I’ve an older Skat Trak Skidsteer. This has been a fantastic basic heavy duty Skidder. It has a Perkins 1004.4 4cyl. Rated at 76 hp. It almost sounds like a rod knocking but another guy thinks it’s just an injector making the hammering sound. Does a bad injector sound kinda like a rod knocking? Are they easy to change out? Just unbolt or do they need special tools to remove? Around 6000 hrs. on this old girl.
HeavyEquipmentForums Here is a recent thread on the same topic. It’s something you may run into.
i think an injector can cause knocking when it gets stuck open and dumps too much fuel inside. do you have excess smoke? the injector is technicaly called an atomiser. there is just a needle and spring inside that moves up and squirts fuel when the injector pump sends fuel to the injector. there is nothing inside the injector that will actually knock.
You're correct, but if an injector is squirting at the wrong time due to wear or a mechanical defect it can produce a sound in the engine somewhat similar to that of pre-ignition on a petrol engine.
Start your engine and loosen the injector lines one at a time. Once you find the cylinder that is having the issue, notice if the knock stops.
Arent the injectors under the valve cover on that series.?? The diagnostics are still the same.. Post # 5,, & once u narrow it down to a cylinder.. MOVING the injector will tell u if the injector or an actual cylinder problem..{rod knock} SWAP IT w/ the furthest away from the suspect cyl.. Heres hope'n for the best..
Well, that went a lot easier than expected. Especially after reading other post about getting injectors out. Nothing to it, take off clamps & lines & they popped right out. Very dirty, just going to replace all 4. Appreciate the help gentlemen. Where’s best place to buy these?
i bought mine at: https://shop.perkins.com/parts/fuel-systems/injectors-and-nozzles $154 per injector $1 rubber seal and they are currently offering free next day shipping.
PM sent..
So did you confirm the problem was an injector by moving it to a different hole? Or are you just replacing them in hopes that that is/was the problem?
Ah, the good old "fault finding by substitution" Parts sales guys love 'em ........
Well, replaced all 4 injectors. Diesel Injection Service in Deforest, WI rebuilt all 4 for $105 a piece. Went back together smoothly. Only problem, it still has a knock? It appears that it is a rid knocking. My experts may not quite be the experts they think they are!!! Anyway, what are your guys opinions as to a long or short block? Or, cost to completely go though a Perkins 1004.4? Not sure how much money I want to put into this ‘Ol Girl. It’s a ‘98 I believe with approx. 6000 hours.
I know as soon as I replace motor some other thing major will fail. Just kicking around best/least costly ways of repairing or just start looking at newer machines. I’ve run a few newer rigs with supposedly more HP and power but they really don’t seem to be anymore capable than what I have power wise, just more bells & whistles.
Many things can Knock. Carbon broken loose from head laying on piston rim, Piston slop in bore or scored to bore, rod bearings even a valve sticking Open and the piston slapping it shut, if has glow plugs a broken of tip will generally anchor to a piston head as well and slap the face of the engine head.. Until start opening the engine up have no clue which you will find.
The problem with experts is that it's your money they're spending, not theirs. Once you're paying someone to fix the broken bit of kit then the dynamic changes.
BTW, a bad engine to drive system coupling or connection bolting loose can also knock.
dont run it anymore. tear it apart and see whats wrong. if its bearings, you may be able to just change them if the crank isnt scored. bearings cost maybe $40. i see cylinder liner, piston, and gasket kits for under $400, if its a piston issue.
Guess taking the time to move injectors around to see if the knock changed or moved would have been a good idea after all huh? Did the shop that rebuilt the injectors even bother to test them before hitting you for $105 each? Sure would have been nice to know there was a real problem other than them just needing to make a boat payment! Have you done any basic things like pulling and cutting open the oil filter? Or maybe give those here trying to help some basic background information. Like when did this "knock" start. Was it after you dumped a whole can of starter fluid down the intake when trying to get it started. Did it start after it sat out in a downpour with the exhaust pointed toward the wind? Did your brother-in-law borrow it for the weekend and bring it back saying it did that all weekend he had it? I'm sure others here can think of many other possibilities, but may be too polite to suggest them!
Is it firing on all four? A misfire will usually indicate a failing wrist pin or rod bearing . If it's not misfiring than problem is in cylinder head,
That’s a little misleading.