has anyone dropped oe bore cp pistons in a new short block? if so any issues? i need input on this topic. i have done several searches with no luck on new motor . i have seen several on used motors,and them having problems :)

Some have, but its still a gamble.....some guys luck up and have zero problems, where others have problems w/ oil consumption, piston slap, ect.... If your going to build a motor IMO the block needs to be machined to fit the piston. If your blocks apart then why not take the extra time to do it right.

Here you go, McFly:

http://forums.nasioc.com/forums/showthread.php?t=952483

IMO, if you mic the new block and it's within the piston manuf's recommended clearance, you're wasting your money machining it...unless you want a different finish on the cylinder walls.

S.

Here you go, McFly:

http://forums.nasioc.com/forums/showthread.php?t=952483

IMO, if you mic the new block and it's within the piston manuf's recommended clearance, you're wasting your money machining it...unless you want a different finish on the cylinder walls.

S.


thanks biff. i am kind of nervous about this setup,as i do not want to pay to do it twice

DO NOT USE DROP IN PISTONS.
Do it once and do it right. Machine or hone the block to the piston manuf's specs.
I will never use "drop in's" again. If I had to do it over(wich I will), I will go 1mm over size and have a machine shop install them propperly.

I have a brand new 257 block that has drop in crawford forged pistons. Oil consumption is ~1/4 quart in 3000miles running dino 10W40. The piston slap is is "really" bad. Bad to the point that people that don't know a thing about cars comment on it. I get embarassed sitting at a red light, people looking at my car like it is going to blow up.

TMS

has anyone dropped oe bore cp pistons in a new short block? if so any issues? i need input on this topic. i have done several searches with no luck on new motor . i have seen several on used motors,and them having problems :)

Measure your bore and pistons, if the clearances are as specked and you install them correctly, you will more than happy.

Quirt Crawford
Crawford Performance.com

Measure your bore and pistons, if the clearances are as specked and you install them correctly, you will more than happy.

Quirt Crawford
Crawford Performance.com

thanks quirt :) . that is what was done. i will be posting up results of this adventure soon

Don't feel too bad. Just dropped a set of Weisco 92.5 mm pistons in my ej205 and had Techworks bore and hone the block. Slaps like a dying fish and it's spec'd to 3 thou. Skirts even dry moly coated. Starting to drive me nuts as it's getting louder and it's still noticeable when it's fully warm if you can hear it over the lifter noise. It's been there from initial start up and it's already worse after 2200 Km. Also burning a bit of oil but I can't figure out yet if it's rings or valve seals. I mad ethem listen to it and they say it's normal but man, I've been rebuilding V6/V8's for a long time and if one of them sounded like this going out my door, I would have made them bring it back in.

i have heard some stories about wiesco. the reason i did not get those is they were big into dirt bike applications when i was younger,and they sucked then.
i bought a motor from worldone ,and this is the setup. i am not dropping in myself. so i am not worried :) ,and they use cp pistons

www.subarumotors.net

DO NOT USE DROP IN PISTONS.
The piston slap is is "really" bad. Bad to the point that people that don't know a thing about cars comment on it. I get embarassed sitting at a red light, people looking at my car like it is going to blow up.

TMS


but then you wouldn't have NESIC's only *remaining/uncrashed* turbodiesel STi!

I have a brand new 257 block that has drop in crawford forged pistons. Oil consumption is ~1/4 quart in 3000miles running dino 10W40. The piston slap is is "really" bad. Bad to the point that people that don't know a thing about cars comment on it. I get embarassed sitting at a red light, people looking at my car like it is going to blow up.

Wow, I've got the Axis variation in my car. Slap is so bad my mechanic friends laugh at me.

Wow, I've got the Axis variation in my car. Slap is so bad my mechanic friends laugh at me.

Meh, I just tell people "yup it is suposed to sound like that".:mad:
I have put 26,000 miles on this motor.


It has lasted longer than the last one.:lol:

TMS

I also add that these forged pistons have exceptionally short piston skirts, too - whether that's true or not, I don't care, at least it makes it look like I know what I'm talking about.

I'm glad your motor is lasting - I hope I have the same luck.

I have the Axis variety also. A little bit of piston clatter at startup, which goes almost completely away when up to temp. It took several thousand miles to queiten down.

The customer service has been more than exceptional, and I trust Ron.

Sorry to hear some of you are having problems.

I am at 550 kms on my new S2 and piston "noise" has already quieted down significantly. I think the S2 uses drop-ins but at least they are ones that are selected to be within a given tolerance range. I am assuming a place like crawford has quite a few pistons lying around so they can mix & match for the best fit. So, one piston might be 0.0037 and another 0.0033 but at those kinds of numbers, you are really splitting hairs. Spec is 0.0035.

But I agree, just buying 4 pistons and then trying to match them up with the 4 cylinders you have to put them in could leave you with quite a variation in clearances.