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MG MGF Technical - Tappet Trouble

Hi,

First a little background. My 1.8i ran on Rover oil up to its first service, at 8,500 miles, when it was filled with Mobil 1. After that cold starts would produce a slight sizzle for about a second as the tappets pumped up. General opinion from Mobil and others was that this was fairly common and would not cause any harm. My 214, with the same cylinder head design, has been running on synthetics for half of its 60,000 life and has no tappet noise at startup. I do however start the F in the garage which amplifies any noise. Now, at 13,000 miles, the F is ready for its 24-month service.

A fortnight ago I came back from a 15-mile run and whilst opening the garage I could hear a quite pronounced ticking from one of the tappets. Another run last weekend showed the same symptoms, quiet at cold but tapping when hot. It's loud enough for someone to comment when I drove into the dealer's forecourt.

The car is going in on Monday for diagnosis and I hope a cure. I'm not too keen on the cam carrier being removed but I don't think there's an alternative. If the fault is in one (or more) of the check-valves in the hydraulic tappets then one (or all of them!) will have to be replaced.

The point is that I am now debating the value of using a 0W-40 oil. In theory when the engine is hot and the ticking starts the oil should be at the same viscosity as any other 40 weight oil, so there should be no problem there. So why does the engine have this sizzle when cold using Mobil 1 when it didn't when it was using a 10W-40 oil? Is it just check-valve machining differences? I use Mobil 1 partly because of the better flow when cold, so the results are a little disappointing. And why is my 214 quiet on the same diet?

Who would have thought that so much time could be spent agonising about grades of oil?

Regards, Kes.
Kes

Kes, engines vary in build tolerances and the Rover 214 engine is further away from your ear. I have had this same problem from customers using a synthetic oil on the MX5 OHC design engine, I would use a semi synthetic oil and change it every 6-8k miles. When hot some engines will loose some tappet pressure and hence the noise.I would try the oil change first.
Mike.
mike

My Elise has had the same tappety noise for the last 30,000 miles. Don't worry about it!


Simon.
Simon

I would try a high quality 10W/40 semi synthetic or mineral oil. Just to see if the oil spec has a bearing on the noise.

I have seen a number of like engines display different characteristics in this area and even when new parts are fitted the problem remains. It may not be the actual tappet, but the machining tolerances within the head casting. A different oil spec may cope with tolerances differently, but don't rush into an expensive change of hydraulic tappets.

Rog
Roger Parker

Hi,

Thanks for all the comments everyone. I should point out however that it's not the sizzle at startup that worries me (although I could do without it), nor the normal muted rustle of the valve gear, but it's the pronounced ticking from one or more of the tappets when the engine is hot that concerns me.

On Saturday I decided to change the Mobil 1 for a semi-synthetic to see what effect that would have. I started the car up to go for the oil and the ticking was there from cold. After some 30 seconds or so it just stopped abruptly. I bought a can of GTX Magnatec Advanced. I dislike the way that synthetic oil is sold in 4-litre cans, so you have to fork out another tenner for the additional litre (do they think we won't notice?), but even the GTX is sold in 4.5 litre cans, just about enough. I also bought a can of Forte Engine Flush, as used at the dealers, for another tenner. I don't think for a moment that the engine needed it, at 13,000 miles with an oil change at 3,000 and 8,500, but I decided to try everything. When I returned home, after a round trip of some 8 to 10 miles, the tappet was ticking away. In went the Forte for 10 minutes, tappet still ticking, then I drained the oil and wrestled the filter off. I let the oil drain for an hour, half filled the new filter and fitted it, and poured in a little oil to push the remains of the old stuff out. Back went the sump plug and in went the rest of the oil. Filling through the remote filler is easy, use a small funnel, just put in 250 ml at a time and wait a minute between fills. Using the dipstick to check the level is a no-no, as oil covers the length of the stick and drips everywhere when you look at it. Just put in four litres to start with.

When I started the engine there was no noise at all, even though the filter and galleries had been drained. Off I went for about 8 miles, and there was no tappet noise. Back I came, and the tappet was ticking as usual. Ah well.

On Sunday there was the familiar sizzle at startup from cold. Bum. After a 15 mile run the tappets were silent. All I seemed to have done was to confuse things. I washed the car ready for it's trip to the dealers on Monday for its 24-month service and tappet inspection (and made sure the windscreen washer reservoir was full!).

The car was silent when I arrived at the dealers, I should have left the Mobil 1 in! They serviced it on Monday and attended to the tappets today (Tuesday). I was a little apprehensive as the hydraulic tappets are £11.96 each plus VAT, and there are 16 of them! Not to mention that half the engine has to be dismantled to get at them. I picked the car up tonight. All 16 tappets had been replaced, as it wasn't worth trying to find and replace a few. The cost of the service, including brake fluid change but excluding oil and filter (as they were only two days old) was £95.25. All the work on the tappets was borne by Rover as a gesture of goodwill! The foreman had spoken of getting a contribution, but I didn't expect it to be the total cost. Although the car was bought new from the dealers and has been serviced there since, it is 28 months old, and I do not have any extended warranty. At my previous service a leak from the cam cover was identified and this also was rectified (out of warranty) at no cost to me. At no time have I had to ask for any of this, the dealer has always pursued this for me. The dealer is Clarks of Bromsgrove, and I have nothing but praise for them. They are civil and you can talk to the mechanics, even if the receptionists aren't always struck by my banter. The proof of the pudding is in the eating, and we (or I) will see how the tappets get on. Returning home tonight, about 10 miles, they were silent. I am still on the GTX, and if the tappets remain silent I will then agonise for ages whether to go back to Mobil 1.

Paul, yes, I will put an entry in the dealer guide!

Regards, Kes.
Kes

The followers in the K are designed to turn as they open and this means that the fill hole/ drain hole in the foolower will be in a different position each time the engine is stopped, if the drain hole is on the upper side of the follower then most of the oil will be retained even over a long period of time, if it happens to be in the lower position the oil will quickly drain down especially if it very low viscosity, it may be that one or more of your followers is not turning as it should, this can happen if the surface becomes pitted, its worth a quick inspect by removing the cam cover and checking each follower will turn in its bore and that the surface is not too badly pitted, make sure the heel of the cam is against the follower when checking so that the valve is not lifted... If you find a pitted or sticky follower, that could be your problem.

I have a couple of bags full of K followers kicking around, let me know if you need any.

Dave
David Andrews

Hi,

Thanks for the info Dave, each bit of knowledge helps as I can't find a detailed description of the Rover hydraulic tappet operation on the web, not down to the last detail anyway. What I really need is one to play with! I did find a mail from Mazda on a MX5 BBS which explained why there may be noise at startup, which was quite helpful.

Clarks at Bromsgrove have replaced all the tappets for me FOC, and all is quiet so far, apart from the tiniest zing at startup which I can live with. So I'm happy!

Regards, Kes.
Kes

This thread was discussed between 07/03/2001 and 15/03/2001

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