black smoke and running rough

[sky blue]

been using the dexta a lot over the sunmmer, everything been good untill
yesterday when i noticed that when at idle she was puffing out black smoke,
when reved up t it cleared back to idle an black smoke again , also is harder to start
and and when it does loads of black smoke, any ideas welcome
sky blue

[Bensdexta]

Over fuelling?
http://www.bellperformance.com/blog/bid ... -explained

[sky blue]

thanks for that ben , ihave now replaced fuel filters , cleaned air filter,
and checked timming which is spot on , the injectors where bought ,new from peter strong
about 4 years ago when i rebuilt engine, have roughly 5oohrs on tractor since not a lot
she wont start now even with heat from a blow lamp , that is going from starting first tip to not
starting even with the blowlamp lamp overnight strange one

[oldcharlie]

Have you bled all the air out of the fuel lines? After changing the the fuel filter I have had trouble until I got ALL the air out of the fuel lines.

[sky blue]

thanks for your input oldcharlie, yes iv got good flow when i pump lift pump
from both the filter and injection pump , i have disconnected the injector pipes at injectors
and they are squirting diesel intermittly as they should when turning over engine,
this means the injection pump and lift pump are ok smoke is white
when turning over , iam thinking now possible somthing inside head
but really dont want to go in there
compression seems good although there is alot of dry soot on exhust pipe ,
would cloged up head cause this problem ,what anm i missing any one

[PghBill]

Sure sounds like the fuel/air mix is off. Do you have a tap on the preheat fuel line? If so ,is it closing all the way? Or if you have an atomizer on your preheat line is it working properly?
If ether doesn't close, gravity will cause flooding. Or the vacuum of the engine will suck fuel from your fuel tank causing the same effect.

[sky blue]

thank you pghbill , ihave automoizer which was not in use and a made up resivor rigged
up, which i never really needed to use, ihave now removed and compleaty sealed holes
update to what ihave done. took out injectors a connected to pipes and turned over engine
there is a great spray from all three injectors , ihave replaced fuel filters and cleaned air
oilbath ichecked this without o/bfilter connected , battery is new and strong , checked timeing
and done the tappets , running out of ideas now, the tractor drove into shed
but now wont start even with heat just to recap the tractor is a super dexta with
mechnical pump so no air set up as pnematic/type,

[oldcharlie]

Have you checked to be sure injector pump in in time?

[sky blue]

yes pump is def in time checked and re checked that was my thinking
from start ,but how can an engine go out of timming
this is my take on this problem i may be wrong
when i rebuild engine ijust done the bottom half eg new linners pistons
new shells and polished crank, ididdnt do head except for regrind the valves by hand
ialso broke the rule by not putting her into hard work like plowing ect becuse ihad no land which
icould plow an no garage with in 40miles which i could put her on a dyometer , now im
thinking she has gummed up or glazed the bores which has caused the problem
ihave just read a post on another site i think it was forestry and this fellow has a ford 3000 with same
problem and as a last resort he removed the head an cleaned it up put it back on and it started up
with out changing anything put new gaskets , this will be my next move,
i wil do this and let you know if this works

[tom lad]

hi
my thoughts would be remove the head / have a look

at least its fairly good access on the dexta
good luck

[sky blue]

hi tom lad head removed some black dry soot on top pistons
valves look very gummy carbon soot, cylinders look ok to my un trained eye
they are not crome shinny, but a grey colour,
ii have now left the head into a machine shop to-day
have not see anything that was stopping it to fire up ,
mybe getting the head done up will sort it hopefuly

[Bensdexta]

Thanks for the update - look forward to hearing more...

[Nick]

any news on your engine?

[sky blue]

hi Nick ,i was out with machine shop yesterday, but he hasnt got around
to it yet , he said end of week or early next , ihave been on to an old diesel mech i know and
and he said to try pulling the timming cover and check the key ways
as this could upset timming also ,just something eles to check if head doesnt do the trick
will keep the board informed what ever untill i get it sorted

[Nick]

What sort of condition is the camshaft in?

[sky blue]

well had a look at it and to tell the truth ihave not a clue what i need to
to be looking for , it looks the same as when i rebuild the bottom end
what should i be looking for , the loobs seem round and pointed no flat bits ,on them
pity i cant post pictures, im thinking they are ok, ihave another engine for spares and the
cam shaft looks much the same on both but will keep that in mind thanks all ideas most welcome

[Nick]

Yeah if they look all roughly the same and have no flat spots, sounds like they are ok. There cant be much more wrong! Other than like you say something has broken under the timing cover, have you looked there?

[sky blue]

no ihavent had timming cover off yet , id rather put head back on and see
if that makes any improvement first, that then will be every thing checked barr
the keyways ect . ithink at that stage i will have elimated all the main reasons,
then it must be down to injector pump dont want to think about that yet

[sky blue]

just been to machine shop and they have found a crack , between two cylinders.
dont know if this was stopping it starting but along with the stuffed valves
was probley causing the black smoke at idle, either way the head is scrap.
i have a spare head on scrap engine
so that will be going out to shop next week for testing so heres hopeing

[tom lad]

the valves weren't sealing ?

[sky blue]

as the head is now scrap , i have been thinking about buying a new one
instead of going down the road of getting another old one tested and done up
has anyone had issiues with the new cylinder heads, as the the machine shop
guy has told me the metal is not as good in new as the old ,and better with an old head
if i can get one which is not cracked
dont know which is best way to go

[oldcharlie]

Back in the spring when I built my engine I to had a a cracked head. I bought a new one and have had had no problems with it. I did have a tough time getting the covers to seal on the combustion chambers, but that seems to be automatic when they are removed.

[Bensdexta]

It's worth a search on here; various folk have bough new heads, eg Russelm, and fitting has not always been straightforward. Maybe the newer ones are better?

[sky blue]

have seen russlem post thanks ben and old charlie,
isupose all the new heads come from the same sorce makers as is usual or are there
different makers of the heads in uk or ireland[ not supliers] it seems abit of amine feild
trying to just buy a new head from a maker and inntall without worring about is
quality good or not or having to adapt it to fit, is there any stright foward places out there
just buy and fit

[Bensdexta]

have seen russlem post thanks ben and old charlie,
isupose all the new heads come from the same sorce makers as is usual or are there
different makers of the heads in uk or ireland[ not supliers] it seems abit of amine feild
trying to just buy a new head from a maker and inntall without worring about is
quality good or not or having to adapt it to fit, is there any stright foward places out there
just buy and fit

Talk to Bertie Dunlop, your side of the water, a gent, knowledgeable and easy to deal with.