elliotaw
New Member
- Messages
- 221
- Location
- Melbourne, Australia
I'd appreciate any advice from the experienced engine builders amongst you lot.
I've just had my engine bores and pistons measured to check for wear etc.
Results are :-
Piston 1 - 3.446"
Bore 1 - 3.449" 0.003" clearance
Piston 2 - 3.4455"
Bore 2 - 3.4475" 0.002" clearance
Piston 3 - 3.446"
Bore 3 - 3.448" 0.002" clearance
Piston 4 - 3.4455"
Bore 4 - 3.4475" 0.002" clearance
Piston 5 - 3.445"
Bore 5 - 3.4475" 0.0025" clearance
Piston 6 - 3.4455"
Bore 6 - 3.4475" 0.002" clearance
Piston 7 - 3.446"
Bore 7 - 3.4475" 0.015" clearance
Piston 8 - 3.4455"
Bore 8 - 3.448" 0.0025" clearance
I think the clearances should be between 1 and 1.5 thou at their optimum.
My engine builder thinks I am nuts trying to improve on what I have, but as far as I'm concerned, if the manufacturer has recommended a dimension, I'd like to get as close to it as possible. He has suggested the cheapest option is to have the pistons ceramic coated (about $30 each) and he says that will increase the piston diameters of the skirt by about 0.001". That will obviously reduce the clearances by the same amount, thus bringing 7 of the 8 clearances into the recommended range with only number 1 being slightly out of range.
Is am concerned with the longevity of such a coating in a volatile situation like on a piston, but from what I've been told, some major performance engines are now doing this to their pistons to reduce noise, friction etc. Anyone had any experience with this ?
What are my other options? Can I buy new pistons from toyota which are oversize ? What are the standard dimensions for this engine? 1991 US spec LS400 ?
Anybody ?
Elliot
I've just had my engine bores and pistons measured to check for wear etc.
Results are :-
Piston 1 - 3.446"
Bore 1 - 3.449" 0.003" clearance
Piston 2 - 3.4455"
Bore 2 - 3.4475" 0.002" clearance
Piston 3 - 3.446"
Bore 3 - 3.448" 0.002" clearance
Piston 4 - 3.4455"
Bore 4 - 3.4475" 0.002" clearance
Piston 5 - 3.445"
Bore 5 - 3.4475" 0.0025" clearance
Piston 6 - 3.4455"
Bore 6 - 3.4475" 0.002" clearance
Piston 7 - 3.446"
Bore 7 - 3.4475" 0.015" clearance
Piston 8 - 3.4455"
Bore 8 - 3.448" 0.0025" clearance
I think the clearances should be between 1 and 1.5 thou at their optimum.
My engine builder thinks I am nuts trying to improve on what I have, but as far as I'm concerned, if the manufacturer has recommended a dimension, I'd like to get as close to it as possible. He has suggested the cheapest option is to have the pistons ceramic coated (about $30 each) and he says that will increase the piston diameters of the skirt by about 0.001". That will obviously reduce the clearances by the same amount, thus bringing 7 of the 8 clearances into the recommended range with only number 1 being slightly out of range.
Is am concerned with the longevity of such a coating in a volatile situation like on a piston, but from what I've been told, some major performance engines are now doing this to their pistons to reduce noise, friction etc. Anyone had any experience with this ?
What are my other options? Can I buy new pistons from toyota which are oversize ? What are the standard dimensions for this engine? 1991 US spec LS400 ?
Anybody ?
Elliot