The Fordson Tractor Pages Forum

Hi all!

I am interested in finding out how to do a compression test on my '61 Supermajor!
I have white smoke with no loss of radiator fluid, oil is uncontaminated, all injectors
'seem' to be working, timing is spot on, all rockers appear to be functioning well, so I'm
left with testing compression. Any and all advice is welcome. I would like to make sure
I have adequate compression before I invest in new injectors which appears to be my next step.

Thank you all in advance!

I think you've missed something. If you haven't done any hard work the smoke will always come and you'll only get rid of it by doing something like ploughing. If the engine isn't run hard the temperature of each part will be a bit below design, so the parts won't quite be the right shape, this apart from other problems causes significant carboning, which on other engines like those in locomotives can even catch fire in the exhaust. This is a general problem for Diesel engines, and lots of engines are very often in trouble.
Notice in these two pics of Billy the difference from a few minutes ploughing after many days of doing light jobs (note the acute lack of water causing lots of dust):


And for anyone wanting the extreme version of smoke see this (not mine, nor is it a Fordson, quite a noisy one):https://www.youtube.com/watch?v=HKUdTDV ... PhilMackin
Sandy

Thank you Billy!

I’m sorry, I may have not made myself clear. The engine won’t fire. Smoke is white, which to me indicates unburnt diesel and makes me conclude that it’s either bad injectors, bad fuel injector pump, or bad compression. That’s why I’m asking if anyone knows what method or tooling required to test compression. Since trouble shooting and process of elimination for the ‘home’ mechanic is often the way to a solution, I’m looking to see how compression is tested on diesel engines that don’t have glow plug ports. Thank you again for your assistance with this matter and any additional insights are happily welcome.

How sure are you about injection timing?

White smoke indicates wrong timing to me and I once encountered that on a fresh rebuilt engine. Clamp bolts on drive shaft were loose, injection retarded. Lots of smoke and barely running.

I’ve never seen a major diesel with such a low compression that you couldn’t get it running.

Can you pull start? Then revs are higher then on starter and more succes can be expected.

If it is a 1961 it will have a vacuum governed pump, if it is a non runner and has been parked up for a while with the stop control out the pump rack may be stuck so that not enough fuel is being injected for a start but enough to produce white smoke. Clean off carefully the side cover on the pump and undo the 8 bolts holding it on, you will see the rack, pull the engine stop in and out and check that the rack is freely moving back and forwards. With the stop in run position push the excess fuel button in and make sure it clicks and latches, then pull the stop out and make sure the excess fuel button pops out, a stuck excess fuel button can cause issues. As Emiel says a Fordson engine would have to be virtually without any compression to prevent it from starting at all, your problem is more likely to lie on the fuel and fuel injection side.

Agree about trying to advance the timing (meant to be 23ºBTDC), probably worth checking the rack too but don't do that unless you can be certain that no dirt can get in to the pump. If it doesn't work then test the injectors.
Sandy

Have you taken the pump coupler apart for any reason? It is possible to have it 180° out

Following John's remark, you need to be sure that it is number 1 cylinder, i.e. the cylinder nearest the radiator, that is on compression stroke when you have the 23 degree mark coming up on the flywheel, you can check this by removing the rocker cover and ensuring that both valves on no 1 cylinder are closed well before the 23 degree mark comes up. As John says it is possible that the pump is 180 degrees out if it and the coupler has been taken off and refitted incorrectly.

Easiest way to spot both valves are closed: look on cil 4, there will be a spot where exhaust valve closes and right after the inlet starts opening

Another way of telling that it's no. 1 cylinder on compression is to ensure the coupling clamp bolt is below the shaft as shown in the manual. This is of course assuming the timing gears are correctly fitted. Brian often mentioned this too.
Sandy