Proper piston fitment

[spyderdrifter]

I'm planning to get upgraded pistons and rods late next week. Upon receiving them, I'll be taking my block to the machine shop to get decked, hot tanked, and bored out for the new pistons. I did this same thing last year with my last eclipse, but gave the shop the pistons so they could bore each cylinder to match each piston, then they assembled the rotating assembly. Is it really nessesary for them to bore match each piston, or will I be fine to have them bore the block without the pistons present? Trying to cut down the labor expense. I know I can install the pistons and everything else myself, I have the tools and knowhow. Thanks.

 

[1983gsp]

Have them bore match the pistons. That way the ptw is correct for all 4 pistons. They are already boring the block so there shouldn't be any extra expense.

 

[vingasoline]

Is it really nessesary for them to bore match each piston

yes, and if you find a shop that will do it without the pistons don't go there.

You can give them the pistons so they can machine it properly, and still install them yourself. Wouldn't be any extra labor involved.

 

[bryanwheat]

IF you want your piston to cylinder clearances right than you will want the pistons present when the final hone on the block is done.

 

[WES_393]

I agree with everyone else. Each piston manufacturer has different piston-to-wall clearances for how much they will expand. It's also important that the machinist doesn't assume the pistons are a perfect 85mm (or whatever size) and just add a generic PTW clearance.

I highly suggest you go talk to Micheal down at Burts Auto Supply. The guy does 3-4 4g63's a week and REALLY knows what he is talking about. The price is very decent as well.

 

[spyderdrifter]

Sweet. Only other question is what lubes to use when assembling everything?

I agree with everyone else. Each piston manufacturer has different piston-to-wall clearances for how much they will expand. It's also important that the machinist doesn't assume the pistons are a perfect 85mm (or whatever size) and just add a generic PTW clearance.

I highly suggest you go talk to Micheal down at Burts Auto Supply. The guy does 3-4 4g63's a week and REALLY knows what he is talking about. The price is very decent as well.

I'll look them up. Where are they located? I've been taking my parts to Lee's Automotive Machining over on Auburn. Never had a problem with them, and I always end up with the same guy doing my parts too.

 

[bryanwheat]

For lubrication oil works well in the cylinders. On the crank, in the oil pump and for the cam journals i use moly graphite lube.

 

[spyderdrifter]

So for the cylinders I'd just lightly coat the walls before dropping the pistons in? Is the molt graphite common at the part stores? I just looked through a few online vendors I get my parts from and couldn't find it.

 

[bryanwheat]

So for the cylinders I'd just lightly coat the walls before dropping the pistons in?

I usually wipe the piston skirts down with oil before installing them in the ring compressor. From there wipe the cylinders down with a rag that has fresh clean oil on it.

 

[spyderdrifter]

Couldn't be easier then. Thanks.