Re: '66 912 resurrection
Posted: Sat Jan 11, 2020 8:58 pm
So engine in, all easy from here right? Nope.
The Motronic loom was in a pretty shitty state but was good enough for the time being to run the motor, so it was loosely run in and by the time I was finished she looked like a test rig of some sort. An oil pressure gauge from a 924 was bought to keep it all VDO and temporarily rigged up and we were ready for a test fire. With shaky hand and king lead from the coil off I went for the oil pressure crank. Instead of the sound of a freely turning flat six with no spark plugs fitted all I got was a hefty clang and that was that. Damn.
A brief swing on the crank pulley nut would confirm that we were locked solid, so I replayed the engine/gearbox union in my head. Gearbox span free. Check. Engine turned. Check. Did you try test the engine turned with the clutch fitted.......? No. You spanner.
So you remember what I said about things being thrown if the motor had to come out again - well it did. Instead of throwing something though I took a breather then set to it. Thankfully with the experience from my first attempt behind me the whole process was a whole lot less painless. Anyway, back to the problem - the only hunch I had is that the bolts I was given to fit the clutch were too long, and the third one I pulled would prove me right with a slight witness mark on the end where it'd bottomed out - thankfully not very much but enough to lock it out. So shorter bolts in, and problem solved.
With that done, you know the drill and with help from the wife one afternoon we were back to where I was a week previous.
This time the noise made when cranking was a lot more cranky-esque and we had good oil pressure. Lovely.
Fuel next, I ran the pump direct to check for leaks and we were all good. I'm running an external FPR and adapted the end of the rails to AN6, they meet at a T and then back to the FPR. Fuel pressure set.
With that, I thought it was about time I stopped procrastinating and tried to make it go so king lead reconnected, we gave it a go.
Nothing, just cranked. Aaah, flywheel sensors were back to front.
This time we have pops and farts and an attempt to start but nothing more than that and some impressive flames and that's pretty much all we mustered out of her all afternoon, try as we might she just wouldn't go. We had all the ingredients for it to happen, but just didn't happen. I bought some noid lamps and this showed that my pulse to the injectors was very weak. I sent the DME off to get bench tested and they diagnosed a few issues that were sorted there and then, £250 later I had my 'ready to go DME' back with me. I added a heap of extra earth straps and had another crack. This time, marginally more successfully. She'd fire straight away, but not attempt to run or even idle. After some more head scratching and reading I checked the impedances on the flywheel sensors and they came back in spec. Running low on options I took the flywheel sensors off to take a look with a view to regap, and I found the end of the speed sensor had been ground down by the teeth. Not gapped right then eh.
I bought the BMW equivalent sensor which is far cheaper but identical all bar the length of the cable and regapped to 0.8mm, which anyone who has carried out this task with the engine and box in the car will testify is, an absolute twat of a job to get right especially when I wasn't blessed with a spare full length sensor to glue a 0.8mm washer to. Cue smug chortles from the carb guys.
Anyhoo, with that done - she runs albeit not very discreetly with the special home made exhaust it currently has, but still - small victories and all that. Now that I have verified the motor runs I might bin the Motronic completely but we'll see.
I'll take some up to date pictures at some point but up till now when I've been out there I've not been in the frame of mind to be operating a camera.
Anyone want to buy a recently refurbed DME?
The Motronic loom was in a pretty shitty state but was good enough for the time being to run the motor, so it was loosely run in and by the time I was finished she looked like a test rig of some sort. An oil pressure gauge from a 924 was bought to keep it all VDO and temporarily rigged up and we were ready for a test fire. With shaky hand and king lead from the coil off I went for the oil pressure crank. Instead of the sound of a freely turning flat six with no spark plugs fitted all I got was a hefty clang and that was that. Damn.
A brief swing on the crank pulley nut would confirm that we were locked solid, so I replayed the engine/gearbox union in my head. Gearbox span free. Check. Engine turned. Check. Did you try test the engine turned with the clutch fitted.......? No. You spanner.
So you remember what I said about things being thrown if the motor had to come out again - well it did. Instead of throwing something though I took a breather then set to it. Thankfully with the experience from my first attempt behind me the whole process was a whole lot less painless. Anyway, back to the problem - the only hunch I had is that the bolts I was given to fit the clutch were too long, and the third one I pulled would prove me right with a slight witness mark on the end where it'd bottomed out - thankfully not very much but enough to lock it out. So shorter bolts in, and problem solved.
With that done, you know the drill and with help from the wife one afternoon we were back to where I was a week previous.
This time the noise made when cranking was a lot more cranky-esque and we had good oil pressure. Lovely.
Fuel next, I ran the pump direct to check for leaks and we were all good. I'm running an external FPR and adapted the end of the rails to AN6, they meet at a T and then back to the FPR. Fuel pressure set.
With that, I thought it was about time I stopped procrastinating and tried to make it go so king lead reconnected, we gave it a go.
Nothing, just cranked. Aaah, flywheel sensors were back to front.
This time we have pops and farts and an attempt to start but nothing more than that and some impressive flames and that's pretty much all we mustered out of her all afternoon, try as we might she just wouldn't go. We had all the ingredients for it to happen, but just didn't happen. I bought some noid lamps and this showed that my pulse to the injectors was very weak. I sent the DME off to get bench tested and they diagnosed a few issues that were sorted there and then, £250 later I had my 'ready to go DME' back with me. I added a heap of extra earth straps and had another crack. This time, marginally more successfully. She'd fire straight away, but not attempt to run or even idle. After some more head scratching and reading I checked the impedances on the flywheel sensors and they came back in spec. Running low on options I took the flywheel sensors off to take a look with a view to regap, and I found the end of the speed sensor had been ground down by the teeth. Not gapped right then eh.
I bought the BMW equivalent sensor which is far cheaper but identical all bar the length of the cable and regapped to 0.8mm, which anyone who has carried out this task with the engine and box in the car will testify is, an absolute twat of a job to get right especially when I wasn't blessed with a spare full length sensor to glue a 0.8mm washer to. Cue smug chortles from the carb guys.
Anyhoo, with that done - she runs albeit not very discreetly with the special home made exhaust it currently has, but still - small victories and all that. Now that I have verified the motor runs I might bin the Motronic completely but we'll see.
I'll take some up to date pictures at some point but up till now when I've been out there I've not been in the frame of mind to be operating a camera.
Anyone want to buy a recently refurbed DME?