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BMC 1.8 failure to start after tickover cut out


marksbrown

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5 minutes ago, marksbrown said:

 

 

The NRV is a hex bolt with a tiny pin hole through it situated on the fuel filter and was not blocked. The banjo bolt through it has copper washes in between NRV, return pipe and bolt head.

 

I'm satisfied that the fuel line from tank to fuel filter is acceptable so I'm thinking the next step will be to carefully take out the inlet filter and check it for obstructions. If that doesn't solve it, I will try running a day tank to the injection pump.

The NRV is not the banjo union, that is the air bleed hole back to the tank.

The NRV is in the fuel line connection to the side of the filter head, its the long union.

 

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30 minutes ago, marksbrown said:

As in the bottom left?out.thumb.jpg.6066b7e25b9e1fceb851684b6a14aa7b.jpg

 

No, for some reason you don't have a NRV. If you did there would be an extra long hexagon screwed into the port on the right-hand side of the filter head where there is an "into filter" arrow head.

 

You also do not seem to have a return to the tank, although I can not be certain from your photo. It looks as if the small banjo, the one with the bolt and 0.5mm bleed port you mentioned, is just connected to the injector leak off pipe. It should have a pipe on the other side of the banjo running back to the tank. This bleeds any air in the system back to the tank. Without it, air is exceptionally likely to build up in the filter head and cause air locks or revving as pressure in the pump drops.

 

At this time, I am far more concerned about the apparent lack of the leak off pipe from the filter head than the apparent lack of NRV/PRV on the return to the filter, but it would be as well to address that.

 

I have no idea what "bottom left" refers to.

52 minutes ago, marksbrown said:

I have bled the anti-damper screw and a great deal of air came out of here. I will definitely need to adjust the idle damper now and it seems loose and won't stay in one place regardless of the locking nut.

 

The steel insert in the governor housing that the damper adjustment screws into is often "glued" into the pump. I can't see you stripping the adjuster, the lock nut or the steel insert, so I fear that you may have twisted the insert in the housing.

 

52 minutes ago, marksbrown said:

Furthermore, I can see the oil level on the dip stick drops from mid to just below low when I do crank but returns to mid by the next day. From reading this forum it sounds like a seal on the rear of the crankshaft is gone and will need replacing but wouldn't be a reason for the over-revs on the engine.

 

 

If the level drops that much just under cranking (starting) and then returns on its own, it makes little sense UNLESS you have a major oil leak, and if you did, then it would not recover like that. If it is a massive leak then the only way I can see it getting "made up" is from a leaking injector pump main shaft seal, but then the oil would be thin and stink of diesel.

 

One symptom of fuel getting into the sump is, as the level rises, fumes and fuel/oil mist gets drawn into the engine via the crankcase breather. Then the engine may well rev up on its own.

 

Make sure you have the correct dipstick and that it is correctly marked.

Edited by Tony Brooks
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The rubber pipe off the first injector goes back to the tank. There's a coupler between  the end of the rubber pipe and a metal pipe back to the tank - no NRV.

 

edit : the oil dip stick is visible in the top left of the image.

out.thumb.jpg.4b2ca899acbf736ae9c715253f4891f9.jpg

Edited by marksbrown
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The return to the tank should work OK then. However, you seem fixated that the NRV/PRV (whichever it is - both seem to be available for the CAV system) is in the return to the tank. It is NOT, it screws into the filter head where the return from the INJECTOR PUMP connects to the filter head - thus the "go into" arrow cast on the filter head. You don't really want a NRV in the return to tank line if the return enters the top of the tank and does not have a dip tube.

Further to the drop in oil level. The oil level in a rested engine will drop a bit under cranking because oil has been pushed into the galleries that emptied themselves while stationary and has also built up around the rocker gear in the head. If it is around 4 or 5 mm I would not worry.

Edited by Tony Brooks
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Its been a long time since I have looked at a BMC engine but the two copper pipes that go into the side of the filter head look a bit odd to me. I guess there are olives on the end but the nuts are screwed all the way into the head as far as they will go so there is no thread left to tighten  I think on my old engine there were some sort of unions that went into the head and then the copper pipe and olive screwed into that so that there was a bit of thread left to squash the olive. Worth a quick look to see if they are actually OK.

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1 minute ago, Bee said:

Its been a long time since I have looked at a BMC engine but the two copper pipes that go into the side of the filter head look a bit odd to me. I guess there are olives on the end but the nuts are screwed all the way into the head as far as they will go so there is no thread left to tighten  I think on my old engine there were some sort of unions that went into the head and then the copper pipe and olive screwed into that so that there was a bit of thread left to squash the olive. Worth a quick look to see if they are actually OK.

 

I agree, but I THINK some of those CAV union nuts had a taper on the end so as they were tightened the aper collapsed onto the pipe, giving a seal. However, it is certainly worth investigating.

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If the governor valve has become stuck, can this be serviced in situ? At this stage I'm pondering just removing the injection pump and checking both the inlet filter and the governor housing somewhere warmer and cleaner than my engine bay. I've attached the diagram from the repair operation manual. I'm presuming that I could disconnect the control wiring and take the governor housing off in one piece but I imagine that sounds like a great way to loose a few pieces.

out-0.jpg

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1 hour ago, marksbrown said:

If the governor valve has become stuck, can this be serviced in situ? At this stage I'm pondering just removing the injection pump and checking both the inlet filter and the governor housing somewhere warmer and cleaner than my engine bay. I've attached the diagram from the repair operation manual. I'm presuming that I could disconnect the control wiring and take the governor housing off in one piece but I imagine that sounds like a great way to loose a few pieces.

 

 

Once you remove the screw 66 and its pair on the other side, you can pull the throttle and stop control spindles straight out of the housing, but if you leave them in place, nothing should fall out.  However if you want to drop the governor valve out of the housing you have to pull at least one, possibly both, out.

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1 hour ago, Bod said:

Is that  filter the correct way up?

 

Bod

 

Unless it is faulty printing, I think you are correct, good spot. If you are correct, I don't see how the flat bottom (now top) of the filter would seal on the O ring, I also don't see how the "nose" with the smaller O ring on the filter head would seal to the filter. Looks like lack of mechanical aptitude to me.

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If that filter element is upside down it would not operate as a filter, so with the degree of muck in the lift pump (is I remember correctly) there is every chance the strainer in the injector pump inlet is blocked, so sort the filter and then check the strainer before touching the governor.

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How is the damper screw and lock nut loose?.........both parts are steel and screw into a steel fitting.........anyhoo,the whole ally housing can be lifted off with both screws removed ,and by removing one screw at a time,the housing will stay put,and the adjacent lever shaft will come out......In my experience ,the O ring seals on these two shafts can leak air into the pump,and may need replacing.

I have a governor assy in front of me,however its from a Perkins 4/203 and a bit different to the diagram.........the plunger /valve assy is easily pulled out with both lever shafts removed ,so easily determined if its sticking..........Ive never seen one stick,but with all the dirty water and intermittent running,I can see how it could be stuck.

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1 hour ago, Tony Brooks said:

If that filter element is upside down it would not operate as a filter, so with the degree of muck in the lift pump (is I remember correctly) there is every chance the strainer in the injector pump inlet is blocked, so sort the filter and then check the strainer before touching the governor.

I don't believe you could fit a 296 filter upside down in the CAV housing.  The fuel pipes around that filter head and the lack of a return to tank off the banjo suggests that it is a dogs breakfast installation.

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47 minutes ago, Tracy D'arth said:

I don't believe you could fit a 296 filter upside down in the CAV housing.  The fuel pipes around that filter head and the lack of a return to tank off the banjo suggests that it is a dogs breakfast installation.

 

I, too, can't see how an upside down 296 element would seal, but apart from the leak off pipe and the missing valve the pipes on the actual filter head look normal to me providing the ones on the right go to the correct connections on the pump. That is, the one shown by the IN arrow going to the connection at the front (mounting) end of the pump, and the OUT arrow going to the connection at the injector pipe end of the pump.

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So it was quite easy to take out the governor housing in the end. When the stop lever is turned the meter valve moves upwards. When the throttle increases there is no change in height but it does become stiffer. In the low throttle position the whole assembly is quite...wobbly.

out.jpg

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36 minutes ago, marksbrown said:

So it was quite easy to take out the governor housing in the end. When the stop lever is turned the meter valve moves upwards. When the throttle increases there is no change in height but it does become stiffer. In the low throttle position the whole assembly is quite...wobbly.

out.jpg

 

That is what is supposed to happen. On opening the throttle, all you do is preload a small spring. that causes the stiffening.

 

Have you addressed the apparent upside down filter yet?

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9 minutes ago, marksbrown said:

The filter is installed with the holes within it pointing upwards towards the top of housing with the o-rings as shown in the diagram below.

out.jpg

Its right. Perhaps Baldwins always print them that way up. It will not fit the other way.

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6 minutes ago, marksbrown said:

The filter is installed with the holes within it pointing upwards towards the top of housing with the o-rings as shown in the diagram below.

out.jpg

 

That is correct, so good, but I don't recall ever seeing the printing on a filter element upside down, so I wonder if it really is a Baldwin rather than a rip off.

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  • 2 months later...

Fixed! In the end I took the injection pump off to a refurbishers (I can highly recommend CJ Diesel, Sunbury-On-Thames). After some false-starts (and a tube of hylomar blue) I was able to get the engine to run. Thank you all for your kind assistance.

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