engine issues

john.n · Post by **john.n** » Thu Jun 10, 2010 4:47 pm

my engine seems to be rather worn. it will run fine with no knocks. only problem is it breathes quite alot, and does not like starting without the cold start, with the cold start there is no problem starting. looks like someone has the head off in the not too distant past. the exhaust smoke looks to be black. the smoke isnt too bad, dosent look like a steam train. where should i start looking to repair the problem? my thoughts at the moment are clean the bores with something like this
http://www.machinemart.co.uk/shop/produ ... ze-breaker
and then refit new piston rings. i would like to avoid removing the head if i can, would i be able to remove the pistons through the sump. how could i support the engine with the sump removed? i have no access to an engine hoist.
once the engine has had new rings what could i do to run the engine in?

many thanks

Post by **Brian** » Thu Jun 10, 2010 5:13 pm

When a Dexta starts breathing heavy, being bad starting and having no power it is time for an engine overhaul. There is really no easy way, Dextas were fitted with Cord rings from new and these are excellent rings but when they are worn up so are the bores.

It is a waste of money to put rings in, you need to fit new liners as well, you will also need to fit new bearings to the crank and oil seals as well.

You cannot do all this with the engine in situ so you should be prepared to lift it out. Pistons will not come by the crank, they have to go out through the head. Liners have to be machined too.

There really is no way to do a cheap job if you want a good tractor.

john.n · Post by **john.n** » Thu Jun 10, 2010 8:20 pm

i guess there is no way of telling what state the engine is in till the head is removed
would glazed bores result in heavy breathing?
there are signs of the engine having been removed before, at how many hours is a major rebuild normally needed? the clock shows 4500 hours.

many thanks

naildriver · Post by **naildriver** » Thu Jun 10, 2010 9:23 pm

What do you mean by "heavy breathing", I've never heard that expression before.

john.n · Post by **john.n** » Thu Jun 10, 2010 10:03 pm

lots of gasses out of the engine breather pipe.

Post by **Brian** » Thu Jun 10, 2010 10:21 pm

Glazed bores were never a problem with the Dexta, however, if you have been using oil which has additives for "anti-squark" on wet brakes then it is possible.

You need to run a straight HD20 engine oil or a 20/30W. Not any of the Castrol MP or similar types of oil. A number of people on the board run 15/40W and I myself used to, but found that I got low oil pressure even with a new engine. I changed to a 20/30W and my oil pressure went up and holds up all day.

The other thing to try is hard work. This cures many problems like yours. Perhaps the engine has not "bedded in".

Glaze busting additives would be a last resort and , if your problem is work related or oil related it will not cure it.

YorkshireDextaMan · Post by **YorkshireDextaMan** » Thu Jun 10, 2010 11:37 pm

Reading some of these posts poses a number of questions, and and probably some answers as to why the engines on some of these Dextas are in such a poor condition, (Diesels Brian) .
mature years, yard scrapping , light jobs , Road runs ect, and lots of either, infact some may never even get hot, Could go on with things like no oil changes ,but one thing i imagine is, that the thermostat was not working. One more thing on the question front, is why is the cooling system on a Dexta not under pressure, most others are ??? Jim

john.n · Post by **john.n** » Fri Jun 11, 2010 6:49 pm

i know nothing of the history of the tractor, other than the clues i have found. has clearly been a scrapper in its recent life. when i drained the engine oil it looked to be in resonable way. unlike the gearbox and back end that looked like melted ice cream. the tractor has stood for a few years im guessing i might have been since foot and mouth, one of the front tires is like new even with the mold seem down the middle. but has slight cracks on the sidewalls where left under compression. could this be a lightly used engine, therefore needing heavy work? what can i do to put the engine under heavy load? i dont have anywhere to plough. although i could get a heavy trailer and there are plenty of hills round here.

many thanks

pottyperkins · Post by **pottyperkins** » Fri Jun 11, 2010 9:45 pm

If you want to try to give the engine some hard work, i would suggest a pto driven implement such as pz type drum mower, or even a pasture topper in long grass, dont worry about smoke or it smelling hot, but dont overheat it
If you do 2 or 3 hours of of proper work this should give you a better indcation as to the state of your engine

john.n · Post by **john.n** » Fri Jun 11, 2010 11:38 pm

would chain harrowing count as hard work?

Post by **Brian** » Sat Jun 12, 2010 8:15 am

No, you really need something like a topper in long grass or a cultivator. The other possibility is a friendly person with a dynomometer.

pottyperkins · Post by **pottyperkins** » Sun Jun 13, 2010 5:22 pm

I would think of chain harrowing as light work
The reason i suggested mowing was the fact you are driving an implement needing a constant amount of power and then as you travel along the load on the engine varies due to the thickness of the grass and speed of travel

john.n · Post by **john.n** » Sun Jun 13, 2010 6:04 pm

what about running in oil? i have heard about it but what is it?? and will it help in my situation?

many thanks

pottyperkins · Post by **pottyperkins** » Sun Jun 13, 2010 9:20 pm

If this is a recently rebuilt engine then changing to running in oil may help to some degree, But as you dont know the condition of your engine, giving in some proper work will give you some idea of what contdition the engine is in
Bad signs would be low oil pressure
Heavy breathing
Lack of power
Blowing oil from dipstick or breather, etc etc