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| Split breather hose |
Still waiting for the refurbished brake master cylinder, so I was no longer able to put off getting into the engine. After a trip to Lotus Bits, I came home with a new cambelt, oil filter, air filter, spark plugs and carburettor seals, so lots to get on with! Getting the Dellorto carburettors off was pretty straightforward, although there are a few cables and hoses to disconnect. While taking the breather connection off between the intake cam cover and the plenum assembly, I noticed the short hose is split. This would explain the obvious signs of oil over the cam cover in this area. Hopefully, a replacement is easy to get hold of.
The Dellortos are pretty complex bits and will probably need rebuilding at some point, but for now replacing a few seals should help get the engine going. I picked up 8 o-rings for the seal carriers to the intake ports and 2 paper gaskets for the top seal face.
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| Dellorto Carburettors (still attached to airbox backplate) |
The guys at Lotus Bits recommended cleaning up the insides, but this might be best done with a compressed air line (which I don't have) so I might have to get some help with that bit. But replacing the seals was straightforward and I also took the opportunity to sort out the covering and bracket clips on the airbox with some new rivets and screws. I'll also need to make sure the pipe that goes across the back of the engine to the breather hose (see above) is properly sealed into the back of the airbox. It just slid out while disassembling which means dirty air could potentially bypass the filter and go straight through the carburettors into the engine - not good! Anyway, some decent high temperature silicon sealant, or similar, should sort that out.
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| Starter motor removed for flywheel access |
With these parts out of the way, I was able to start the process of a timing belt change. Most advice suggests this isn't too easy with the engine in the car and that involves working from underneath as well as sitting in the rear engine compartment and working from the top. But, having jacked up the car at the rear, it seems there isn't a lot of access from underneath - just a couple of cut-outs in the chassis. So I decided to have a go just from the top. There are quite a few components to remove, starting with the alternator. This has one bolt through the alternator bracket and a metal strap to position it and tension the V-belt. Once these were removed, the V-belt could get prised off fairly easily and then it was straightforward to get to the timing belt auto-tensioner. But before touching that, it was important to set the engine to TDC by using a socket wrench on the crank pulley bolt and watching the marks on the flywheel. The engine turned over OK, so I'm reasonably confident the major rotating components and valvegear are OK. With TDC set, the white dots on the camshaft sprockets lined up, as indicated in the workshop manual, so all was well. It was important at this stage to mark the position of the distributor drive sprocket as this will be free to rotate once the belt is off. Then getting the starter motor off allowed access to the flywheel where I was able to jam a utility / pry bar into a flywheel tooth to hold the crank while undoing the crank pulley bolt. This was on pretty tight and I had to use the wheel nut wrench from my Audi as an extension bar to a wrench to eventually get it off. This will be going back on with some anti-seize grease to hopefully make it easier next time! Even with the bolt and retaining plate off, getting the pulley off still required quite a bit of effort to slide it off the crank towards the bulkhead - a bit of WD40 helped here. Next, getting the timing belt auto-tensioner off involved quite a bit of manipulation. Like most of the jobs down the front of the engine, a hand-held mirror and good lighting were important!
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| Timing belt auto-tensioner |
With the adjustment screw backed off to release the belt tension, the best method turned out to be wiggling the belt off the sprockets first and then sliding the tensioner off. In the end, the workshop manual warning about not removing the adjustment screw completely and using a 4mm pin to retain the piston seemed a bit unnecessary. The springs are fairly powerful, but it isn't difficult to retain the parts when the screw is removed - so, I'll know better next time... The bearing (or idler wheel, as I would have referred to it during my engine design days) has some evidence of belt rubber deposits so, while it seems to spin reasonably freely, it is probably wise to take this opportunity to replace it.
The final task in removing the belt involved getting the coolant hose down the front of the engine off the pipe to allow the belt to pass through the gap. This sounds pretty simple, but actually needed quite a lot of effort! I'll need to use a suitable lubricant to reassemble this joint and also make it easier for next time.
So, with the belt off, I loosely fitted the new one and will now get the tensioner sorted out before starting the job of getting all the engine parts back on. Then it will be time to get some fuel in and turn the key....
