Engine Rebuild - It Runs!!!!!!!

[rbgosling]

Yesterday, the engine finally fired up for the first time:

YouTube Proof

At the first attempt (once I got it to turn over) it span up, backfired once or twice, but no sign of catching. The backfire supported my earlier suspicion of a timing problem.

Now, I had an issue setting the timing - my oil pump / distributor drive pulley is missing the punch in the rim that should be used to set the timing. So I had set it up as best I could based on the position of the woodruff key on the shaft. Turns out that was pretty close, BUT removing the distributor cap and one cam cover confirmed without doubt that the distributor was 180 degrees out - Cyl 1 spark was firing at TDC Exhaust, rather than TDC Firing. Rather than remove and refit the distributor the right way round, I figured it was easier to turn the pulley 180 degrees and set the timing belt up that way. And it ran!!!

OK, it ran roughly, and it's possible the belt is still a tooth or two out on the distributor, but at least with it running I can check the timing and adjust as required. That sorted, I can start tweaking the carbs.

As others have discovered, I was unable to prime the oil pump to get any pressure just by cranking over, so I took my chances (knowing it was all assembled with plenty of Graphogen so nothing was going to be running totally dry). Sure enough, after 2-3 seconds the oil gauge leapt up to a nice re-assuring pressure.

I was warned to expect a bit of smoke on first start-up from the exhaust, so I'm hoping that's what you can see, it is in the right place for the exhaust.

With light fading (and needing to give my bigger sons a lift to the airport) I was happy to finish knowing that it will start, and I'll get onto the rest next weekend...

[Pete Boole]

Well done Richard!! Just ready for the depths of winter!!

Pete

[Alan_M]

Well done. I bet that was satisfying after all the work building it.

[Esprit2]

Richard,

Congratulations. I always get a rush of satisfaction when a freshly rebuilt engine fires up for the first time. It's like an 'attaboy' reward.

The distributor 'shaft' only goes in one way. Yes, you can rotate the distributor's 'body' as required to time it, but the shaft (and the rotor on it's back end) is driven by an offset dog, and can only go into the auxiliary shaft one way. If your goal was to move the rotor & shaft 180° to correct the timing, then the only way to accomplish that would be to remove the timing belt from the auxiliary pulley, rotate the pulley, shaft & rotor 180°, then re-install the timing belt. So, whether it was your intent or not, you re-timed the distributor 180° the right way... by removing the timing belt and rotating the auxiliary pulley.

On the other hand, the distributor itself doesn't care what position it's in. It only needs the rotor to be 'approaching' the cap's #1 terminal when the engine is at TDC. The easiest way to do that... easier than what you did... is to remove all the plug wires from the cap, and remove the cap from the distributor. Looking at the open distributor from the rear (from the flywheel end), the rotor moves counter-clockwise. Note the rotor's location and it's CCW direction of rotation. Temporarily install the distributor cap, and note which terminal the rotor is approaching. That terminal is now #1, so install the plug wire from the #1 cylinder to that terminal. Then install the rest of the plug wires in 1-3-4-2 order, counter-clockwise around the distributor cap... as viewed from the rear of the engine. Re-positioning all the plug wires on the cap could have accomplished the same thing for you as removing the timing belt and rotating the auxiliary pulley. But it's done, and moving the aux. pulley got you there.

I wrote:
> On the other hand, the distributor itself doesn't care what position it's in.

Not 'totally' true. The distributor itself, doesn't care; but if your distributor has a vacuum diaphragm on the outside, then that protrusion can interfere with the oil filter, carbs & manifold, and the engine block. The open gap between the oil filter and the bottom of the carbs is the only sweet spot where the diaphragm can be without causing an interference problem. And it's best to have the diaphragm up closer to the carbs in order to free up as much 'hand' space as possible around the oil filter. That will make future oil filter changes much easier.

Also, some distributor positions end up with a distributor cap retaining clip facing the engine block, making it difficult to remove/ replace the cap. First place the diaphragm far away from the oil filter, then tweak the distributor position enough to ease access to the cap clips. Think ahead.

When all that is done, timing changes can be made by loosening the distributor retaining clamp, rotating the distributor as required, then tightening the clamp. However, if the distributor needs to be moved significantly to achieve proper timing, and if that will compromise the ideal position of the diaphragm and cap clips, then remove the timing belt from the auxiliary pulley, rotate the pulley as required to time the rotor within a tooth-width, then re-install the timing belt. Tension it properly.

Regards,
Tim Engel

[chrisw2811]

Great progress Richard - lovely to see and hear the engine running. Very clean engine - there was a lot more smoke when I started mine after a top-end rebuild. Well done.

[Lotus-e-Clan]

Well done Richard.

Got to admit that the backfire though the carbs worried me a bit, but once you have timed it properly all should be well. Check for petrol leak-back from the venturis before fitting the air box... you don't want petrol dripping on to the distributor.

[rbgosling]

Good point Tim, I'm sure you're right - I had set up the pulley and the distributor correctly (I did think that the distributor could only fit one way, but then thought I must have remembered that wrong when I found the timing error), but connected the spark plug leads up wrong. That makes far more sense. But, as you say, it's working now, so I'll probably leave as is, until the next rebuild.... or at least next cambelt replacement.

[JerryS]

Nice one Richard! Always magical to hear an engine fire up after long rebuild. Excellent!