Quote:
Originally Posted by Offgrid
I bought a 740 saloon with a B230E replacement engine which was destined for the scrap yard. It has a multitude of minor problems, and I've fixed a few of them, and I'm really enjoying driving the car. There is a ticking noise from the engine, and I read somewhere that sometimes this can be cured by advancing the ignition. Today I tried an experiment. On checking the distributor, I noticed that the timing mark on the distributor was below the mark on the cam cover, and I would guess it was about 2 degrees. I realigned these, and the engine sounded as rough as anything, so I moved it back and added what I would guess to be another degree. This seems to have made the car more responsive, so the first question is - have I advanced the engine by another degree? The improvement may be a bit subjective, as the Volvo feels like a McLaren after driving my 3.5 tonne LDV for a few years.
The next Q relates to the timing chain. The engine is of unknown vintage and mileage, but I believe it is older than the 1988 740. I understand that the timing chain may have stretched a bit, and at what stage should I consider replacing it? That is assuming that chains are still available. Is it an interference head, and I should play safe by replacing it?
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If the dizzy is mounted on the back of the head, the timing is non-adjustable but make sure the nylon hose from the inlet manifold through the bulkhead to the EZK ignition ECU above the brake pedal is intact and the manifold stub is clean internally - will make a world of difference if that's loose and/or blocked and you remedy it!
Have a look at the timing belt and find out whether you have square or round teeth on it. Square teeth are 36k miles/3 years, round teeth are 4 years or 40k miles if memory serves - if in doubt err on the side of caution and renew at 36k miles but for the cost of a new belt, do it ASAP and you know it's been done - don't forget to retension it after 600 miles too!