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Looking for help please as I have never experienced the above before in spite of driving some really old cars with worn out engines in the early seventies. I have just taken out my TR6 1975 CR to the bottle bank for the first time this year approx one mile and on the return journey and almost immediately I notice the engine was misfiring a bit( not unusual for the first journey of the year). Then I noticed a rattle from the engine above 1000 RPM. Stopped immediately had a looking thinking I had left something under the bonnet, but no such luck the noise was coming from under the rocker cover.

I limped home keeping the revs below 1000rpm avoiding any tapping. On investigation at first I couldn’t see anything wrong after taking the Rocker cover off. Then I noticed that the inlet valve push rod on cylinder No 1 was disconnected from the rocker and resting on the next push rod cylinder no 2 which must have been the source of the tapping. The only work I carried on the engine apart from changing the oil and filter this year has been adjusting the tappets. I am pretty sure I adjusted it correctly as I always do them twice.

Ok so on a quick inspection there seems to be no damage to the push rod it looks straight and the cup and ball ends look fine. The rocker appears to have no wear and  the adjuster and nut are not loose. Has anybody experienced this before and what the likely cause is. My hunch(hoping) is that I haven’t adjusted the tappet correctly although there was no loud tappet noise during the first part of the journey.

I have partially lifted the tappet using the push rod by suction and it seems to lift smoothly and nothing seems to have broken off it. Should I take it out to inspect and if so suggestion on the best way to do it would be great.

Any ideas  on what I should do. I am leaning towards having a look at the Tappet if I can and if ok reassemble the push  rod and see what happens.

Roger

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Hi Roger , had this a few times over the years ( moggy 1000's and fiesta's )

If it's not your tappet adjustment it's probably the valve sticking in the guide,

as the engine has been idle for a while it might be just a bit of rust and should clear.

Mick

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Roger

beware if you valve caps are the replacement lightweight alloy type!! They wear as they turn on the valve springs and the alloy runs down the valve stem and jams the valve in its guide .

graham

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I would check for proper lubrication of tappets, valves, rockers and fluid movement of the tappets. If all ok assemble and let it run with valve cover off so you can see how it behaves. Then check clearances again and hope all remains ok.

Waldi

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+1 for stuck valve.

Check the pushrod for straightness before reassembly. Happened to me and bent 2 pushrods - slightly different reason for stuck valves but shows what will happen.

Jerry

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Graham Thanks for your info and I will check whether the caps are alloy or not.  I don't think they will be as the engine was rebuilt in 1989 and has done around 40,000 miles since.

Waldi/Mick

I think you are right it is probably a sticky valve.  I am a bit worried that if it happens again at higher RPM that it will wreck the engine. There was a lot of oil around when I took  the cover off and the tappet was moving smoothly in bore.  I think I will assemble the push rod and then take out the spark plugs and turn over the engine to check that the valve is not seized. If ok I will do as you say Waldi then run the engine to check that its oiling properly.

Many thanks I will let you know how it goes.

Roger

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