stripped Cosworth engine down of the day that I bought it’s 200 block and found this on every piston The valves all seem in good condition The head seems in good condition The pistons are in good condition except these marks The almost seems too deep that it in the valves has done this all I can presume at the moment is somebody put it together with the timing wrong does anyone have any ideas and where to go from here thanks Paul
id say from the burrs around the deeper cutouts yes its valve piston contact. its been running like that for some time. these engine run very close so its fairly common to see contact on engines which have been revved hard.
you could just use it as is, but a safer bet would be to properly machine some cutouts in the pistons. alternatively buy a set already done
I was thinking the same have a machine out a little bit might alter the compression bit I don’t think it will make much difference I will Machine them out a little bit but strange Valves look perfect Do you think I will need to machine some off the top of the pistons as well Do you think I will need to machine some off the top of the pistons as well Origin of the gasket that’s a bit thicker I can use
Are you absolutely sure about the valves as the marks to the lower cut outs show multiple touches in several positions which sort of suggests either the valve stem got softened in use and touched or that happened and they stayed bent giving contacts as valve rotated? Out with the Plasticine and dry built, valve reliefs and HG thickness compensation calcs.
Previous owner must have replaced the valves after the old ones did the damage.
Yes I think you’re right new valves must’ve been put in after damage i’m presuming timing was out or had different cams in it i’m going to machine in a bit As the new ones are very dear but definitely think you’re right about dummy build with plasticine on
yep, this is an old damage, there is no way the valves in the engine are ok after this contact if they are the same.Originally Posted by Miniliteman
If the valves have been in contact with the pistons the biggest enemy then becomes fatigue. You need to see if the valves are seating correctly in the head before going any further, if they are there’s a good chance that they might not be bent. You can’t just assume someone has fitted new valves and not addressed the contact problem.
What cams are installed in the head at the moment? Std Cosworth cams are very easy to time up if someone knows what they are doing so there’s a good chance that the engine has been over revved constantly at some time. The deeper marks on the inlets look a bit more of a mystery than the exhausts. As for head gasket I would be inclined to use a genuine Reinz GPA item.
Yes they are very deep Marked I wonder if somebody roughly gowned them out a bit and they still got Marked it’s hard to believe that they would mark that much you would’ve thought it would smash the engine to bits
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