frank_s Posted June 9, 2017 Report Share Posted June 9, 2017 Hi I've just replaced my timing chain and tensioner etc on my 80 dhc (AC Delco dizzy). I have correctly lined up the jackshaft, distributor, camshaft and crankshaft timing marks, put it all back together and the timing is way out - off the scale, more than 20degs BTDC at about 1800 rpm. I cannot adjust the distributor to make up the discrepancy. I cannot understand why it should be out and have taking it all apart again to check I hadn't slipped a tooth on the jackshaft putting it back, but it all looks fine. The car was running ok before, might have been a little out on timing but negligible. Any ideas why? And how to adjust - should I just slip the chain off again and realign the jackshaft (incorrectly) to accommodate it? Cheers Frank Quote Link to post Share on other sites
frank_s Posted June 9, 2017 Author Report Share Posted June 9, 2017 Just had second thoughts on this, having spoken with mate owning TR4 - he questioned whether >20degs BTDC at 1800 was that far out given modern fuels i.e. you'd expect it to be different to the timing requirements when out the factory running 4star. I don't know what it was before I did the job and have never set the timing on this car, so I wonder whether I might just have another issue causing the misfiring I got after putting it back together. So in addition to any views on my original post, can I also ask what people have found are typical static and/or dynamic timing settings for their standard 2.0L 8 valve engine? The manual says 10degs static, and 11, 15.7 and 20 degs dynamic at 1000, 1800 and 2400 revs respectively. Thanks! Frank Quote Link to post Share on other sites
Peter Cobbold Posted June 9, 2017 Report Share Posted June 9, 2017 Just had second thoughts on this, having spoken with mate owning TR4 - he questioned whether >20degs BTDC at 1800 was that far out given modern fuels i.e. you'd expect it to be different to the timing requirements when out the factory running 4star. I don't know what it was before I did the job and have never set the timing on this car, so I wonder whether I might just have another issue causing the misfiring I got after putting it back together. So in addition to any views on my original post, can I also ask what people have found are typical static and/or dynamic timing settings for their standard 2.0L 8 valve engine? The manual says 10degs static, and 11, 15.7 and 20 degs dynamic at 1000, 1800 and 2400 revs respectively. Thanks! Frank Check the manual carefully. I think you need to add the 10 static to the dynamic degrees, That gives 30 BTDC at 2400, which sounds about right to me. Peter Quote Link to post Share on other sites
frank_s Posted June 9, 2017 Author Report Share Posted June 9, 2017 Thanks Peter. You're right, and timing was a complete red herring, it's running ok now. I opened up the distributor to check the advance/retard mechanism wasn't an issue and I noticed I'd somehow managed to knock off the condenser lead. One thing led to another, as it does... Still, I've learnt a bit I guess. Frank Quote Link to post Share on other sites
DaveR Posted June 10, 2017 Report Share Posted June 10, 2017 You are correct the UK TR7 8 Valve 2 Litre static timing is 10 deg BTDC. The dynamic at idle is also given as 10 deg BTDC. Dave Quote Link to post Share on other sites
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