230GE Engine Tappets?
My 203GE developed a tapping, around cylinder #4 at the back/top, which comes and goes. Really annoying.
Sometimes on tick-over, the tapping almost goes away completely, or when driving going round a slight corner it will ease for a short time then return. The theory/recommendation is that it might need a flush and maybe an additive in the replaced engine oil (which is already new oil) because maybe the oil is not being drizzled to the one set of tappets or cam).
I wondered if it was tappet/cam clearance out of adjustment, but mechanic (non G specialist) says he doesn't expect the engine is a manually adjustable one. They should be hydraulically adjusted automatically? I don't want to get back into removing rocker cover etc myself because although I have the enthusiasm and past knowledge to look, I don't have the tools or expertise to do anything about what I find. So I will book it in.
Can any of you G 230GE engine gurus explain the setup on this engine in the meantime? Mechanic mentions something about maybe the valve pushrod(?) might not be holding hydraulic pressure. Is that a common thing and easy to fix with new rods/rings ?? In fact this means the engine is not Overhead Cam based? Is that the case?
I am possibly thinking a thicker engine oil was used before and when I had it serviced with an oil change the oil is thinner, resulting in that wear and tear manifesting itself?
-jd
My 203GE developed a tapping, around cylinder #4 at the back/top, which comes and goes. Really annoying.
Sometimes on tick-over, the tapping almost goes away completely, or when driving going round a slight corner it will ease for a short time then return.
-jd
I am sure you meant 230GE. The 230's had adjustable and hydraulic tappets in them.
To distinguish between the two without taking off the rocker cover is to look at the front end of the rocker cover.
If it has a round or semi-circular disc in the middle of the front face of the rocker cover and the disc part is in the head then you have adjustable tappets. If the front rocker cover face is flat, i.e. no disc or semi-circular then you have hydraulic tappets.
From your description, it seems likely a hydraulic tappet issue. This is common. You may try to rev the engine for three to five minutes on a hot engine at 2500 - 3000 continuous rpm and see if this clears any restriction in the hydraulic tappet, other wise tappet renewal is a cure. Oil flush may work but this depends on engine condition and previous oil change history. I have found oil flush can cause problems such as this if used on a heavily carbonized engine if not cured it. Regular use of oil flush from a clean engine gives no problems. Changing to thicker oil will not help; there is a slim chance going thinner could help but I feel it less probable.
Lets hope I am right. I re-read your thread and had not answered the latter part of your thread. You were asking if this engine has push rods - that technology went out the window with Mercedes a long, long time ago. It has overhead camshaft and rockers which sit on the tappet. The tappet head has a small inverted bucket (me thinks) if I can call it that.
I cannot clearly remember the full set up but the intermittent noise usually comes on a revolving disc between the rocker and the valve stem. If the disc has excessive wear at one part of the disc, it becomes noisy; that's the theory but as I say I can not clearly remember the full set up. I have not worked on a M102 engine for a number of years. The other aspect of this type of noise is un-even wear on the cam lobe.
The engine should be a M102. And the top should look like this:
I am Youtubing to find the a view of adjusting noisy tappet clearance and to see how the oil distribution works.
There's a reasonable top-end re-build video (russian) here: https://youtu.be/9XK82Pxvu2s
Thank you for that link, looking at that I can confirm that the valve clearances are adjustable. Hint: These are best adjust on a stone cold engine - my preference, although there is a setting given for warm engines.
OK, I should take pictures, but the engine turns out to be hydraulic and the tapping is a case of a couple of the followers not holding oil pressure and hence (I assume) leaving a gap with the tappet causing the tap, which comes and goes.
So I am having all 8 done this week, which should tighten up everything.
I think it was suggested that those engine flush treatments can lead to this type of issue, which might be what happened here.
Oil flushes could cause an issue whilst doing its job. This largely depends on engine condition; if it is an engine heavily coked inside of carbon then No, oil flush is likely to cause an issue but if there is no heavy coking then you should be O.K. That is my experience. If you are going to change the hydraulic tappets any way; in this case I would suggest an oil flush before the tappets are replaced. Of course you will need new oil and oil filter.
Hydraulic followers done and new steering damper (standard duty).
Now quite smooth with no tapping at all and the steering doesn't jiggle.
Engine still smokes a bit - most likely oil down the valve stems. Nothing too bad for an older motor and will monitor.
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My 203GE developed a tapping, around cylinder #4 at the back/top, which comes and goes. Really annoying.
Sometimes on tick-over, the tapping almost goes away completely, or when driving going round a slight corner it will ease for a short time then return.
-jd
If it has a round or semi-circular disc in the middle of the front face of the rocker cover and the disc part is in the head then you have adjustable tappets. If the front rocker cover face is flat, i.e. no disc or semi-circular then you have hydraulic tappets.
So, this 1989 230GE engine has the semi-circular disk in the head at the front, so they should be adjustable. In which case it may be a simple fix, though that is not consistent with it coming and going (that suggests oil is sometimes masking the tapping and not other times). From inspection through the Oil Cap, the overhead cam and gear looks really clean. I suspect it had some TLC, including flushing, in the past - it was well cared for.
Its not in the garage until Wednesday now, so will have to live with it for a few more days. I wasn't using it much before, but need to use it each day until then.