13/06/2007

24hrs

Engine commissioning

It lives, breathes and moves under it's own power., but not without a struggle.  I got the call from Simon last week that the bell housing was back and that the gearbox should be refitted in time to commission the engine yesterday (Tuesday). I got to Creech in time to see Chris put the final touches to the refit, fitting the transmission  tunnel.  I filled the tank with Petrol checked around and there were no leaks. So far so good.  Filled the radiator with water (NB water only, just in case we had a problem and had to drain it down again). Prudence paid off because we immediately  found two pin hole leaks in the radiator. At some stage the radiator must have damaged, I can't remember how or when. It means the radiator must be taken out again for repair.  However we decided to  press on with commissioning the engine and get the repair done afterwards.  We pressed some mastic in to the radiator core and this stemmed the flow sufficiently for  us to continue.

First fuel in the tank

We switched on the ignition and the fuel pump ran. Even though the fuel lines were now under pressure there were still no leaks.  Turned the key further to see if it would start.  The engine turned over, ran for about 10 specs and stopped.  This fault remained with us despite checking electrics, wiring fuel lines and various components throughout  the system. During checks on the fuel relays we found that one of the relays did not have a 12v supply.  We rigged a temporary supply and tried again. 

This time the fault change slightly and in that the engine would fire erratically but not run.  At this point Simon had a stoke of genius, surmising that the initial fire up was the engine running on the cold start injector and that the main fuel injectors were not working.  By this time my meagre knowledge of fuel injection systems was exhausted and Simon and Chris were scratching there heads. Having talked to a mate I found a way of testing the supply to the injectors was to place a small side light bulb across  the pins the engine over. If there is a pulsed supply from the ECU to the injectors the  bulb will glow, not fully on but with a discernable brightness. We tested the theory on a working engine and it worked. Trying on our engine we were struggling to get it to work possibly because of poor contacts and we were getting tired. It was time to finish for the day.
 

I arrived at Taunton about 11:00 a.m. today to be greeted by the noise of the engine still struggling to turn over. and fire consistently. Simon had Chris had used the bulb trick  and found out we had power to each injector but  only the two centre ones were working.  Chris had said yesterday that sometimes the injectors stick and tapping them whilst turning the engine over shocks them in to working.  We had tried this but without success.  We took a couple of injectors that we knew were not working and continued to tap them whilst cranking the engine but to no avail. I phone HGL, the company  that had refurbished the injectors last September, they confirmed that sticking  was the most likely cause and to continue tapping on the body of the injector.  After much tapping we noticed the the two injectors we had taken out were beginning to show signs of weeping fuel at the pintle valves. We refitted them and tried to start the engine again. It was running better but not right. more tapping and the more we ran it the better it got.  We now seemed to have 4 cylinders out of 6 running. The final two were persuaded with a long steel bar resting on the injector and gently tapped with  hammer. Gradually the engine running improved until all 6 cylinders were firing.  We were not out of the wood yet, the engine would not idle.  We had debated during the misfire phase about engine timing. I had taken photographs before and after I fitted the new distributor cap and HT leads, to make sure I refitted them exactly as the originals.  The problem was the ht wiring to the distributor cap was exactly 180 degrees out from the Haynes Manual and in comparison with two other 120's, but the same as a 140, that were n the workshop.  To prove that the static timing was right we removed all the plugs and put the car in to 4th gear. Pushed the car forward until the No6 piston (the front one was on its compression stroke (checked buy placing a thumb over the plug hole and feeling the pressure build up). We continued moving the cat until the 8 BTDC mark on the flywheel pulley was aligned with the pointer on the crank case. We then removed the distributor cap an noted where the rotor arm was pointing. It was pointing at the n06 contact and so was correct.  We surmise (without taking the distributor out) that the distributor  can be fitted 180 degrees out but that his doesn't matter because, the distributor is symmetrical, and it is just a case of plugging the leads in the correct firing order.  The static timing was OK
 

Much checking of air flow meters and other air elated components  when we noticed that I had forgotten to connect the pipe from the aux air valve to the plenum. It was struggle to connect but we  did it.  As soon as we tried it the engine ran perfectly. We let it warm up and adjusted the idle speed.  All the gauges read correctly except the coolant temperature gauge appears to be over reading.   Both Chris and Simon remarked on what a good engine it was, even though it was a struggle to get it going.  There are no fuel oil or coolant leaks.  The engine is quiet with no tappet noise, very smooth and responsive to the throttle.   To end the day we engaged the gears and gently tested each one. I happy to say all gears were present and the car moved under it's own power.
 

Engine

To see and hear the Black Cat purring

Instruments & Electrics

The water temperature gauge on the XJ6 indicated the engine was overheating when the engine was last run before dismantling.  The gauge was replaced with new a new gauge from the Smiths Classic Range. During the engine commissioning the new gauge reached an indicated temperature of  140 °C.  Clearly this wasn't the case because the water in the header tank was not boiling.  First suspect was the temperature sender. The original XJ6 one was still fitted in the water rail.  To replace the temperature sensor you have two choices, a replacement XJ6 part or a  part that matches the gauge from Speedy Cables (suppliers of Smiths Instruments). There shouldn't be a difference between the two but to be on the safe side I ordered the one to match the new gauge and a 5/8 UNF (M) to 1/8 NPT (F). During the conversation with Speedy cables the subject of voltage stabilisation came up.  The Fuel, Water Temperature gauges & Oil Temperature gauge (if fitted) need to have their supply voltage stabilised to 10V. At this point the penny dropped. I had not fitted the XJ6 voltage stabiliser and in any case, given the original temperature fault , it was probably faulty. I've added a new voltage stabiliser to the order and confidently expect that this and the new sensor will fix the problem.
 

Total hours this Month = 25 hrs

Total hours to date
= 2063 hrs