valve question

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Heinrich Spreeth

valve question

Unread post by Heinrich Spreeth »

I have a question about a clicking in my valve gear.

This is the best online pic i could find of the cilinder head (from huib's website)
Image

My question is about the two place I encircled with red.

When i bought my car it looked like my valves top touched the metal part in witch that pin is that pushes it down. When the car gets hot the clicking gets worse.

can It be that my valves are just so deep in it's seats that it touches there?

I have checked al my valve clearences and made shure that they are ok and that can be the only reason for the clicking. I have recently had the head of and new valves fitted. When i got the head back the valves was that close to that metal part again. I had the valves replaced.

Will it be stupid if i tried to take the cam out and just grind away about a mm of that metal part (where the loose pin goes through that goes between valve clearence screw and the valve) so that the valve's top doesn't hit it?

OR

what are the reasons for the valve to touch that part?

thanks for any input.

Heinrich
P. de R. Leclercq

Re: valve question

Unread post by P. de R. Leclercq »

On my first Fulvia, I had a persistent noise like this.

I had adjusted the valve clearances numerous times without success and exasperated, I finally ran the engine without the valve cover in place.

This was very messy, but did reveal the problem. This was that one of the Helicoils, into which the camshaft bearing cap bolts screw, had failed and the cap was lifting under the load. Once this had been repaired, the engine was quiet again.

Since those early days I have found many such failures. I suspect that the very hard alloy that Lancia used, eventually seems to crystallise and break up. Helicoils are inferior to the "Time Sert" system; Time Serts screw into the same threads as the Helicoils, which is helpful. However, sometimes the alloy is too degraded. In such cases we have used two Time Serts, one inside the other, to cure the problem; we used an 8 x 1.25 TimeSert inside a 10 x 1.25 Timesert which was enough in most cases. However on one of my engines, the damage was so bad that we had to make a special stud, that was 14mm diameter at the bottom.

Very often this problem has been caused by stupid people over-tightening the bolts. They should be torqued to 16lbs ft or 2.2mkg and no more. And sometimes people have not noticed that two of the bolts are slightly shorter. They screw the longer bolts in place of them and "bottom" them, thus destroying the Helicoils.

I hope that this is helpful

Paul
Huib

Re: valve question

Unread post by Huib »

The problem as Paul described does sometimes occur. When assembling the head also note that the input and output rocker shafts are slighlty different. Trying to force the wrong shaft in the wrong place results in ruined threads of bolts and helicoils
And also note as Paul says that there are 3 different lengths of M8 bolts for fastening the caps. The longest ones go where the dowels are. The helicoils in the head are placed under the dowels so obviously the bolts need to be a bit longer. The slightly shorter bolts go where there are no dowels. The short bolts go where the caps are lower.

From the top if my head (no guarantee)
The longest ones are M8x65
The slighlty shorter ones M8x60
The short ones M8x40
Bolt quality 8.8

These bolts have to provide the counterforce for opening the valves. If not the rockershafts are lifted instead of the valves being pushed down.

When torquing these bolts the tool should click sharply. If not, best replace the helicoils with inserts.

A couple of days ago I solved a ticking problem by replacing the tappet screw. Its tip had broken off which resulted in a clearance of several mm.
justin

Re: valve question

Unread post by justin »

Just a thought... sometimes the timing belt tensioner assembly can present a click sound if the oil feed is blocked or the chain gear lubricating 'nozzle' has been knocked off, allowing pressure drop.
Jus
Heinrich Spreeth

Re: valve question

Unread post by Heinrich Spreeth »

Thanks for all the replies!!!

I have thought of running the engine with the tappet cover off also. I did it once with another car i owned when i couldn't figure out where a clicking came from that also came down to a dodgy tappet screw.
I'll probably do this with the fulvia.
If it's cold it runs at very low idle (about 400rpm) and check everywhere.

i'll report back what i found.

And when i loosen the bolts i'll make sure that they are the correct lengths at the correct places.
P. de R. Leclercq

Re: valve question

Unread post by P. de R. Leclercq »

Well, if you do run the engine with the cover off, try to cover the exhaust manifold at least. Apart from the tremendous oily mess, there will be a lot of smelly smoke!

Paul
Heinrich Spreeth

Re: valve question

Unread post by Heinrich Spreeth »

Agreed

This weekend i helped my brother to fit his fiat 125 special's cylinder head and while working a few drops of engine oil came on the exhaust manifold , what a smokey mess it was when we started her up at the end.

I ran the then engine of my mk1 1600GT capri (kent engine) with the tappet cover of once and it spit a few drops here and there but not that bad. I'll see how much the fulvia squirts out at the top.

I hate sitting at work the whole day when I can be working on my car :)

Last weekend i solved the problem with the clicking "in the back seat" It was actually one of the right rear shock absorber mountings bolts that was missing. The other three had been holding it tight luckily.

also greased my passanger door window winder which was a bit hard to turn and oiled the key and door locking mechanism which improved locking and opening A LOT.

Now it's just that clicking on the valve gear and the loose gearbox mouting thats bothering me. the whole gear lever moves up and down when i pull away and clutch shudders badly on pullaway in reverse gear.
william

Re: valve question

Unread post by william »

Another reason for a tappety engine is a worn tappet rod. The little rods which on four valves connect the tappet screws with the valve stems. The tappet screw can wear a smal dent in the ends of those rods. Which adds to the valve clearance. No amount of valve clearance adjusting can get this right. i.e. the valve will be noisy. The quickest and cheapest solution is to remove the rods and install them upside down. The dent will sit in between the valve stem which is wider than the dent so it won't have an influence.
You will need to remove the cams for this operation. I also have experienced worn rod holes in the aluminium blocks which caused the rod to move not only up and down but also sideways!
P. de R. Leclercq

Re: valve question

Unread post by P. de R. Leclercq »

The Fulvia will make a far bigger mess: the engine is inclined at 45 deg. of course, and a great deall of oil is pumped up to the valve gear. Choose your spot carefully!

As for the gear lever problem, the most likely cause is that the bracket on top of the gearbox (we call it "the Eiffel Tower") is broken. This is quite common. The central silentbloc mount is attached to this with a 13mm bolt (24mm AF).

If your car is S2 or 3 then the broken bracket could have been caused by the engine steady on the right-hand side not being correctly adjusted. The rubber pad should just touch the subframe; there should be no load on it.

Paul
Heinrich Spreeth

Re: valve question

Unread post by Heinrich Spreeth »

"The rubber pad should just touch the subframe; there should be no load on it"

Thanks a LOT , i have allways been wondering HOW tight should that be screwd , so you say , Just touching , NO pressure. I'll check up on that!!

I do have an S3 1.3s fulvia ,i'll check up on that mounting also.


Thanks for the input william. As i said in my first post , It actually looks to me like the top of the valve stem is hitting the bottom of that rod hole, that's why i want to have the engine running with tappet cover OFF , to see.

I'll carefully inspect the rods for indentation on the top.
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