john stewart
Member
Hi
I have a d8h cat (46a24576) with which I have recently finished a rebuild on the motor. A few of you might have seen a previous thread of mine about a high oil pressure problem, this is a seemingly minor problem at the moment as I have recently had a world of trouble with this engine.
The engine was a full rebuild in every sense, all bearings, pistons, liners, ground crank, etc. Ran the motor out of frame first, all good no leaks, then into the frame. Put the tractor to work, all good, heaps of power, no noises, ran beautifully, for a while. Then while working the engine, it loaded up and squeaked briefly. Sensing the problem instantly, went back to idle and the engine stalled.
Within a few seconds I restarted the engine and white smoke coming out the breather.
In disgust it was shut it down and left, the next day i ran it briefly back to the workshop. After a few conversations, I feared the worst, that a bearing had failed.
After a snap decision I pulled the engine back out, and after much searching found the rear pump drive bearing had grabbed and spun. After deliberating, it was found to be my fault, I had machined up this bronze bearing myself (reasons I wont go into) and hadn't given enough clearance.
It damaged the shaft, so shaft was ground undersize, and a new custom bronze bearing was made, with much more clearance (same as new cat bearing bought).
The engine was put back in with the oil system reprimed. From start up the engine didn't sound right, unlike the first round. There was a rhythmic squeak which went up through the rpm range.
First thing I checked was the pump drive, all good.
Didn't like the situation but persisted to give it a run, only drove it a few hundred meters, when another issue occurred. It blew the guts clean out of a glow plug. On inspection the bulb of the plug had been burnt or broken off, as well as one other. These bulbs have gone into the engine, been crushed up and have been blown out. I know this, as there is peening on no.1 piston and signs of light peppering of debree, on the turbine of the turbo (no major damage there luckily).
The manifolds and head ports were inspected and cleaned, new CAT plugs put in, and the engine was re run.
Currently think that the glow plug issue was due to the cheap aftermarket plugs used, as the machine has been rerun and no trouble since.
Now I still have this issue of this strange noise, made worse by the fact that the engine doesn't seem to perform, it definitely doesn't have the power that it did when i first put the engine in. Lately I have done a compression test, which seemed to be ok (400-450psi).
Few final notes
The noise gets worse when working
The noise seems to be coming from the back of the motor
Noise doesn't start till 10 to 20 sec after startup
Seems to be fair bit of blowby coming out the breather when the engine is working, but compression seems good????????
The fuel pump, fuel and cam timing were never disturbed on the 2nd dismantle.
Just about to do a stall test, maybe now a problem with converter, but was perfect on the first run????
Tearing my hair out, so any thoughts would be greatly appreciated
I have a d8h cat (46a24576) with which I have recently finished a rebuild on the motor. A few of you might have seen a previous thread of mine about a high oil pressure problem, this is a seemingly minor problem at the moment as I have recently had a world of trouble with this engine.
The engine was a full rebuild in every sense, all bearings, pistons, liners, ground crank, etc. Ran the motor out of frame first, all good no leaks, then into the frame. Put the tractor to work, all good, heaps of power, no noises, ran beautifully, for a while. Then while working the engine, it loaded up and squeaked briefly. Sensing the problem instantly, went back to idle and the engine stalled.
Within a few seconds I restarted the engine and white smoke coming out the breather.
In disgust it was shut it down and left, the next day i ran it briefly back to the workshop. After a few conversations, I feared the worst, that a bearing had failed.
After a snap decision I pulled the engine back out, and after much searching found the rear pump drive bearing had grabbed and spun. After deliberating, it was found to be my fault, I had machined up this bronze bearing myself (reasons I wont go into) and hadn't given enough clearance.
It damaged the shaft, so shaft was ground undersize, and a new custom bronze bearing was made, with much more clearance (same as new cat bearing bought).
The engine was put back in with the oil system reprimed. From start up the engine didn't sound right, unlike the first round. There was a rhythmic squeak which went up through the rpm range.
First thing I checked was the pump drive, all good.
Didn't like the situation but persisted to give it a run, only drove it a few hundred meters, when another issue occurred. It blew the guts clean out of a glow plug. On inspection the bulb of the plug had been burnt or broken off, as well as one other. These bulbs have gone into the engine, been crushed up and have been blown out. I know this, as there is peening on no.1 piston and signs of light peppering of debree, on the turbine of the turbo (no major damage there luckily).
The manifolds and head ports were inspected and cleaned, new CAT plugs put in, and the engine was re run.
Currently think that the glow plug issue was due to the cheap aftermarket plugs used, as the machine has been rerun and no trouble since.
Now I still have this issue of this strange noise, made worse by the fact that the engine doesn't seem to perform, it definitely doesn't have the power that it did when i first put the engine in. Lately I have done a compression test, which seemed to be ok (400-450psi).
Few final notes
The noise gets worse when working
The noise seems to be coming from the back of the motor
Noise doesn't start till 10 to 20 sec after startup
Seems to be fair bit of blowby coming out the breather when the engine is working, but compression seems good????????
The fuel pump, fuel and cam timing were never disturbed on the 2nd dismantle.
Just about to do a stall test, maybe now a problem with converter, but was perfect on the first run????
Tearing my hair out, so any thoughts would be greatly appreciated