Valtra 8050 Smoking

[Mark7810s]

I’ve got a 8050 which we’ve recently rebuilt the engine on including recon fuel pump and injectors.

It has a slight hint of white/grey smoke when running this stops when cracking injector number 3 and the exhaust is clean. Removed the injector and swapped with number 4, the problem did not move!

It has a standyne DP4 pump could this be at fault with the fuel delivery to cylinder 3 or if the pump was at fault would the problem be across the board?

There is no smoke from the engine breather and the oil level is bang on the mark and hasn’t used a drop in the last 60hrs.

Any input much appreciated

Regards
Mark

 

[startinghandle]

When you rebuilt engine did you fit new valves?
Did you grind in valves ?
The only suggestion I can think of is
to check valve clearance on number 3
cylinder

 

[Timbo]

Poor compression on number 4 i'd say... Get a gauge on it.

 

[Mark7810s]

Head has had valves ground and seats recut with new guides and stem seals. Rechecked clearances yesterday and made no differences.

I think its getting to the point where I've exhausted the simple things and its getting to a head back off stage! ?

 

[Deerefarmer]

Sounds like an injector issue to me
I'd test those before pulling head,
Were they new or rebuilt injectors

 

[startinghandle]

This is baffling!!
Are valve springs fitted correct way
round?

 

[Mark7810s]

Injectors were rebuilt with new tips but the problem has stayed at cylinder 3 when swapping with another injector.

would the delivery valve for cyl 3 be sticking/ blocked in the pump?

Will check in the manuals as i think the springs are the same.

 

[Mur Huwcun]

Injectors were rebuilt with new tips but the problem has stayed at cylinder 3 when swapping with another injector.

would the delivery valve for cyl 3 be sticking/ blocked in the pump?

Will check in the manuals as i think the springs are the same.

It's a rotary fuel pump yes? If so they only have one plunger as such for all cylinders. Have you given it some real hard work just in case? As suggested go for a compression test before removing head if possible.

 

[startinghandle]

Does it have glowplug on manifold?

 

[thesilentone]

Un-burned fuel / over-fuelling is black smoke, burning oil is usually blue/grey and water is usually white smoke.

Why do you want to take the head off ? If it has been rebuilt correctly, there is no reason to do that. Run it hot for a while and stop the engine, check and listen carefully for leaks, or water noises in the system that many indicate a leak.

Check the excess fuel line when running, and see how much is returning to tank, a DP4 pump has a delivery setting of x cc of fuel per cylinder per injection depending on the model of engine/tractor and is easily adjusted, but you have to know what you are doing. This is best done on a dyno.

You have eliminated the injector, however the cylinder still has a smoke problem, the obvious is head gasket, however there is no reason for this to be the case if you have just re-built it.

 

[Timbo]

You have loss of compression, a sticking injector, or incorrect injection timing on that cylinder.

A quick n dirty test is disable the fuel system so the engine cant start and wind it over on the starter - does it sound consistent or is the a lope to the cranking? If the latter pull the head. IF the former, compression test anyway, but be prepared to look else where.

Can you arrange injector 4 outside of the cylinder so you can observe the injector with the engine running? Is it dribbling or leaking when its not spraying? This will determine if you have an injector fault or a delivery valve problem (unlikely)

 

[Teddy99]

Did you find out the reason for it smoking slightly ?

 

[Mark7810s]

Got to the bottom of this today! Went to do a compression test and on removing injector 3 noticed there was still an injector washer in the head after pulling one out with the injector.
Removed the bottom one and shes smoke free??
Thanks everyone for your input was hopefull it could be solved like this without delving inside.

 

[thesilentone]

Got to the bottom of this today! Went to do a compression test and on removing injector 3 noticed there was still an injector washer in the head after pulling one out with the injector.
Removed the bottom one and shes smoke free??
Thanks everyone for your input was hopefull it could be solved like this without delving inside.

Hang on !

I like these problems, as you learn something new.

So, if there was one extra washer, we can assume (1) a possible leak around the injector, which is unlikely, and can usually be seen, or (2) the injector was not sufficiently into the cylinder swirl chamber area causing the fuel not to burn 100% efficiently, or some being injected onto a surface after being atomized and returning to liquid (and not burning efficiently)

Anyone any ideas ?