Royalratch wrote:
Hi-end trebly tappety noise sounds like Hydraulic Lifters need replacing @£16 each, 4 per Cylinder not factoring labour -
Low end raspy sound between 2.5K rpm - 3.5K rpm is tensioner or whole timing case. £500 in parts and 4 hours labour.
Any M42 that gets to 100K+ is due some major TLC. You can't ask them to go on forever without coughing up big every 15
It's almost guaranteed to be a lifter. For what it costs to rebuild one of these properly it's worth taking the cheap option first, i.e putting 3 new tappets into the area the noise is coming from. They're not hard to do - TDC the engine, cam cover and front timing cover off and scribe/paint mark the cam to sprocket. Remove the chain tensioner and slacken the 10mm sprocket bolts. This is where it can get lively; you need a mate to hold the sprocket in place whilst you remove the four bolts - stuff a load of clean rag down the front of the timing case to stop that dropped bolt going into the engine.
At the speed of light, evenly slacken the cam carrier nuts so the cam is lifted evenly - if you just start at one end, the cam may well fracture under stress. Lift the cam out, lift out the three followers you want to replace and press the new ones in - you should leave them overnight in oil as well. Then reassemble it, but make sure you clean the camshaft threaded holes AND the four sprocket bolts in carb cleaner, give them a dab of goodly threadlock and do them finger tight for now. Refit the tensioner and you'll see the sprocket move on the cam. Now, you should really use the proper locking tool for the cam but I've always used a dab of paint and done it by eye. Line the paint marks up and torque them to 10nm (M6 bolts) or 15nm (M7). Don't 'do it up' with a ratchet.
The main weak point of the E30 iS engine is the chain idler gear above and to the left of the crank sprocket. The retaining through bolt is known to snap, chain comes off etc. The E36 cured this with a simple nylon slipper guide. Actually doing an M42/44 chain swap is a reasonable job but it takes longer than 4 hours - nearer to 6. The first biggie is getting the crank bolt out and even with the special BMW tool that bolts to the crank and rests against the o/s chassis let it can be a real bastard. Ultimately though, not much harder than an M10 chain.
After 108'000 my chain seemed unworn as were the sprockets which were perfect for re-use - I had a load of new bits 'in stock' so I changed them anyway.
