Help with Stothert Pitt 32RD roller engine please

[cartoony]

Well we've had the fuel pump reconditioned & the injector set up & checked. It's all back together & I can hear the 'plink' noise mentioned before which shows that the injector is working. If I loosen the big nut on the fuel pipe to the injector & turn the engine over, fuel pumps out when the engine is turned over. When we turn it over & flick the decompression lever, it tries to start - you can hear the odd 'compression bang' & smoke comes out of the exhaust, however it still won't run. Anyone got any more ideas as to what to look at next? The only other thing I can think of is that it's full of 'Red Diesel' rather thank normal 'Pump' diesel. Would this make any difference?

[cartoony]

The spring that attaches to the fuel pump rack was indeed disconnected. I've reattached it & the rack now moves back to the left on the spring, & to the right when the brass lever is turned. Now, when I turn it over & try to start it, I get black smoke from the exhaust. Is it just a case of keep on turning it over until it goes? I'm guessing that, as I'm getting smoke, it's 'trying'. Thanks for all your help so far folks.

[Tom]

Perhaps a shot of oil down the injector hole into the cylinder will help boost the compression enough to get it to start.

[cartoony]

Thanks for the tip. Do I need to take the injector out to do this or can I squirt some oil down the valve stem? How much should I squirt in - I've got one of those old-fashioned oil cans with the flexible nozzle & a lever to squirt the oil - a couple of sqiirts or should & do more than that?

[rmchambers]

If you can get it past the valve stem into the cylinder that's all you need.  put a few squirts in there and let it sit for a bit so the oil can flow out and get in the gap between piston and cylinder.  roll it over by hand with the decompression on so as to ensure a good coating.  Then you're ready to give it a whirl and see if she fires.

Good luck.

[Tom]

I'd pull the injector and put 1 or 2 squirts of oil down the hole. Down the valve stem you will never know how much you really got.

[cartoony]

Tried the oil down the injector & it tried to start but still just smokes - it won't actually run. I'm srarting to run out of ideas now. One thing I tried, just to test things, was to turn the engine over backwards. With the compression lever on, it seems much harder to turn over backwards as if there's more compression. This doesn't make a lot of sense to me!. One other idea was to take the engine out, put it on a bench & use a belt driven from another engine. That way we could turn it over at pretty much full speed. Does anyone think that's worth trying? I want to check before I do it as taking it out obviously isn't a 5 minute job!

[rmchambers]

Do you see the valves opening as they should based on the push rods doing their thing?

If you turn the engine the way you think it should run and the injector fires and then the intake valve opens then you know you're going the wrong way round.

The beauty of a diesel is it's simplicity.  If you have sufficient compression to generate heat then as long as the fuel goes in the cylinder in a nice spray you get ignition.  Is the compression good? like if the flywheel is spinning and you drop the compression handle will the last compression stroke kick the flywheel back the other way round?

If it does that I'd guess your compression is good.

That leaves fuel.  Can you pull the injector out and see if it does in fact spray when it is supposed to?  keep fingers and other fleshy parts away from the injector head - subcutaneous diesel injection is not a pleasant thing to do to ones self.

If you're getting spray then I dunno why it wouldn't start.  Winding the engine up to a higher speed would certainly help if it's "almost" catching, plus successive compressions would warm the combustion chamber which might be just enough to get you over the hump.

It's all great fun isn't it!

Robert

[cartoony]

I finally got to drive the roller around the ground yeaterday! It's a bit of a pig to start but at least it does. The 'trick' we've found to get it going is to get it spinning, engage the compression lever but to keep turning the engine over. It's not as hard as it sounds because the engine is firing & so helping turn itself over. After a couple of goes it catches & runs. There's tons of black smoke but only for around 5 seconds. However I understand that these things are a bit of a pig to start at the best of times. It now leaks a bit of oil out of the crank oil seal which got damaged when taking the cover off (or more precisely when putting it back on!) but it's only weeping. The only thing left to do (apart from putting all the bodywork back on) is to get a new dipstick - does anyone have any idea where I might be able to pick one up? Thank you to you all for your help - I'm extremely grateful.

[cartoony]

Now we have a separate (although probably related) problem. It started fine for a couple of weeks but now it won't start - it tries but doesn't 'catch' - wheras it used to go 'chug chug chug' faster & faster & would then run, it goes 'chug chug chug' slower & slower & dies. There is black smoke from the exhaust, so it is firing. Does anybody have any ideas please? I've checked the air filter & it is filthy, although I get the same problem with the air filter removed. Is the presence of an air filter that critical? Also there is no fuel filter in the filter bowl. Is this also a critical problem?
One alternative I have been contemplating is ripping the old engine out & putting a small petrol engine in. I'm guessing that I could put, say a 5.5hp Honda engine on the roller & use a V-pulley on the output shaft to drive the rubber belts that turn the transmission input pulley. Does anyone have any experience of doing this? What size (power) engine would I need? Obviously I can adjust the gearing by varying the diameter of the pulley on the engine, or I could connect it direct with a fenner coupling. There's a new engine on eBay, item no 290124504460. I'm wondering whether this sort of thing would be powerful enough.

[rmchambers]

There's only a couple of things it could be at this point.  Low compression (how hard is it to pull the engine over the compression stroke with the decomp lever out?) and fuel.  The injector might be fouled by dirt and crud in which case you may not be getting a decent spray pattern, more of a dribble.

It would be a shame to replace the engine but it does sound like it needs a little bit of work to make it generate power again.  It won't sound the same with some noisy stinky petrol engine in it.  It will lose all its character!

Robert

[cartoony]

Guys
Thanks you for all your replies & for pointing out my muppetry re the filters.
I have replaced the fuel & air filters & bled the entire fuel system & guess what - I managed to start it on my own!
Ran it for about an hour then left it. Started it another 2 times no problem.
Touch wood it now seems fine. Ran a treat & restarted fine.
I'm extremely grateful. Now I just need to change the drive belts (does anybody know what size I need & a cheap place to get them?) & wire brush the whole thing & paint it up. I also need a new dipstick for it - anybody know where I can get one of these too? I'm in the UK.
Finally, any tips on what I need to dismantle to get the new drive belts on would be appreciated.
Cheers guys.

[rmchambers]

How are the belts tensioned?  is there a pulley system there to keep tension on them or does the engine slide back and forth on elongated holes and get bolted in place when the belts are tight?

Any way you can get a picture or two, (worth a thousand words mate).  If you have some sort of tensioner in place then that would need to be released and slip the belt(s) off.  Once you get the belts off I'd take them to a reputable belt supply place.  Given what they are used for and the originals in hand they should be able to find you a suitable replacement.  If the replacements work out I'd get a couple of spares to hang in the shed for that Sunday afternoon when the belts invariably decide to fail on you and everywhere is closed.

No idea where to get a dipstick but perhaps someone on this site has the same kind of engine and might be kind enough to give you the measurements and you could make your own out of a bit of steel rod and some plug arrangement.  Once you know the length and where the markings are for full/empty you can get inventive with a file and cobble one together for yourself.

Robert