Sounds like Tappets

[krusty2000]

Does Anyone have any ideas how to fix the following:
About six months ago I changed the engine oil in my MK2 2000 with some 20/50 from h**fords. The next day I was driving to a show up the M40 four up @ 80 while going up a hill the car slowed down & the engine cut out. We Opened the bonnet & steam was comming out of the rocker cover & distributor base. It appeared the the engine oil had over heated (but the water temperature was normal). So I let the engine cool down. When I restarted it the engine made a tappet noise at 2000rpm. When I got home I changed the oil to castrol GTX & it has not overheated. So far I have replaced the rockers & shaft with new ones, changed the pushrods, swaped the distributor from my MK1, ran the engine without the petrol pump in the block, but the tapped noise is still there. The noise is starting to get worse now as it is now doing it at 1500rpm 3000 miles after it first happen. A part from doing a total engine rebuild does anyone have any ideas how to fix it?

[Richard B]

Big end?   Sorry.........

[AlanChatterton]

I'm thinking Big Ends too. If you cooked the oil enough to have it smoking........ (although even cheap oil should be ok!) then it is the big ends and main bearings which will have taken the brunt of the oil starvation.

Do you have access to an oil pressure gauge...................?

Sounds like you need to drop the sump (suspension crossmember needs to come off) and take out a main bearing and a big end. I'm guessing you'll find they are both shot.

The good news is that they are only about £25 for mains and £20 for big ends (replace the oil pump whilst you are there!) and it might be ok................ check the crank as it might have picked up and damaged that too.......

[Dizzy]

But worn big ends and mains don't sound like tappets; mains in particular make a very deep rumble.  As Alan says, a pressure gauge will show for sure if its the bottom end that's gone, though the oil light would almost certainly come on at tickover anyway if the bottom end is shot.

Alec on the T2000 Register forum suggested a problem in the area of the pistons - and broken rings for example can sound very much like tappets.  A big end or main bearing half-shell that has managed to slip round and jam up the bearing can cause an engine to slow and stall but I think this is more likely to happen with a piston that's scuffing on the bore or a ring that's broken and either twisted or has got between piston and bore.

Seems to me that the easiest answer in the long run will be to have the engine out and stripped.  Whatever the actual cause of the problem, the whole engine really needs inspecting for collateral damage.

[Mj17]

Long shot but give your pully a wang.

If this has started to wear in the keyway it will rotate slightly around the crank shaft with a tappet-esque, engine speed related umm, tapping noise that gradually gets worse/louder/more persistant.

Well mine did anyway :)

[piman]

Hello all,

the warning sign to me was 'steam' or smoke that came out of the rocker cover and distributor base, To me that sounded like crankcase pressure, and is easily checked by running the engine with the oil filler cap off.

Alec

[krusty2000]

Hi All
Thanks for your answers. But I'm sure it's not the main bearings the noise is not a rumble (although I can see why you mentioned them with the oil overheating). At the time when the engine overheated & cut out the engine was fitted with an external oil rocker booster pipe. The Valve guides are worn on the head so it was suggested by other owners that this might have caused the plugs to foul up so I have removed it. Although I don’t have an oil pressure gauge there seems to be plenty oil getting to the head. Just after I changed the push rods & replaced the rockers I ran the engine with the rocker cover removed & lots of oil was flow everywhere after 15 sec. I have tried pushing a screwdriver on the rockers with the engine running but it doesn’t make any difference. I have also tried listening to the engine with a screwdriver to my ear & the noise appears to be coming from the cam shaft area. Pitman has mentioned crankcase pressure what causes this & what should I look for if I run the engine with the cap off.  At present I think the problem lies in the camshaft/ followers, oil pump, distribution drive area. Could the small ends also cause this sort of noise? I was also wondering if weak valve springs might be the cause (but I think that I have eliminated this by the screwdriver on rocker test)? At present I would really like to avoid pulling the engine out of the car (as my MK 1 restoration is hogging the space in my garage).  

[piman]

Hello Krusty,

excessive fumes is what you could see if there is a piston or ring failure. Parts can break off the piston land but the bits normally get exhausted out of the engine eventually.

A little trick to detect valve train noise is to idle the engine with the rocker cover off, then using, preferably an old set of feeler gauges insert one under every tappet in turn to see if the noise goes away, if it does that is the guilty one. Sounds a little awkward but is actually quite easy.

Weak valve springs should not be the cause of your problem, valve bounce is difficult to describe but quite distinctive and much more of a very high frequency rattle (almost a buzz) than a tap.

Alec