The Fordson Tractor Pages Forum

Hi
Just wondered if I could tap into the wealth of knowledge on here.

Engine Perkins 6.354 (in Hymac excavator)

Injectors recently serviced, air cleaner OK, Diesel appears to bleed thro' OK
It runs very unevenly on start up, copious amounts of pale blue/white smoke.
Smoke clears as put to work and engine appears to run more smoothly as warms up.
Engine will sound reasonably normal from idle to 2/3 throttle although the exhaust note still sounds slightly rough.
If engine is put to full throttle then the fun starts. It kind of spits, farts and backfires. If the engine is loaded is seems to stop this.

Any ideas? Thanks in advance.
Peter

Pete,

On combines fitted with that engine we used to get what Perkins called "IEB" (Irregular Exhaust Beat). I had an engine that sounded absolutely terrible when running light but sounded great when under full load.

I spent two days trying to sort it, having the pump off and serviced, valves, head gasket etc. (In the middle of harvest too). Still could not get it to run right. Then for some reason, I replaced the gasket on the lift pump with gasket cement. Straight away the engine ran on all six and was never any problem after that.

We thought the lift pump gasket was too thick and reduced the amount of fuel getting to the pump. Perkins had fitted bleed back valves in the return line to the tank but these did nothing. The lack of fuel at high revs made her miss on all cylinders.

I used that trick many times after that on both the 6.354, 4.270 and 4.236 engines.

Thanks for the info Brian. Do you mean the gasket between the lift pump body and the block or a gasket between lift pump sections?

Another suggestion was weakened valve springs.

I am trying to look at the alternatives before pulling to pieces.
If it turns out to be a major (no pun intended) fault I might go down the road of an alternative engine.

Thank you Peter

Between the lift pump and the block. The lift pump was operated by a short round "pin" and we suspected that this had worn meaning the lift pump did not travel the full distance on each stroke.

Would have thought weak valve spring would have made the engine run rough even under load.

Hi Pete,
We have a 6.354 in a forklift, and it was running similar to yours. It had a small leak in the fuel line where it connects to the lift pump on the suction side. It wouldn't leak fuel, but it would suck air when it was running. It's been running fine since I fixed that.

Thank you for the replies.

Would these fuelling issues actually make the engine miss fire and pop etc? I have only ever experienced loss of power and engine dying with other engines. Would this be the nature of the 6.354?

Something else I have wondered: would it be possible to have a head gasket blow between cylinders without fluid loss/mix? What sort of symptoms would that have?

Its been too cold to investigate the other ideas!

Regards Peter

The engines I worked on would mis-fire all over the place. It would not be on any one cylinder. And yes, they would pop in the exhaust.

If you are getting valve bounce it would give your popping and banging. I think you should get it in the air cleaner too.

With a head gasket, it would loose a couple of cylinders and you would be able to identify it by the usual means of slackening an injector pipe.

Thanks for all the ideas. I will check by cracking off the injectors again before I pull anything to pieces.
Regards Peter

Hi Peter - was the Perkins acting like this before you got the injectors serviced? Is it easy to start when cold? Which injector pump is fitted? The reason I ask this is that I had a 6-354 on a front end loader and it worked well until I got the Injectors serviced and the pressures were brought up to specifications. The Injector pump apparently was worn but it was working with the lower pressures on the injectors. After the recon injectors were fitted, it ran terribly - similar to what you described.- just a thought - Best regards - Michael

Thanks for the advice guys. Have not got around to any more checks yet. The injector pressures were ,I am told, all over the place with some set too high. It definitely runs better and starts better since injector overhaul.
Regards Peter

Thought I would give you an update on the old Hymac engine.
After changing the injectors it still seemed to run rough at high speed. (popping and spiting). It also smoked more than it had when I first bought it (Blue). Thought I would give the scouring powder a try. Ran the engine without cleaner and tipped in scourer. Ran for while, replaced cleaner. Worked it fairly hard for a few hours shifting muck. Dropped the oil and changed the filter. Gradually the engine appears to have improved. It still runs rough on start up, particularly now as the temps have dropped but it clears very quickly and runs so much better than it did. I also chucked a big dollop of ATF into the diesel tank.
I am not sure what has really happened here but it has done quite a lot of work including running all day cleaning out a neighbour's pond!