Valves Hitting Pistons

[phil Laing]

PS, the marks are from the inlet valves only and the mark on piston No1 is quite severe, however the marks on the other pistons are only slight

[phil Laing]

We really don't know what the mechanic did, everything seems a little shady as the car was fine before he got hold of it and why the person supposedly looking after the car sent it to the mechanic (overheating) also seems suspect.

Would you mind explaining in a little more detail your screwdriver method, I understand the principle of determining TDC, but this shouldn't even be necessary as we had visually set piston No1 to TDC prior to replacing the head. What I am not clear on is what you mean about checking the screwdriver agasinst the cam and valve position. What position should the cam and valve be in?

Regards and thanks for your input
Phil

[phil Laing]

I found the data on pdf page 30. Yes we are setting tappet clearance at .15mm and .25mm clearance. But how would one be able to determine if for example the head had been skimmed too many times that the relevant valve clearance was in fact 2.2 mm. Clearly it can't be otherwise the valves would not hiit the pistons

[phil Laing]

The knocking is coming from the top. I don't think anything was done to the waterpump as the hex screws are still fixed in their somewhat old and corroded manner. (I have stripped 6 waterpumps in the past to build one good one)

[Neil Cundy]

If you have visually set the piston then no need to do what I and Huib suggest, I agree. It just the first thing I do when setting the timing as I have been caught out before by relying on the marks.

[Huib Geurink]

Valve clearance is a literal translation from Dutch and also used by Lancia to describe what you call tappet clearance. I agree that tappett clearance would be more correct.

PDF page 30 (DT Fulv. 01/400) is correct. The 2.2 mm is a measurement setting only used to check cam timing.

Either by design, accident or act of god the inlet valve has opened 2.2 mm at TDC and the exhaust valve is still 2.2 mm open. This was discovered by a clever student who worked at Lancia in the late sixties. It wasn't Claire. She is too young but she certainly is bright enough.
You can turn this around and use it to check if the camshaft is timed correctly.

The smart way to check it without trying to attach a micrometer to an aluminium head using a magnetic foot is to subtract 2.2 mm from the opening by relaxing the tappet celarance to 2.2 mm and check if the valve opens (IN) resp closes (EX) at TDC. To check for the point of touching (opening for inlet, closing for outlet) you can move a cigarette paper between valve stem and tappett. After destroying a dozen boxes of cigarette paper without getting any results I changed to using the 0.10 feeler instead and relax the valve clearance to 2.3 mm.

If the inlets left marks on the pistons there can only be one cause and that is inlet camshaft set too early. The valves must be bent as the piston and inlet valve run into each other.

BTW I use cilinder 1. Valve clearances on 1 are set with the corresponding valve at #4 fully open.

[Neil Cundy]

I'm not sure you can deduce if the head has been skimmed too much by measuring the valve timing (i.e. the 2.2mm valve opening at 0 deg), because the only thing that would change that dimension is if the valve had moved relative to the cam profile. This change would more likely to be from seat recession. Skimming the head may bring the valves closer to the piston but we are only talking a few thou, so again unlikely - and nothing like the change in relationship needed to cause contact. As Huib says, that must come from a change in cam timing.

[phil Laing]

Thanks Huib .... and Neil

I think I understand. Fortunately I smoke a lot so ciggarette paper shouldn't be a problem. I'll discuus the suggestions with the owner of the car (Now 84 years old) and building yet another fulvia.

I'll let you know when we succeed. Now that's a positive reponse!

[Albert]

Mabey it is a sticking/ bent valve staying open?

[Johnny48]

where do we go from here this can't be the end of this thread ! or can it ? the mystery is still unsolved. !
L'ufficio Roma non è stato sviluppato in giorno...(but, Rome wasn't built in a day) so I assume we will hearr more about this !