Broken again...

I've been enjoying driving BART for the last few months as the weather has been dry and on a recent sunny day went for a bit of a blast. Some fast A roads, bit of country lane driving and some dual carriageway...about a mile from home approaching a T-junction in a 30mph zone BART cut out as I changed into third. I couldn’t get him restarted and ended up having to be towed home. Thinking the issue may have been the replacement points module I installed a while back I reverted back to the stock points system but no joy.

I'd been putting off rebuilding the carb. I had bought a refurb kit and now seemed like a good time to fit  it...maybe the issue was fuel related...the plugs where dry after all my attempts to restart the engine.  I also took the opportunity to replace the fuel lines in and around the engine, they had started to harden and experience had taught me they would eventually crack and break.

Still no joy, freshly rebuilt carb with new parts and BART was still having none of it.  The only thing left to check was the Cam and ignition timing.  I rechecked the ignition timing and made a small adjustment but it wasn't out far enough to cause the none starting, I checked I still has a spark...all good.

OK, cam timing...lining up the Cam wheel mark with the rotor arm pointing at Cylinder #4 (these engines are timed to #4) on the distributer cap should have seen the flywheel timing mark at top dead centre (TDC)... it wasn't, not even close!  In fact I couldn't find the TDC mark on the flywheel at all!  I've since found out that whoever did the engine rebuild fitted the flywheel 180deg out...great.

Luckily these engines also have timing marks on the cam cover and the front crankshaft V-pully so using these marks I found TDC and confirmed it by removing the plug from Cylinder #4 but the cam wheel mark was out by a couple of belt teeth.  The cam belt had jumped.  The picture below shows the cam wheel (dot) correctly aligned with the mark on the engine 'snail' mount.

This meant the cam timing was retarded by about 16~20deg.  No wonder BART didn't want to fire up.  Also as these engines are an interference fit, meaning if the cam timing is too far out the pistons can meet the valves which would result in a very expensive rebuild!

At some point during my drive or when I down shifted the cam belt must have jumped a couple of teeth, not far enough to cause a catastrophic break down but enough to prevent the engine from idling and restarting.

New Tensioner fitted.

Looking at the belt is was immediately obvious it wasn't new.  Junction59 who sold me the car had been working on the head prior to my purchase and I suspect they had reused the old belt and tensioner.  This is a big no no.  The belts stretch and should always always always be replaced if they are removed.  They seemed to have cut corners and I nearly paid the price!

Rubber from the old cam belt on the old tensioner.

I ordered a new belt and tensioner from Eurosport, fitted it and timed it correctly as above.  BART fired up on the very first turn of the starter!  Comparing the old and new belt showed the old belt had indeed stretched by a small amount.  Junction59 if you are reading this...thanks boys for a great job...not.