TR6 Piston clearance

[tinman58]

I have the new block at the machine shop. He will be doing the .030 bore, He needs the clearance from the cylinder wall to the piston. I can't find it in the books, or I don't understand what I am reading. It is a 1973 TR6 block.

 

[Guest]

That depends on type of piston (cast or forged) and use of engine (street, turbo or race). I'm surprised he asked you for that as he should be able to figure that out on his own or have enough experience to know offhand. The best thing you can do is contact the supplier you got them from and ask their tech dept.

 

[PAUL161]

For a non racing engine, .005 is a good number. Remember, measure below the rings, the ring grove area usually sets back a tad more than the skirt. For a racing engine, more clearance is needed. PJ

 

[Guest]

Triumph Competition prep manual says .004-.005 but doesn't state what type of piston (and this for an engine to see race duty). Type of piston is key; hypers and cast are tighter than forged, call your supplier! https://www.triumph-tr6.co.uk/docs/competitiontr6preparationmanual.pdf

 

[TR3TR6]

I agree with kellysguy, I was surprised he asked you about the clearance. My machine shop always told me how much the engine needed bored. They did ask me how I was going to drive the car and what my options were for increasing the power.