W@nker machinist didnt mark piston to bore

[JC evo1]

how did you measure? If your measurements are correct I would take it back and make them fix it, no point putting it together and wrecking it if its too tight. I ran .0027 on my wiseco's with no problems, different pistons call for different clearance though.

 

[JC evo1]

theres a tip in this vid how to remove the rods, same as the other guys described http://www.youtube.com/watch?v=MtTXA9_a8sI

 

[EVO-00X]

Brian always take into consideration what the Manufacturer specs inside the box state as manufacturers use different metal compositions in their pistons which expand differently to other brands.
Some manufacturers, especially Wiseco with the teflon side wall coating ask for a tighter clearance due to the special coating.
I know for my JE's though the spec sheet says NA engines with our piston bore diameters require a 0.030-0.035" ptw clearance with up to + 0.001"-0.003" for turbo/supercharge/nos applications.
Always err on the side of caution and run a little looser that what the manufacturer says
It that machinist bore it out tighter than what the spec sheet recommends as minimum then he's fukd up.

 

[blackvr]

Its very important for the machinist to follow the piston manufacturers recommendations !! They are the only guys who have done all the testing for heat expansion on their own products. Its at your own risk to use anything else, especially if it is tighter than recommended. Personally, the clearance you are quoting sounds too tight for my liking. Ask the machinist to recheck his work ??

Especially important is to set the correct piston ring end gap.... if they are too tight , the ring lands will break out if the rings butt up after expanding from heat. Be careful... especially if you use tighter than recommended piston/bore clearance .

Mike

 

[BMGTZ]

Brian always take into consideration what the Manufacturer specs inside the box state as manufacturers use different metal compositions in their pistons which expand differently to other brands.
Some manufacturers, especially Wiseco with the teflon side wall coating ask for a tighter clearance due to the special coating.
I know for my JE's though the spec sheet says NA engines with our piston bore diameters require a 0.030-0.035" ptw clearance with up to + 0.001"-0.003" for turbo/supercharge/nos applications.
Always err on the side of caution and run a little looser that what the manufacturer says
It that machinist bore it out tighter than what the spec sheet recommends as minimum then he's fukd up.

mmm...well if he has stuffed up. he owes me a set of rings now. all gapped!! but strangley the second rings didnt need anything taking off ...when comp[ared to the spec given with the pistons. top rings did tho

I have spent a shit load on measuring tools in the last two days and I am confident that the measurement is accurate......now for the show down with the twat that bored the block!

 

[bazeng]

Brian, do those pistons have a coating?

They add about a thou to the clearance.

piston to bore I always go by manufacturer spec.

 

[EVO-00X]

Guys in the biz know who the good machinists are. Talk to a few places and get a general gist of who to deal with locally. Maybe even get a second opinion/measurement through somebody with a precision mc.
A bad machinist will cost you a lot of money and downtime in the future so think of it as being proactive now and sorting it out BEFORE assembly, iinstead of accepting his work as gospel. Putting the engine together and then have it fail within a short time frame is the worst scenario that you want to avoid. Its good you're double checking the work actually plus its a bit of a learning curve for next time

 

[BMGTZ]

Brian, do those pistons have a coating?

They add about a thou to the clearance.

piston to bore I always go by manufacturer spec.

No Mate ...no coating.

 

[BMGTZ]

. Its good you're double checking the work actually plus its a bit of a learning curve for next time

been doing this a while now...52. that is how I knew it is not quite right.

I have been and spoken to them today and they are going to double check it and to make it right on saturday ...While I am there.

 

[Smutt]

I would recommend the machinist / engine builder that I have used (times 3), he's also built my mates R32 GTR with a 3.0ltr bottom end..