaptor from my kit to be thread in the end. this will achieve my fuel pressure did it with shop air and it works. as for dead ending i don't have a pressure relive valve but if i see it climb over 750 psi quickly there is a blow off valve on the gauge to dump the pressure quick before something bad happens. as for cylinder pressure i made a similar tool since the person i borrowed the adapter from last year is no longer available. I purchased a store bought adapter for my self as seen in the picture and its the wrong size so resourceful made my own. drilled out the old injector removed the spring and ball tapped in a threaded adaptor to the gauge works on shop air also so should do the trick.
there is no part # on the new pump there a little differant like the fuel tube has a O ring instead of the tapered rubber gasket and its body is little differant on the outside but it fits just fine and everything lines up nicely. keep in mind today i moved all of #2 stuff to #3 that's why is there
The You should be able to access the big ends through four plates on the side of the block without the need to drop the skid plate and pan
I ask on the pump because there are at least for pumps available, all with 10mm diameter plungers but various rates of scroll to deliver a certain amount of fuel at specific rack settings. They are not all the same.
hum interesting very interesting. did not know this and was not a question that the part sender asked last year. but I if i have the wrong flow rate piston and cup then i should have a new problem on #3 now since its all been moved to that cylinder I will defiantly keep and eye on that tomorrow during the tests. so I am assuming to change the flow rate the helix grove is cut on a piston at a faster rise per twist or lower rise per twist to slow rate of fuel? or is the groove cut deeper to change volume of flow? is there a way it can be measured to check my new one is the same as the old ones?
No specs to measure the helix that I know of and probably to close to eyeball. Difference would have to be checked on a pump and injector test apparatus. So many strokes delivers a specific quantity of fuel at specified speed is how they are measured. Do not mix plungers and barrels, they are a matched set fit.
Im quite impressed on how methodical you are in your troubleshooting.
Thank you puffie40 doing my best to get it running again. as for values of pressure going to have to wait an hour or so found a new problem with the starter bad ground was causing only 12v at the starter instead of 24V and drained the one battery down to nothing so solved that problem with a new better ground location and a battery charger plus a 3red battery as an extra amperage battery to keep that big engine a turning. probably going to take all day to get the the values since the starter can only run for so long before she runs out of juice. thanks for the tip to remove the rod without the pan disassembly route that probably would save an easy 8 hours and a gasket by the time you get the skid down and rigged up on jacks to go back up.
The correct injection pump originally was a 4H5238 with current replacement a 8M3137 also supplied under 7F6042, 8F2590, 8M3277 and 8M3280 part numbers. Rack setting is 0.375".
on the injection pump/plunger for the original bad cylinder, did you check for a stuck delivery(check) valve?
so here is my finding so far first picture is psi on cylinder #1 it actually was more like 325psi but by the time i ran all the way back to the house got the camera and took the picture it leaked down to what you see in the picture at 310psi. the reason for the leak is i didn't; have any thread sealant on my custom adaptor and left it for like 5 minutes so it probably was not the cylinder leaking just my joint. Picture #2 is of Cylinder #2 the "dead Cylinder" in question it was the same psi as #1 325psi. I am not going to do cylinder 3 and 4 because its a pain since there behind the turbo i have a chance of damaging all the new gaskets i installed last year in the kit and # 3 and 4 are running fine. will post fuel pressure #'s as the batteries charge.
so all 4 existing piston pump caps were 4f5019 I still had the original box from last year the new piston and cap is a 8m3280. I tried to do a fuel pressure test no go i think since i am using a long line as an adaptor is not making any pressure i will have to get a super short double female swivel made tomorrow at the parts store i think, to do it. where do i do this Rack setting is 0.375"? "on the injection pump/plunger for the original bad cylinder, did you check for a stuck delivery(check) valve?" where is this check valve you speak of from what i see its a common fuel port that supplies all pistons from a 1/4 tube in the top of the pump casting.
My Fuel Injection Testing Manual does not show a 4F5019 for a 5-3/4" bore. Is it a 10mm diameter plunger? Fuel is supplied from a common chamber within the injection pump housing. There is a check valve built in to the individual pumps. (attached) Pumps are designed to give a specific volume at various rack positions (0.375") would be maximum opening travel of the rack quadrant for the late 17A.
so i measured the old piston it is 0.3935 = 9.9949 mm so i am sure it is a 10mm piston and cap because am am sure after 60+ years of use its has a little play
I'm suspect of the hose in your testing arrangement. When properly tested all connections should be rigid fittings. Even steel line is eliminated on the test apparatus but that is not absolutely required in the field. Capsule unseating pressure range is 300 to 800 psi. Under 300 psi should be discarded. As far as pump pressure, they are considered a positive displacement pump and could build pressure to destruction. On the test stand pumps are run checked at 125 and 600 rpm. Normal cranking speed on fully charge batteries is about 250 to 300 rpm so at half engine speed for the pump you should get close to meaningful readings.
so my findings for today are good and bad. I put everything back together today since i can't do a injection pump test i figured if the engine was rotating with the starter i should watch for pop at the injector out side of the head and low and behold finely excellent spray pattern on #2 injector, it was magic. I don't know what happened threw all the troubleshooting but it is working as it was intended. My best guess is the lifter had to be sticking and not returning fast enough to do its job properly at higher rpm ( engine running), and i come to this conclusion because after swapping all of #2 components to #3. #3 did not go dead. Now as for the bad news it is still not fixed it still is only running on 3 cylinders of power and if i can find a way to post the 1 min video of it running you will most defiantly concur. so I did a leak down test, now i have never done one before. ( if I did something wrong please inform me so i can learn thank you) so made a special tool will some old gauges and fittings watch a you tube video and off I was. started at cylinder #1 to get a base line. brought cylinder #1 up to TC on the compression stoke and put 30psi in found out after 20psi it moves the crank so consulted the video and changed to 10 psi like they were doing. the cylinder it failed every bit of air was coming out the exhaust turbo. so not a good sign defiantly have a valve seat problem in #1. Next off to #2 do the same thing TC on compression 10 psi and total fail every bit of air i could hear moving around in the crank case. So definitively i have bad rings or a untrue liner. Now i have fixed the injection pump problem definitively can say i have proper pop pressure on #2 and since all the other cylinders are firing they have to be good also. I can move on from that knowing its solved but my real question to everyone is why can i have perfectly fine compression in both cylinders both fail a leak down test and 1 will still operate fine? All in all i very appreciative for all you good folk helping me out on this project and i really mean that, especially you old magnet for taking the time to answer a young guys questions. I know what my next steps are now tomorrow i will be ordering a new head gasket, probably 2 cylinder liners 2 sets of rings and 2 rod bearings and doing at least a lap job on the valve train in my near future. if i am going to open it up again do it all so it can move dirt for another 30 years.
Well, your making good progress...but we never did get what you are calling perfectly good compression. So what exactly did you get? Even on the ragged edge these old buggers will run. Better add at least one piston to your parts list and a closer look at rod/bearing #2. I meant to post a procedure for leak down testing.I know I have it but I'll be damned if I can find it. Will look some more but in general I think you got the drift.
i had to make a a you tube account to upload the video this forum won't allow videos. so as they say "a picture is worth a thousand words" so a video has to be a million. Got to youtube.com and in the search bar copy and paste ?v=Pp9F7djs3HE for the misfire video ?v=wf2V_wfYfyI for the blow by video
by perfectly fine compression i meant it was 325psi for both #1 and 2 from what i read it should be 275- 400 Psi and mostdefinatly within 10% of each other
I'll check you video but before I forget, be sure to check liner projection on all cylinders when you next have the heads off.
Those compression numbers are way to low, it's a wonder your making auto ignition compression temperature. For that engine you should be in the 445-486 psi when cranking. 490 -530 psi at idle run speed. Anything below about 365 psi leads to combustion and starting problems. Finally found the leak down procedure.... You've got one tired engine.... https://ch-part.com/i.caterpillar/gmg006940001/ My bad on your pressure readings. At first I couldn't tell if you were reading compression or fuel injector pressure.
Since you plan to take the head off, take a good look at the valves. Chances are they would love some refurbishing as well.
in my opinion, may be worn out rings, stuck rings or broken rings. if excessive starting fluid is used on an engine with loose rings(ring lands worn out) it can cause ring breakage. could also be a combination of issues and valve problems, but my money is on a piston/ring/cylinder problem
today i had a few hours to tear down the motor again. Both heads are off this time this project turned into a new top end project. My findings are not good. #2 is the worst cylinder out of the bunch next is #1 and #3 and 4 are not terrible. #2 the top 1inch of the liner is shot with deep pitting in the liner and lots of heat damage to the top of the piston deep popcorn like cavities i have seen this before in a lean burndown condition scenario before so I assume that #2 was starved for fuel and burnt everything up inside. and that would confirm my injection pump problems. so in the long run i think it paid off repairing the pump problem on this damaged motor before i rebuilt any internals. #1 shows similar signs of were just not as bad. and a wet consistency on top of the piston and in the exhaust port correlates with the leak down test that exhaust valve seat is bad in that cylinder #3 and 4 look the best and defiantly were doing most of the work with a nice dry burn over the entire piston top and no damage( so far). tomorrow's job will include pulling all the liners and inspecting for more damage. My current plan is to get gasket kit, 2 full cylinder rebuild kits for # 1 and 2 witch consist of piston wrist pin liner and rings, if #3 and 4 pistons is ok get a ring and liner kit for them cylinders, 4 new big end connecting rod bearings ( might as well replace just to say its done ) and defiantly lap all the valves and replace ones as need be. if there is any other parts or things i am forgetting please chime in I don't want to miss something on my order because shipping to Canada from the U.S is terrible
#2 & 3 piston may look ok but if the top compression ring land is worn out of spec the only choice is to cut a wider groove and use a wider ring or replace the piston. Might as well do all four while your in there anyway.
so today was productive had to build a homemade liner puller because the one I borrowed from the neighbor was 1/4 to small to pull the liner. removed all the junk in the belly pan, cleaned the outside of the engine for grease and oil, removed inspection covers had a hell of a time to get the rod cap bolts off that is one sucky job with the area you have to work in upside down laying on the track. Got #4 piston and rod out. now I am looking for your input is this piston reusable or just bite the bullet and get all 4 changed?
What is the top ring side clearance? Maximum allowable is 0.012". New is 0.005 to 0.006"
I have never don't a side ring clearance measurement. can you please explain how the test is done.
Insert a flat feeler gauge between the ring and the ring gland.
Refer to photo below. Push the compression ring upwards until it is hard up against the top of the groove. What size of a feeler gauge can you get in the space (arrowed) between the bottom surface of the ring and the piston.?
All piston rings have side clearance specifications, it's just the top compression ring that wears the most. As I previously mentioned pistons can be recovered if the grooves (lands) are out of spec but it means cutting a new clean land and providing a wider/thicker ring. That was the old school recovery method but now it's more common to just replace the piston. This step is often overlooked when rebuilding but leads to compression issues.
or in the really old-school times, they machined the groove wider to add a spacer alongside the ring to make up the difference. i have one of those tools in my obsolete/antique collection
You mean one of these!!!!
ya, mine is similar but a different brand. i can't tell the manufacturer though. i always watch for that old stuff at auctions and yard sales. to me , that old stuff is interesting. its from an era where mechanics kept stuff working--before we became parts replacers such as electronics on new machines and are now called 'technicians'
Yes, back when a shop was a "shop"!!!!!
Thats a big piston Old Magnet what was it out of do you know? Love all the knowledge that you and 56wrench and others provide on the old gear its of huge benefit to the younger generation I have just finished pushing dirt with my 17A in down here in NZ and have noticed Final drives leaking through to the Steering clutch compartments - about 200mls every 10 hours Dont really want to spend a week pulling her apart to replace the seals and have brought some 140w gear oil to see if that helps but does anyone know what else can be tried? Many thanks
Not a heck of a lot you can do...might get a crowbar in on the sprocket to see if it wiggles followed by adjustment if needed. Heavier oil should help some.
well its been a few days on the project in my other other spare time. Bad news struck when #2 piston was removed from the bore. turns out there was physical damage to the crank shaft. The barring did not fully spin up its messed up, half of the bottom half is gone and the top half was pretty scored up. worked all weekend dismantling the tractor and getting the engine ready for removal, and constructing a heavy duty enough cart to do the engine rebuild on. I estimate the engine is 4000-5000 lbs. dressed but could any one confirm my estimate with an actual number? just don't want my engine stands tires to be overloaded. I am going to take that hard road and give this old machine new life again just can't bare to see it turn into a Kia.
To bad your not in NZ i have a spare engine that runs mint found a spare machine that hadnt been running for 11 year but she goes like a dream Good luck with the re build though That steel is far to good for a Kia
The messed up bearing is probably why the compression was so low - even a few thou up-down slop would affect the compression ratio. It might be worth keeping an ear out for junker D7s for a replacement crank. Ontario has Fawcett tractor that occasionally junks out old crawlers, but General Gear over in Boise Idaho regularly deals in old cat parts. Old magnet may be able to confirm or not, but the older D7 3Ts might be a potential source of parts as well.
I show a different part number for the 5-3/4" bore piston/sleeve/ring assemblies for the 3T D7's. (4H7074) The 17A uses 3S4032 assemblies. I didn't check the parts books for piston only numbers. Is that needed?
So I am back at this project again slowly getting it ready for a winter time rebuild. Summer was to busy for me to even think about working on the old Cat. Having a little trouble finding main bearings. Any Ideas of places to look? found rod bearings, Cylinder piston kits, connecting rods, and full gasket kit so far from AGkits.com If anyone else has any ideas of places to find a full engine overhaul kit or the remaining missing parts it would be much appreciated.
making progress on the old Cat this week, almost have the crank out. Had to by an old dump truck chassis to make a cart from a local farmer. Built some beams on it, engineered an overhead support bracket system out of some old I beams. Presto 1 Caterpillar D339 engine rebuild stand. Patent pending hahah. Lots of pressure washing left to do but I can finally see the belly pan.
pictures 2